JPH04344663A - Decurler device - Google Patents

Abstract

PURPOSE:To eliminate curl to an image surface side by providing a heat pipe which cooperates with a carrying belt so that the temperature of the image surface of the transfer paper may be lowered. CONSTITUTION:The transfer paper S ejected from a fixing device 2 is held between the carrying belt 3 and a driven roller 7 and carried to a paper ejecting tray 5. When the transfer paper S is held in a nip part between a heat pipe 8 and the carrying belt 3, the heat of the transfer paper is taken away by the pipe 8, and the temperature of the transfer paper S is lowered by allowing a refrigerant inside the pipe 8 to which the heat is transferred to repeat liquefaction and gasification and circulate between a heat receiving range and a heat radiating fin. By setting a bite amount between the pipe 8 and the belt the pipe 8 acts to perform pressuring for causing back curl to the transfer paper S.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decurler device for removing curls from paper.

0002

2. Description of the Related Art As is well known, in image forming apparatuses such as copying machines, a transfer sheet onto which an image on a photoconductor has been transferred is transferred to a fixing device consisting of a heating roller and a pressure roller. The image is then fixed. By the way, the transfer paper that undergoes the above-mentioned fixing may curl depending on the water content on the paper surface. Therefore, the image bearing surface that is heated in the fixing device is in a state where curls are formed that wrap around that side because the moisture content including the unfixed image is higher than the back side that is not heated. It is often excreted.

[0003] Therefore, in order to eliminate the curling, that is, the curling tendency, of such transfer paper, the pressing force of a backup roller that presses against the conveyance roller is controlled to prevent curling. The transfer paper may be curled in the opposite direction to the paper side (for example, Japanese Patent Laid-Open No. 63-134464), or the transfer paper may be conveyed between a pair of rollers having different hardness, similar to the case described above. Curl in the opposite direction, so-called back curl (for example, Japanese Utility Model Publication No. 58-159557, Japanese Patent Application Laid-Open No. 52-91334)
No. 2) has been proposed.

0004

[Problem to be solved by the invention] However, the above-mentioned car
In the curl correction method, it is possible to correct the curl to some extent by considering the curl as a distortion and applying a load to correct this distortion in the opposite direction of the curl. The cause of curling due to the difference in moisture content on the surface of the transfer paper after adding it remains, so curling may occur again after some time has passed, so it is difficult to completely remove curls. The problem was that it was difficult to make it a reality.

SUMMARY OF THE INVENTION In view of the above-mentioned problems with the curl removal method, an object of the present invention is to provide a decal that can prevent curls from occurring on transfer paper after fixing, regardless of the passage of time. - The objective is to obtain a full-scale device.

[0006]

[Means for Solving the Problems] In order to achieve this object, the present invention provides a method for fixing an unfixed image on a transfer paper and disposing it in a conveyance path of the transfer paper, which is ejected after fixing an unfixed image on the transfer paper, The transfer belt is characterized in that it is comprised of a conveyor belt, and a heat pipe that is disposed opposite to the conveyor belt so as to be able to bite into it, and that can come into contact with the transfer paper.

The present invention is also characterized in that the conveyor belt is made of a material with good thermal conductivity.

Furthermore, the present invention is characterized in that the heat pipe has a structure in which the amount of bite into the conveyor belt can be varied.

The present invention also provides a conveyor belt or an elastic roller located in the conveyance path of the transfer paper that is discharged after fixing the unfixed image on the transfer paper, and a conveyor belt or an elastic roller that faces the conveyor belt or the elastic roller. In the decurler device, which is composed of a heat pipe that can be bitten into the heat pipe, the temperature signal from the temperature detection sensor is input, and by comparing the detected temperature with the set temperature, - It is characterized by being equipped with a control unit that variably controls the air volume in a cooling fan attached to the top pipe.

Furthermore, the present invention is characterized in that the temperature detection sensor is provided at a position where it can detect the temperature of the heat pipe.

[0011]The present invention also provides that the temperature detection sensor
It is characterized by being provided at a position where the temperature of the transfer paper after passing through the top pipe can be detected.

