JP3805740B2 - Heating device for heat development - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heating device for heat development used in an image recording apparatus.
[0002]
[Prior art]
In recent years, as an image recording apparatus, an image recording apparatus that performs a heat development process using a heater is widely known. In such an image recording apparatus, if the temperature of the portion to be thermally developed by the heater is non-uniform, density unevenness occurs in the image and an appropriate image cannot be obtained.
[0003]
In this regard, in the image recording apparatus, paying attention to the fact that the temperature of the heating plate tends to decrease on both the left and right sides in the heating and conveying direction, three (or three or more) heaters in the direction perpendicular to the heating and conveying direction. The temperature distribution in the direction (width direction) perpendicular to the conveying direction is made uniform by changing the set temperature in each heater (see, for example, Patent Document 1).
[0004]
However, in such a configuration, a large number of temperature sensors and control components are required according to the number of heaters (for example, a total of nine heaters in the case of three blocks and three blocks).
[0005]
[Patent Document 1]
JP 2000-321743 A (page 8, FIG. 9)
[0006]
[Problems to be solved by the invention]
In view of the above fact, an object of the present invention is to provide a heating device for thermal development that realizes uniform temperature of a portion to be thermally developed with a small number of parts.
[0007]
[Means for Solving the Problems]
The heating device for heat development according to the first aspect of the present invention is a heating device for heat development that performs heat development while transporting the heat-developable material, and is disposed at the center in the transport width direction to heat the heat-developable material. A central heater that is disposed on both sides of the central heater along the conveyance width direction, and that is disposed on both sides of the central heater in the conveyance width direction. A temperature sensor that detects temperature; and a control unit that receives a detection signal of the temperature sensor and controls the amount of heat generated by the central heater and the both-side heaters based on the detection signal, The both-side heaters generate more heat than the heat generated by the central heater.
[0008]
According to the heating apparatus for heat development of the present invention described in claim 1, the heat developing material conveyed is heated and developed by the central heater and the both side heaters. Here, the heating includes both direct heating and indirect heating (for example, heating from the heater through other members such as a heating plate). The temperature of the central heater is detected by a temperature sensor. Upon receipt of the detection signal of the temperature sensor, the control means controls the amount of heat generated by the central heater and the both-side heaters based on the detection signal, and the both-side heaters generate more heat than the heat generated by the central heater per predetermined time. . Here, as a case where both sides of the heater generate more heat than the amount of heat generated by the center heater, when energizing both sides of the heater only for a time that is always longer than the energization time of the center heater (not limited to continuous time) as a whole, The case where the energization time is the same and the voltage to the heaters on both sides is increased or a large amount of current is passed, the case where the energization time is the same and a heater with a large amount of heat generation is used on both sides is included. As described above, the temperature sensor is arranged only at the center in the conveyance width direction, and the amount of heat to the central heater and the two side heaters is controlled by one control means, so that the temperature of the portion to be thermally developed with few parts is made substantially uniform. be able to.
[0009]
A heating device for heat development according to a second aspect of the present invention is a heating device for heat development that performs heat development while transporting the heat-developable material, and is disposed at the center in the transport width direction to heat the heat-developable material. A central heater that is disposed on both sides of the central heater along the conveyance width direction, and that is disposed on both sides of the central heater in the conveyance width direction. A temperature sensor for detecting temperature and a detection signal of the temperature sensor, and controlling energization to the central heater and the both side heaters based on the detection signal, and energizing time to the both side heaters from the central heater And control means for controlling so that the length becomes longer. Here, the conveyance width direction refers to the width direction of the conveyance path, that is, the direction perpendicular to the conveyance direction. “Detecting the temperature” includes both a case where the temperature is directly detected by contacting the temperature sensor with the central heater and a case where the temperature is detected indirectly by a non-contact temperature sensor.
[0010]
According to the heating apparatus for heat development of the present invention described in claim 2, the central heater and both side heaters heat and thermally develop the conveyed heat developing material. Here, the heating includes both direct heating and indirect heating (for example, heating from the heater through other members such as a heating plate). The temperature of the central heater is detected by a temperature sensor. Upon receiving the detection signal of the temperature sensor, the control means controls the energization to the central heater and the both side heaters based on the detection signal. Here, the control means performs control so that the energization time to the heaters on both sides is longer than that of the central heater. In this way, instead of arranging a plurality of temperature sensors for a plurality of heaters and controlling the temperature respectively, a temperature sensor is arranged only at the center in the conveyance width direction, and the central heater and both side heaters are controlled by one control means. By controlling the energization and controlling the energization time to the heaters on both sides to be longer than that of the central heater, the temperature of the portion to be thermally developed can be made substantially uniform with fewer parts.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a heating device for heat development in the present invention will be described with reference to the drawings. FIG. 2 shows an outline of an image recording apparatus 100 including the heating device for heat development according to the present embodiment.
