JP2542840B2 - Image recording device - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording device.

B. Conventional technology Conventionally, as an electro-optical element having a so-called electro-optical effect in which birefringence changes with applied voltage, (Pb _1-X , Lax)
A PLZT crystal represented by (Zry, Tiz) _{1-1 / 4} O ₃ is known. This PLZT is a transparent ferroelectric ceramic, and has the property that its birefringence changes depending on the applied voltage based on its electro-optical effect. Between the analyzer and the analyzer), the linearly polarized light of the polarizer changes its polarization state as it passes through the PLZT, and only the light components that match the polarization plane of the analyzer are emitted from the analyzer. It will be emitted. Such an optical modulation function is used as an optical shifter, but the PLZT shutter has a very fast response speed, a light transmittance ratio of 2000: 1 when turned on and off, a wide operating temperature range, and a long service life. It has advantages such as

C. OBJECT OF THE INVENTION It is an object of the present invention to provide an apparatus capable of skillfully incorporating an electro-optical element as described above and recording a color image with high quality.

D. Structure of the Invention That is, the present invention includes a light source, an optical shutter array including a combination of a polarizer, an electro-optical element, and an analyzer, a photoconductor, and a driving unit that supplies an electric signal to the optical shutter array. An image recording apparatus, wherein the photoconductor has a plurality of high-sensitivity regions, and the electro-optical element comprises a PLZT crystal having a thickness of 300 to 1000 μm and a counter electrode at an interval of 100 to 300 μm. The counter electrode has an electrode width of 30 to 100 μm, an interval between the electrodes of 30 to 100 μm, and the light source has a main emission wavelength in a high sensitivity region of the photoconductor. Alternatively, the present invention relates to an image recording device characterized by being of a plurality of types.

E. Examples Hereinafter, examples of the present invention will be described.

First, with reference to FIG. 1, a main part of the color image recording apparatus according to the present embodiment will be described. According to this device, the white light source 1
A slit plate 3 with a slit 4 and a PLZT optical shutter array 6 in which a large number of pixels (pixels) 7 are arranged are sequentially arranged between the photosensitive material 2 and the photosensitive material 2. The slit light 5 that has passed through the slit plate 3 enters the optical shutter array 6, is optically modulated as described above, and then exits to be used for exposure of the photoconductor 2. The optical shutter array 6 is made to function as a color filter that substantially transmits only light of a specific wavelength by a drive voltage corresponding to each color from a control unit (or drive unit) 9 that operates by receiving the image signal 8. The control unit 9 also gives a signal to the drive motor 10 of the photoconductor 2 to control the rotation thereof.

The image signal 8 input to the control unit 9 is obtained, for example, as shown in FIG. That is, the original 11 is illuminated and the image portion 12 is illuminated.
The reflected light 13 from is incident on the CCD 15 which is a charge-coupled device through the imaging lens 14, and the electric signal of this CCD is controlled by the control unit 9.
To enter. The controller 9 also controls the movement 16 of the optical unit with respect to the original 11.

FIG. 3 shows an example of a color image recording apparatus incorporating the above-mentioned optical shutter array 6 (however, the control unit 9 is not shown). In this apparatus, instead of the photoconductor 2 shown in FIG. 1, a belt-shaped photoconductor 2 that is moved along the peripheral surface of the guide roller 17 from the state of being wound into a roll is used. A photographic paper coated with a photographic emulsion is used as the photoconductor 2, and the optical shutter array 6 sequentially performs the exposure for each color as described with reference to FIG. 23 is a lens). Then, the photographic printing paper 2 is sent to the drying section 53 through the color developing section 28, the bleach-fixing section 29, and the stabilizing sections 30, 31 and 52 in that order, and is taken out as a color print (note that 54 in the drawing indicates It is a replenisher).

In such a device, the optical shutter array 6 is driven so as to function as a filter for each color by a control voltage corresponding to each color (blue, green or red) from the control unit 9.

According to the present invention, the above-mentioned image recording apparatus has a spectral sensitivity distribution (that is, a high sensitivity region for blue B, green G, and red R) as shown in FIG. 4 as the photosensitivity of the photoconductor 2. In this case, as the light source 1, light sources each having a main emission wavelength as shown in FIG. 5 are used in the wavelength range corresponding to the high sensitivity range.

