JPS60250327A - Picture recording device - Google Patents

Abstract

PURPOSE:To make a titled device cope with a recording material different in sensitivity by providing a means for changing the intensity of an optical beam separately from an optical beam modulating means, on a device which is provided with an optical beam generating means, the optical beam modulating means, and an optical beam scanning means, and records a picture on the recording material. CONSTITUTION:An optical beam emitted from a beam generating means 1 passes through an optical modulating means 2 consisting of a bem compressor 5, an acoustic optical element, etc. placed along an optical axis C, and a beam expander 6, and it is made incident on a beam scanning means 3 consisting of a polygon mirror, etc. through an ND filter 8 driven by a driving device 7. Also, the optical beam reflected by the means 3 is projected onto a recording material 4 through an f.theta lens 9. The filter 8 is rotated intermittently or continuously, and the intensity of the optical beam is changed in accordance with the sensitivity of the recording material 4. In such a way, this device can cope with recording material different in sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to, for example, XCT (X-ray tomography), NMR
The present invention generally relates to an image recording apparatus such as a nuclear magnetic resonance apparatus (nuclear magnetic resonance apparatus) or an ultrasonic tomography apparatus that records a medical image consisting of a plurality of images on a single recording sheet.

Conventionally, as shown in Fig. 1, rice seedling equipment uses He-N.
A halftone image is output onto a recording material 4 such as a film using a beam generating means 1 such as an e-laser, a light modulating means 2, and a beam scanning means 3 such as a polygon mirror or a galvano mirror. Here, the power of the beam generating means 1 is selected to match the sensitivity of the recording material 4, and the power of the beam generating means 1 is selected to match the sensitivity of the recording material 4.
is now used.

In this conventional apparatus, a method is known in which an acousto-optic element is used as the light modulation means 2 to change the intensity of the light beam in order to correspond to recording materials having different sensitivities.
As explained below, this method cannot be said to be preferable. A in FIG. 2 is a logarithmic curve representing the intensity P of the diffracted light with respect to the corrected input signal V of the acousto-optic element. In addition, E is energy, D is recording density, b is a characteristic curve of the dedicated recording material,
c and d are characteristic curves of recording materials having different sensitivities from b.

In FIG. 2, the optimum density range DO for the correction input signal vO to v1 of the acousto-optic element is determined by the dedicated recording material.
If ~D1 is obtained, then in the case of recording material d, which has lower sensitivity than recording material A, the correction input signal vO~ of the acousto-optic element is obtained.
Only a narrow concentration of DO-02 can be obtained by V1,
If an attempt is made to obtain the optimum density range DO to D1 using the recording material C, which has higher sensitivity than the recording material C, the input signal of the acousto-optic element can only be used in the range vO to v2.

An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples and to provide an image recording apparatus that can be used with recording materials of various sensitivities. An apparatus having a beam scanning means and recording an image on a recording material is characterized in that a means for changing the intensity of the light beam is provided separately from the light beam modulating means.

The present invention will be explained in detail based on the embodiment shown in FIG. 3 and below.

FIG. 3 is a block diagram of the optical system, and the same reference numerals as in FIG. 1 indicate the same members. Here, 1 is a light beam generating means, and along its optical axis C, a beam compressor 5,
A light modulating means 2 consisting of an acousto-optic element and a beam expander 6 are arranged, and the light beam that has passed through these is passed through an ND filter (Neutral Filter) driven by a drive device 7.
Density Filter) Pass through filter 8,
The beam is made incident on a beam scanning means 3 consisting of a polygon mirror or the like. Further, the light beam reflected by the beam scanning means 3 is projected onto the recording material 4 via the f/θ lens 9.

Here, the light beam emitted from the beam generating means 1 is modulated by the light modulating means 2, and is scanned by the light scanning means 3 onto the recording material 4 in the main scanning direction.
This will be done by moving the

In the present invention, the beam is rotated intermittently or continuously to change its transmittance at a position in the optical system, that is, between the beam generating means 1 and the scanning optical means 7, where the beam is parallel light. That is, for example, an ND filter 8 as shown in the front view in FIG. 4 is inserted, and the intensity of the light beam is changed according to the sensitivity of the recording material 4.

Therefore, as shown in the characteristic graph of FIG.
The image density can be changed to a' or a'', and images with the same density D1 can be obtained using the same input signal V1 even for recording materials S, C, and D having different sensitivities.

