JP2000214565A - Thermal developing device and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with different-sized thermal developing material, and also, to secure high image quality while forming an image in a short time by supplying the thermal developing material at such the timing shifting a position where the leading end of the thermal developing material is held in a drum rotating direction among the thermal developing materials. SOLUTION: In the case of continuously heating films F, if each film is held at a different position, the outer peripheral surface of the drum 14 is nearly uniformly cooled and the nearly uniform distribution of humidity is maintained. Thus, the time TR for rotating the drum 14 once and the time T for supplying the leading end of the film F to the drum 14 are set so as to satisfy the following expression; T≠N×TR (provided that N denotes an optional natural number). That is, by supplying the film F to the drum 14 at the timing shifting the film F lead end holding position in the rotating direction of the drum 14 among the continuously supplied films F, the films F are prevented from being continuously held at the same position on the drum 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat development apparatus and a heat development method, and more particularly to a heat development apparatus and a heat development method for forming an image by holding a heat development material on a heated drum outer peripheral surface.

[0002]

2. Description of the Related Art By continuously supplying a sheet-like heat developing material to an outer peripheral surface of a heated drum, a thermal reaction occurs in the heat developing material, whereby an image formed as a latent image can be visualized. A heat developing device capable of forming a target image has been developed (see Japanese Patent Application Laid-Open No. 10-500977).
According to such a thermal developing device, a sheet-like thermal developing material is
It is supplied to the outer peripheral surface of the drum rotating at a constant rotation speed, and after the drum rotates by a predetermined rotation angle while holding the thermal developing material, the heated thermal developing material is peeled off from the outer peripheral surface of the drum, and at the same time, a new one is obtained. Since the thermal developing material is supplied to the outer peripheral surface of the drum, it is possible to efficiently heat the sheet-like thermal developing material.

[0003]

In such a heat developing apparatus, the time TR during which the drum makes one rotation is equal to the time interval T during which the leading end of the heat developing material is supplied to the drum. Therefore, the heat developing material continuously heated by the heat treatment can be developed under the same conditions, and a mechanism for chucking the heat developing material can be provided on the drum, which is considered to be preferable.

However, it has been found that, in such a case, after a large number of thermal developing materials are thermally developed, density unevenness occurs at the front end and the rear end of the developed thermal developing material in the drum rotation direction. In particular, it is a device that can thermally develop a plurality of different sizes of heat-developable materials in the direction of rotation of the drum. Then, it was found that density unevenness also occurred at the center of the screen, and image quality was significantly impaired.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to suppress the occurrence of such density unevenness and enable high-speed, high-quality thermal development.

Further, it is considered that the drum in the heat developing device of the prior art is premised on heating the same size heat developing material, and it is considered that heating the different size heat developing material is not planned. Therefore, if the drum of the prior art is used as it is for heating the heat developing materials of different sizes, a mismatch occurs between the circumferential length of the drum and the length of the heat developing material in the drum rotation direction. If the heat development material is too small, curl or the like may occur.

In view of the problems of the prior art, the present invention is applicable to a heat developing material of a different size, and a heat developing apparatus and a heat developing apparatus capable of ensuring high image quality while performing image formation in a short time. An object is to provide a developing method.

[0008]

The present inventors have made intensive studies on the causes of such density unevenness, and as a result, have found the following, and made the present invention. The means for solving the above-mentioned problems are shown below.

According to a first aspect of the present invention, there is provided a supply means for supplying a sheet-like heat development material, and the heat development material supplied by the supply means is heated while being held on an outer peripheral surface, and is substantially heated. In a heat developing apparatus having a drum rotating at a constant rotation speed, the supply unit holds a tip of the heat developing material at least between the heat developing materials continuously heated by the drum. The thermal developing device supplies the thermal developing material to the drum at a timing such that the position shifts in the rotation direction of the drum.

Thus, even when a small-sized heat developing material is supplied to the drum, only a part of the outer peripheral surface of the drum is cooled by changing the position where the front end of the heat developing material is held. Therefore, the temperature of the entire outer peripheral surface can be made uniform, thereby suppressing the occurrence of density unevenness and improving the quality of the thermally developed image.

According to a second aspect of the present invention, there is provided a supply means for supplying a sheet-like heat development material, and the heat development material supplied by the supply means is heated while being held on an outer peripheral surface, and substantially. In a heat developing apparatus having a drum rotating at a constant rotation speed, a time TR during which the drum makes one rotation and a time interval T at which the leading end of the heat developing material is supplied to the drum are determined by an arbitrary natural number N. This is a thermal developing device that satisfies the following equation.

T ≠ N × TR Thus, even when a small-sized thermal developing material is supplied to the drum, the position at which the leading end of the thermal developing material is held is changed so that the outer peripheral surface of the drum can be reduced. The temperature of the entire outer peripheral surface can be equalized without cooling only the portion, thereby suppressing the occurrence of density unevenness,
The quality of the thermally developed image can be improved.

Further, a time TR required for the drum to make one rotation is TR.
And the time interval T at which the leading end of the thermal development material is supplied to the drum satisfies the following expression with respect to an arbitrary natural number N: (N−1 / 20) × TR ≧ T or (N + 1) / 20) × T
R ≦ T Since the leading end of the heat developing material is not substantially supplied to the same position on the drum, temperature unevenness in the rotation direction on the drum is less likely to occur, and density unevenness occurs. Can be effectively suppressed.

The time TR required for the drum to make one revolution TR
And the time interval T at which the leading end of the thermal development material is supplied to the drum satisfies the following expression with respect to an arbitrary natural number N: (N−1 / 100) × TR ≧ T or (N + 1) / 100)
× TR ≦ T Since the front end of the thermal development material is not substantially supplied to the same position on the drum, temperature unevenness in the rotation direction on the drum is less likely to occur, so that density unevenness is reduced. This can be effectively suppressed.

According to a third aspect of the present invention, there is provided a supply means for supplying a sheet-like heat development material, and the heat development material supplied by the supply means is heated while being held on an outer peripheral surface, and substantially. In a thermal developing apparatus having a drum that rotates at a constant rotation speed, a time required for the drum to make one rotation is TR,
If the time interval between the time at which the leading edge of the n-th supplied thermal developing material is supplied to the drum and the time at which the leading edge of the n + 1-th thermal developing material is supplied to the drum is T (n), it is arbitrary. Is a thermal developing apparatus in which the natural number n that satisfies all of the following expressions with respect to the natural number N is 50% or more.

(N-1 / 20) × TR ≧ T (n) or (N + 1/20) × TR ≦ T (n) and (N−1 / 20) × TR ≧ T (n + 1) or (N + 1/20) ) × TR ≦ T (n + 1) and (N−1 / 20) × TR ≧ T (n) + T (n + 1) or (N + 1/20) × TR ≦ T (n) + T (n + 1). Since the probability that the leading end of the material is substantially continuously supplied to the same position on the drum is reduced, temperature unevenness in the rotation direction on the drum is less likely to occur, thereby reducing the temperature unevenness. It can be suppressed effectively. Incidentally, the existence rate of the natural number n satisfying the above equation is M
When developing the sheets of thermal developing material, the time at which the leading ends of these thermal developing materials are supplied to the drum is recorded sometime, and from the time TR during which the drum makes one rotation, a natural number n satisfying the above expression is obtained. % Can be obtained, but the method of obtaining is not limited to this. In addition, the existence ratio of the natural number n satisfying the above equation is 7 from the viewpoint of more effectively suppressing density unevenness.
It is preferably at least 0% (particularly at least 90%).

According to a fourth aspect of the present invention, there is provided a supply means for supplying a sheet-like heat development material, and the heat development material supplied by the supply means is heated while being held on the outer peripheral surface, and substantially. In a thermal developing apparatus having a drum that rotates at a constant rotation speed, a time required for the drum to make one rotation is TR,
If the time interval between the time at which the leading edge of the n-th supplied thermal developing material is supplied to the drum and the time at which the leading edge of the n + 1-th thermal developing material is supplied to the drum is T (n), it is arbitrary. Wherein the natural number n satisfying all of the following expressions is 90% or more of the natural number N.

(N-1 / 100) × TR ≧ T (n) or (N + 100) × TR ≦ T (n) and (N−1 / 100) × TR ≧ T (n + 1) or (N + 1/100) ) × TR ≦ T (n + 1) and (N−1 / 100) × TR ≧ T (n) + T (n + 1) or (N + 1/100) × TR ≦ T (n) + T (n + 1) Since the probability that the leading end of the material is substantially continuously supplied to the same position on the drum is reduced, temperature unevenness in the rotation direction on the drum is less likely to occur, thereby reducing the temperature unevenness. It can be suppressed effectively. Incidentally, the existence rate of the natural number n satisfying the above equation is M
When developing the sheets of thermal developing material, the time at which the leading ends of these thermal developing materials are supplied to the drum is recorded sometime, and from the time TR during which the drum makes one rotation, a natural number n satisfying the above expression is obtained. % Can be obtained, but the method of obtaining is not limited to this. In addition, the existence ratio of the natural number n satisfying the above expression is 9 from the viewpoint of more effectively suppressing the density unevenness.
It is preferably at least 5% (particularly at least 97%).