0012

[Function] According to the present invention, the transfer paper after fixing is cooled by a heat pipe to cause back curl to the back side by setting an environment corresponding to a state in which the water content is high on the back side of the image bearing surface. cause

Furthermore, according to the present invention, the temperature of the heat pipe can be maintained at a temperature at which blocking does not occur.

[0014]

[Embodiment] Details of an embodiment of the present invention will be explained below with reference to FIGS. 1 to 12.

FIG. 1 is a model diagram showing the main parts of a decurler device according to an embodiment of the present invention. It is located in That is, the fixing device 2 described above
A conveyance belt 3 forming the lower surface of the conveyance path is located on the conveyance path of the transfer sheet S discharged from the transfer sheet S. This conveyance belt 3 is connected to a driven pulley 4 on the fixing device 2 side and It is hung around a drive pulley 6 located on the side of the tray 5 and rotates in a direction in which the conveying direction of the transfer paper S can be set. A driven roller 7 is in opposing contact with a driven pulley 4 in this pulley, sandwiching the conveying belt 3, and is configured to nip and convey the transfer paper S discharged from the fixing device 2. .

On the other hand, a heat pipe 8 is provided on the surface of the conveyance path at a position slightly away from the center of the conveyor belt 3 in the stretching direction, specifically, at a position biased toward the paper discharge tray 5 side. They touch each other in a biting state, forming a nip portion for the transfer paper S. The contact position of the heat pipe 8 mentioned above is a position for obtaining the amount of reaction from the conveyor belt 3 toward the heat pipe 8, and it is needless to say that it is not limited to this position. That is, as shown in FIG. 2, the axial direction of the heat pipe 8 is perpendicular to the conveyance direction of the transfer paper moving on the conveyance belt 3, and each end of the heat pipe 8 in the axial direction is connected to a bearing of a stationary part. By being rotatably supported by the conveyor belt 3, the conveyor belt 3 can be rotated by friction between the conveyor belt 3 and the conveyor belt 3. The heat pipe 8 has a refrigerant sealed inside, and has a plurality of heat radiation fins 8A provided along the axial direction at one end in the axial direction. There is a cooling fan 9 nearby.
is placed. Therefore, the heat pipe 8 receives heat from the transfer paper side in the area where it comes into contact with the transfer paper S on the surface facing the conveyor belt 3, and in this range, the transfer paper S
The internal refrigerant is vaporized by the heat transfer from the heat transfer area, and this vaporized refrigerant moves from the heat receiving range to one end in the axial direction at a speed of about the speed of sound, and the heat dissipation located at this end The fins 8A perform heat exchange and are cooled to liquefy. This liquefied refrigerant moves again to the heat receiving range due to capillary action, receives heat from the transfer paper S, repeats liquefaction and vaporization, and thereby lowers the temperature of the transfer paper S.

On the other hand, the above-mentioned heat pipe 8 has its bearing portion supported by one of the swinging ends of a sector gear 10 as shown in FIG. The stepping motor 11 is engaged with the gear 12 attached to the output shaft.
The amount of biting into the conveyor belt 8 can be varied according to the rotation of the conveyor belt 8.

Since this embodiment has the above configuration,
The transfer paper S discharged from the fixing device 2 is nipped and conveyed by the conveyor belt 3 and the driven roller 7, and is conveyed toward the distributing conveyor belt 13 and the paper discharge tray 5. During conveyance, when the transfer paper S is held in the nip between the heat pipe 8 and the conveyance belt 3, heat is removed by the heat pipe 8, and the heat pipe 8 transfers the heat.
The internal refrigerant circulates between the heat receiving range and the heat radiation fins 8A while repeating liquefaction and vaporization, thereby lowering the temperature of the transfer paper S.

During heat exchange between the transfer paper S and the heat pipe 8, the heat pipe 8 is connected to the conveyor belt 3.
By setting the biting amount between the transfer paper S and the transfer paper S, pressure is applied to cause back curling of the transfer paper S.

Therefore, the transfer paper S is cooled when it comes into contact with the heat pipe 8, and an environment corresponding to a state in which the water content on the back side is greater than that on the image side is set, and the transfer paper S is transferred to the back side. curls, so-called back curls, and
This back curl is promoted by the pressure applied by the heat pipe 8 at the nip portion.