[0012]
The image recording apparatus 100 takes out the sheet-like recording material 11 as a heat developing material one by one from a heat developing material stocker (not shown) and sends it to the exposure unit 10. Here, the sheet-like recording material 11 is a material on which a latent image is formed by laser exposure, and an image is formed by heat development treatment. The exposure unit 10 includes a conveyance unit 12 that conveys the sheet-like recording material 11 and a scanning unit 20 as a scanning unit that irradiates the conveyance unit 12 with laser light modulated based on image data.
(Configuration of exposure unit 10)
The transport unit 12 includes a guide plate 14 that supports the sheet-like recording material 11. In the present embodiment, the non-recording surface of the sheet-like recording material 11 faces the guide plate 14. The guide plate 14 serves as a conveyance path through which the sheet-like recording material 11 enters and passes. The drive roller 16A provided corresponding to the guide plate 14 applies this conveyance force.
[0013]
The driving roller 16A receives the driving force of a driving means such as a motor (not shown) via a transmission means such as a gear or a belt, and rotates in the clockwise direction in FIG. A driving roller 16B having the same configuration as that of the driving roller 16A is provided for discharging the sheet-like recording material.
[0014]
A scanning unit 20 is disposed above the center of the guide plate 14 in the conveying direction of the sheet-like recording material 11. The scanning unit 20 includes a control unit, a semiconductor laser, a modulation unit, a polygon mirror, and an optical member (not shown). For this reason, the laser beam B is scanned on the sheet-like recording material 11 in a direction orthogonal to the conveyance direction (main scanning), and the image is exposed by being conveyed (sub-scanning) by the conveyance unit 12 together with this. Is done.
[0015]
A heat developing unit 24 is disposed on the downstream side of the exposure unit 10. The heat developing section 24 is a dry development type that heat-treats the sheet-shaped recording material 11 by heating, and is entirely covered with a casing 26, and has an insertion section for the sheet-shaped recording material 11 at one end thereof. A roller pair 27 is provided. The distance between the roller pair 27 and the final stage of the exposure unit 10 (the end on the downstream side of the guide plate 14 in the conveyance direction) is at least shorter than the length in the conveyance direction of the sheet-like recording material 11. As a result, the leading end of the sheet-like recording material 11 during the scanning exposure in the exposure unit 10 enters the heat developing unit 24.
(Configuration of the thermal development unit 24)
The conveyance path of the sheet-like recording material 11 in the heat developing unit 24 has an arc shape, and a three-block developing unit 28 is disposed in the casing 26 of the heat developing unit 24. The developing unit 28 includes a heating plate 30 whose one surface (a surface facing the sheet-shaped recording material 11) is an arc-shaped heating surface 30A, and the sheet-shaped recording material 11 and the friction with the heating surface 30A interposed therebetween. And a plurality of rollers 32 conveyed by force. The heating plate 30 can change the control temperature in units of the three blocks as necessary.
[0016]
The sheet-like recording material 11 inserted from the insertion portion of the developing unit 28 is heated while being conveyed at a predetermined conveyance speed, and is sandwiched between the roller pair 44 provided in the discharge portion of the casing 26 and discharged. In the meantime, it receives the amount of heat required for development and is thermally developed. The description of the heat development heating device 25 (see FIG. 1) in the heat development section 24 will be given later.
[0017]
A cooling unit 46 is disposed on the downstream side of the heat developing unit 24.
(Configuration of cooling unit 46)
The cooling unit 46 includes a plurality of cooling rollers 48 that support the sheet-like recording material 11, and a cooling plate 50 that faces the cooling roller 48 and contacts the upper surface side of the sheet-like recording material 11 in FIG. 2. Yes. The cooling roller 48 and the cooling plate 50 are formed of pipes having a so-called warming and easy-to-crush property such as metal (for example, aluminum) at least on the surfaces thereof. It has the role of taking heat away from the material 11. For this reason, the sheet-like recording material 11 is cooled and discharged by passing through the cooling unit 46.
[0018]
Here, as shown in FIG. 2, the cooling section 46 is divided into a slow cooling section 52 at the front stage and a quenching section 54 at the rear stage. The slow cooling part 52 is an area for gradually cooling the sheet-like recording material 11 having a relatively high heat (about 120 ° C.) immediately after development, and the quenching part 54 abruptly cools the discharged sheet-like recording material 11. It is an area. On the cooling plate 50 in the slow cooling section 52, cooling fins 56 are provided, and an air cooling fan 58 is disposed. As a result, the cooling plate 50 is radiated by the cooling fins 56 and is radiated forcibly by the air cooling fan 58.