Further, since a plurality of sizes of heat development materials having different lengths along the rotation direction of the drum can be developed, a plurality of sizes of heat development materials having different lengths in the rotation direction of the drum are developed. First, before and after the rotation direction of the position on the drum where the rear end of the thermal developing material is located, to suppress the occurrence of temperature unevenness, and then, even if the thermal developing material of a larger size is thermally developed, It is possible to suppress the occurrence of density unevenness at the center of the screen and improve the image quality.

Further, a diameter D of the outer peripheral surface of the drum for holding the heat development material and a length L in the rotation direction of the heat development material having a minimum length along the rotation direction of the drum.
When min satisfies the following expression, Lmin <π × D (π is a circular constant) The processing capacity of the heat developing material can be increased, and the heat developing material can be increased by adjusting the diameter of the drum. It is possible to suppress the occurrence of density unevenness while suppressing the occurrence of curl.

According to a fifth aspect of the present invention, there is provided a supply means for supplying a sheet-like heat development material, and the heat development material supplied by the supply means is heated while being held on an outer peripheral surface, and substantially. In a heat developing device having a drum that rotates at a constant rotation speed, a heat developing material of a plurality of sizes having different lengths in the drum rotation direction can be developed, and in the drum,
The diameter D of the outer peripheral surface that holds the heat development material and the length Lmin in the rotation direction of the heat development material whose length along the rotation direction of the drum is the minimum is a heat development device that satisfies the following expression. is there.

Lmin <π × D (π is a circular constant) This makes it possible to develop a plurality of sizes of heat developing materials having different lengths in the rotation direction of the drum, and to increase the processing capacity. By adjusting the diameter of the drum, curling of the heat development material can be suppressed.

The diameter D of the outer peripheral surface of the drum, which holds the heat development material, and the length Lmax of the heat development material, which has the maximum length along the rotation direction of the drum, in the rotation direction are: By satisfying the following expression, π × D <2 × Lmax (π is a pi) The size of the drum can be reduced, and the occurrence of density unevenness can be suppressed or the processing capacity can be increased. At the same time, curling of the heat developing material can be suppressed.

Further, the heat developing material contains photosensitive silver halide particles, an organic silver salt, and a silver ion reducing agent,
Thermal development is not substantially performed at a temperature of 40 ° C. or less, and is performed at a temperature of a minimum developing temperature of 80 ° C. or more, so that development is performed carelessly at a normal temperature of 40 ° C. or less. Never.

Further, the drum heats the heat developing material at a developing temperature equal to or higher than the minimum developing temperature for a predetermined heat developing time.
The thermal development material can be thermally developed by the drum.

Further, by having a rotatable roller urged against the drum, the heat development material can be in close contact with the outer peripheral surface of the drum.

The thickness of the drum is 0.1 mm.
By having the above elastic layer, the heat developing material is
The outer peripheral surface of the drum can be in close contact.

The elastic layer has a thickness of 2 mm or less,
The thermal development material has a thermal conductivity of 0.4 (W / m / K) or more, and the drum has a metal support member that directly or indirectly supports the elastic layer, so that the heat development material can be favorably heated. At the same time, the elastic layer can be firmly supported by the metal supporting member.

According to a sixth aspect of the present invention, a step of rotating a drum having a heated outer peripheral surface at a substantially constant rotational speed, and a step of supplying a first heat developing material to the outer peripheral surface of the drum are provided. Holding the supplied first thermal developing material on the outer peripheral surface of the drum for a predetermined time;
Separating the first heat development material from the outer periphery of the drum; and holding the front end of the second heat development material following the first heat source image material with the front end of the first heat development material. Supplying the second thermal developing material to the outer peripheral surface of the drum while shifting the second thermal developing material with respect to the outer peripheral position of the drum in the rotational direction of the drum.

Thus, even when a small-sized heat developing material is supplied to the drum, only a part of the outer peripheral surface of the drum is cooled by changing the position where the front end of the heat developing material is held. Without this, the temperature of the entire outer peripheral surface can be made uniform, thereby suppressing the occurrence of density unevenness and improving the quality of the thermally developed image.

According to a seventh aspect of the present invention, there is provided a supply means for supplying a sheet-like thermal development material, and the thermal development material supplied by the supply means is heated while being held on an outer peripheral surface, and is substantially heated. In a heat developing apparatus having a drum that rotates at a constant rotation speed, a distance between an outer radius R of the drum, a rotation speed V of the drum, an insertion interval T of the film, and a length L in the rotation direction of the heat development material is determined. , There is a real number P satisfying the following relationship.

When L ≦ 2πR, T = (2πR ± (2πRL) / P) / V, where 0 <
When P ≦ 10 L> 2πR, T = (2πR ± (L−2πR) / P) / V, where 0 <
P ≦ 20 By this, the supply timing of the thermal developing material supplied subsequently to the thermal developing material previously supplied to the drum is shifted in the rotational direction of the drum with respect to the same position on the outer peripheral surface of the drum. At this timing, temperature unevenness in the rotation direction on the drum is less likely to occur, so that the occurrence of density unevenness can be effectively suppressed.

Here, the film insertion interval T is defined as the time from the supply time of the heat developing material supplied to the drum immediately before this time.
It is a time interval until the supply time of the supplied thermal developing material.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments and examples of the present invention, which are examples of the present invention, will be described. Therefore, 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 is needless to say that the invention can be appropriately changed / improved. FIG. 1 is a front view of a heat developing apparatus according to an embodiment of the present invention, and FIG.
FIG. 2 is a left side view of the heat developing device. Thermal developing device 1
Reference numeral 00 denotes a storage unit 110 for the film F which is a sheet-like heat developing material shown in the embodiment, and an exposure unit 12 for exposing the film F taken out and fed one by one from the storage unit 110.
0 and a developing unit 130 for developing the exposed film F. Referring to FIG. 1 and FIG.
Will be described.

In FIG. 2, storage units 110 are provided in two upper and lower tiers, and store the film F stored in the case C together with the case C. The film F is taken out of the case C by a take-out device (not shown) and pulled out in the direction (horizontal direction) shown by the arrow (1) in the figure. Further, the film F pulled out of the case C is transported by a transport device 141 comprising a pair of rollers.
As a result, the sheet is conveyed in the direction (downward) indicated by the arrow (2) in FIG.

The film F conveyed below the heat developing device 100 is further conveyed to a conveying direction changing unit 145 below the heat developing device 100, and the film F is conveyed by the conveying direction changing unit 145.
The transport direction is changed (arrow (3) in FIG. 2 and arrow (4) in FIG. 1), and the process proceeds to the exposure preparation stage. Furthermore, film F
From the left side of the heat developing device 100 by an arrow (5) in FIG.
In the direction (upward) shown in FIG.
2 is conveyed, and at that time, the infrared region 780
Scanning exposure is performed using a laser beam L within a range of 860 nm, for example, a laser beam of 810 nm.

The film F receives the laser beam L to form a latent image in a manner described later. Thereafter, the film F is transported in the direction (upward) indicated by the arrow (6) in FIG.
4 That is, they are supplied at random timing. Alternatively, the vehicle may be temporarily stopped at the time of arrival. In this case, the supply roller pair 143 has a function of determining the timing of supplying the film F to the drum 14 of the developing unit 130 rotating at a constant rotation speed, and at the next supply position on the circumference of the drum 14 The film F may be supplied onto the outer periphery of the drum 14 when the supply roller pair 143 starts rotating when the film F is rotated to a certain predetermined position. The specific configuration will be described later.

Further, the drum 14 rotates together with the film F in the direction shown by the arrow (7) in FIG. 1 while holding the film F on the outer periphery of the drum 14. In this state, the film F is heated from the drum 14 and thermally developed to form a visible image from a latent image in a manner described later. Thereafter, when rotating to the right of the drum 14 in FIG. 1, the film F is separated from the drum 14, transported in the direction indicated by the arrow (8) in FIG. 1, cooled, and then transported by the transport device 144 in FIG. Arrows (9) and (1)
0), and is discharged to a discharge tray 160 so that it can be taken out from the upper part of the thermal developing device 100.

FIG. 3 is a schematic diagram showing the configuration of the exposure unit 120. The exposing unit 120 deflects the laser light L, the intensity of which has been modulated based on the image signal S, by the rotating polygon mirror 113 to perform main scanning on the film F, and also moves the film F in the main scanning direction with respect to the laser light L. The sub-scanning is performed by relatively moving in a direction substantially perpendicular to the above, and a latent image is formed on the film F using the laser beam L.

