JP2738448B2 - Adjustment method of emission luminance distribution of light source for exposure head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is provided with a plurality of light sources, light rays emitted from these light sources are condensed by an optical system, and these light rays are imaged on a recording material. The present invention relates to a method of adjusting a light emission luminance distribution of an exposure head light source that adjusts a light emission luminance distribution of an exposure head for recording an image by simultaneously recording a plurality of sub-scanning lines.

(Prior art)

An image is exposed on a photothermographic material, and the photothermographic material is superimposed on an image receiving material and heated, whereby the photothermographic material is thermally developed and an image is transferred to the image receiving material to obtain an image. Devices are known.

In this type of image recording apparatus, when exposing the photothermographic material, the photothermographic material is wound around an exposure drum,
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-scan). In the image recording apparatus, a heating drum and an endless pressure contact belt that presses against the outer periphery of the heating drum are arranged. Further, a rubber superimposing roller that contacts the outer periphery of the heating drum near the endless pressure contact belt. Is arranged. The photothermographic material to which the image has been exposed is superposed on the image receiving material by the superimposing roller, and then supplied between the heating drum and the endless pressure contact belt.

The exposure head has a light source such as an LED chip and a lens inside the lens barrel, and collects light emitted from the light source with the lens, emits the light from the emission port of the lens barrel, and forms the light on the photothermographic material. I try to image it.

In some cases, a plurality of (for example, two) LDE chips are provided in one exposure head, and a plurality of main scanning lines are simultaneously recorded. As described above, when a plurality of main scanning lines are simultaneously recorded by one rotation of the exposure drum, there is an effect that the recording speed is increased in proportion to the number of LED chips.

However, if the accuracy of the pitch dimensions of a plurality of LED chips provided side by side is not good, the sub-scanning line pitch becomes non-uniform, and the quality of the finished image deteriorates. Therefore, each LE
It has been proposed to change the light amount of the D chip to match the apparent pitch between the LED chips.

[Problems to be solved by the invention]

However, in order to separately control the light amount of each LED chip, a component for changing the light amount is required, so that the number of parts is large and the control is plural.

In consideration of the above facts, the present invention provides a light source for an exposure head that can adjust the light emission luminance distribution to make the pitch dimensions of a plurality of light sources uniform by simple control with a small number of parts and can easily select an appropriate mask. It is an object to obtain a method for adjusting the emission luminance distribution.

[Means for solving the problem]

The method for adjusting the light emission luminance distribution of the exposure head light source according to the present invention includes a plurality of light sources, light beams emitted from these light sources are condensed by an optical system, and the light beams are focused on a recording material to form a plurality of light beams. In adjusting the emission luminance distribution of the light source of the exposure head for simultaneously recording the scanning lines and recording an image, the emission luminance distribution of light beams emitted from the plurality of light sources is measured, and the emission luminance center of each light source is measured. By comparing the pitch size between them with a predetermined pitch size,
It is characterized in that a mask is attached so that the pitch between the light emission centers and the predetermined pitch are matched.

[Action]

When a plurality of light sources are provided, it is necessary that the pitch between these emission luminance end peaks is exactly the same as a predetermined pitch, for example, the sub-scanning pitch. May not be in the position. In such a case, the luminance distribution is changed by mounting a mask on the light source. The shape of the light source shielded by the mask differs depending on how the luminance distribution is changed. That is, when various types of masks are prepared in advance, it is necessary to select a mask depending on how the luminance distribution is changed.

According to the present invention, a luminance peak position, which is a light emission luminance center of a plurality of light sources, is determined from a light emission luminance distribution, and a pitch between the peak positions of each light source matches a predetermined pitch dimension, for example, a sub-scanning pitch. Judge. When the pitch between the luminance peak positions is smaller than the sub-scanning pitch, a mask for correcting the luminance distribution is selected so that the peak position of the light source is separated. If the pitch between the luminance peak positions is larger than the sub-scanning pitch, a mask for correcting the luminance distribution is selected so that the peak position of the light source approaches.

As described above, by selecting an appropriate mask, complicated control such as light quantity control is not required, and the number of components for this control is not required. Can be matched with the pitch.

