JPH02277056A - Temperature detecting device for sheet material drying device - Google Patents

Abstract

PURPOSE:To accurately measure the temperature of a sheet material by cutting the incidence of infrared rays on a thermometer from a heater and detecting only infrared rays from the sheet material. CONSTITUTION:A photosensitive material after development processing is conveyed into the drying device where mirror boxes 30 are arranged, and dried while controlled to desired temperature with infrared rays from heaters 36 in the boxes 30. Then detectors 38 for detecting the surface temperature of the photosensitive material are provided opposite the heaters 36 and only the infrared rays from the photosensitive material are made incident on the detector 38 by hoods 40 above them, reflecting plates 42 for reflecting infrared rays, and shield plates 46 for preventing infrared rays from the heaters 36 from being incident directly. The photosensitive material is passed between the reflecting plates 42 and shield plates 46.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is used in a sheet material drying apparatus suitable for drying a wet sheet material, particularly a photosensitive material immediately after development processing, to control the temperature of the sheet material. The present invention relates to a sheet material temperature detection device.

[Prior Art] When drying a sheet material, such as a photosensitive material immediately after processing, conventionally, the photosensitive material is transported into a drying chamber, and warm air is sent into the drying chamber to raise the temperature inside the drying chamber. It is dried by evaporating the moisture contained in the material. The warm air sent into the drying chamber is obtained by sending air to a heater using a fan or the like and raising the temperature of the air by this heater. Further, the temperature of the hot air sent in this way is adjusted by turning on and off the heater.

[Problems to be Solved by the Invention] However, in conventional drying using hot air, a large amount of heat escapes to the outside together with the air, resulting in large energy loss. In addition, it is necessary to raise the temperature of the air in addition to the photosensitive material to be dried, so a large amount of heat is required, and even more heat is required when the outside air is low temperature. Furthermore, when the temperature of the air rises too much, it is not possible to lower the temperature immediately, so it is difficult to maintain a predetermined temperature constant, and the response speed of warm skin regulation is slow. Since the temperature control response is slow as described above, there is a problem in that when the temperature of the air rises too much, the photosensitive material becomes too dry, resulting in so-called overdrying.

Furthermore, the temperature of the hot air inside the drying chamber varies depending on the location within the drying chamber, and it has been impossible to accurately measure the temperature of the hot air with a temperature detector placed at one location. For this reason, it has been impossible to control the temperature of the hot air by accurately determining the temperature of the photosensitive material.

In consideration of the above facts, the present invention utilizes thermal radiation to achieve high energy efficiency and quick response to temperature control, and also to accurately measure the temperature of the sheet material to keep the sheet material at a constant temperature. An object of the present invention is to provide a temperature detection device for a sheet material drying device that can dry the sheet material while maintaining the temperature of the sheet material.

[Means for Solving the Problems] A temperature detection device for a sheet material drying device according to the present invention is a temperature detection device for detecting the temperature of a sheet material, and is arranged opposite to the heater, and has a temperature detection device for detecting the temperature of a sheet material. a non-contact thermometer that measures the temperature of the sheet material passing between the sheet material and the heater; and a cutoff means for cutting off.

[Function] In the present invention having the above configuration, the sheet material passing between the heater and the non-contact thermometer is dried by radiating infrared rays from the heater. The infrared rays emitted from the heater are blocked from entering the non-contact thermometer facing the heater by the blocking means, and only the infrared rays from the sheet material are detected, making it possible to accurately detect the temperature of the sheet material. can.

Therefore, the temperature of the sheet material can be accurately measured, and the sheet material can be dried while maintaining the sheet material at a constant temperature.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7. In this embodiment, a sheet-shaped photosensitive material is dried.

This drying device IO includes a stand 12 formed of a frame. This table 12 has a pair of parallel side plates (
However, in Figure 1, the side plate on the near side is omitted)1
4 are installed upright, and between these are six pairs of conveyor rollers 16.
26 are arranged in parallel along the horizontal direction. These transport roller pairs 16 to 26 are rotated by the driving force of a drive means (not shown), and transport the photosensitive material 28 in a substantially horizontal direction (from the left side to the right side in the first drawing). Further, on the upstream side of the pair of conveying rollers 16 (the side where the photosensitive material 28 is inserted into the drying device 10), there is a pair of conveying rollers 17 and a guide roller 15.
is located. Furthermore, the downstream side of the conveying roller pair 26 (
A guide roller 19 is arranged on the exit side of the photosensitive material 28 from the drying device 10. A mirror box 30 is disposed between each pair of transport rollers.

