JP2005301303A - Image recording method and image recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording method and an image recording apparatus, capable of improving the quality of the image to be formed on a photosensitive material, by reducing the interference fringes of laser beams. <P>SOLUTION: The image recording apparatus constituted so as to form a photosensitive layer containing silver halide grains, of which the average grain size is ≤0.1 μm and a silver salt of an organic acid on a support body and scan and expose a silver halide heat developing photosensitive material, of which the light transmissivity in the average wavelength of laser light is ≥20% and γ is ≥2 with/to laser light to form an image on the photosensitive material comprises: a laser light source for oscillating the laser light; a scanning optical system for scanning the surface of the silver halide heat developing photosensitive material with the laser light oscillated from the laser light source; and a laser light source control means for controlling the laser light source so as to switch the wavelength of the laser light oscillated from the laser light source in each prescribed number of scanning lines. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image recording method and an image recording apparatus.

  Conventionally, a silver halide photographic light-sensitive material has been exposed with a laser beam in order to record an image based on image data. In recent years, a silver halide photothermographic material that does not require liquid processing and can visualize an image by thermal development has appeared. However, it has been found that when this is exposed with laser light, interference fringes are generated and image unevenness occurs. This phenomenon will be described with reference to FIG. 12, which is a conceptual diagram showing the relationship between the film cross section and the laser beam.

  As shown in FIG. 12 (a), when laser light is incident from the front surface F1 onto a film F composed of a photosensitive layer of a silver halide photothermographic material and a support such as PET, a part of the light is reflected by the back surface F2. By returning to the front surface F1, interference occurs between the light B1 directly applied to the recording layer and the light B2 reflected by the F2 surface and reflected by the F1 surface among the light transmitted through the photosensitive layer. . For this reason, the amount of light applied to the photosensitive layer varies depending on the thickness of the film. As a result, the exposure amount of the silver halide photothermographic material to the photosensitive layer varies, resulting in density unevenness.

  The photosensitive layer is irradiated when the optical path difference δ between the light B1 directly irradiated to the photosensitive layer and the light B2 irradiated to the recording layer after being reflected by the F2 and F1 surfaces is an integral multiple of the laser wavelength. The light intensity is maximized, and is minimized when shifted by a half wavelength from an integral multiple. The reflectance R at the boundary surface of media having different refractive indexes can be expressed by the following equation (1), where nA and nB are the refractive indexes of the respective media sandwiching the boundary surface.

R = ((nB-nA) / (nB + nA)) ² (1)
Here, for example, if the refractive index of each layer of the photosensitive material is the same and uniform, and nB = 1 (air) and nA = 1.5 (photosensitive material), the reflectance at the interface between the air and the photosensitive material. R becomes 4%. Further, the light amount change (peak-to-peak) ΔA due to interference can be expressed by the following equation (2), which is 16% in the above case.

ΔA = 4R (2)
Actually, as shown in FIG. 12B, a laser light absorption layer is provided on the back surface F2 side of the support, and the generation of scattered light s by the silver halide grains contained in the photosensitive layer. Therefore, the change in the amount of light due to interference is less than the above value. However, if there is a slight difference in refractive index between the absorption layer and the support, reflection occurs at the boundary surface F2 between the absorption layer and the support, and the absorption layer does not contribute. In addition, the conventional photosensitive material has a large size of silver halide grains contained therein, and an absorption layer can be provided in multiple layers, so that interference fringes are not easily generated, whereas a photothermographic material has a conventional photosensitive material. Compared with the material, the silver halide grains are finer, and the scattering in the photosensitive layer is much less than that of the conventional film. In particular, in the case of a highly heat developable material having γ of 2 or more, the interference fringe becomes conspicuous.

The light quantity fluctuation due to the interference as described above can be prevented by the following countermeasures 1) to 3).
1) An antireflection film is provided on the back surface (F2) of the support to reduce the reflectance at the surface F2 between the support and the absorption layer.
2) Limit the thickness variation of the support to a fraction of the wavelength of the laser beam (generally 0.5 μm to 1.5 μm).
3) The refractive index difference between the support and the absorption layer is reduced to reduce the reflectance at the interface F2 between the support and the absorption layer.

  However, measure 1) leads to cost increase and is not preferable. As for measure 2), although it is possible to suppress variation in a medium having a thickness of several μm, it is almost impossible to suppress variation in a medium having a thickness of 100 μm or more to sub μm or less. Furthermore, with regard to measure 3), even if the difference in refractive index is only 0.05 or less, interference fringes are formed, so that it is almost impossible to make the difference in refractive index between them below this level.