〔Example〕

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

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

The heat-developable material 16 is pulled out from the outer periphery, cut into a predetermined length by a cutter 18, and then wound around the outer periphery of the rotary drum 20 in the direction of arrow A. An exposure head 22 is arranged corresponding to the outer periphery of the rotating drum 20, and rotates the rotating drum 20 at a high speed to expose the wound photothermographic material 16 to an image.

After the exposure, the photothermographic material 16 is separated from the rotary drum 20 by the scraper 24 due to the reverse rotation of the rotary drum 20 (in the direction of arrow B), and after the water as the image forming solvent The sheet is sent to a thermal development transfer section 28 which is a development transfer device.

In the thermal development transfer section 28, a heating drum 34 and an endless pressure bonding belt 36 as a pressing means are disposed.

The photothermographic material 16 to which the water has been applied is supplied between the heating drum 34 and the endless pressure bonding belt 36, and is substantially
It is nipped and conveyed over 2/3 circumferences and thermally developed.

In the vicinity of a portion where the endless pressure bonding belt 36 is wrapped around the tension roller 37, a superposing roller 60 is arranged in a state of being pressed against and contacting the outer periphery of the heating drum 34.

On the other hand, a plurality of image receiving materials 32 cut to a predetermined size are accommodated in a tray 30 arranged below the thermal development transfer unit. The image receiving materials 32 are sequentially taken out one by one by a supply roller 44 arranged on the side of the tray 30 and sent to the thermal development transfer unit 28.

The image receiving material 32 sent to the thermal development transfer section 28 is heated by a heating drum.
Superposition roller placed in contact with the outer circumference of 34
The photosensitive material 16 is superimposed on the photothermographic material 16 (between the superposing roller 60 and the outer peripheral surface of the heating drum 34) and supplied between the heating drum 34 and the endless pressure end belt 36. .

The photothermographic material 16 is used as an image receiving material
When heated in a state of being superimposed on the image receiving material 32, the image is thermally developed and the image is transferred to the image receiving material 32, so that the image is obtained on the image receiving material 32.

A pair of peeling claws 48 are arranged on the side of the thermal development transfer unit 28 so as to correspond to the outer peripheral surface of the heating drum 34, and the tip ends slightly contact the outer peripheral 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. I have.

Below the peeling claw 48, a pair of separation rollers 50 corresponding to only the both ends in the width direction of the image receiving material 32 are arranged, and a transport belt 52 is wound around the separation roller 50.
The transport belt 52 wound around the separation roller 50 is engaged with only the both ends in the width direction of the image receiving material 32, and separates the image receiving material 32 from the photothermographic material 16 to bend and transport it. .

The separated photothermographic material 16 is placed in a waste photosensitive material storage box 59.
On the other hand, the image receiving material 32 is dried on the heater 54 and then sent out onto a takeout tray 56 formed on the top of the machine base 12.

As shown in FIG. 1, the exposure head 22 includes a cylindrical lens barrel 70 as a main body, and an optical system 72 is provided at one end of the lens barrel 70. 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. On the inner surface of the lens barrel 70 of the substrate 76, a plurality of (two in this embodiment) LED chips 80 as light sources are mounted via a base 78. When the LED chip 80 is energized, the LED chip 80 emits light, and its light source reaches the optical system 72. LED in front of LED chip 80 irradiation direction
An aperture 84 provided with an opening 82 corresponding to the arrangement portion of the chip 80 is attached, and shields the outermost peripheral portion of the low-brightness light beam to prevent the generation of flare light.

The two LED chips 80 are provided side by side in the sub-scanning direction, and perform two rows of main scanning recording simultaneously with one rotation of the rotary drum 20. Therefore, two LED chips 8
The pitch dimension of 0 is the same as the sub-scanning pitch.

By the way, in the LED chip 80, the peak position of the light emission luminance may be shifted in the sub-scanning direction due to the mounting accuracy and manufacturing variations. Therefore, in this embodiment, either the mask 86 or 88 (see FIGS. 1A and 1B) is selectively attached to the aperture 84 to change the peak position of the emission luminance. The mask 86 shown in FIG.
This is for separating the peak positions of the light emission luminance from each other, and a triangular projection 86B is projected from the mask base 86A to block a part of the adjacent sides of the two LED chips 80. Further, the mask 88 shown in FIG.
Is for making the peak positions of the emission luminances close to each other, and a trapezoidal concave portion 88B is formed in the mask base 88A to block a part of the outer side of the two LED chips 80. .

