JP2020020932A - Image forming system - Google Patents

Abstract

To provide a fixing device that comprises an endless belt that conveys a print medium to which a toner image is fixed, a heating roller that heats the endless belt, a pressure roller that presses the endless belt against the pressure roller, and a cooling structure that cools the endless belt passing through between the heating roller and pressure roller, wherein the print medium conveyed on the endless belt is heated and pressed while passing through between the heating roller and pressure roller and is cooled by the cooling structure.SOLUTION: An image forming system comprises: an endless belt 61 that conveys a print medium; a heating unit 62 that heats the endless belt 61 and creates a high-temperature area A1 inside the image forming system; a cooling unit 66 that cools the endless belt 61 and creates a low-temperature area A2 inside the image forming system; and a thermoelectric transducer 70 that has a first end 71 that is thermally connected to the high-temperature area A1 and a second end 72 that is thermally connected to the low-temperature area A2, and generates electric power from a difference in temperature between the first end 71 and the second end 72.SELECTED DRAWING: Figure 2

Description

  The image forming system includes a fixing device that fixes a toner image attached to a print medium. The fixing device includes an endless belt that conveys a print medium to be fixed, a heating roll that heats the endless belt, a pressure roll that presses the endless belt against the heating roll, and an endless belt that passes between the heating roll and the pressure roll. A cooling structure for cooling the belt. The print medium conveyed on the endless belt is heated and pressed between the heating roll and the pressure roll, and then cooled by the cooling structure.

1 is a schematic diagram of an imaging system with an exemplary fusing device that can be used to implement the various examples disclosed herein. FIG. 2 is a diagram illustrating the exemplary fixing device of FIG. 1. FIG. 3 is a diagram illustrating an exemplary thermoelectric conversion element of the fixing device of FIG. 2. FIG. 3 is a diagram illustrating another exemplary fixing device different from FIG. 2.

  Hereinafter, examples of various embodiments of the image forming system will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements have the same reference characters allotted, and redundant description will not be repeated. The drawings may be simplified or exaggerated to illustrate examples more clearly. First, an exemplary image forming system will be described. The image forming system includes, for example, both an image forming device and a fixing device, and may include various devices related to image formation.

  As shown in FIG. 1, the image forming system 1 as an example forms a color image using each color of magenta, yellow, cyan, and black. The image forming system 1 includes, for example, a recording medium transport device 10, a plurality of developing devices 20, a transfer device 30, a plurality of photoconductors 40, and fixing devices 50 and 60. The recording medium transport device 10 transports the print medium P. The print medium P is paper as an example. The photoconductor 40 forms an electrostatic latent image, and the developing device 20 develops the electrostatic latent image formed on the outer periphery of the photoconductor 40. The transfer device 30 secondarily transfers the toner image to the print medium P. The fixing devices 50 and 60 fix the toner image on the print medium P. As an example, the fixing device 50 is a primary fixing device that performs the first fixing of the print medium P, and the fixing device 60 is a secondary fixing device that performs the second fixing of the print medium P.

  The recording medium transport device 10 includes, for example, a paper feed roller 11 that transports a print medium P on which an image is formed along a transport path R1. The print medium P is stacked and accommodated in the cassette C, and is picked up and transported by the paper feed roller 11. The paper feed roller 11 is provided, for example, near the exit of the print medium P in the cassette C. The recording medium transport device 10 causes the print medium P to reach the secondary transfer area R2 via the transport path R1 at the timing when the toner image transferred to the print medium P reaches the secondary transfer area R2.

  The developing device 20 is provided, for example, for each color. Each developing device 20 includes a developing roller 21 that causes the photoconductor 40 to carry toner. In the developing device 20, for example, the toner and the carrier are adjusted to have a predetermined mixing ratio, and the toner and the carrier are mixed and stirred to uniformly disperse the toner. The developer is carried on the developing roller 21. The developing roller 21 rotates and transports the developer to a region facing the photoconductor 40. Then, the toner in the developer carried on the developing roller 21 moves to the electrostatic latent image on the photoconductor 40, and the electrostatic latent image is developed.

  The transfer device 30 conveys, for example, the toner image formed by the developing device 20 and the photoconductor 40 to the secondary transfer region R2. For example, an image developed on the photoconductor 40 is transferred to the transfer device 30. The transfer device 30 includes, for example, a transfer belt 31, suspension rollers 32a, 32b, 32c, 32d, a primary transfer roller 33, and a secondary transfer roller. The transfer belt 31 is suspended by, for example, suspension rollers 32a, 32b, 32c, and 32d. The primary transfer roller 33 is provided, for example, for each color. Each primary transfer roller 33 holds the transfer belt 31 together with each photoconductor 40. The secondary transfer roller 34 sandwiches the transfer belt 31 together with the suspension roller 32d.