A more specific configuration will be described below. In FIG. 3, an image signal S which is a digital signal output from an image signal output device 121 is converted into an analog signal by a D / A converter 122 and input to a modulation circuit 123. The modulation circuit 123, based on the analog signal,
Driver 124 of semiconductor laser (laser light source unit) 110
Is controlled so that the laser light L modulated from the semiconductor laser 110 is emitted.

The laser beam L emitted from the semiconductor laser 110 is converged only in the vertical direction by the cylindrical lens 115, and is applied to the rotating polygon mirror 113 rotating in the direction of arrow A in FIG. As incident light. The rotary polygon mirror 113 reflects and deflects the laser light L in the main scanning direction.
After passing through an fθ lens 114 including a cylindrical lens formed by combining two lenses, the light is reflected by a mirror 116 provided on the optical path and extending in the main scanning direction, and is conveyed in the direction of the arrow Y by the conveying device 142. The main scanning is repeatedly performed in the arrow X direction on the scanned surface of the film F (sub-scanned). That is, the laser beam L is scanned over the entire surface to be scanned on the film F.

The cylindrical lens of the fθ lens 114 causes the incident laser light L to be projected onto the surface of the film F to be scanned.
The convergence is performed only in the sub-scanning direction, and the distance from the fθ lens 114 to the surface to be scanned is f
It is equal to the focal length of the entire θ lens 114. As described above, in the main exposure section 120, the fθ lens 114 including the cylindrical lens and the mirror 116 are provided, and 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 deviated, the film F
On the surface to be scanned, the scanning position of the laser beam L is not shifted in the sub-scanning direction, so that scanning lines of equal pitch can be formed. The rotating polygon mirror 113
For example, there is an advantage that scanning stability is superior 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 film F. The details of a specific chemical reaction for forming a latent image will be described later with reference to FIG.

FIGS. 4 to 6 are views showing the structure of the developing section 130 for heating the film F. More specifically, FIGS.
5 is a perspective view of the developing unit 140, FIG. 5 is a cross-sectional view of the configuration of FIG. 4 taken along the line IV-IV and viewed in the direction of the arrow, and FIG. 6 is a view of the configuration of FIG. FIG.

The developing section 130 has a drum 14 which can heat the film F while holding it on the outer periphery. Drum 14
Has a function of forming a latent image formed on the film F as a visible image by maintaining the film F at a predetermined minimum heat development temperature or higher for a predetermined heat development time. Here, the minimum thermal development temperature is a minimum temperature at which the latent image formed on the film F starts to be thermally developed, and is 80 ° C. or more in the present embodiment. On the other hand, the term "thermal development time" refers to the time during which the latent image on the film F must be maintained at the minimum thermal development temperature or higher in order to develop it into desired development characteristics. The specific chemical reaction for visualizing the latent image by heating will be described later with reference to FIG.

In the present embodiment, the developing section 130 is incorporated in the thermal developing apparatus 100 together with the exposing section 120, but may be an apparatus independent of the exposing section 120. In such a case, it is preferable that there is a transport unit that transports the film F from the exposure unit 120 to the development unit 130.

Outside the drum 14, fifteen or twenty-seven rollers 16 having a small diameter are provided as guide members, which are arranged in parallel to the drum 14 and at equal intervals in the circumferential direction of the drum 14. . At both ends of the drum 14, three guide brackets 21 supported by the frame 18 are provided on each side. In addition, by combining the guide brackets 21, opposed C-shaped shapes are formed at both ends of the drum 14.

Each guide bracket 21 has five or nine elongated holes 42 extending in the radial direction. This long hole 42
, The shafts 40 provided at both ends of the roller 16 project. Each of the shafts 40 has a coil spring 28
Is mounted, and the other end of the coil spring 28 is mounted near the inner edge of the guide bracket 21. Therefore, each roller 16 is urged to the outer periphery of the drum 14 by a predetermined force based on the urging force of the coil spring 28. When the film F enters between the outer periphery of the drum 14 and the roller 16, the film F is pressed against the outer peripheral surface of the drum 14 by the predetermined force, thereby uniformly heating the film F over the entire surface.

The shaft 2 coaxially connected to the drum 14
The reference numeral 2 extends outward from the end member 20 of the frame 18 and is rotatably supported by the end member 20 by a shaft bearing 24. A gear (not shown) is formed on a rotating shaft 23 of a micro step motor (not shown) which is arranged below the shaft 22 and attached to the end member 20. On the other hand, a gear is also formed on the shaft 22. Through a chain or a timing belt (belt with gears) 25 connecting both gears,
The power of the microstepping motor is transmitted to the shaft 22, which causes the drum 14 to rotate. The rotation shaft 23
Transmission of power from the shaft to the shaft 22 may be performed via a gear train.

As shown in FIG. 5, in the present embodiment, the roller 16 is
Alternatively, it is provided over an angle range of 234 degrees. 2
The reinforcing members 30 (FIG. 5) connect the both end members 20 of the frame 18 and additionally support the both end members 20.

A plate-like heater 32 is provided on the inner periphery of the drum 14.
Are mounted over the entire circumference to heat the outer circumference of the drum 14 under the control of the control electronic device 34 shown in FIG. Power is supplied to the heater 32 through a slip ring assembly 35 connected to an electronic device 34.

In this embodiment, the drum 14 is formed in a rotatable cylindrical shape in order to make the structure of the heat developing apparatus 100 compact, but another structure is used as a means for heating the film F. Is also good. For example, it is conceivable that the film F is placed on a belt conveyor provided with a heater, and the film F is heated while being conveyed by the belt conveyor.

If the width of the heating area on the outer periphery of the drum 14 is formed larger than the width of the film F, a visible image can be formed over the entire surface of the film F. On the other hand, the diameter D of the outer peripheral surface of the drum 14 that holds the film F and the length Lmin in the rotation direction of the film F whose length along the rotation direction of the drum 14 is the minimum are Lmin <π × D (π is By satisfying the equation (1), it is possible to prevent the outer diameter of the drum 14 from becoming too small, thereby suppressing curling of the film F.

As shown in FIG. 5, the drum 14 includes an aluminum support tube 36, which is a metal support member, and a flexible layer (elastic layer) 38 attached to the outside of the support tube 36. ing. The flexible layer 38 may be indirectly attached to the support tube 36. The support tube 36 according to the present embodiment has a length of 45.7.
cm, the wall thickness is 0.64 cm, and the outer diameter is 16 cm. However, it is possible to arbitrarily change the diameter of the support tube 36 within a range satisfying the above expression (1).

On the other hand, the thickness unevenness of the support tube 36 is as follows.
For example, it is preferable to keep it within 4%. Further, the flexible layer 38 has a sufficiently smooth surface to increase the degree of adhesion to the film F to be heated.
The surface roughness Ra is desirably smaller than 5 or 6.3 μm (particularly 2 or 3.2 μm).

However, in order to prevent the film F from sticking to the drum 14, the surface roughness Ra of a specific material such as a silicone rubber based
It is preferable that the thickness be 0.3 μm or more, and it is more desirable that the thickness be 2.3 μm or more. The surface roughness Ra is 0.3 or 2.
If it is 3 μm or more, a gas, particularly a volatile material, is easily discharged from between the flexible layer 38 and the film F.

The flexible layer 38 has a sufficient thermal conductivity of 0.3 W / m / K or more, so that the surface temperature of the outer peripheral surface of the drum 14 is maintained uniformly. In the present embodiment, the thermal conductivity of the flexible layer 38 is 0.4 W / m /
K or more.

Since the flexible layer 38 is used, the film 16 is more securely adhered to the drum 14 by the roller 16 without sacrificing wear resistance. The flexible layer 38 has a Shore A measured with a durometer.
The hardness is preferably 70 or less (especially 60 or less). In the present embodiment, the Shore A hardness measured by a durometer is 55 or less.

The specific material contains an additive for increasing thermal conductivity and silicon rubber.
Such a material has been found to be particularly useful for forming the compliant layer 38. Although the thermal conductivity of the silicone rubber contained in such a material is relatively small, the silicone rubber improves the pressing performance of the film F and the durability (abrasion resistance) to the film F.

On the other hand, in order to improve the processing capacity of development, it is necessary to increase the thermal conductivity. However, the above-mentioned additives in the material contribute to maintaining the thermal conductivity at a high level. It is. However, in the material forming the flexible layer 38, if the amount of the additive is increased, the pressing performance and durability of the silicone rubber are reduced.
It is necessary to balance the amounts of the additives and the silicone rubber within a certain range. The silicon rubber-containing material has an advantage that it is easily separated from the film F and is chemically inert.