FIG. 4 shows the results of an experiment on the curl removal effect when the heat pipe 8 described above is provided and the amount of bite between the heat pipe 8 and the conveyor belt 3 is set.
and as shown in FIG. That is, FIG. 4 shows the difference in curl removal, so-called decal amount, depending on the diameter of the heat pipe 8 when the heat pipe 8 is provided. - The smaller the diameter of the top pipe 8, the larger the amount of decal. In addition, FIG. 5 shows the difference in curl amount depending on the presence or absence of the heat pipe 8, and as is clear from this figure,
It can be seen that when the same nip amount, that is, the same biting amount for the transfer paper S is set, the amount of curl is greater when the heat pipe 8 is provided. For example, for paper type A, when the nip amount is "A2", the curl amount is "0".
In order to achieve this, it is necessary that the heat pipe 8 is not provided, but if the heat pipe 8 is provided, the nip amount will be smaller than the nip amount "A2", In other words, when obtaining the same effect of reducing the amount of curl to "0", the amount of nip can be reduced by providing the heat pipe 8, so the amount of nip can be reduced by that much. In this case, a new effect can be obtained in that it is not necessary to apply unnecessary loads to the conveyor belt 3 and the transfer paper S.

Furthermore, in FIG. 6, when the toner in the image area carried on the transfer paper S is heated in the fixing device 2, the toner in the image is hardened if the heating temperature is high. The effect of the presence or absence of the heat pipe 8 on the occurrence of blocking, which means that transfer papers stick to each other when they are stacked on the paper output tray 5 without any heat pipes, is shown. In other words, heat pipe 8
If there is no heat pipe 8, there is a risk that blocking will occur when the temperature exceeds 80°C, regardless of whether it is one-sided or double-sided copying. However, if a heat pipe 8 is installed, blocking will occur when the temperature exceeds 80°C. It can be seen that blocking is also prevented.

By the way, in this embodiment, a structure may be provided to ensure the results shown in FIGS. 4 to 6. That is, the structure shown in FIG. 7 keeps the temperature of the conveyor belt 3 low until the transfer paper S contacts the heat pipe 8 in order to maintain water retention on the surface behind the image surface of the transfer paper S. In order to maintain this condition, the conveyor belt 3 is made of a material with good thermal conductivity, and is brought into contact with the heat pipe 8 to lower the temperature before the transfer paper S is placed and conveyed. . Therefore, in this structure, heat transfer from both sides of the transfer paper S is improved, the cooling effect is promoted, and the effect of the back curl at the time when the image surface contacts the heat pipe 8 is improved by improving the water retention on the back side. This can be ensured by maintaining the In this case, if a metal belt or the like is used as a material with good thermal conductivity, the belt often does not stretch, so roller 1 for tension adjustment is used.
3 and a spring 14 which is an elastic body.

Furthermore, as shown in FIG. 8, the structure for constructing the nip portion of the transfer paper S mentioned above uses a roller 15 that comes into contact with the heat pipe 8, and this roller 15 is made of elastic material. This makes it easy to apply pressure for back curling to the transfer paper S which is held between the two sides.

By the way, as a result of using the heat pipe 8 in the above-described embodiment, as shown in FIG. 4, the smaller the diameter of the heat pipe 8, the larger the decal amount. Therefore, in this embodiment, a structure may be adopted to ensure this result. That is, in FIG. 9, the heat pipe 8 that cooperates with the conveyor belt 3 to form the nip portion of the transfer paper S is connected to another heat pipe 17 via the heat transfer belt 16 having good thermal conductivity.
The diameter of the heat pipe 8 on the side forming the above-mentioned nip portion is made smaller than that of the other heat pipe 17. Therefore, the diameter of the heat pipe 8 on the side that forms the nip portion of the transfer paper S in cooperation with the conveyance belt 3 is reduced to ensure the effect of generating back curl of the transfer paper S, and further This heat pipe 8 is connected to another heat pipe 1 via a heat transfer belt 16.
The cooling effect from 7 can be ensured.