As shown in FIG. 2, the mirror box 30 is formed by molding a stainless steel plate into a cylindrical box shape, and the inner wall side is a reflective surface. The entire outer circumference of the mirror box 30 is covered with a box-shaped heat insulating material 32 (FIG. 1). In addition, the upper part of the mirror box 30 is covered with a heat insulating material 3.
It is closed at 4. A reflective plate 31 made of the same material as the mirror box 30 is also arranged on the inner wall side of the heat insulating material 34, and a heater 36 is mounted on the reflective plate 31 via the insulating material, as shown in FIG. installed.

Note that the mirror box 30 and the reflecting plate 31 may be made of a material other than stainless steel that has good heat reflection, for example, the surface is plated with gold.

As shown in FIG. 3, the heater 36 is formed in a zigzag shape to increase its surface area. Invar can be used as the material for this heater, and the surface of the heater 36 is coated with a paint containing infrared emitting ceramic. Thereby, when the heater 36 is heated, infrared rays are emitted from the infrared ray emitting paint. This paint may be applied to only one side of the heater 36, or may be applied to both sides. This heater 36 is connected to a control device 52 as shown in FIG. 1, and the amount of heat of the heater 36 is controlled. In addition, the material of the heater 36 is nichrome,
Kanthal, Kovar, Super Invar, etc. can be used.

The mirror box 30 and the reflecting plate 31 reflect the infrared rays emitted from the heater 36 and uniformly radiate the infrared rays onto the surface of the photosensitive material 280. In addition, the dimension from the heater 36 to the lower end of the mirror box 30 (see Fig. 4) is such that the influence of the loss of heated air inside the mirror box 30 and the influence of the loss of radiated infrared rays can be tolerated. It is set to a certain length. Also, if the dimension L2 is long,
The temperature of the air within the mirror box 30 is locally increased by the heater 36, and thermal convection occurs due to the non-uniformity of the air temperature. Therefore, the dimension L2 is set to such an extent that no convection occurs.

Further, the heat insulating materials 32 and 34 prevent the heat of the mirror box 30 raised by infrared rays emitted from the heater 36 from escaping to the outside, thereby preventing heat loss due to thermal conduction.

Further, at the bottom of the conveyance path of the photosensitive material 28, there are a plurality of temperature detectors 38 for detecting the temperature of the photosensitive material 28 without contact.
are arranged along the conveyance direction. This temperature detector 3
8 includes a plurality of detection elements arranged in a direction perpendicular to the direction in which the photosensitive material 28 is transported. This temperature detector 38 is a thermal detector (bolometer-1 thermocouple, pyroelectric detector) or a photon (quantum) detector (PbS, InSb).

It is possible to use an intrinsic photoconductive cell such as HgCdTe), an impurity-doped photoconductive cell in which gold, mercury, etc. are added to a germanium matrix, and the like. The temperature detector 38 is the photosensitive material 2
The temperature of the photosensitive material 28 is detected by detecting the infrared rays emitted from the photosensitive material 8 . Furthermore, the temperature detector 38 is connected to the control device 52 .

A hood 40 is disposed directly above the temperature detector 38, and a reflection plate 42 is disposed above the hood 40.

This reflecting plate 42 receives radiation from the heater 38 and
The infrared rays transmitted through the photosensitive material 8 and the infrared rays emitted from the photosensitive material 28 are reflected and emitted to the photosensitive material 28 again, thereby improving the absorption efficiency of infrared rays into the photosensitive material 28. A plurality of through holes 44 are formed in the reflection plate 42 in correspondence with a plurality of detection elements of the temperature detector 38. Also, the reflective plate 420
A shielding plate 46 is arranged in the through hole 44 . These hood 40, reflector 42, and shielding plate 46 are connected to the temperature detector 3.
This is to prevent infrared rays from directly entering the heater 36 and allow only infrared rays emitted from the photosensitive material 28 to enter. The photosensitive material 28 is connected to the reflection plate 42 and the shielding Vi
, 46.

A temperature detector 38 is disposed between each pair of conveyance rollers 16 to 26, respectively. In this embodiment, five stages from stage 0 to stage 4 are provided, and a mirror box 30 and a temperature detector 38 are provided for each stage.

Further, on the entrance side of the photosensitive material 28 of the drying device 10, there is a photosensitive material 2
A detector 48 is arranged to detect the passage of 8. This detector 48 is connected to the control device 52 and detects the leading edge of the photosensitive material 28. A detector 5° is disposed on the side of the drying device 10 from which the photosensitive material 20 is exposed. This detector 5
0 is connected to the control device 52 and detects the rear end of the photosensitive material 28.

Next, the operation of this embodiment will be explained.

The photosensitive material 28 that has been developed in a developing device (not shown) is guided by the guide roller 15 and inserted between the pair of conveyor rollers 17, and then conveyed sequentially from stage 0 to stage "4" by the pairs of conveyor rollers 16 to 26. The dried photosensitive material 28 is guided by a guide roller 19 and discharged.