The thickness of the flexible layer 38 is from 0.1 mm to 2 m
m, it is possible to use a thinner flexible layer 38. However, as the thickness becomes thinner, the function of the flexible layer 30 deteriorates, and there is a problem that its manufacture becomes difficult. Therefore, the thickness of the flexible layer 38 is
It is preferably 0.4 mm or more. Further, the variation in the thickness of the flexible layer 38 is preferably 20% or less (particularly 10% or less) on the surface region. In the present embodiment, it is suppressed to 5% or less.

In the present embodiment, a rotatable roller 16 is used as the guide member. However, other means, such as a small movable belt, can be used. In the present embodiment, an aluminum tube having an outer diameter of 1 to 2 or 2.18 cm and a wall thickness of 2 or 1 mm is used as the roller 16. Since the roller 16 is hollow, the suppression of heat conduction is assisted, whereby the influence of the heat of the roller 16 during development can be eliminated as much as possible. Of course, the roller 16 may be formed of a solid or filled cylindrical member instead of being hollow.

As described above, the urging force of the coil spring 28 is used to reduce the pressing force of the roller 16 so that the film F can be brought into close contact with the outer peripheral surface of the drum 14 and receive sufficient heat transfer. Care must be taken when choosing the value, as it is a decision. If the urging force of the coil spring 28 is too small, heat may be unevenly transmitted to the film F, so that image development may be incomplete. Accordingly, the urging force from the roller 16 per 1 cm width of the film F is preferably 3 g or more (particularly 5 g or more).
The roller 16 per 1 cm width of the film F
If the biasing force from the roller is smaller than 14 g, there is a possibility that the roller 16 does not wrap around the drum 14.
In particular, if the urging force is 7 g or less, the ball does not rotate. In such a case, when the film F rotates with the drum 14 and the roller 16 is in contact with the film F, the film F may be damaged by the roller 16. In such a case, it is preferable to provide a rotation driven unit at both ends of the roller 16 and to rotate the roller 16 by a gear drive, a friction drive, or the like via the rotation driven unit. On the other hand, the urging force of the coil spring 28 needs to be small enough that the roller 16 does not cause any indentation on the film F.

Therefore, the urging force from the roller 16 per 1 cm width of the film F is within a range of 200 g or less (in particular,
100 g or less). In the present embodiment, this force is between 5 to 7 g or 14 to 30 g per 1 cm in the width direction of the film F. In addition, a rotationally driven portion is provided at both ends of the roller 16, and is driven to rotate by a gear drive via the rotated driven portion, and the force is maintained within this range, thereby reducing indentations and reducing image quality. Harmony with non-uniformity reduction can be ensured.

In addition, when each coil spring 28 is used for the roller 16 provided around the cylindrical drum 14, the urging force of each coil spring 28 is applied in consideration of the gravity acting on each roller 16. It is good to decide. For example, the coil spring 28 that urges the roller 16 located above the drum 14 responds more to the weight of the roller 16 than the other coil spring 28 that urges the roller 16 at the bottom of the drum 14. By setting the urging force to be smaller than the above, substantially the same surface pressure can be applied to the entire film F.

The space between adjacent rollers 16 in addition to the force exerted by each roller 16 can be said to be important for forming a high quality image on the film F. When the film F is supplied to the drum 14,
The temperature is generally room temperature (approximately 20 ° C.). Therefore, in order to maximize the processing capacity of the developing unit 130,
The film F has a minimum heat development temperature (115 to 120 ° C. or higher in this embodiment,
(4 ° C.) from room temperature and must be rapidly heated.

However, the base material contained in a certain kind of film F, for example, a plate material based on a polyester film or a plate material based on another thermoplastic (material), There is a risk of thermal expansion and contraction (shrinkage). Therefore, in order to make the dimensional change uniform so that wrinkles (folds) are not formed, the film F
Must be uniformly heated as it alternates between being held flat and unconstrained. In order to realize this, the plurality of rollers 16 change the area (region) of the film F located between the adjacent rollers 16 when the film F is not restrained between the rollers 16 and the drum 14. Are provided at intervals so as to allow for

However, as described above, in order to conduct heat sufficiently and uniformly to uniformly develop the film F, the roller 16 is held for a predetermined time while the film F is urged against the drum 14. Must.
As a result, the spacing located between adjacent rollers 16 should be selected so that wrinkles are minimized and that the heating of film F occurs quickly and uniformly. is there.

Further, on the outer periphery of the cylindrical drum 14,
The rigidity of the film F itself causes its leading edge to extend tangentially between the rollers 16, but the rollers 16 must be sufficiently close together to suppress this. Such an arrangement is important for holding the film F between the roller 16 and the drum 14.

As shown in FIGS. 4 to 6, 15 or 29 rollers 16 are provided over 224 or 234 degrees in the rotation direction of the drum 14, and each space is 16 degrees from the center or 16 degrees from the center. 9 degrees apart. In this configuration, the diameter of the drum 14 is 8.9 cm to 20.3 c.
m or 15 cm to 30 cm, and when the roller 16 has a diameter of 2.18 cm or 1 to 2 cm, a film having a base thickness of 0.1 to 0.2 mm, for example, a base having a thickness of 0.1 to 0.2 mm. Effectively works on a film having a relatively hard film F, such as a polyester film having a thickness of 18 mm, or a film having a smaller hardness, such as a polyester film having a base thickness of 0.10 mm. It is something to do.

The heater 32 is mounted on the inner circumference of the drum 14 to heat the outer circumference of the drum 14. As the heater 32 for heating the drum 14, an etched resistive foil heater can be used.

The heater control electronic device 34 includes the drum 1
4 together with the heater 3 according to the sensed temperature information.
2 can be adjusted. The outer surface temperature of the drum 14 can be adjusted by the heater 32 and the control electronic device 34 so that the temperature becomes suitable for the development of the specific film F. In the present embodiment, the drum 14 can be heated to a temperature of 60C to 160C by the heater 32 and the control electronic device 34.

Here, the heater 32 and the control electronic device 34
Accordingly, it is preferable to maintain the temperature in the width direction of the drum 14 within 2.0 ° C. (particularly, within 1.0 ° C.). In the present embodiment, the temperature is maintained within 0.5 ° C.

The undeveloped film F supplied at a predetermined timing from the supply roller pair 143 is supplied to the nip 52 formed by the heating member 14 and the most upstream roller 16 in the developing section 130. . Next, the film F rotates together with the drum 14. At this time, the film F is urged against the drum 14 by the roller 16 and is brought into contact with the outer periphery of the drum 14 for a predetermined time during the rotation.

Since the drum 14 can move at substantially the same speed as the film F to be developed, the possibility that the surface of the film F is scratched (damaged or damaged) is reduced, thereby ensuring a high quality image. can do. After being transported between the drum 14 and the roller 16, the developed film F is guided by a nip 50 formed by the roller 16 and the drum 14 located at the most downstream side, and
0 from the drum 14.

The developing section 130 is configured to develop various films F such as a 0.178 mm polyester base layer coated with a photosensitive heat-developable emulsion containing an infrared-sensitive silver halide as described in Examples. be able to. The drum 14 is maintained at a temperature of 115 ° C. to 138 ° C., for example, at 124 ° C.
For about 15 seconds, which is a predetermined time, at a rotational speed such that it is held in contact with its outer peripheral surface. At the predetermined time and the temperature, the film F can be raised to a temperature of 124 ° C.

The thickness and the thermal conductivity of the flexible layer 38 are selected so that a plurality of films F can be continuously processed efficiently. Of course, these parameters can be varied according to the specific characteristics (properties) of the film F to be developed and according to the desired throughput. For example, the temperature and rotation speed of the drum 14 can be varied, as well as the predetermined time that the film F contacts the drum 14, to develop a film F having different development requirements.

In addition, similarly to the drum 14, the rollers 16
A flexible layer can also be provided. Also, instead of providing the roller 16 with a flexible layer, the drum 14 may be provided with a less flexible outer layer. Further, the drum 14 may be a rotating roller, and a cylindrical drum or a supported flat endless belt may be configured to function as the roller 16.

The surface of the film F on the side having the photosensitive heat-developable emulsion layer is preferably in contact with the outer peripheral surface of the drum 14 (the flexible layer 38 in this embodiment). However, the opposite surface of the film F can also be in contact with the outer peripheral surface of the drum 14 (the flexible layer 38 in the present embodiment). In addition, it is desirable that the thermally developed emulsion layer of the film F be in contact with the outer peripheral surface of the drum 14.
However, the opposite side of the film F also
It can be in contact with the drum 14. Subsequent to the thermal development of the image, the film F is transferred to the drum 14 of the developing unit 130.
Of the cooling device 150A, and then guided in the direction of the cooling device 150A. As a result, the risk of scratching (damage) is reduced, and the risk of surface wear is also reduced. The developed film F is gradually cooled in the cooling device at first, and then rapidly cooled.