Further, Patent Document 1 includes a surface layer that diffuses and transmits near-infrared light that is a wavelength region of laser light, a back surface layer that diffusely reflects or absorbs near-infrared light, and a support and a photosensitive layer. A silver halide photothermographic material having a layer that diffusely transmits or absorbs near infrared rays is disclosed. Conventionally, it has been common to suppress interference fringes by devising the photosensitive material itself. Patent Document 2 discloses driving a laser diode by superimposing a high frequency on an input signal to the laser diode.
US Pat. No. 4,711,838 Japanese National Patent Publication No. 10-500229

  However, suppression of interference fringes by devising the photosensitive material may adversely affect other characteristics of the photosensitive material, for example, visibility after development, the cost of the photosensitive material, or may not be sufficient. Moreover, it is technically difficult to superimpose the high frequency on the input signal to the laser diode, resulting in an increase in cost, and there is a risk that the operation will become unstable. It has the disadvantage of being about half. In addition, in a high-sensitivity photosensitive material having a γ (film contrast) of 2 or more, interference fringes were not sufficiently suppressed.

  The present invention has been made in view of these problems of the prior art, and an image that can improve the quality of an image formed on a photosensitive material by reducing interference fringes of laser light by a method different from the conventional one. It is an object to provide a recording method and an image recording apparatus.

  In order to achieve the above object, an image recording apparatus according to the present invention has a photosensitive layer containing silver halide grains having an average grain size of 0.1 μm or less and organic acid silver on a support, and an average of laser light. In an image recording apparatus for forming an image on a photosensitive material by scanning and exposing a silver halide photothermographic material having a light transmittance at a wavelength of 20% or more and γ of 2 or more with a laser beam, A laser light source that oscillates the laser light, a scanning optical system that scans the silver halide photothermographic material with the laser light oscillated from the laser light source, and the laser light source that oscillates for each predetermined number of scanning lines. And laser light source control means for controlling the wavelength of the laser light to be switched.

  According to the present invention, interference fringes can be effectively reduced even if the photosensitive material is a high-contrast silver halide photothermographic material having γ of 2 or more.

  The laser light source may be a laser diode.

Further, another image recording apparatus according to the present invention has a photosensitive layer containing silver halide grains having an average grain size of 0.1 μm or less and organic acid silver on a support, and has an average wavelength of laser light. In an image recording apparatus for forming an image on a silver halide photothermographic material by scanning and exposing a silver halide photothermographic material having a light transmittance of 20% or more and γ of 2 or more with a laser beam. A laser diode that oscillates laser light, a scanning optical system that scans the laser light emitted from the laser diode onto the silver halide photothermographic material, and a scan that scans onto the silver halide photothermographic material. A means for inputting an image signal of an image to be recorded and a wavelength of the laser light to be oscillated are changed by changing an input current to the laser diode for each predetermined number of scanning lines. According to the present invention, it is possible to effectively prevent interference fringes even if the photosensitive material is a high-sensitivity silver halide photothermographic material having a γ of 2 or more. Can be reduced.

  According to the image recording method and the image recording apparatus of the present invention, it is possible to reduce interference fringes of laser light during exposure of a photosensitive material, and to improve the quality of an image formed on the photosensitive material.

First, the principle of preventing interference fringes with two laser beams having different wavelengths will be described with reference to FIGS.
(1) Case where the laser has a single wavelength (a fluctuation in the amount of light occurs due to interference) As shown in FIG. The thickness D2 of the photosensitive layer of the film F, which is a silver halide photothermographic material, is 20 μm, the refractive index n2 is 1.5, the thickness D1 of the support 1 is 180 μm, the refractive index n1 is 1.5, and the laser beam When the wavelength is 0.800 μm, the optical path difference δ = 2 (D1 × n1 + D2 × n2) = 2 × (180 × 1.5 + 20 × 1.5) = 600 μm is an integral multiple of 600/600 = 750. It becomes. The laser light in FIG. 1 has a phase as shown in FIG. 2A at the incident point 5 on the surface F1 of the film F on the photosensitive layer 2 side, and part of the incident light is reflected on the back surface F2 of the film. The light is reflected at the incident point 5 of the film F, and the incident point 5 has a phase as shown in FIG. 2B and the two phases coincide with each other, so that the amount of light applied to the recording layer 2 is maximized. On the other hand, when the thickness of the support is 180.13 μm, the optical path difference δ is 750.5 times the wavelength, the laser beam reflected by the back surface F2 and further reflected by the front surface F1 is incident at the incident point 5 as shown in FIG. Since the phase is as shown in FIG. 2C and is exactly opposite to the phase in FIG. 2A, the amount of light irradiated onto the recording layer 2 is minimized when the amount of laser light perpendicularly incident on the film F is the same. As described above, the amount of light applied to the recording layer 2 varies depending on the thickness variation of the support 1 of the film F.
(2) When the laser has two wavelengths (no change in the amount of light) In the above example, if exposure is performed with two laser beams having wavelengths of 0.8 μm and 0.80053 μm, respectively, the above optical path difference 600 μm is 750 times and 749.5 times the wavelength of the two laser beams, respectively, and the amount of light applied to the photosensitive layer 2 is the sum of the two, that is, between the maximum and the minimum. Here, for example, even if the optical path difference is 600.4 μm, the optical path difference 600.4 μm is 750.5 times and 750 times the wavelength of the two laser beams, respectively. The amount of light emitted is between the minimum and maximum. That is, even if the thickness of the support 1 is changed, the amount of light applied to the photosensitive layer is not changed.