This drying will be explained according to the flowchart shown in FIG. In this embodiment, the production speed of the photosensitive material 28 transported by the transport roller pairs 16 to 26 is a constant speed.

In step 100, the tip of the photosensitive material 28 is connected to the detector 48.
It is determined whether or not it has been detected.

When the leading edge of the photosensitive material 28 is detected, the heater 36 of stage 0 is activated in step 102, and then the process proceeds to step 10.
3, the heater 36 at stage 0 has the target resistance value P. It will be judged whether or not it has become. In other words, the resistance value of the heater is calculated based on the voltage of the heater and the current flowing through the heater, and this resistance value is the target resistance value P0 corresponding to the target temperature of the heater (for example, 400°C in stage 0). The temperature of the heater is controlled by controlling the power so that At this time, the target temperature of the heater is set to a value such that the temperature of the photosensitive material 28 being conveyed by heat radiation from the heater does not exceed the set temperature T (for example, 55° C.) at stage 0, as shown in FIG. ing.

In step 104, it is determined whether the leading end of the photosensitive material 28 has been inserted into the stage 1 by determining whether it has been conveyed for a predetermined time, and if it is determined in the affirmative, step 105
Then, the surface temperature of the photosensitive material 28 is detected by the detector 38 disposed on the stage 0, and based on this detection result, the heater 36 of the stage 1 is activated in step 106, and then the target resistance of the stage 1 is activated in step 107. It is determined whether the value has reached P+. That is, from the set temperature T of the photosensitive material 28 and the temperature of the photosensitive material detected by the temperature detector 38, the target resistance value P1 of the heater for controlling the surface temperature of the photosensitive material to the set temperature T is determined. The temperature of the heater is controlled by controlling the electric power so that the resistance reaches the target resistance value P1.

In step 108, it is determined whether a predetermined period of time has elapsed to determine whether the leading edge of the photosensitive material 28 has reached stage 2, and in steps 109 to 111, the temperature is determined based on the surface temperature of the photosensitive material 280 detected by the detector of stage 1. The target resistance value P0 is set in the same way as above, and the heater temperature is controlled in the same way as above to maintain the temperature of the photosensitive material 28 at the set temperature T8. Hereafter, in the same manner as above, the target resistance value P
3. P- is set and the temperature of the heater is controlled up to stage 6. Therefore, the surface temperature of the photosensitive material 28 is controlled to a set temperature T as shown in FIG. 6 while drying.

Since the photosensitive material 28 is gradually dried in stages 0 to 4 during this drying, the amount of heat required is smaller in later stages, and as a result, the target resistance value of each heater is shown in FIG. As a result, from stage 1 onwards, it is gradually lowered.

In step 112, it is determined whether the detector 50 has detected the rear end of the photosensitive material 28, and if the rear end has not been detected, steps 112 and subsequent steps are repeatedly executed. When the detector 50 detects the rear end of the photosensitive material 28, step 11
At step 4, the output of the heater of each stage is stopped.

In this embodiment, the output value of the heater for drying the photosensitive material 28 is controlled by detecting the surface temperature of the photosensitive material 28 using an infrared detector; however, the present invention is not limited to this. The target resistance value of the heater may be controlled based on this result.

[Effects of the Invention] As explained above, the temperature detection device for a sheet material drying device according to the present invention has a shield between the sheet material and the heater that blocks infrared rays from the heater from entering the non-contact thermometer. Since the means is provided, it has the excellent effect of being able to accurately measure the temperature of the sheet material.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a sheet material drying apparatus to which the present invention is applied, FIG. 2 is a perspective view showing a mirror box, FIG. 3 is a perspective view showing a heater and a reflector, and FIG. The figure is an enlarged cross-sectional view of a part of Figure 1 showing the relationship between the temperature detector and the mirror box, Figure 5 is a diagram showing the target resistance value of the heater in each stage versus drying time, and Figure 6 is the drying time. FIG. 7 is a flowchart showing temperature control for drying the photosensitive material. DESCRIPTION OF SYMBOLS 10... Drying device, 16-26... Conveyance roller pair, 30... Mirror box, 31... Reflection plate, 36... Heater, 38... Temperature detector, 46... Shielding Board. Figure 4

Claims (1)

[Claims] (1) A temperature detection device for detecting the temperature of a sheet material of a sheet material drying device that dries the sheet material by emitting infrared rays from a heater while conveying the sheet material, the temperature detection device being arranged opposite to the heater. a non-contact thermometer that is disposed between the sheet material and the heater and measures the temperature of the sheet material passing between the heater; and a non-contact thermometer that is disposed between the sheet material and the heater and transmits infrared rays from the heater to the non-contact thermometer. 1. A temperature detection device for a sheet material drying device, characterized in that the temperature detection device has a blocking means for blocking the incidence of.