As described above, when a light source having a plurality of main emission wavelengths (three in the above, B, G, and R) is used, when the above-described exposure of each color is performed, the light in the wavelength range corresponding thereto is sufficiently emitted. The light can be guided from the light source 1, whereby the exposure amount can be made sufficient and the sensitivity characteristics can be made good at the same time, and a high quality color image can be realized.

In order to make the light source 1 have a plurality of main emission wavelengths as described above, a fluorescent lamp having a phosphor layer in which a plurality of types of phosphors are mixed and contained may be used. For example, a target phosphor layer can be prepared by mixing phosphors (three kinds) showing each spectrum as shown in FIG. 5 in a binder and baking the mixture after coating.
3 (Ba, Mg) O ・ 8Al ₂ O ₃ / as a usable blue fluorescent material
Eu ²⁺ , La ₂ O ₃ · 0.2SiO ₂ · 0.9P ₂ O ₆ / Oe as green phosphor
³⁺ , Tb ³⁺ , and Y ₂ O ₂ S / Eu ³⁺ , Y ₂ O ₃ as red phosphors
/ Eu ³⁺ is an example. Among these, the blue phosphor and the red phosphor can achieve the brightness enhancement of the phosphor by the high-temperature crystallization technique, and the green phosphor can be reviewed from the raw material to realize the performance improvement.

Next, the optical shutter array 6 will be described in detail with reference to FIGS.

The optical shutter array 6 basically comprises a polarizer 33 on the light incident side, a PLZT crystal 34, and an analyzer on the light emitting side as shown in FIG.
The PLZT crystal 34 is coated with counter electrodes 35 and 36 so as to form each pixel. As shown in FIG.
Are provided as a plurality of signal electrodes, and a common electrode 36 is provided in a state where the pixels 7 are formed between these signal electrodes. In the pixel 7, since the birefringence of the PLZT crystal changes according to the voltage between the electrodes 35 and 36, only a specific wavelength component can be transmitted by selecting the voltage as described later. In FIG. 7, for example, the spacing a between the electrodes 35, the width b of the electrodes 35, the spacing l between the electrodes 35-36, and the thickness d of the crystal 34 are preferably in the following dimensional ranges.

30 μm ≦ a ≦ 100 μm 30 μm ≦ b ≦ 100 μm 100 μm ≦ l ≦ 300 μm 300 μm ≦ d ≦ 1000 μm In FIG. 8, the element shown in FIG. 6 is shown in principle. To do.

(I: outgoing light amount, I ₀ : incident light amount, π: circular constant, λ: wavelength of used light, Γ: retardation) Therefore, I changes depending on the value of Γ, At that time, I = I ₀ and the maximum _value .

Γ can be written as follows.

Γ = Δn · t (Δn: birefringence, t: optical path length) = (-n ³ RE ^a / 2) · t (R: electro-optic coefficient, n: refractive index of material, E: electric field, a: depending on material It is a real number determined by 1 or 2) = (-n ³ RV ^a / 2l ^a ) · t (V: applied electric field, l: distance between electrodes) That is, V changes Γ, and I changes accordingly. .

I becomes the maximum at V when V becomes, and this V is called a half-wave voltage.

FIG. 9 shows the light transmittance for each wavelength of light, but it can be seen that the half-wave voltage is different and the change in light transmittance is also different depending on the wavelength. Therefore, by switching the voltage applied to the optical shutter array 6, the transmission amount of the specific wavelength light can be changed and the function as a color filter can be exerted. For example, when the voltage is set to 137V, it becomes a blue filter that substantially transmits only blue light. Figure 10 shows
The light transmittance for wavelengths at typical voltages for blue, green, and red filters is shown.

As described above, the image recording apparatus according to the present embodiment is
Since a desired filter function can be exhibited by simply sequentially supplying a voltage to the ZT optical shutter array 6 to serve as a filter for each color, a color image can be recorded faithfully and with high quality. Moreover, since the electro-optical effect is utilized, the response speed as a shutter and the on / off ratio can be made sufficient.