As described above, it can be seen that the influence of interference can be reduced when the irradiated laser beams have two different wavelengths. Halogenation having a photosensitive layer containing silver halide grains of 1 μm or less and organic acid silver on the support, light transmittance at an average wavelength of laser light of 20% or more, and γ of 2 or more In the film F of the silver photothermographic material, as shown in FIG. 1, the wavelengths (λ1, λ2) of the two laser beams, the thickness D1 of the support 1, the refractive index n1 of the support 1, and the photosensitive layer When the thickness D2 of 2, the refractive index n2 of the photosensitive layer 2, and γ of the photosensitive material satisfy the formula (3) for any of the integers N, preferably satisfy the formula (4) It was found that the effects as described above can be obtained.
(N + 0.5- (0.7 / γ)) <2 (D1 ・ n1 + D2 ・ n2) ((1 / λ1)-(1 / λ2)) <(N + 0.5 + (0.7 / γ)) (3)
(N + 0.5- (0.4 / γ)) <2 (D1 ・ n1 + D2 ・ n2) ((1 / λ1)-(1 / λ2)) <(N + 0.5 + (0.4 / γ)) (4)
Embodiments and examples which are examples of the present invention will be described below. Accordingly, the meaning of the terms of the invention and the invention itself should not be construed as being limited by the description of the embodiments and examples of the invention, and it goes without saying that changes / improvements can be made as appropriate.

  FIG. 3 is a front view of the image recording apparatus of the present embodiment, and FIG. 4 is a left side view of the image recording apparatus. The image recording apparatus 100 according to the present embodiment includes a feeding unit 110 that feeds the film F, which is a sheet-like heat developing material, one by one, an exposure unit 120 that exposes the fed film F, and an exposure. And a heat developing section 130 for developing the film F. The film F has a photosensitive layer containing silver halide grains having an average particle diameter of 0.1 μm or less and organic acid silver on a support, and has a light transmittance of 20% or more at an average wavelength of laser light. A silver halide photothermographic material having γ of 2 or more. Hereinafter, the image recording apparatus of the present embodiment will be described with reference to the drawings.

  3 and 4, the feeding unit 110 is provided with two trays T for storing a plurality of deposited films F. An adsorption unit 111 that adsorbs the front end portion of the film F and moves up and down is provided at the upper portion of each tray T on the front end side. Further, in the vicinity of the suction unit 111, a feed roller pair 112 that feeds the film F supplied by the suction unit 111 in the direction of arrow (1) (horizontal direction) is provided. Further, the suction unit 111 can be moved back and forth to carry the sucked film F to the feed roller pair 112. A plurality of transport roller pairs 141 are provided for transporting the film F fed by the feed roller pair 112 in the vertical direction. The film F is transported in the direction (downward) shown by the arrow (2) in FIG.

  A conveyance direction conversion unit 145 is provided at the lower part of the image recording apparatus 100. As shown in FIG. 3 and FIG. 4, the transport direction conversion unit 145 is configured so that the film F transported downward in the vertical direction indicated by the arrow (2) in FIG. 4 by the transport roller pair 141 is indicated by the arrow (3). The film F transported in the horizontal direction and then transported by changing the transport direction from the arrow (3) to the arrow (4) at a right angle and then transported after the transport direction is changed is shown by an arrow (5) in FIG. It is transported by changing the transport direction upward in the vertical direction.

  As shown in FIG. 3, a plurality of transport roller pairs 142 are provided for transporting the film F transported from the transport direction converting section 145 upward in the vertical direction indicated by the arrow (6) in FIG. The recording apparatus 100 is conveyed upward in the vertical direction indicated by an arrow (6) in FIG.

  In the middle of the conveyance upward in the vertical direction, the exposure unit 120 scans and exposes the photosensitive surface of the film F with a laser beam having a wavelength in the infrared range of 780 to 860 nm, and forms a latent image corresponding to the exposure image signal. Let

  A heat developing unit 130 is provided in the upper part of the image recording apparatus 100, and is conveyed upward in the vertical direction indicated by an arrow (6) in FIG. 3 by a conveying roller pair 142 near the drum 14 of the heat developing unit 130. A supply roller pair 143 for supplying the film F to the drum 14 is provided.

  The timing at which the film F is supplied to the drum 14 is supplied at random timing depending on the event. Instead of supplying at random timing, the timing may be supplied.