By the way, in this embodiment, the temperature of the heat pipe used for the above-mentioned cooling is changed according to the temperature of the transfer paper, so as to obtain an optimal cooling effect according to the temperature of the transfer paper. It is set as. That is, in order to uniformly cool the transfer paper to cause back curl even when the temperature of the transfer paper S changes, the temperature of the transfer paper S in the heat receiving range of the heat pipe 8 must be adjusted. Possible ways to do this include selecting a material that takes into account the thermal efficiency of the heat pipe, changing the outer diameter, and changing the diameter or number of heat dissipation fins. However, with such a method, it is difficult to respond immediately to temperature changes of the transfer paper S, and moreover, it is physically impossible to prepare various types of structures corresponding to each of these aspects. Therefore, the uniform cooling effect described above cannot be expected.

Therefore, in this embodiment, the temperature of the heat pipe 8 is adjusted by changing the air volume of the cooling fan 9 that cools the radiation fins 8A provided on the heat pipe 8 shown in FIG. It is designed to do so. For this reason, in FIG. 1, a first temperature sensor 17 is arranged above the heat pipe 8 to detect the temperature of the heat pipe in a non-contact manner. S
A second temperature sensor 18 for detecting the temperature of the transfer paper S in a non-contact manner is arranged above the conveyance path. Both the first temperature sensor 17 and the second temperature sensor 18 described above are connected to the control section 19. Although the details are not shown, the main part of the above-mentioned control section 19 is constituted by a microcomputer capable of arithmetic and control processing, and the above-mentioned first and second temperature sensors 17
, 18 are connected to the input side, and a driving section (not shown) of the cooling fan 9 is connected to the output side.

The above-mentioned control unit 19 compares the temperatures of the heat pipe 8 and the transfer paper S with a predetermined set temperature, and adjusts the air volume of the cooling fan 9 according to the comparison result. It is supposed to be done. In other words, the heat radiation amount (QH) of the heat pipe 8 is determined by the following equation.

QH(W)=ΔT/Rt ΔT=T0−Ta>0 However, T0: Heat pipe surface temperature (°C) Ta: Cooling air temperature (°C) Rt: Thermal resistance (°C/W) The above thermal resistance As mentioned above, (Rt) can be changed by the structural elements of the heat pipe 8, but it is physically impossible, so it can be reduced by changing the air volume of the cooling fan 9, as shown in FIG. By increasing the air volume of the cooling fan 9, the amount of heat dissipation (QH) shown in equation 1 above can be increased. 8 temperature adjustments are made.

Furthermore, based on such an operating principle, the control section 19 also uses temperature information from the transfer paper S to suppress the occurrence of blocking on the transfer paper. That is, as shown in FIG. 11, the amount of heat dissipated by the above equation 1 affects the cooling effect, and the air volume of the cooling fan 9 is controlled according to the temperature detection of the transfer paper S to reduce the temperature of the heat pipe 8. Adjustments are being made.

Since this embodiment has the above configuration,
The operation of the control section 19 will be explained below using a flowchart showing the operation of the control section 19. That is, the detected temperature T0 from the first temperature sensor 17 or the second temperature sensor 18 is measured, and this temperature T0 is compared with the set temperature T.
When T>T0, that is, when the temperature of the heat pipe 8 or the temperature of the transfer paper S is higher than the set temperature (T), the air volume of the cooling fan 9 is increased to increase the cooling effect of the heat pipe 8. enhance Further, when the detected temperature and the set temperature are equal (T=T0), the air volume of the cooling fan 9 is maintained as it is. On the other hand, the detected temperature is lower than the set temperature (
If T<T0), the air volume of the cooling fan may be left as is, but in this embodiment, the air volume is lowered. This is to provide advantages in terms of noise generation from the cooling fan 9 and fan life. Therefore, especially at the maintenance point where the transfer paper S is not being conveyed, that is, when the heat pipe 8 and the transfer paper S are not in contact, the detected temperature is low, so setting the air volume to "0" or a small amount will save energy. - is also effective.

[0032] In the explanation of the effect, it was explained that the temperature information from both the first and second temperature sensors 17 and 18 is used, but the air volume control of the cooling fan 9 is not limited to the heat pipe. Of course, it is possible to use either the temperature information of 8 or the temperature of the transfer paper.

In summary, since there is a certain relationship between the temperature of the heat pipe 8, the temperature of the transfer paper, and the set temperature, it is possible to predict the temperature of the transfer paper from the temperature of the heat pipe 8. good.