[0019]
Next, in the image recording apparatus 100 described above, the heat developing heating device 25 (see FIG. 1) of the heat developing unit 24 will be described.
(Configuration of heating device 25 for heat development)
FIG. 1 shows the inside of the heating plate 30 in the heat development heating device 25 of the heat development section 24 (see FIG. 2). The heating plate 30 is configured to sandwich the sheet-like recording material 11 between the roller 32, and three heaters are provided in the heating plate 30 along the conveyance width direction (arrow W direction). Is provided. These are composed of a central heater 34 disposed in the center in the transport width direction (arrow W direction), and both-side heaters 36 disposed on both sides of the central heater 34 along the transport width direction (arrow W direction). ing. As described above, the three heaters are arranged because the heating plate 30 has a temperature drop at both ends in the conveyance width direction (arrow W direction). This is because the heat development temperature distribution can be made substantially uniform by disposing of. In order to prevent temperature unevenness in the conveyance width direction (arrow W direction), it is preferable that there is no gap between the central heater 34 and the side heaters 36.
[0020]
In this embodiment, the central heater 34 and the side heaters 36 are the same type of heater. However, the central heater 34 and the both side heaters 36 are not necessarily the same type, and may be arbitrarily selected according to the conditions of the heat treatment. The central heater 34 and the side heaters 36 are respectively constituted by heating elements 34A and 36A (for example, heat wires such as nichrome wire) serving as heating sources, and are connected to a power source (not shown). By supplying power from the power source, the central heater 34 and both side heaters 36 generate heat, and this heat is transmitted to the heating plate 30. In the present embodiment, the heating plate 30 is a simple heat transfer body, but a plate heater that itself serves as a heating body may be disposed.
[0021]
A temperature sensor 38 is disposed in the center of the conveyance width direction (arrow W direction) in the vicinity of the central heater 34. The reason why the temperature sensor 38 is arranged in the center in the conveyance width direction (arrow W direction) is that this portion has a higher temperature and is more stable than both sides. For the temperature sensor 38, for example, temperature detection means such as a thermocouple or a thermistor is used, but the type is not particularly limited as long as the temperature can be measured. The temperature sensor 38 detects the temperature of the central heater 34.
[0022]
The temperature sensor 38 is connected to a control unit 40 as control means. The temperature detected by the temperature sensor 38 is output to the control unit 40 as a detection signal. In response to this, the control unit 40 is configured to perform ON / OFF control of the central heater 34 and both side heaters 36 based on the temperature detected by the central heater 34. The central heater 34 is controlled independently, and the temperature sensor 38 detects the temperature of the central heater 34 and the control unit 40 performs control to keep the detected temperature at a set temperature (for example, 120 ° C.). To do. That is, the control unit 40 compares the detected temperature with the set temperature, and when the detected temperature is lower than the set temperature, gives an ON command to the central heater 34. At this time, the output to the central heater 34 is further increased as the detected temperature is lower than the set temperature, and the output to the central heater 34 is decreased as the detected temperature approaches the set temperature. Also good.
[0023]
When the control unit 40 issues an ON command to the central heater 34, it simultaneously issues an ON command to both side heaters 36. In addition, the control unit 40 performs control so that the energization time to the heaters 36 on both sides is longer than that of the central heater 34. The energization time to the heaters on both sides is preferably about 1.0 to 3.0 times the energization time to the central heater, preferably about 1.5 to 2.0 times, more preferably Is preferably about 1.8 times. Therefore, when a certain time elapses from the ON command of the control unit 40, only the central heater 34 is turned off first, and then the both side heaters 36 are turned off when a predetermined time elapses thereafter. This is because the heat easily escapes at both ends in the conveyance width direction (arrow W direction), and thus a large amount of heat is required by the both-side heaters 36, which corresponds to this. By switching ON / OFF of the central heater 34 and both side heaters 36 for a very short time, the surface temperature of the heating plate 30 is further contributed to uniformity.
[0024]
Here, the set energization time ratio between the central heater 34 and the side heaters 36 will be described. In this example, after a uniform original image is exposed in advance and a sheet-like recording material is obtained by heat development, a test is performed to measure the density distribution of the image, and the sheet-like recording material is based on the measurement result. 11, the set energization time ratio of the central heater 34 and the both-side heaters 36 in which the distribution of the image density obtained on 11 is substantially uniform is calculated. For example, in a preliminary test measurement, at a set temperature of 120 ° C., a measurement result is obtained that the distribution of image density becomes uniform when the set energization time of both side heaters 36 is 1.8 times the set energization time of the central heater 34. If the set temperature is 120 ° C., the controller 40 sets the set energization time of the both-side heaters 36 to 1.8 times the set energization time of the central heater 34 based on this. Control.