The masks 86 and 88 are made of a photocurable resin as shown in FIG.
90 is interposed between the aperture 84 and the mask 86 or 88,
It is fixed by ultraviolet rays generated from the ultraviolet ray generator 92.

The selection of the masks 86 and 88 is as shown in FIG.
This is performed based on the measurement result by the light emission luminance measuring device 94.

As shown in FIG. 4, the light emission luminance measuring device 94 includes a CCD.
It is composed of a camera 95 and a storage medium 96 for storing images captured by the CCD camera 95. CCD camera 95
Is mounted with an objective lens 97, and the stem 74 is positioned so that the focal position of the objective lens 97 is arranged with the LED chip 80. Here, by turning on the LED chip 80, it is possible to photograph the light emission state.

The video stored in the storage medium 96 is configured to be loaded into the analyzer 98.

The analyzer 98 has a function of integrating a video (see FIG. 5) to obtain a light emission luminance distribution (see FIG. 6). Sixth
As shown in the figure, 50% of the luminance peak in the emission luminance distribution
Is determined as the luminance peak position, and the dimension ΔX between the two luminance peak positions is measured. This dimension ΔX must be the same as the sub-scanning pitch dimension X.
The number of times the LED chips are multiplied (in this embodiment, twice) is set as the actual sub-scanning movement amount of the exposure head 22 once.

Therefore, when ΔX <X, the mask 86 shown in FIG. 1A is selected, and when ΔX> X, the mask 88 shown in FIG. 1B is selected. . In addition,
When ΔX = X, the masks 86 and 88 are not required.

 Next, the operation of the present embodiment will be described.

 First, the operation of the image recording device 10 will be described.

When the photothermographic material 16 pulled out of the magazine 14 is cut by the cutter 18 and then wound around the outer periphery of the rotary drum 20, the rotary drum 20 rotates at a high speed, and is exposed in the auxiliary direction of the photothermographic material 16 by the exposure head 22. The image is exposed at the center.

After the exposure, the photothermographic material 16 is peeled off by a scraper 24, water-applied by a water-applying unit 26, and sent to a heat-developing transfer unit 28.

On the other hand, the image receiving material 32 in the tray 30 is sequentially taken out one by one by a supply roller 44, and further, is superposed on the photothermographic material 16 by a superposition roller 60 arranged in the heat development transfer section 28, so that the heating drum 34 It is supplied to between the endless pressure bonding belt 36 (the portion wound around the tension roller 37).

The heat-developable photosensitive material 16 and the image-receiving material 32 sent to the heat-development transfer unit 28 are kept in a superposed state with a halogen lamp.
Between the heating drum 34 heated to about 90 ° C. by the endless heating belt 34 and the endless pressure-bonding belt 36, the heating drum 34 is nipped and conveyed over approximately 2/3 of the circumference to be thermally developed and recorded on the photothermographic material 16 The transferred image is transferred to the image receiving material 32.

After the transfer, the peeling claw 48 engages with the photothermographic material 16 located inside and moves together with the heating drum 34, and peels the photothermographic material 16 together with the image receiving material 32 from the outer periphery of the heating drum 34.

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

Here, in the image recording apparatus 10 of the present embodiment, the exposure head
Two LED chips 80 are arranged at 22, and two main scans are performed simultaneously by one rotation of the rotating drum 20. Thereby, the image recording speed can be reduced. Therefore, two LEs
When mounting the pitch of the D chip 80, high precision is required. If there is an error, the mask 86 or 88 is attached to the aperture 84.
The pitch at the peak position of the light emission luminance of the two LED chips 80 is the same as the sub-scanning pitch. The procedure for selecting the masks 86 and 88 will be described below.

First, before mounting the stem 74 to which the LED chip 80 is attached to the lens barrel 80 of the exposure head 22, the stem 74 is positioned at a predetermined position of the light emission luminance measuring device 94. In this state, the LED chip 80 is turned on, and the object lens 97 of the CCD camera 95 captures the lighted state. The captured video is stored in the storage medium 96,
The storage medium 96 is loaded into the analyzer 98. The analyzer 98 integrates the image stored in the storage medium 96 to obtain a light emission luminance distribution (see FIG. 6).