FIG. 7 is a cross-sectional view of the film F shown in the example, schematically showing a chemical reaction in the film F during exposure. FIG. 8 is a cross-sectional view similar to FIG. 7, 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) made of PET, and a protective layer made of cellulose butyrate is further formed thereon. The photosensitive layer contains silver behenate (Beh. Ag), a reducing agent and a toning agent.

When the film F is irradiated with the laser beam L from the exposure unit 120 during the exposure, as shown in FIG.
Silver halide grains are exposed to the area irradiated with the laser beam L, and a latent image is formed. Meanwhile, the film F is heated,
When the temperature is equal to or higher than the minimum thermal development temperature, as shown in FIG. 8, silver ions (Ag +) are released from silver behenate, and the behenic acid releasing silver ions forms a complex with the toning agent. Thereafter, silver ions are diffused, and the reducing agent acts with the exposed silver halide grains as nuclei to form a silver image by a chemical reaction. As described above, 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 less,
Thermal development is performed at a temperature not lower than the minimum development temperature of not less than ° C.

One problem in the image formation based on the thermal development is that if the sheet-like thermal development material (film F) is not uniformly heated, the thermal development material will have a temperature variation, which will result in the formation. That is, the density of the image may vary. Therefore, the drum 14
Needs to be heated to a uniform temperature of, for example, about 120 ° C. over the entire circumference.

On the other hand, the sheet-like heat developing material (film F) is maintained at room temperature before being supplied to the drum 14, so that heat development is not performed carelessly. I have. However, the temperature of the heat developing material before being heated by the drum 14 is usually lower by about 90 to 100 ° C. than the temperature of the outer peripheral surface of the drum 14, and the heat developing material is supplied to the drum 14 to cool the drum surface. As a result, the outer peripheral surface of the drum 14 with which the heat developing material comes into contact is cooled, and the temperature in that region is reduced.

Here, when the size of the heat developing material supplied to the drum 14 is constant and the position held on the outer peripheral surface of the drum 14 is also constant, the leading end and the rear end of the heat developing material Except for the above, the outer peripheral surface of the drum 14 is uniformly cooled, so that there is no particular variation in the density of the image located at the center. However, there are cases where it is desired to suppress variations in the density of the images located near the front end and the rear end of the heat developing material and to ensure high image quality. Note that the size used here refers to the length of the heat development material in the rotation direction of the drum 14.

In addition, there is a case where it is desired to supply heat developing materials of different sizes to the drum 14 in any order. In such a case, at the same holding position on the outer peripheral surface of the drum 14,
For example, when a plurality of small-sized thermal developing materials are supplied, the outer peripheral surface of the drum 14 in contact with the thermal developing material is cooled, and a region where the surface temperature is partially reduced is generated. Thereafter, when a large-size heat-developable material is supplied over an area where the temperature has decreased and an area where the temperature has not decreased, a large change in the image density occurs at the boundary. Becomes Such density changes may degrade the quality of the image.

On the other hand, when the temperature of the outer peripheral surface of the drum 14 is partially lowered, the heated heat developing material is peeled off from the drum 14 and then the temperature of the outer peripheral surface of the drum 14 becomes uniform. It is also conceivable to wait until the temperature becomes and then supply a new heat developing material. However, it takes a relatively long time until the temperature of the outer peripheral surface of the drum 14 becomes uniform, which causes a new problem that the processing time is delayed.

FIG. 9 is a diagram for explaining such a problem. FIG. 9A shows the drum 14 and the films F1, F
2 is an expanded view, in which the vertical axis indicates the position of the drum 14 in the width direction, and the horizontal axis indicates the position of the drum 14 in the rotation direction. FIG. 9B is a diagram illustrating a temperature distribution on the outer peripheral surface of the drum 14, where the vertical axis indicates the temperature and the horizontal axis indicates the position of the drum 14 in the rotation direction. 9 (c) and 9 (d)
Is a diagram showing the density distribution of the image of the film F, wherein the vertical axis represents the density and the horizontal axis represents the position of the drum 14 in the rotation direction. Note that, as shown in FIG. 9, the sizes of the films F1 and F2 are shorter than the circumference of the drum 14.

Here, it is assumed that two or more small-sized films F1 are heated in the same area P1 or P2 of the drum 14. In such a case, the areas P1 and P2 on the outer peripheral surface of the drum 14 are cooled, and as shown in FIG. 9B, lower by about 3 degrees than the other areas, depending on conditions such as the temperature of the film. Might be. From such a state, when the film F1 of the same small size is heated in the same region P1 or P2 of the drum 14, the temperature distribution follows the temperature distribution on the outer peripheral surface of the drum 14 shown in FIG. 9B. Becomes

According to the heat development of the present embodiment, the higher the heating temperature, the higher the density of the image tends to be. Accordingly, as shown in FIG. 9C, the density of the image on the film F1 increases at the positions P1 and P2, that is, near the leading end and the trailing end of the film F1, and decreases at other places. When a main image is not formed near the leading end and the trailing end of the film F1, it is unlikely that the density of the image becomes a problem, but it may be near the leading end and the trailing end. However, there are cases where it is desired to suppress variations in image density.

Further, when two or more small-sized films F1 are heated in the same areas P1 to P2 of the drum 14, and then a large-sized film F2 is heated in the areas P1 to P3 of the drum 14, Its temperature distribution includes
As shown in FIG. 9B, a relatively large change portion (near the position P2) occurs in the central region of the film F2.

When the film F2 is heated with the portion where the temperature distribution changes, the density of the image greatly changes at the center of the film F2 as shown in FIG. 9D. It is difficult to secure a high quality image. In particular, since there is a high possibility that the main image of the observer's attention is located at the center of the film F2, the observer may feel uncomfortable even with a slight change in density. Therefore, in the present embodiment, variations in image density are reduced in the following manner. FIG. 10 is a diagram for explaining an aspect of reducing the density variation of an image. FIG. 10 (a)
Is a development view showing a position for sequentially holding a plurality of films F with respect to the drum 14, the vertical axis shows the supply order of the films F, and the horizontal axis shows the position in the rotation direction of the drum 14. . FIG. 10B is a diagram illustrating a temperature distribution on the outer peripheral surface of the drum 14, where the vertical axis indicates the temperature and the horizontal axis indicates the position of the drum 14 in the rotation direction. FIG. 10 (c) and FIG.
4D is a diagram illustrating the density distribution of the image on the film F, where the vertical axis indicates the density and the horizontal axis indicates the position of the drum 14 in the rotation direction.

That is, when the film F is continuously heated, if the film F is always held at the same position,
Since the temperature at the position on the outer peripheral surface of the drum 14 decreases, if the drum 14 is held at a different position,
Since the outer peripheral surface of the drum 14 is cooled substantially uniformly, the temperature distribution can be maintained substantially uniform.

More specifically, the time TR during which the drum 14 makes one rotation and the time interval T during which the leading end of the film F is supplied to the drum 14 are given by the following equation (2) for an arbitrary natural number N: To satisfy.

T ≠ N × TR (2) That is, the position at which the leading end of the film F is held at least between the continuous films F by the supply roller pair 143 is shifted in the rotation direction of the drum 14. It is sufficient that the film F is supplied to the drum 14 at the timing so that the film F is not continuously held at the same position on the drum 14.

More specifically, as shown in FIG. 10A, the film F to be heated first is held from the position P1, and the film F to be heated next is moved to the position P2 shifted from the position P1. , The degree of cooling of the outer peripheral surface of the drum 14 becomes uniform. Therefore, the temperature distribution on the outer peripheral surface of the drum 14 becomes uniform as shown in FIG. Therefore, the small size film F
Irrespective of the film F2 having a size of 1 or a large size, it is possible to uniformly heat the entire surface of the film F2, thereby making the density distribution of the image substantially constant (FIGS. 10C and 10D). )reference).

Further, in this embodiment, the drum 1
The time TR during which the film 4 makes one rotation and the time interval T during which the leading end of the film F is supplied to the drum 14 satisfy the following equation (3) for an arbitrary natural number N.

(N−1 / 20) × TR ≧ T or (N + 1/20) × TR ≦ T (3) As a result, the supply position of the continuously supplied films on the drum 14 becomes 360/20 = By displacing by 18 degrees or more, the temperature distribution on the outer peripheral surface of the drum 14 can be efficiently made uniform, whereby temperature unevenness in the rotation direction on the drum 14 is less likely to occur, and density unevenness occurs in the image. Can be suppressed more effectively.

The time TR during which the drum 14 makes one revolution,
Time interval T during which the leading end of the film F is supplied to the drum 14
And (N−1 / 100) × TR ≧ T or (N + 1/100) × TR ≦ T (3 ′) (3 ′) with respect to an arbitrary natural number N. It has been found that the occurrence of temperature unevenness on the outer peripheral surface of can be suppressed.