  The transfer belt 31 is, for example, an endless belt that is circulated by suspension rollers 32a, 32b, 32c, and 32d. The primary transfer roller 33 presses the photoconductor 40 from the inner peripheral side of the transfer belt 31. The secondary transfer roller 34 presses the suspension roller 32d from the outer peripheral side of the transfer belt 31. The photoconductor 40 is, for example, a photoconductor drum, and is provided for each color. The plurality of photoconductors 40 are arranged along the moving direction of the transfer belt 31. For example, a developing device 20, an exposure unit 41, a charging device 42, and a cleaning device 43 are provided at positions facing the outer peripheral surface of each photoconductor 40.

  The image forming system 1 as an example includes a process cartridge 2 integrally including a developing device 20, a photoconductor 40, a charging device 42, and a cleaning device 43, and an apparatus main body 3 to which the process cartridge 2 is attached and detached. The process cartridge 2 is detachable from the apparatus main body 3 by, for example, opening the door of the apparatus main body 3 and inserting and removing the process cartridge 2 from the apparatus main body 3.

  For example, the charging device 42 uniformly charges the outer peripheral surface of the photoconductor 40 to a predetermined potential. The charging device 42 is, for example, a charging roller that rotates following the rotation of the photoconductor 40. The exposure unit 41 exposes the outer peripheral surface of the photoconductor 40 charged by the charging device 42 according to an image formed on the print medium P. The potential of the portion of the outer peripheral surface of the photoconductor 40 exposed to the exposure unit 41 changes, whereby an electrostatic latent image is formed on the outer peripheral surface of the photoconductor 40.

  For example, a toner tank 25 is disposed to face each of the plurality of developing devices 20. Each toner tank 25 contains, for example, magenta, yellow, cyan, and black toners. Each developing device 20 is supplied with toner from each toner tank 25. Each developing device 20 develops the electrostatic latent image with the supplied toner to form a toner image on the outer peripheral surface of the photoconductor 40. The toner image formed on the outer peripheral surface of the photoconductor 40 is primarily transferred to the transfer belt 31, and the toner remaining on the outer peripheral surface of the photoconductor 40 after the primary transfer is removed by the cleaning device 43.

  The fixing device 50 fixes the toner image secondarily transferred from the transfer belt 31 to the print medium P, for example, to the print medium P. The fixing device 50 includes, for example, a heating roller 51 that heats the printing medium P and fixes a toner image on the printing medium P, and a pressing roller 52 that presses the heating roller 51. The heating roller 51 and the pressure roller 52 are, for example, both formed in a cylindrical shape. As an example, a heat source such as a halogen lamp is provided inside the heating roller 51. Between the heating roller 51 and the pressure roller 52, a nip portion N1, which is a fixing area of the print medium P, is provided. As the print medium P passes through the nip portion N1, the toner image is fused and fixed to the print medium P.

  The fixing device 60 smoothes the toner on the print medium P on which the toner image has been fused and fixed by the fixing device 50, for example, to give the image of the print medium P gloss. That is, the fixing device 60 increases the glossiness of the image by melting and pressing the toner of the print medium P having minute irregularities and smoothing the toner. For example, the fixing device 60 is a gloss control device that controls the gloss of an image formed on the print medium P. The configuration of the fixing device 60 will be described later in detail. The image forming system 1 may be provided with discharge rollers 45 and 46 for discharging the print medium P, the gloss of the image of which is controlled by the fixing device 60, to the outside of the image forming system 1.

  Next, an example of an image forming method by the image forming system 1 will be described. First, an example of a printing process performed by the image forming system 1 will be described. For example, when an image signal of a recorded image is input to the image forming system 1, the print medium P stacked on the cassette C is picked up by the rotation of the paper feed roller 11, and the print medium P is moved along the transport path R1. Transported. Then, the charging device 42 uniformly charges the outer peripheral surface of the photoconductor 40 to a predetermined potential. Thereafter, the exposure unit 41 irradiates the outer peripheral surface of the photoconductor 40 with a laser beam based on the image signal to form an electrostatic latent image on the outer peripheral surface of the photoconductor 40.