From the obtained light emission luminance distribution, two LED chips 80
Are determined. The light emission luminance peak position is a position at which the luminance of 50% of the luminance peak is equally distributed, and the pitch dimension between them is ΔX.

By comparing the determined ΔX with the sub-scanning pitch dimension X, if ΔX <X, it is determined that the two LED chips 80 are too close, and the mask shown in FIG. Select 86. If ΔX> X, two LED chips 8
It is determined that 0 is too far away, and the mask 88 shown in FIG. 1 (B) is selected. When ΔX = X, the mask
86 or 88 is not required.

When the mask 86 or 88 is selected, the photocurable resin 90 is applied to the aperture 84, and the selected mask 86 or 88 is placed thereon, and is irradiated with ultraviolet light generated from the ultraviolet light generator 92. Then, the mask 86 or 88 is fixed to the aperture 84.

As described above, by attaching the mask 86 or 88 as necessary, the emission luminance peak positions of the two LED chips 80 can be changed and can be matched with the sub-scanning pitch, so that the finished image can be obtained. Can be of high quality. Also, since there is no need to control the light amount of the LED chip 80, no component for controlling the light amount is required,
No complicated control is required.

In this embodiment, the light emission luminance distribution of the LED chip 80 is C
The image taken by the CD camera 95 is obtained by integrating the image by the analyzer 98. However, as shown in FIG.
A knife knife # 100 is arranged in front of 22 and the LED chip 80 provided with the knife knife # 100 is gradually inserted from one end into a light beam. Alternatively, the light emission luminance distribution may be obtained by differentiating the detected light amount (see FIG. 9). Further, a rotary ring 106 partially provided with a slit hole 104 as shown in FIG. 10 may be used instead of the knife edge 100. In this case, the output characteristic of the light amount sensor 102 (see FIG. 11) directly corresponds to the emission luminance distribution.

In this embodiment, two LEs are provided in one exposure head 22.
Although the D chip 80 is provided, the present invention can be applied to the pitch adjustment of the exposure head in which three or more LED chips 80 are provided.

〔The invention's effect〕

As described above, the method of adjusting the light emission luminance distribution of the exposure head light source according to the present invention can be adjusted to a light emission luminance distribution in which the pitch dimensions of a plurality of light sources are uniform by simple control with a small number of components, and an appropriate mask can be obtained. It has an excellent effect that it can be easily selected.

[Brief description of the drawings]

1 (A) and 1 (B) are plan views showing a state where a mask is attached to a light source section of the exposure head according to the present embodiment, and FIG. 2 is an image recording apparatus to which the exposure head according to the present embodiment is applied. Schematic diagram, FIG. 3 is an explanatory diagram showing a procedure for mounting a mask, FIG. 4 is a schematic diagram of a light emission luminance distribution measuring device and an analyzer, and FIG. 5 is a light emitting LED chip photographed by a CCD camera. FIG. 6 is a plan view, FIG. 6 is a light emission luminance distribution characteristic diagram of the LED chip analyzed by the analyzer, FIG. 7 is a schematic diagram of measurement of the light emission luminance by knife edge, and FIG. Output characteristic diagram, FIG. 9 is a light emission luminance distribution characteristic diagram obtained by differentiating the characteristic of FIG. 8, FIG. 10 is a schematic diagram of measuring light emission luminance by a rotating ring, and FIG. 11 is an output characteristic of the light amount sensor of FIG. FIG. 10: Image recording device, 22: Exposure head, 80: LED chip, 86, 88: Mask, 94: Emission luminance measurement device, 98: Analysis device.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02B 26/10 G03G 15/04 113

Claims (1)

(57) [Claims] 1. An image recording system comprising a plurality of light sources, wherein light beams emitted from these light sources are condensed by an optical system, and these light beams are imaged on a recording material to simultaneously record a plurality of scanning lines to record an image. In adjusting the light emission luminance distribution of the light source of the exposure head to be exposed, the light emission luminance distribution of the light emitted from the plurality of light sources is measured, and the pitch between the light emission luminance centers of the respective light sources and a predetermined pitch size are determined. And adjusting a light emission luminance distribution of the exposure head light source by mounting a mask so that a pitch between light emission centers matches a predetermined pitch.