11 and 12 show another optical shutter array 6 (however, the upper and lower polarizers and analyzers are not shown), but in this example, a PLZT crystal has a rectangular or square elongated columnar body 44 in cross section. And fix it on the transparent substrate 40,
Counter electrodes 35 and 36 are formed on the side surfaces of the crystal 44. These electrodes are connected to the lead wires 45 and 46 on the substrate 40 and are supplied with an electric signal. Then, in the columnar body 44, the pixels 7 are arranged between the counter electrodes 35 and 36.

Although the present invention has been illustrated above, the above-described example can be further modified based on the technical idea of the present invention.

For example, a plurality of types of the above-mentioned fluorescent materials are mixed, but they may be laminated as separate layers. Further, although only one (one type) light source is used, two or more types of light sources having a plurality of main emission wavelengths may be used in combination at the same time. Further, the main emission wavelength of each light source may be two depending on the fluorescent body used. Further, a photosensitive material such as Se-Te or phthalocyanine used in electrophotography can be used as the photoconductor, and a color image can be formed by a known electrophotographic method. The present invention can also be applied to the formation of color images other than full color. Also for the optical shutter array, the configuration, structure, material or the like may be changed. The recording method may be variously changed, and for example, the development may be performed in a non-contact manner or a magnetic brush method. The developer used may be either a two-component or one-component developer.

F. Advantageous Effects of the Invention As described above, the present invention makes good use of the characteristics of the electro-optical element as a filter and can particularly well record a color image. Also, the response speed as a shutter,
The on / off ratio can also be sufficiently exhibited. Moreover,
Since a light source having a plurality of main emission wavelengths corresponding to the photoconductor is used, it is possible to sufficiently guide the light in the wavelength range corresponding to this when exposing each color. Thus, the exposure amount can be made sufficient and the sensitivity characteristics can be made good at the same time, so that a high quality color image can be realized.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a schematic perspective view of an essential part of an image recording apparatus, FIG. 2 is a schematic view of one system for obtaining an image signal, and FIG. FIG. 4 is a schematic sectional view of the entire apparatus, FIG. 4 is a spectrum diagram showing the photosensitivity distribution of the photoconductor, FIG. 5 is a spectrum diagram showing the spectral characteristics of the light source, FIG. 6 is a sectional view of the optical shutter array, and FIG. FIG. 8 is a perspective view of an electro-optical element made of a PLZT crystal, FIG. 8 is a diagram for explaining the principle of an optical shutter, FIG. 9 is a graph showing a change in transmittance with voltage of the optical shutter for each wavelength used, and FIG. FIG. 11 is a graph showing a change in transmittance depending on the wavelength of the optical shutter for each applied voltage, FIG. 11 is a perspective view of an optical shutter array according to another example, and FIG. 12 is a sectional view taken along line XII-XII of FIG. . In the drawing, reference numerals 1 ... Light source 2 ... Photoconductor 3 ... Slit plate 6 ... Optical shutter array 7 ... Pixel (pixel) 9 ... Control unit (driving unit) 28 ... Color development unit 29: Bleach-fixing unit 30, 31, 52: Stabilizing unit 33: Polarizer 34: PLZT crystal 35, 36: Electrode 38: Analyzer 53: Drying unit.

Continuation of the front page (56) Reference JP-A-54-130128 (JP, A) JP-A-57-100450 (JP, A) JP-A-59-152455 (JP, A) JP-A-62-244014 (JP , A) JP 62-260470 (JP, A) JP 60-134259 (JP, A)

Claims (1)

(57) [Claims] 1. An image recording apparatus comprising a light source, an optical shutter array including a combination of a polarizer, an electro-optical element, and an analyzer, a photoconductor, and a drive section for supplying an electric signal to the optical shutter array. The photoconductor has a plurality of high-sensitivity regions, and the electro-optical element includes a PLZT crystal having a thickness of 300 to 1000 μm, and counter electrodes provided at intervals of 100 to 300 μm. The counter electrode has an electrode width of 30 to 100 μm and an interval between the electrodes of 30 to 100 μm, and the light source is one or more kinds each having a main emission wavelength in the high sensitivity region of the photoconductor. An image recording device characterized by being a thing.