  The drum 14 of the heat developing unit 130 heats and develops the film F while rotating in the direction indicated by the arrow (7) in FIG. 3 while the film F and the outer peripheral surface of the drum 14 are in close contact with each other. To do. That is, the latent image of the film F is formed into a visible image. Thereafter, when the drum 14 shown in FIG. 3 is rotated to the right, the film F is separated from the drum 14. A plurality of conveying roller pairs 144 are provided on the right side of the heat developing unit 130, and the film F separated from the drum 14 is conveyed obliquely downward to the right as indicated by an arrow (8) in FIG. Cooling. The densitometer 118 measures the density of the film F while the transport roller pair 144 transports the cooled film F. Thereafter, the plurality of transport roller pairs 144 transport the film F away from the drum 14 in the horizontal direction as indicated by an arrow (9) in FIG. 3 and take it out from the upper part of the image recording apparatus 100. Are discharged to a discharge tray 160 provided in the upper right part of the.

Basic Example FIG. 5 is a conceptual diagram showing a configuration of the exposure unit 120. The exposure unit 120 deflects the laser light L, which has been intensity-modulated based on the digital image signal S, by the rotary polygon mirror 113 to perform main scanning on the film F, and performs main scanning on the film F with respect to the laser light L. Sub-scanning is performed by relative movement in a direction substantially perpendicular to the direction, and a latent image is formed on the film F using the laser beam L.

  The image recording apparatus 100 receives the image signal S transmitted from the image signal generation apparatus 121 such as a radiation CT apparatus or a scanner via the image I / F 122 and inputs the image signal S to the modulation unit 123. The modulation unit 123 analog-converts the image signal S and sends the analog-converted exposure image signal to the driver 124. The driver 124 irradiates the laser light with the laser light source units 125 and 127 according to the sent exposure image signal. To control.

  The two laser light source units 125 and 127 are configured by laser diodes that emit laser beams having different wavelengths. As shown in FIG. 5, the laser light L2 emitted from the laser light source unit 127 is a mirror 128a and a half mirror 128b. Thus, the laser beam L1 emitted from the laser light source unit 125 is combined, and the combined laser beam L enters the condenser lens 126. The wavelength (λ1) of the laser light emitted from the laser light source unit 125 is set to, for example, 800 nm, and the wavelength (λ2) of the laser light emitted from the laser light source unit 127 is set to, for example, 800.53 nm.

  The laser light L emitted from the laser light source units 125 and 127 and combined is converted in beam diameter by the condenser lens 126 and converged only in one direction (vertical direction in the present embodiment) by the cylindrical lens 115, In FIG. 5, the mirror surface of the rotating polygon mirror 113 rotating in the rotation direction indicated by the arrow A is incident as a line image perpendicular to the rotation axis of the rotating polygon mirror. The rotary polygon mirror 113 reflects and deflects the laser light L in the main scanning direction, and the deflected laser light L passes through an fθ lens 114 including a cylindrical lens formed by combining four lenses, and then enters the optical path. Reflected by the mirror 116 extending in the scanning direction and repeatedly in the arrow X direction on the surface to be scanned of the film F being conveyed in the arrow Y direction (sub-scanned) by the conveying device 142 Main scan is performed. In this way, the laser beam L scans over the entire surface to be scanned on the film F.

  The cylindrical lens of the fθ lens 114 converges the incident laser light L on the surface to be scanned of the film F only in the sub-scanning direction. As described above, the exposure unit 120 includes the fθ lens 114 including the cylindrical lens and the mirror 116 so that the laser light L is once converged on the rotary polygon mirror 113 only in the sub-scanning direction. Therefore, even if the rotary polygon mirror 113 is tilted or the shaft is shaken, the scanning position of the laser beam L is not shifted in the sub scanning direction on the surface to be scanned of the film F, and the scanning lines are formed at equal intervals. Can be done. The rotary polygon mirror 113 has an advantage that it is superior in scanning stability compared to other optical polarizers such as a galvanometer mirror.

  As described above, a latent image based on the image signal S is formed on the above-described film F having an optical path difference of 600 μm. In this case, the above-described equations (3) and (4) are applied to any integer N. Since the film F is exposed with two laser beams having different wavelengths (wavelength λ1 = 800 nm, wavelength λ2 = 800.53 nm) that satisfy the above conditions, the thickness of the film F varies as described with reference to FIGS. Even if it exists, since an interference fringe can be reduced effectively and density unevenness can be reduced in the film F after heat development, image quality improves.