[0025]
Next, the operation of the above embodiment will be described.
(Operation of the embodiment)
As shown in FIG. 2, the sheet-like recording material 11 is exposed to an image while being conveyed by the exposure unit 10, and reaches the heat development unit 24.
[0026]
As shown in FIG. 1, the sheet-like recording material 11 being conveyed is heated by a central heater 34 and both-side heaters 36 via a heating plate 30. The temperature of the central heater 34 is detected by a temperature sensor 38. Upon receiving the detection signal of the temperature sensor 38, the control unit 40 performs ON / OFF control of the central heater 34 and the side heaters 36 based on the detection signal. Here, the control unit 40 performs control so that the energization time to the heaters 36 on both sides is longer than that of the central heater 34.
[0027]
In this way, instead of arranging a plurality of temperature sensors for a plurality of heaters and controlling the temperature, respectively, the temperature sensor 38 is arranged only at the center in the conveyance width direction (arrow W direction), and one control unit 40 is provided. By controlling the ON / OFF of the central heater 34 and the both side heaters 36, and controlling the energization time to the both side heaters 36 to be longer than that of the central heater 34, the temperature of the part to be thermally developed with few parts is substantially uniform. Can be Further, it is possible to cope with a change in the temperature distribution in the conveyance width direction (arrow W direction) of the portion to be thermally developed with time. As a result, the image density on the sheet-like recording material 11 can be made substantially uniform.
[0028]
As shown in FIG. 2, the above-described heat development processing is performed on the sheet-shaped recording material 11 by the plurality of development units 28, and is sent to the cooling unit 46. In the cooling unit 46, the heated sheet-shaped recording material 11 is cooled in two stages of slow cooling and rapid cooling.
[0029]
In the above-described embodiment, the configuration in which three heaters are arranged side by side along the conveyance width direction has been specifically described as an example. However, four or more heaters may be arranged side by side. Is not limited to this.
[0030]
Moreover, in said embodiment, although the heating surface is made into the circular arc surface, it is not limited to this, Surfaces other than circular arc shapes, such as flat form, may be sufficient.
[0031]
Furthermore, in the above-described embodiment, the roller and the heater sandwich and convey the sheet-like recording material, but a configuration may be adopted in which conveying means are provided before and after the heater to convey the sheet-like recording material.
[0032]
Furthermore, in the above embodiment, the case where the heating element is a nichrome wire heater has been described as an example, but other heating elements such as a ceramic heater or a resistance heating element may be used. It is not limited to a heater. Moreover, it is good also as a structure of the heating by a hot air.
[0033]
In the above embodiment, the case where the set temperature is 120 ° C. has been described as an example, but it is needless to say that the present invention is not limited to this.
[0034]
【The invention's effect】
As described above, according to the heating apparatus for thermal development of the present invention, there is an excellent effect that the temperature of the part to be thermally developed can be made uniform with a small number of parts.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing the inside of a heating plate, a control configuration, and the like in a heating apparatus for heat development according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of an image recording apparatus including a heating device for heat development according to an embodiment of the present invention.
[Explanation of symbols]
11 Sheet-shaped recording material (thermal development material)
25 Heating device for heat development 34 Central heater 36 Both side heaters 38 Temperature sensor 40 Control unit (control means)

Claims (2)

A heating device for thermal development that performs thermal development while conveying the thermal development material,
A central heater disposed in the center of the transport width direction for heating the heat developing material;
Both side heaters that are arranged on both sides of the central heater along the conveyance width direction and heat the heat developing material together with the central heater;
A temperature sensor disposed at the center in the transport width direction and detecting the temperature of the central heater;
Control means for receiving a detection signal of the temperature sensor and controlling the amount of heat generated by the central heater and the both-side heaters based on the detection signal;
Have
The heating device for heat development, wherein the both-side heaters generate a heat amount larger than a heat amount generated by the central heater per predetermined time. A heating device for thermal development that performs thermal development while conveying the thermal development material,
A central heater disposed in the center of the transport width direction for heating the heat developing material;
Both side heaters that are arranged on both sides of the central heater along the conveyance width direction and heat the heat developing material together with the central heater;
A temperature sensor disposed at the center in the transport width direction and detecting the temperature of the central heater;
Control that receives a detection signal of the temperature sensor, controls energization to the central heater and the both-side heaters based on the detection signal, and controls to energize the both-side heaters longer than the central heater. Means,
A heating device for heat development, comprising:

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