Thus, the temperature distribution on the outer peripheral surface of the drum 14 can be efficiently made uniform by setting the amount of deviation between the continuously supplied films to 360/100 = 3.6 degrees or more. As a result, temperature unevenness in the rotation direction on the drum 14 is less likely to occur, and the occurrence of density unevenness in the image can be more effectively suppressed.

Further, the time required for the drum 14 to make one rotation is represented by TR
If a time interval between the time when the leading edge of the n-th supplied film is supplied to the drum and the time when the leading edge of the n + 1-th supplied film is supplied to the drum is T (n), an arbitrary natural number For N, the following (5) (6)
It is desirable to adjust the supply timing such that the abundance of natural numbers n that satisfies all the expressions (7) is 50% or more. As a result, the temperature distribution on the outer peripheral surface of the drum 14 can be efficiently made uniform, thereby making it difficult for the temperature unevenness in the rotation direction on the drum 14 to occur, and to reduce the occurrence of density unevenness in the image. It can be suppressed effectively.

(N−1 / 20) × TR ≧ T (n) or (N + 1/20) × TR ≦ T (n) (5) and (N−1 / 20) × TR ≧ T (n + 1) or ( (N + 1/20) × TR ≦ T (n + 1) (6) and (N−1 / 20) × TR ≧ T (n) + T (n + 1) or (N + 1/20) × TR ≦ T (n) + T (n + 1) (7) Explaining this relationship, when n = 1, the film F
The time interval T1 between 1 and the subsequent film F2 is:
Formula (5) is satisfied, the time interval T2 between the film F2 and the subsequent film F3 is satisfied with the formula (6), and the time interval T1 + T2 is satisfied with the formula (7). However, when n = 2, the film F3
And the subsequent time interval T3 between the film F4 and
When the formula (6) is not satisfied, the above-mentioned existence rate is 50%. As described above, the above-described existence rate can be statistically obtained from the supply timing.

Incidentally, the existence rate of the natural number n satisfying the above expression is determined by recording the time when the leading ends of these films F are supplied to the drum 14 when developing the M films F, and From the time TR for one rotation, a percentage of the natural number n that satisfies the above equation can be calculated, but the calculation method is not limited to this. Also, a natural number n satisfying the above equation
From the viewpoint of more effective suppression of density unevenness,
It is preferable to make it 70% or more (especially 90% or more).

The time required for the drum 14 to make one rotation is represented by TR
If a time interval between the time when the leading edge of the n-th supplied film is supplied to the drum and the time when the leading edge of the n + 1-th supplied film is supplied to the drum is T (n), an arbitrary natural number N, the following (15) (1)
6) The natural number n that satisfies all the expressions (17) is 90%.
As described above, it is desirable to adjust the supply timing. As a result, the temperature distribution on the outer peripheral surface of the drum 14 can be efficiently made uniform, thereby making it difficult for the temperature unevenness in the rotation direction on the drum 14 to occur, and to reduce the occurrence of density unevenness in the image. It can be suppressed effectively.

(N−1 / 100) × TR ≧ T (n) or (N + 1/100) × TR ≦ T (n) (15) and (N−1 / 100) × TR ≧ T (n + 1) or ( (N + 1/100) × TR ≦ T (n + 1) (16) and (N−1 / 100) × TR ≧ T (n) + T (n + 1) or (N + 1/100) × TR ≦ T (n) + T (n + 1) (17) Explaining this relationship, when n = 1, the film F
The time interval T1 between 1 and the subsequent film F2 is:
Formula (5) is satisfied, the time interval T2 between the film F2 and the subsequent film F3 is satisfied with the formula (6), and the time interval T1 + T2 is satisfied with the formula (7). However, when n = 2, the film F3
And the subsequent time interval T3 between the film F4 and
When the expression (6) is not satisfied, the above-mentioned existence rate is 90%. As described above, the above-described existence rate can be statistically obtained from the supply timing.

Further, in this embodiment, since the temperature distribution on the outer peripheral surface of the drum 14 can be made substantially constant as described above, not only the length of the drum 14 in the rotational direction is the same but also the size of the drum 14 is different. Can be heated in any order. More specifically, even after heating a plurality of small-sized films, it is possible to suppress the occurrence of temperature unevenness before and after the rotation direction at the position on the drum 14 where the rear end of the film is located. Therefore, thereafter, for example, as shown by a dashed line x in FIG. 10A, even if a film of a larger size is heated, it is possible to prevent image density unevenness from occurring in any part. Image quality can be improved.

Further, in this embodiment, the drum 1
No. 4, the diameter D of the outer peripheral surface holding the film F and the drum 1
4. The length L in the rotation direction of the film having the smallest size in the rotation direction
min satisfies the following equation (8).

Lmin <π × D (π is the pi) (8) That is, since the diameter of the drum is made larger than a predetermined value with respect to the minimum length of the film, the processing capacity of development can be increased. Will occur if the drum diameter is reduced,
It is possible to prevent the film from curling.

In this embodiment, the drum 14
The diameter D of the outer peripheral surface holding the film and the length Lma of the film in the rotational direction of the drum 14 having the largest size in the rotational direction
x satisfies the following equation (9).

Π × D <2 × Lmax (π is a circular constant) (9) With such a configuration, the size of the drum 14 can be small, and the configuration of the heat developing device 100 can be made compact. it can.

FIG. 11 is a diagram showing another embodiment of the present invention. First, in the heat developing device schematically shown in FIG. 11C, the radius of the outer circumference of the drum 14 rotating at a constant speed V (mm / sec) is set to R (mm),
When the circumferential length of the drum 14 of the film F wound around the outer peripheral surface of the drum 14 is L (mm) and the supply interval T of the film F is T (sec) = 2πR / V,
The front end of the film F is always supplied to the same position on the outer periphery of the drum 14.

FIG. 11A shows such a state. First, when the first film F is supplied to the drum 14 when the initial temperature of the outer peripheral surface of the drum 14 is set to t ° C., as shown by a solid line A in FIG. Since the film is cooled by the film F, the temperature becomes lower than the initial temperature t ° C. over the range from the point p (the point where the leading end of the film F is supplied) to the circumferential length L. The temperature of the area not cooled by the film F is increased by the heating of the built-in heater.

Subsequently, the second film F is placed on the drum 14.
Is supplied with the tip part coincident with the same point p, FIG.
As shown by the dotted line B in FIG. 7A, since heat is conducted from the periphery to the area cooled by the film F on the outer peripheral surface of the drum 14, the area exceeding the circumferential length L from just before the point p. As a result, the range of the temperature lower than the initial temperature t ° C. slightly widens, and the maximum temperature difference further increases between the range of the circumferential length L from the point p and the other range. This tendency becomes more remarkable as the third and fourth films F are continuously supplied.

On the other hand, the entire outer peripheral surface of the drum 14 can be heated by the built-in heater, but it is difficult to heat only a part of the outer peripheral surface of the drum 14. Therefore, as shown in FIG. 11A, the outer peripheral surface of the drum 14 is constantly cooled over a range of the circumferential length L from the specific point p in accordance with the film F which is repeatedly supplied. When the surface temperature difference increases, it becomes difficult to suppress the occurrence of remarkable temperature unevenness on the outer peripheral surface of the drum 14 only by heating control of the built-in heater. Remarkable temperature unevenness on the outer peripheral surface causes unevenness in the density of an image to be thermally developed, thereby deteriorating image quality.

Therefore, in the present embodiment, such a problem is solved as follows. Specifically, the outer radius R of the drum, the rotation speed V of the drum, and the film F
Insertion (supply) interval T and the length L in the rotational direction of the heat developing material
If the length of the film F is shorter than the circumference of the drum 14 (L ≦ 2πR), T = (2πR ± (2πR-L) / P) / V (10) (0 <P ≦ 10)
The film F is supplied to the drum 14.

FIG. 11B shows the temperature distribution on the outer peripheral surface in the rotation direction of the drum 14 when the film F is supplied at the supply timing. First, assuming that the initial temperature of the outer peripheral surface is t ° C., when the first film F is supplied to the drum 14, as shown by a solid line A in FIG. Figure 11
The distribution becomes substantially the same as the distribution shown in FIG.

However, the second film F is supplied to the drum 14 at the supply timing shown by the equation (10).
When the supply is performed with the tip shifted from the point p, as shown by the dotted line B in FIG. 11B, the temperature range lower than the initial temperature t ° C. is separated from the point p by the length m in the rotation direction. Starts from position.

Therefore, for example, when n = 3, the film F is supplied three times shifted in the rotational direction, and the position of the tip of the fourth film F is set to the position of the first supplied film F. The position of the rear end (point p) coincides with the position of the rear end, whereby the outer peripheral surface of the drum 14 can be uniformly cooled by the film F. If the outer peripheral surface of the drum 14 is uniformly cooled, it is possible to uniformly heat the outer peripheral surface of the drum 14 using the built-in heater. As a result, the temperature of the outer peripheral surface of the drum 14 can be maintained uniform. This makes it possible to suppress density unevenness of an image to be thermally developed.