[0034]

As described above, according to the present invention, a structure is provided in which a heat pipe that cooperates with the conveyor belt is provided to lower the temperature of the image surface of the transfer paper. It is possible to set an environment corresponding to a state where the amount of water is increased, and by creating a surface with a high water content, it is possible to easily cause back curl and eliminate curl toward the image surface side. In other words, with a simple configuration that simply lowers the temperature on the image surface side, decaling can be caused without applying an excessive load to generate backcurl, and a special structure for applying the load can be used. can be made unnecessary.

Further, according to the present invention, the above-mentioned back curl can be efficiently generated by adjusting the size or the amount of biting of the nip formed by the heat pipe with respect to the transfer paper.

Furthermore, according to the present invention, the cooling effect of the transfer paper can be ensured simply by adjusting the air volume of the cooling fan used for cooling the heat pipe.
There is no need to change the cooling structure in response to changes in the temperature of the heat pipe or transfer paper, which are factors that affect the cooling effect.

[Brief explanation of the drawing]

FIG. 1 is a front view model diagram showing the main part configuration of a decal device according to an embodiment of the present invention.

FIG. 2 is a plan view model diagram of the main part configuration shown in FIG. 1;

FIG. 3 is a model diagram showing a heat pipe biting amount adjustment mechanism in the main part configuration shown in FIG. 1;

4 is a diagram for explaining the relationship between the diameter of the heat pipe and the amount of decal in the main part configuration shown in FIG. 1; FIG.

5 is a diagram for explaining the relationship between the amount of bite and the amount of curl of the heat pipe in the main part configuration shown in FIG. 1; FIG.

FIG. 6 is a diagram for explaining the relationship between the presence or absence of a heat pipe and the transfer paper temperature regarding the occurrence of blocking.

FIG. 7 is a schematic diagram showing the configuration of a conveyor belt that cooperates with a heat pipe in the main part configuration shown in FIG. 1;

8 is a schematic diagram showing a modification of the structure of the heat pipe and conveyor belt shown in FIG. 1. FIG.

9 is a model diagram showing a modification of the heat pipe in the main part configuration shown in FIG. 1. FIG.

10 is a diagram for explaining the relationship between the air volume of the cooling fan and the thermal resistance in the main part configuration shown in FIG. 1. FIG.

11 is a diagram for explaining the relationship between the air volume of the cooling fan and the cooling effect in the main part configuration shown in FIG. 1. FIG.

FIG. 12 is a flowchart for explaining the operation of the control section in the main configuration shown in FIG. 1;

[Explanation of symbols]

1 Decurler device 2 Fixing device 3 Conveyor belt 8 Heat pipe 8A Radiation fins 9 Cooling fan 17 First temperature sensor 18 for detecting the temperature of the heat pipe Second temperature sensor 19 for detecting the temperature of the transfer paper Control section

Claims (6)

[Claims] Claims: 1. Located in the conveyance path of the transfer paper that is discharged after fixing the unfixed image on the transfer paper, and capable of biting into the conveyance belt that constitutes the conveyance path and facing the conveyance belt. 1. A decurler device comprising: a heat pipe which is provided in a heat pipe and which can come into contact with the transfer paper. 2. The decurler apparatus according to claim 1, wherein the conveyor belt is a decurler made of a material with good thermal conductivity.
La equipment. 3. The decurler apparatus according to claim 1, wherein the heat pipe has a structure in which the amount of biting into the conveyor belt can be varied. 4. A conveyor belt or an elastic roller located in the conveyance path of the transfer paper after fixing the unfixed image on the transfer paper and ejecting the transfer paper; In the decurler device, which is composed of a heat pipe that can be inserted into the heat pipe, the temperature signal from the temperature detection sensor is input, and by comparing this detected temperature with a set value temperature, the heat pipe is 1. A decurler device comprising a control unit that variably controls the air volume of an attached cooling fan. 5. The decurler apparatus according to claim 4, wherein the temperature detection sensor is provided at a position where the temperature of the heat pipe can be detected. 6. The decurler apparatus according to claim 4, wherein the temperature detection sensor is provided at a position where the temperature of the transfer paper after passing through the heat pipe can be detected.