Modification 1
Two laser beams having different wavelengths may be oscillated from a laser diode having a plurality of light emitting points that oscillate laser beams having different wavelengths. For example, a modification regarding an apparatus that performs scanning using four light beams will be described. This modification relates to a laser printer. As shown in FIG. 14, the laser printer here includes a laser beam output device (71) that outputs four substantially parallel light beams, in which the intensity of the output laser light is modulated in accordance with image information, and this A converging lens for converging four laser beams from the laser beam output device (71) and four laser beams from the converging lens (72) are scanned on the surface to be scanned (73). The light deflecting element (74) that swings and the reflecting mirror (75) that changes the optical path of the laser beam from the light deflecting element (74) and guides it onto the surface to be scanned (73). The surface to be scanned is the photosensitive surface of the film F and is conveyed in a direction perpendicular to the scanning direction of the laser beam. As shown in FIG. 15 which is a cross-sectional view of the laser beam output device (71), a semiconductor laser (76) having four emission points having different oscillation wavelengths and a collimator lens (77) are accommodated. A laser beam output section (78), a cylindrical support (79) fitted with the laser beam (78), and an optical fitted with the support (79) and containing the optical element (80). And an element storage portion (81). However, the laser beam part (78) and the optical element storage part (81) are provided with through holes so as not to hinder the progress of the laser beam.

  As is well known, a plurality of semiconductor lasers are simultaneously formed on a wafer using a semiconductor integrated circuit technique and then cut into the semiconductor laser. The semiconductor laser (76) having four light emitting points used in this modification is cut out and used as four chips (91) without cutting the wafer individually. At this time, the interval between the light emitting sources is 300 μm. Also, the electrodes of each laser are electrically decomposed. Such a chip (94) is provided on a heat sink (92) as shown in FIG. Then, the lead wire (98) is connected to the electrode on the chip (94). The lead wire (98) is supplied with an electrical signal adjusted according to an image signal by a modulator (not shown).

  Laser light from such a semiconductor laser (76) spreads, and the collimating lens (77) incident on the collimating lens (77) shown in FIG. 15 has an aperture of 2.4 mm and a focal length f of 8.4 mm. Yes, at a position of 8.4 mm from the light emitting surface of the laser semiconductor (76). Accordingly, the four spread laser beams incident on the collimating lens (77) are emitted as four parallel light beams. However, these four parallel light beams are latent because their optical paths are not separated immediately after the collimating lens. Therefore, an optical element (80) is provided after the collimating lens (77).

The optical element (80) is made of optical glass. As shown in FIG. 17, the optical element (80) includes first to fourth emission surfaces (101), (102), (103), (104) and a flat incident surface (100). The fifth to eighth surfaces (105), (106) sharing sides with the incident surface (100) and the first to fourth emission surfaces (101), (102), (103), (104). ), (107), (1
08). The first to fourth emission surfaces (101), (102), (103), and (104) are formed symmetrically.

  As shown in FIG. 18, the angle A formed by the first or fourth exit surface (101), (104) and the entrance surface (100) is about 6 °, and the second or third exit surface (102). , (103) and the incident surface (100) is approximately three times the angle B.

  The four parallel light beams incident on the optical element (80) are spatially separated on the incident surface (100) by the arrangement as described above. The four parallel light beams are refracted at the entrance surface and the exit surface. As a result, the directions of the four parallel light beams are aligned by the optical element (80) while maintaining the respective parallel light beams. However, the parallel light beams are not completely aligned and parallel to each other, but are caught between them. With respect to such an optical element (80), the optical element storage portion (81) is provided with a through hole into which the optical element (80) can be inserted and fixed, as shown in FIG.

  Now, the four parallel light beams from the optical element (80) are focused on the surface to be scanned (78) by the focusing lens (72) as shown in FIG. As described above, the four parallel light beams are not parallel to each other and enter the focusing lens (72), so that four spots are obtained on the surface to be scanned (73) to form a scanning line.

  It is preferable that the four light emission points in the first modification have oscillation wavelengths of, for example, 800 nm, 800.53 nm, 801.06 nm, and 801.59 nm, respectively.

Modification 2
Next, a modification of the basic example of the exposure unit 120 and the modification 1 will be described with reference to FIG. In the second modification, a temperature difference is given to two laser diodes (a plurality of chips in the modification of the first modification) that oscillate a laser beam having the same wavelength at the same temperature, thereby generating a wavelength difference in the emitted laser light. It is made to let you. The laser light source units 125 and 127 are composed of laser diodes, and oscillate laser beams having the same wavelength at the same temperature. As shown in FIG. 6, the laser light source units 125 and 127 are provided with temperature control elements 125a and 127a and temperature detection elements 125b and 127b, respectively. Based on the detected temperatures detected by the temperature detection elements 125b and 127b by the temperature control unit 128, the temperature control elements 125a and 127a are controlled so that a temperature difference occurs between the laser diodes of the laser light source units 125 and 127.