According to the experimental results of the present inventors, the drum 1
4, the ratio of the shift amount (2πR-VT) to the difference between the circumference 2πR of the film F and the length L of the film F, that is, (2πR-V
T) / (2πR-L) is effective when ± 10% or more,
If it is ± 20% or more, the effect becomes more remarkable, and further ±±
It has been found that the effect becomes more conspicuous if it is 50% or more.

When the length of the film F is longer than the circumference of the drum 14 (L> 2πR), the real number P satisfying T = (2πR ± (L−2πR) / P) / V (11) The film F may be supplied to the drum 14 so that (0 <P ≦ 20) exists.

If the film F is supplied to the drum 14 at the supply timing according to the equation (11), even if the length of the film F is longer than the circumference of the drum 14,
Can be made uniform, thereby making it possible to suppress density unevenness of a thermally developed image.

And, according to the experimental results of the present inventors,
The ratio of the shift amount (2πR-VT) to the difference between the length L of the film F and the circumferential length 2πR of the drum 14, that is, (2
When πR−VT) / (L−2πR) is ± 5% or more, the effect is significant. When ± 10% or more, the effect is more significant.
It has been found that the effect becomes more remarkable when the value is ± 50% or more.

In the example shown in FIG. 11, the case where the films F having the same length L are supplied has been described.
Is supplied while shifting, the outer peripheral surface temperature in the rotation direction of the drum 14 can be made uniform. Further, the film F may be supplied to the front side in the rotation direction from the point p to which the leading end of the preceding film F was supplied, as long as Expression (10) or Expression (11) is satisfied.

Next, a mechanism for determining a supply timing for supplying the film F to the drum 14 according to the present embodiment will be described. In FIG. 4, a motor 1 is provided on one roller of the supply roller pair 143 located below the drum 14.
51 are connected. Further, the motor 151 controls the film F sent from the exposure unit 120 at random timing.
Is supplied to the drum 14 as it is.

However, by appropriately driving under the control of the control device 150, all of the expressions (5) to (7) are satisfied, or the expression (10) or the expression (11) is satisfied. The supply timing can also be adjusted. The supply roller pair 143, the motor 151, and the control device 150 constitute a supply unit. In this case, since the rotation of the supply roller pair 143 has stopped, the film F transported from the lower transport unit 142 (FIG. 1) temporarily stops before the supply roller pair 143. Here, the control device 150 detects the phase of the drum 14 by a sensor (not shown), and outputs a drive signal at appropriate timing to the motor 15.
Send to 1. The rotation of the motor 151 operates the supply roller pair 143 to supply the film F to the drum 14. Note that the supply roller pair 143 may be rotating depending on the timing at which the film F is transported. Further, since the film F is held at an arbitrary position by the outer peripheral surface of the drum 14 and the roller 16, it is not necessary to provide a film holding mechanism on the drum 14, but an appropriate chucking mechanism may be provided if necessary. May be provided.

As described above, the control device 150
Since the supply timing of the film F to the film F is adjusted, for example, as shown in FIG. 10A or FIG. 11B, the holding position of the film F is appropriately shifted.
Variations in the density of the image to be developed can be minimized.

The light-sensitive silver halide used in the heat-developable material is typically 0.75 to 25 with respect to the organic silver salt.
mol% can be used, preferably
It can be used in the range of 2 to 20 mol%.

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

The organic silver salt is any organic material containing a reduction source of on in silver. Silver salts of organic acids, especially long-chain fatty acids (10 to 30 carbon atoms, preferably 15 to 28 carbon atoms) are preferred. It is preferred that the ligand is an organic or inorganic silver salt complex having a certain stability as a whole between 4.0 and 10.0. It is preferable that the amount is about 5 to 30% of the weight of the image forming layer.

The organic silver salt which can be used in the heat developing material is a silver salt which is relatively stable to light, and is composed of an exposed photocatalyst (for example, silver halide for photography) and a reducing agent. Is a silver salt that forms a silver image when heated to a temperature of 115 to 120 ° C 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 silver salt of an aliphatic carboxylic acid include silver behenate, silver stearate and the like. Silver salts with halogen atoms or hydroxyl in aliphatic carboxylic acids can also be used effectively. Silver salts of compounds having a mercapto or thione group and derivatives thereof can also be used. Further, 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 capable of reducing 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 is used in the image forming layer.
It should be present at 10% by weight. In a multi-layer configuration,
If the reducing agent is added to a phase other than the emulsion layer, a slightly higher proportion, about 2 to 15% by weight, is more desirable.

[0131]

Hereinafter, the film F will be described.

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

The thermally developed emulsion was homogenized with 455 g of the above-mentioned 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 60 g of 2-butanone were cooled to 12.8 ° C. while stirring. Pyridinium hydrobromide perbromide (0.92 g) was added and stirred for 2 hours.

3.25 ml of a calcium bromide solution (CaBr (1 g) and 10 ml of methanol) were added, followed by stirring for 30 minutes. Further, polyvinyl butyral (158 g; B-79 manufactured by Monsanto) was added, and 20
Stirred for minutes. The temperature was raised to 21.1 ° C. and the following was added with stirring over 15 minutes.

3.42 g of 2- (tribromomethylsulfone) quinoline, 28.1 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane, 5-methylmercapto 41.1 g of a solution containing 0.545 g of benzimidazole, 6.12 g of 2- (4-chlorobenzoyl) benzoic acid 0.14 g of S-1 (sensitizing agent) 34.3 g of methanol Isocyanate (Desmoder N3300, Mobe 2.14 g Tetrachlorophthalic anhydride 0.97 g Phthalazine 2.88 g The dye S-1 has the following structure.

[0136]

Embedded image

An active protective topcoat solution was prepared using the following components: 2-butanone 80.0 g methanol 10.7 g cellulose acetate butyrate (CAB-171-155, manufactured by Eastman Chemicals) 8.0 g 4-methylphthalate Acid 0.52 g MRA-1, Mottle reducing agent, N-ethyl perfluorooctanesulfonylamide Ethyl methacrylate / hydroxyethyl methacrylate / acrylic acid weight ratio 70:20:10 Tertiary polymer 0.80 g This thermally developed emulsion and topcoat And 0.18 at the same time
mm blue polyester film base. The knife coater was set up with two bars or knives coating simultaneously at a distance of 15.2 cm. The silver trip layer and the top coat were multi-layer coated by pouring the silver emulsion on the film prior to the rear knife and the top coat on the film prior to the front bar.

The 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. The knife was adjusted to provide a dry coat weight of 23 grams per square meter for the silver layer and a dry coat weight of 2.4 grams per square meter for the top coat.

(Experiment) Experiment 1 In the thermal developing apparatus described above, various compressed image data having three rows of uniform density regions at both ends in the width direction and at the center are exposed and supplied at a timing at which they can be restored. At a random timing, and at a timing when one film F is supplied at an average time of two rotations of the drum,
Using a 10 inch film F, 100 films were thermally developed. The abundance of natural numbers n satisfying the expressions (5) to (7) was about 90%. Equations (15) to (1)
The existence ratio of the natural number n satisfying 7) was about 98%.

Experiment 2 The image data of Experiment 1 was converted to substantially the same image data by the above-mentioned thermal developing apparatus, so that the time interval of the supplied 7 × 10-inch film F was substantially equal to the time corresponding to two rotations of the drum. Using the above-mentioned film F, 100 films were heat-developed under the same control. Equation (5)-
The existence ratio of the natural number n satisfying (7) was about 60%. The abundance of natural numbers n satisfying the expressions (15) to (17) was about 92%.

Experiment 3 The image data of Experiment 1 was converted to substantially the same image data in the above-described thermal developing apparatus, so that the time interval of the supplied 7 × 10-inch film F was completely equivalent to the time corresponding to two rotations of the drum. Using the above-mentioned film F, 100 films were heat-developed under the same control. Equation (5)-
The existence ratio of the natural number n satisfying (7) was 0%. Further, the existence ratio of the natural number n satisfying the expressions (15) to (17) was 0%.

Experimental Results Experiment 1: No density unevenness was found, and good images were obtained.

Experiment 2: There was a film having some density unevenness, but a substantially good image was obtained at a level that was hardly recognized.

Experiment 3: On the second to fourth sheets, the density was slightly uneven at the edges, but the level was hardly recognized. On the fifth and subsequent sheets, density unevenness was found at the edges, and some were conspicuous. After the above experiment, a 14 × 17 inch film F was thermally developed to evaluate density unevenness.

Experiment 1: No density unevenness was found, and a good image was obtained.

Experiment 2: A substantially good image was obtained at a level where there was a density unevenness but no problem.

Experiment 3: Density unevenness was conspicuous in the center of the screen, making it impractical.