Here, the driving device 7 uses a stepping motor or the like, but this may be removed and the ND filter 8 may be moved manually. In order to obtain the position information of the ND filter 8, a potentiometer 10 and a memory for detecting the rotation angle of the ND filter 8 are connected to the drive device 7 as shown in FIG. Filter 8
The transmittance of the ND filter 8 may be automatically switched by the recording material selection switch in association with the position of .

Next, an embodiment in which a polarizing plate is used to change the intensity of the light beam is shown in FIGS. 7 to 1O. Figure 7 is the previous third
In the figure, it is a plan view of the ND filter 8 and its driving device used in place of the driving device 7, and a polarizing plate holder 12 is rotatable around the optical axis C in a support stand 11 arranged on the optical axis C. This holder 12 is supported by a gear 13.
It is designed to be driven by a motor 15 via a motor 14. As shown in FIG. 8, a polarizing plate 16 is installed inside the holder 12, and the polarization axis of this polarizing plate 16 is aligned with the holder 12.
It is now possible to rotate with it. A separate polarizing plate (not shown) serving as an analyzer is arranged in the light beam optical path shown in FIG. 3, and as shown in FIG. If you change only the 10th
As shown in the figure, the transmittance generally changes as a function of cos 2 θ, and the intensity of the light beam can be changed continuously and arbitrarily.

In the embodiments described above, the intensity of the light beam is varied intermittently or continuously in order to match recording materials of various sensitivities, but the present invention can also be used for other purposes as described below. That is, in this type of image recording apparatus, it is possible to change the beam diameter on the image plane depending on the number of images, that is, the number of divisions, using, for example, the beam expander 6 shown in FIG. The embodiments described above can also be effectively implemented. That is, the average intensity of the light beam emitted from the light beam generating means 1 and passing through the subsequent optical system is expressed as P (
W), the main scanning speed is V, and the sub-scanning interval is d. Since the sub-scanning interval is sufficiently small compared to the main scanning range, the recording material 4
The energy E (J/cm2) given to is E=P/ (
v @d).

If the diameter of the light beam on the image plane is changed, the sub-scanning interval must also be changed accordingly. The original sub-scanning interval is dl, the intensity of the light beam at that time is 21, the main scanning speed is vl, the sub-scanning interval when the light beam diameter is changed is d2, the intensity of the light beam is P2, and the main scanning speed is v2, in order to keep the energy E given to the recording material 4 constant, E = PI/ (vl ・di) = P2/ (v2
−d2)+”+ di/d2= (PI/P2) ・(
v2/vl), and as you can see from this formula, (vl=
72) In other words, even when the main scanning speed is constant, in other words, without changing the rotational speed of the beam scanning means 3, the recording material 4 is The energy E given to can be brought into an ideal state.

As explained above, since the image recording device according to the present invention can vary the intensity of the light beam, the density range can be effectively used for recording materials with different sensitivities, and the dynamic range of the light modulation means is impaired. There's nothing wrong with that. It can also be effectively used when changing the light beam diameter according to the number of divisions using the same recording material.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional optical system, FIG. 2 is a density characteristic curve of a recording material with respect to the output of a light beam, and FIG. The figure is ND
FIG. 4 is a front view of the ND filter; FIG. 5 is a density characteristic curve diagram of the recording material versus light beam output;
6 is a plan view of an ND filter driving device, FIG. 7 is a plan view of a polarizing plate and its driving mechanism according to another embodiment, FIG. 8 is a sectional view taken along line A-A in FIG. FIG. 9 is a relationship diagram between a straight parallel beam and a polarizing plate, and FIG. 10 is a characteristic curve diagram of light beam transmittance by the polarizing plate. Reference numeral 1 denotes a light beam generating means, 2 a modulating means, 3 a beam scanning means, 4 a recording material, 7 a driving device, 8 an ND filter, and 16 a polarizing plate. Patent applicant: Canon Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Ot θS

Claims (1)

[Claims] 1. An apparatus for recording an image on a recording material, which includes a light beam generating means, a light beam modulating means, and a light beam scanning means,
An image recording apparatus characterized in that a means for changing the intensity of the light beam is provided separately from the light beam modulation means. 2. The image recording apparatus according to claim 1, wherein the intensity of the light beam is changed depending on the sensitivity of the recording material. 3. The image recording apparatus according to claim 1, which uses an ND filter whose transmittance changes intermittently or continuously as means for changing the intensity of the light beam. 4. Claim 1, wherein the means for changing the intensity of the light beam is to rotate the polarization axis of the polarizing plate.
The image recording device described in . 5. The image recording apparatus according to claim 1, wherein the intensity of the light beam is changed according to the diameter of the light beam.