  The laser diode has a temperature dependency with respect to its oscillation wavelength, for example, as shown in FIG. 13. For example, if the oscillation wavelength has a characteristic of increasing at a rate of 0.3 nm / ° C., the oscillation wavelength is about 800 nm and the optical path difference is When δ is 600 μm, the necessary wavelength difference Δλ (= λ1−λ2) is 0.53 nm, so the necessary temperature difference ΔT is 0.53 / 0.3≈1.8 ° C. Therefore, by controlling the temperature control elements 125a and 127a so that this temperature difference is obtained by the temperature control unit 128, the same effect as in the case of FIG. 5 can be obtained. In addition, although a Peltier element etc. can be used as a temperature control element and a thermocouple, a thermistor, etc. can be used as a temperature detection element, it is not limited to these. In addition, the two laser light source units do not necessarily oscillate laser light having the same wavelength at the same temperature. If the laser light does not have the same wavelength at the same temperature, the laser can be obtained so as to obtain a predetermined wavelength difference as described above. What is necessary is just to give a temperature difference to a light source part.

Modification 3
Next, another modification of the exposure unit 120 will be described with reference to FIGS. In the third modified example, only one laser light source unit is provided, and the oscillation wavelength of the laser beam is changed by changing the laser input current for each predetermined number of scanning lines. As shown in FIG. 7, a light modulation element 129 is arranged between a laser light source unit 125 constituted by a laser diode and a condenser lens 126, and this light modulation element 129 is converted into an image signal S via a driver 124 '. The laser beam is modulated accordingly. Further, as a laser light source control means, a synchronization signal circuit 131 that outputs a synchronization signal for timing to switch the light emission amount of the laser light source unit 125, and a selection for selecting an input current value to the laser diode based on the synchronization signal The circuit 132 includes a driver 133 that drives the laser diode of the laser light source unit 125 with the input current based on the input current value transmitted from the selection circuit 132. The modulation unit 123 drives the light modulation element 129 in synchronization with the synchronization signal from the synchronization signal circuit 131 via the driver 124 ′. An acousto-optic light modulator or the like can be used as the light modulation element 129.

  The laser light L emitted from the laser light source unit 125 and modulated in accordance with the image signal S by the light modulation element 129 is sub-scanned in the Y direction while being scanned in the X direction on the surface of the film F as described above. . At the time of scanning in the X direction, as shown in FIG. 8, the light emission amount of the laser diode is set by the light emission amount selection circuit 132 in synchronization with the synchronization signal of the synchronization signal circuit 131, for example, from the start of the first scan 1). 5 mW up to 10 mW in the second scanning 2), 5 mW in the third scanning 3), and so on.

  As shown in FIG. 9, for example, as shown in FIG. 9, the wavelength is 800 nm when the optical output is 5 mW, and the wavelength is 800.53 nm when the optical output is 10 mW. Each of the scans shown in FIG. 8 is divided into the first to third scans 1) to 3), the fourth to sixth scans 4) to 6), the seventh to ninth scans 7) to 9),. Thus, when considered in units of three scanning lines, the interference fringes can be effectively reduced when the relationship between the light emission amount of the laser light and the wavelength is as shown in FIG. Also, in order to make the energy at the time of 10 mW light output (wavelength is 80.53 nm) equal to the energy at the time of light output of 5 mW (wavelength is 800 nm), a scan of 10 mW is 1 for a scan of 5 mW twice. The exposure is performed at the rate of times.

  For example, the relationship between the light output of the laser beam and its wavelength as shown in FIG. Further, the two light output levels of the laser light can be selected so as to have a desired wavelength difference from the relationship as shown in FIG.

  Next, the above film F will be described. FIG. 10 is a cross-sectional view of the film F, schematically showing a chemical reaction in the film F during exposure. FIG. 11 is a cross-sectional view similar to FIG. 10 schematically showing a chemical reaction in the film F during heating. In the film F, a photosensitive layer mainly composed of polyvinyl butyral is formed on a support (base layer) composed of PET, and a protective layer composed of cellulose butyrate is further formed thereon. In the photosensitive layer, silver behenate (Beh. Ag), a reducing agent and a toning agent are blended.

When the exposure unit 120 irradiates the film F with the laser beam L during exposure, the silver halide grains are exposed to the area irradiated with the laser beam L as shown in FIG. Is done. On the other hand, when the film F is heated to a temperature equal to or higher than the minimum heat development temperature, silver ions (Ag ⁺ ) are released from the silver behenate as shown in FIG. Form. Thereafter, silver ions are diffused, and a reducing agent acts on the exposed silver halide grains as nuclei, and a silver image is formed by a chemical reaction. Thus, the film F contains photosensitive silver halide grains, an organic silver salt, and a silver ion reducing agent, and is not substantially thermally developed at a temperature of 40 ° C. or lower and is the minimum developed at 80 ° C. or higher. Heat development is performed at a temperature higher than the temperature.

  The photosensitive silver halide used in the heat-developable material can typically be used in the range of 0.75 to 25 mol%, preferably in the range of 2 to 20 mol%, with respect to the organic silver salt. be able to. Moreover, it is preferable that the film F contains 4 times or more of silver in the amount of silver with respect to the silver halide grains in the photosensitive layer. The average grain size of the silver halide grains is 0.1 μm or less.