  Subsequently, the developing device 20 forms a toner image on the photoconductor 40 and performs development. For example, the toner image is primarily transferred from each photoconductor 40 to the transfer belt 31 in a region where each photoconductor 40 faces the transfer belt 31. On the transfer belt 31, for example, the toner images formed on the respective photoconductors 40 are sequentially stacked to form one stacked toner image. The laminated toner image is secondarily transferred to the print medium P conveyed from the recording medium conveyance device 10 in the secondary transfer region R2 where the suspension roller 32d and the secondary transfer roller 34 face each other.

  The print medium P on which the laminated toner image has been secondarily transferred is transported from the secondary transfer area R2 to the fixing device 50. The fixing device 50 fixes the laminated toner image on the print medium P by, for example, passing the print medium P through the nip portion N1 while applying heat and pressure to the print medium P. The print medium P on which the laminated toner image has been fused and fixed is conveyed to, for example, the fixing device 60. The fixing device 60 melts and pressurizes the toner of the laminated toner image, smoothes the toner, and increases the glossiness of the image. Then, the fixing device 60 cools the print medium P having the smoothed laminated toner image to cure the toner. Thereafter, the print medium P is discharged to the outside of the image forming system 1 by the discharge rollers 45 and 46, for example.

  Next, an example of the fixing device 60 will be described in more detail.

  As shown in FIG. 2, a fixing device 60 as an example includes an endless belt 61, a heating unit 62 and support rollers 63 and 64 that are a rotating body that suspends the endless belt 61, and a rotating body that presses the print medium P. , A cooling unit 66 for cooling the endless belt 61, a thermoelectric conversion element 70, and a power storage unit 80. For example, the endless belt 61 passes through the outer surface of the heating unit 62 and has the printing medium P placed thereon. The endless belt 61 conveys the print medium P. As an example, a heating unit 62, support rollers 63 and 64, a cooling unit 66, and a thermoelectric conversion element 70 are provided inside the endless belt 61, and a pressing unit 65 is provided outside the endless belt 61.

  For example, the heating unit 62 heats the endless belt 61 and generates a high-temperature region A1 inside the image forming system 1. On the other hand, the cooling unit 66 cools the endless belt 61 and generates a low temperature region A2 inside the image forming system 1. As an example, the high-temperature region A1 is a region including the heating unit 62 and may include the endless belt 61 heated by the heating unit 62. The low-temperature area A2 is an area including the cooling unit 66, and may include, for example, the support roller 63 and the endless belt 61 cooled by the cooling unit 66. As an example, the temperature difference between the temperature of the high temperature area A1 and the temperature of the low temperature area A2 is 30 ° C. or more and 140 ° C. or less.

  For example, the heating unit 62 may be a roll-shaped heat roller or a belt-shaped heating belt. Between the heating unit 62 and the pressing unit 65, for example, a nip portion N2 which is a fixing region of the print medium P is provided. In this case, the toner T is smoothed on the print medium P by the print medium P passing through the nip portion N2. For example, a contact pressure acts between the heating unit 62 and the pressurizing unit 65, and the nip N2 is formed by the contact pressure.

  As an example, the rotation of the heating unit 62 and the support rollers 63 and 64 is transmitted to the endless belt 61 so that the endless belt 61 rotates. For example, the support rollers 63 and 64 are rollers that support the endless belt 61 from inside the endless belt 61, and the endless belt 61 moves around the heating unit 62 and the outer circumference of the support rollers 63 and 64. As an example, the print medium P is transported along the endless belt 61, is separated from the support roller 63 through the nip N <b> 2 and the cooling unit 66, and is transported outside the fixing device 60. The pressure unit 65 is, for example, a roll-shaped pressure roll, but may not be a roll.

  The cooling unit 66 includes, as an example, a heat sink 67 that contacts the opposite side of the endless belt 61 from the print medium P, and a fan 68 that blows air to the endless belt 61 via the heat sink 67. However, the cooling unit 66 may include, for example, at least one of a Peltier element and a heat pipe. The cooling unit 66 cools and hardens the toner T of the print medium P, which has passed through the nip N2 and is smoothed, for example. By hardening the smoothed toner T, the glossiness of the image quality of the print medium P is increased. The fan 68 operates by receiving power from the power storage unit 80, for example.

  The thermoelectric conversion element 70 is provided, for example, between the endless belt 61 cooled by the cooling unit 66 and the heating unit 62, and generates electric power from a temperature difference between the heating unit 62 and the cooled endless belt 61. As an example, the temperature of the heating unit 62 is 130 ° C. or more and 165 ° C. or less, and the temperature of the endless belt 61 cooled by the cooling unit 66 is 25 ° C. or more and 45 ° C. or less. As an example, electric power generated by thermoelectric conversion element 70 is stored in power storage unit 80. For example, power storage unit 80 is a battery or a capacitor.