[0148]

According to the present invention, it is possible to suppress the occurrence of density unevenness in the heat developing material.

[Brief description of the drawings]

FIG. 1 is a front view of a heat developing device according to an embodiment of the present invention.

FIG. 2 is a left side view of the heat developing device according to the embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a configuration of an exposure unit 120.

FIG. 4 is a diagram illustrating a configuration of a developing unit that heats a film, and is a perspective view of the developing unit.

5 is a cross-sectional view of the configuration of FIG. 4 taken along line IV-IV and viewed in the direction of the arrow.

FIG. 6 is a front view of the configuration of FIG. 4;

FIG. 7 is a cross-sectional view of the film F, schematically showing a chemical reaction in the film F during exposure.

FIG. 8 is a cross-sectional view similar to FIG. 7, schematically showing a chemical reaction in the film F during heating.

FIG. 9 is a diagram for explaining a problem of the related art.

FIG. 10 is a diagram for explaining a mode of reducing density variations of an image according to the present embodiment.

FIG. 11A is a diagram showing a temperature distribution on the outer peripheral surface in the rotation direction of the drum 14 when the film F is supplied to the same position with respect to the drum 14;
(B) shows the film F with its position shifted with respect to the drum 14.
FIG. 11C is a diagram showing a temperature distribution of the outer peripheral surface in the rotation direction of the drum 14 when the heat is supplied, and FIG. 11C is a diagram schematically showing a part of the heat developing device of the present embodiment.

[Explanation of symbols]

 14 Drum 16 Roller 18 Frame 21 Guide bracket 28 Coil spring 30 Reinforcement member 32 Heater 34 Control electronic device 38 Flexible layer 100 Heat developing device 110 Storage unit 120 Exposure unit 130 Developing unit 143 Supply roller pair 150A Cooling unit 150 Control unit 151 Motor F film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yosuke Tateishi 591-7 Kamihirose, Sayama City, Saitama Prefecture Konica Corporation (72) Inventor Yasuaki Tamakoshi 591-7, Kamihirose, Sayama City, Saitama Prefecture Konica Corporation F-term ( Reference) 2H112 AA03 AA11 BA08 BA15 BB03 BC02 BC10 BC17 BC26 BC40 BC41

Claims (17)

[Claims] 1. A supply unit for supplying a sheet-like heat development material, and the heat development material supplied by the supply unit is heated while being held on an outer peripheral surface, and is rotated at a substantially constant rotation speed. In the heat developing apparatus having a drum, the supply unit is configured to rotate a position of the heat development material at least between the heat development materials that are continuously heated by the drum, at which a tip of the heat development material is held. A heat developing device that supplies the heat developing material to the drum at a timing such that the heat developing material shifts in a direction. 2. A supply unit for supplying a sheet-like heat development material, and the heat development material supplied by the supply unit is heated while being held on an outer peripheral surface, and is rotated at a substantially constant rotation speed. In a heat developing apparatus having a drum, the time TR during which the drum makes one rotation and the time interval T during which the leading end of the heat developing material is supplied to the drum satisfy the following formula for an arbitrary natural number N: Characteristic thermal developing device. T ≠ N × TR 3. A method according to claim 1, wherein a time period for the drum to make one rotation and a time interval for supplying the leading end of the thermal developing material to the drum satisfy the following expression for an arbitrary natural number N. The thermal developing device according to claim 2, wherein (N-1 / 20) × TR ≧ T or (N + 1/20) × T
R ≦ T 4. A time TR in which the drum makes one rotation and a time interval T in which the leading end of the heat developing material is supplied to the drum satisfy the following formula for an arbitrary natural number N. The thermal developing device according to claim 2, wherein (N-1 / 100) × TR ≧ T or (N + 1/100)
× TR ≦ T 5. A supply unit for supplying a sheet-like heat development material, and the heat development material supplied by the supply unit is heated while being held on an outer peripheral surface, and is rotated at a substantially constant rotation speed. In a thermal developing apparatus having a drum, the time for one rotation of the drum is TR, and the time at which the leading edge of the n-th supplied thermal developing material is supplied to the drum and the leading edge of the n + 1-th thermal developing material are determined. Assuming that the time interval from the time supplied to the drum is T (n), for any natural number N, the existence rate of natural number n that satisfies all of the following expressions is 50:
%. (N−1 / 2) × TR ≧ T (n) or (N +＋ １)
0) × TR ≦ T (n) and (N−1 / 20) × TR ≧ T (n + 1) or (N + 1/20) × TR ≦ T (n + 1) and (N−1 / 20) × TR ≧ T ( n) + T (n + 1) or (N + 1/20) × TR ≦ T (n) + T (n + 1) 6. A supply unit for supplying a sheet-like heat development material, and the heat development material supplied by the supply unit is heated while being held on an outer peripheral surface, and is rotated at a substantially constant rotation speed. In a thermal developing apparatus having a drum, the time for one rotation of the drum is TR, and the time at which the leading edge of the n-th supplied thermal developing material is supplied to the drum and the leading edge of the n + 1-th thermal developing material are determined. Assuming that the time interval from the time supplied to the drum is T (n), for any natural number N, the existence rate of the natural number n that satisfies all of the following expressions is 90:
%. (N−1 / 100) × TR ≧ T (n) or (N + 1/1)
00) × TR ≦ T (n) and (N−1 / 100) × TR ≧ T (n + 1) or (N + 1/100) × TR ≦ T (n + 1) and (N−1 / 100) × TR ≧ T ( n) + T (n + 1) or (N + 1/100) × TR ≦ T (n) + T (n + 1) 7. The heat developing apparatus according to claim 1, wherein a plurality of sizes of heat developing materials having different lengths along the rotation direction of the drum can be developed. 8. A diameter D of the outer peripheral surface of the drum that holds the heat development material, and a length Lmi in the rotation direction of the heat development material having a minimum length along the rotation direction of the drum.
n satisfies the following expression:
8. The heat developing device according to any one of items 7 to 7. Lmin <π × D (π is pi) 9. A supply unit for supplying a sheet-like heat development material, and the heat development material supplied by the supply unit is heated while being held on an outer peripheral surface, and is rotated at a substantially constant rotation speed. A heat developing device having a plurality of sizes having different lengths in a drum rotation direction; a diameter D of the outer peripheral surface of the drum that holds the heat developing material; and a rotation of the drum. A heat developing material having a minimum length along the direction in a rotational direction, Lmin, which satisfies the following expression: Lmin
<Π × D (π is pi) 10. A diameter D of the outer peripheral surface of the drum, which holds the heat development material, and a length Lmax of the heat development material, which has a maximum length along the rotation direction of the drum, in the rotation direction, The heat developing device according to claim 1, wherein the following expression is satisfied. π × D <2 × Lmax (π is pi) 11. The heat-developable material contains photosensitive silver halide grains, an organic silver salt, and a silver ion reducing agent.
The thermal development is substantially not carried out at a temperature of 0 ° C. or less, and the thermal development is carried out at a temperature of 80 ° C. or more and a minimum development temperature or more. Heat development device. 12. The heat developing material according to claim 11, wherein the drum heats the heat developing material at a developing temperature equal to or higher than the minimum developing temperature for a predetermined heat developing time. 3. The thermal developing device according to claim 1. 13. The heat developing apparatus according to claim 1, further comprising a rotatable roller biased by said drum. 14. The thermal developing apparatus according to claim 1, further comprising an elastic layer having a thickness of 0.1 mm or more on the surface of the drum. 15. The elastic layer has a thickness of 2 mm or less, a thermal conductivity of 0.4 (W / m / K) or more, and a metal supporting the elastic layer directly or indirectly on the drum. 14. The heat developing device according to claim 13, further comprising a support member made of a material. 16. A step of rotating a drum having an outer peripheral surface heated at a substantially constant rotational speed; a step of supplying a first heat developing material to an outer peripheral surface of the drum; Holding the heat-developable material on the outer peripheral surface of the drum for a predetermined time; releasing the first heat-developable material from the outer periphery of the drum; and a second heat source image material following the first heat source image material. While shifting the tip of the heat development material in the rotation direction of the drum with respect to the outer peripheral position of the drum holding the tip of the first heat development material, the second heat development material is Supplying to the outer peripheral surface. 17. A supply unit for supplying a sheet-like heat development material, and the heat development material supplied by the supply unit is heated while being held on an outer peripheral surface, and is rotated at a substantially constant rotation speed. In the heat developing apparatus having the drum, the following relationship is established among the outer radius R of the drum, the rotation speed V of the drum, the insertion interval T of the film, and the length L of the heat development material in the rotation direction. A thermal developing device, wherein a real number P exists. When L ≦ 2πR, T = (2πR ± (2πR-L) / P) / V, where 0 <
When P ≦ 10 L> 2πR, T = (2πR ± (L−2πR) / P) / V, where 0 <
P ≦ 20