  This silver halide is any photosensitive silver halide such as silver bromide, silver iodide, silver chloride, silver bromoiodide, silver chlorobromoiodide and silver chlorobromide. Also good. The silver halide may be in any form that is photosensitive, including, but not limited to, cubic, orthorhombic, flat, tetrahedral and the like.

  An organic silver salt is any organic material that contains an on-reduce source of silver. Silver salts of organic acids, particularly long chain fatty acids (10-30 carbon atoms, preferably 15-28 carbon atoms) are preferred. It is preferable that the ligand is an organic or inorganic silver salt complex having a certain stability between 4.0 and 10.0 as a whole. Further, it is preferably about 5 to 30% of the weight of the image recording layer.

  The organic silver salt that can be used in the heat-developable material is a silver salt that is relatively stable to light, and in the presence of an exposed photocatalyst (eg, photographic silver halide) and a reducing agent, 80 It is a silver salt that forms a silver image when heated to a temperature of ℃ or higher.

  Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. They include silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the aliphatic carboxylic acid silver salt include silver behenate and silver stearate. Silver salts with halogen atoms or hydroxyls in aliphatic carboxylic acids can also be used effectively. Silver salts of compounds having a mercapto or thione group and derivatives thereof may also be used. Furthermore, a silver salt of a compound having an imino group can be used.

  The reducing agent for the organic silver salt may be any material that can reduce silver ions to metallic silver, and is preferably an organic material. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful. However, phenol reducing agents are preferred. The reducing agent should be present at 1-10% by weight of the image recording layer. In multi-layer configurations, a slightly higher proportion of about 2 to 15% by weight is more desirable when the reducing agent is added to a phase other than the emulsion layer.

  When the following film F was exposed and heat-developed by the apparatus of the basic example and the first to third modifications according to the above-described embodiment, density unevenness considered to be caused by generation of interference fringes was not found. Hereinafter, the production of the film F will be described.

  Silver halide-silver behenate dry soap was prepared by the method described in US Pat. No. 3,839,049. The silver halide had 9 mol% of total silver, while silver behenate had 91 mol% of total silver. The silver halide was a 0.055 μm silver bromoiodide emulsion with 2% iodide.

  The thermally developed emulsion was homogenized with 455 g of the above silver halide-silver behenate dry soap, 27 g of toluene, 1918 g of 2-butanone, and polyvinyl butyral (B-79 manufactured by Monsanto). The homogenized heat developed emulsion (698 g) and 2-butanone 60 g were cooled to 12.8 ° C. with stirring. Pyridinium hydrobromide perbromide (0.92 g) was added and stirred for 2 hours.

3.25 ml of calcium bromide solution (CaBr (1 g) and 10 ml of methanol) was added followed by stirring for 30 minutes. Further, polyvinyl butyral (158 g; B-79 manufactured by Monsanto) was added and stirred for 20 minutes. The temperature was raised to 21.1 ° C. and the following were added over 15 minutes with stirring.
2- (tribromomethylsulfone) quinoline 3.42 g,
28.1 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane,
A solution containing 0.545 g of 5-methylmercaptobenzimidazole
41.1g,
2- (4-Chlorobenzoyl) benzoic acid 6.12 g
S-1 (Infectious infection charge) 0.104g
34.3g of methanol
Isocyanate (Desmoder N3300, manufactured by Movey) 2.14 g
Tetrachlorophthalic anhydride 0.97g
Phthalazine 2.88g
The dye S-1 has the following structure.

活性保護トップコート溶液を以下の成分を用いて調製した，
２−ブタノン ８０．０ｇ
メタノール １０．７ｇ
酢酪酸セルロース（ＣＡＢ−１７１−１５５、イーストマン・ケミカルズ製）
８．０ｇ
４−メチルフタル酸 ０．５２ｇ
ＭＲＡ−１、モトル還元剤、Ｎ−エチルペルフルオロオクタンスルホニルアミドエチルメタクリレート／ヒドロキシエチルメタクリレート／アクリル酸の重量比７０：２０：１０の３級ポリマー ０．８０ｇ
この熱現像乳剤とトッブコートとは、同時に、０．１８ｍｍの青色ポリエステル・フィルム・べースにコーティングされた。ナイフ・コーターは、同時にコーティングする２つのバーやナイフを１５．２ｃｍの距離を置いた状態で設定された。銀トリップ層と、トップ・コートとは、銀乳剤をリアー・ナイフに先立ってフィルムに注ぎ、トップ・コートをフロント・バーに先立ってフィルムに注ぐことにより、多層コーティングされた。

An active protective topcoat solution was prepared using the following ingredients:
2-butanone 80.0g
Methanol 10.7g
Cellulose butyrate (CAB-171-155, manufactured by Eastman Chemicals)
8.0g
4-methylphthalic acid 0.52g
MRA-1, mottle reducing agent, N-ethylperfluorooctanesulfonylamidoethyl methacrylate / hydroxyethyl methacrylate / acrylic acid weight ratio 70:20:10 tertiary polymer 0.80 g
This thermally developed emulsion and topcoat were simultaneously coated on a 0.18 mm blue polyester film base. The knife coater was set with two bars and knives to be coated at a distance of 15.2 cm. The silver trip layer and the top coat were multilayer coated by pouring silver emulsion onto the film prior to the rear knife and pouring the top coat onto the film prior to the front bar.

This film was then drawn forward so that both layers were coated simultaneously. This was obtained by performing the multilayer coating method once. The coated polyester base was dried at 79.4 ° C. for 4 minutes. As the knife, as dry coating weight per 1 m ² for the silver layer is 23g, then dry coating weight per 1 m ² is adjusted so as to be 2.4g for the top coat It was. Further, the optical path length obtained from the dry film thickness and refractive index of these layers and the film thickness and refractive index of the film base as a support was 600 μm.

  According to the image recording method and the image recording apparatus of the present invention, it is possible to reduce interference fringes of laser light during exposure of a photosensitive material, and to improve the quality of an image formed on the photosensitive material.

It is sectional drawing of the film for demonstrating the principle of this invention. FIG. 1A shows the wavelength (λ1) and phase of the laser beam at the incident point 5 of incident light in FIG. 1, and the wavelength (λ2) and phase of the laser beam at the incident point 6 of reflected light (same as FIG. 1A). FIG. 5B is a diagram showing the phase), and FIG. 5C is a diagram showing the wavelength (λ2) and phase (opposite phase of FIG. 1 is a front view of a heat development apparatus according to an embodiment of the present invention. 1 is a left side view of a heat development apparatus according to an embodiment of the present invention. FIG. 4 is a schematic diagram showing a configuration of an exposure unit 120 of the heat development apparatus of FIG. 3. It is the schematic which shows the modification of an exposure part. It is the schematic which shows another modification of an exposure part. It is a schematic diagram for demonstrating the scanning state of the laser beam by the exposure part of FIG. It is a figure which shows the relationship between the optical output of the laser diode of FIG. 7, and its wavelength. It is sectional drawing of the film F in this Embodiment, and is the figure which showed typically the chemical reaction in the film F at the time of exposure. It is sectional drawing similar to FIG. 10 which showed typically the chemical reaction in the film F at the time of a heating. It is a conceptual diagram (a), (b) which shows the relationship between the cross section of the film for demonstrating the problem of a prior art, and a laser beam. It is a figure which shows notionally the wavelength change by the temperature of a laser diode. It is a perspective view of the optical system for demonstrating the modification regarding the laser diode which has a several light emitting point. It is sectional drawing of the laser beam output part (78) of FIG. It is a perspective view of the semiconductor laser (76) of FIG. It is a perspective view of the optical element (80) of FIG. It is a side view for demonstrating the shape of the optical element (80) of FIG. It is a perspective view of the optical element storage part (81) of FIG. FIGS. 17A and 17B are diagrams showing light emission points of the semiconductor laser of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film support body 2 Photosensitive layer of film 100 Thermal development apparatus 110 Storage part 120 Exposure part 130 Development part 125,127 Laser light source part 125a, 127a Temperature control element 125b, 127b Temperature detection element 128 Temperature control part 129 Light modulation element 113 Rotating polygon mirror 142 Conveying device F Film D1 Film support thickness n1 Support refractive index D2 Film photosensitive layer thickness n2 Photosensitive layer refractive index λ1 Laser light wavelength λ2 Different laser light wavelength

Claims (3)

The support has a photosensitive layer containing silver halide grains having an average particle diameter of 0.1 μm or less and organic acid silver, the light transmittance at an average wavelength of laser light is 20% or more, and γ is In an image recording apparatus for forming an image on the photosensitive material by scanning and exposing two or more silver halide photothermographic materials with a laser beam,
A laser light source for emitting laser light;
A scanning optical system for scanning the silver halide photothermographic material with laser light oscillated from the laser light source;
An image recording apparatus comprising: laser light source control means for controlling the wavelength of laser light oscillated from the laser light source for each predetermined number of scanning lines. The image recording apparatus according to claim 15, wherein the laser light source is a laser diode. The support has a photosensitive layer containing silver halide grains having an average particle diameter of 0.1 μm or less and organic acid silver, the light transmittance at an average wavelength of laser light is 20% or more, and γ is In an image recording apparatus for forming an image on the silver halide photothermographic material by scanning and exposing two or more silver halide photothermographic materials with a laser beam,
A laser diode that oscillates laser light;
A scanning optical system that scans the silver halide photothermographic material with laser light oscillated from the laser diode;
Means for inputting an image signal of an image to be scanned and recorded on the silver halide photothermographic material;
Laser light source control means for controlling the wavelength of the laser light to be oscillated by changing an input current to the laser diode for each predetermined number of scanning lines;
An image recording apparatus comprising:

Images