  FIG. 3 is an enlarged view showing an exemplary thermoelectric conversion element 70. As shown in FIGS. 2 and 3, the thermoelectric conversion element 70 includes, for example, a first end 71 thermally connected to the high-temperature area A1 and a second end 72 thermally connected to the low-temperature area A2. , An electrode 73 provided between the first end 71 and the second end 72, and an n-type thermoelectric material 74 and a p-type thermoelectric material 75 for connecting the pair of electrodes 73 to each other.

  For example, the first end 71 may be provided at a position adjacent to the heating unit 62, and the second end 72 may be provided at a position adjacent to the endless belt 61 located inside the low temperature region A2. As an example, the first end 71 contacts the heating unit 62, and the second end 72 contacts the endless belt 61. For example, both the first end 71 and the second end 72 are made of ceramic and may be made of an insulating material.

  For example, the thermoelectric conversion element 70 generates an electromotive force from a temperature difference by the Seebeck effect. The thermoelectric conversion element 70 may generate an electromotive force from a temperature difference generated in the fixing device 60, for example, may generate an electromotive force from residual heat when the fixing device 60 is stopped. The stop of the fixing device 60 includes, for example, a sleep of the fixing device 60 or a stop of the image forming system 1.

  As an example, the first end 71 is heated by the heating unit 62, and the second end 72 is cooled by the endless belt 61. The n-type thermoelectric material 74 and the p-type thermoelectric material 75 connect the electrode 73 provided at the first end 71 and the electrode 73 provided at the second end 72 to each other. For example, the n-type thermoelectric material 74 and the p-type thermoelectric material 75 are both semiconductor elements. For example, the thermoelectric conversion element 70 has a sheet shape, and a plurality of n-type thermoelectric materials 74 and a plurality of p-type thermoelectric materials 75 are arranged between a first end 71 and a second end 72. .

  In the n-type thermoelectric material 74, the number of positively charged holes is larger than the number of negatively charged electrons, and the temperature difference between the first end 71 and the second end 72 causes the second end 72 to be closer to the second end 72. Holes collect in On the other hand, in the p-type thermoelectric material 75, the number of electrons is larger than the number of holes, and electrons are collected on the second end 72 side due to a temperature difference between the first end 71 and the second end 72. Accordingly, for example, a current is generated through the n-type thermoelectric material 74, the p-type thermoelectric material 75, and the electrode 73, and an electromotive force is generated. As an example, the thermoelectric conversion element 70 may include an electrode outlet 76, 77 in at least one of the plurality of electrodes 73. In this case, the electromotive force of the thermoelectric conversion element 70 passes through the electrode outlet 76, 77. Is output to the outside of the thermoelectric conversion element 70.

  As an example, the electromotive force of thermoelectric conversion element 70 may be stored in power storage unit 80 connected to thermoelectric conversion element 70. In this case, power storage unit 80 stores the power obtained by thermoelectric conversion element 70. As an example, the thermoelectric conversion element 70 may be directly connected to the fan 68, and the thermoelectric conversion element 70 may directly supply power for driving the fan 68 to the fan 68. In this case, the power storage unit 80 can be omitted.

  FIG. 4 illustrates another exemplary fixing device 90 that is different from the fixing device 60 of FIG. For example, in the fixing device 90, the thermoelectric conversion element 70 faces the heating unit 62 and the cooling unit 66. As an example, the first end 71 is provided at a position adjacent to the heating unit 62, and the second end 72 is provided at a position adjacent to the cooling unit 66. For example, the first end 71 may contact the heating unit 62, and the second end 72 may contact the heat sink 67 of the cooling unit 66.

  As described above, the exemplary fixing devices 60 and 90 and the image forming system 1 can reduce external power supply by including the thermoelectric conversion element 70. The thermoelectric conversion element 70 converts the temperature difference between the high-temperature portion and the low-temperature portion to a relatively high temperature, that is, converts the temperature difference between the fixing devices 60 and 90 into electric power. Heat can be used effectively. When the power storage unit 80 is provided, the electric power generated from the thermoelectric conversion element 70 can be stored in the power storage unit 80.

  The electric power obtained by the thermoelectric conversion element 70 may be supplied to the fan 68 or may be supplied to devices other than the fan 68. As an example, the power storage unit 80 may be provided in the cassette C that heats the print medium P, and the power from the power storage unit 80 may be supplied to a device that heats the print medium P. Further, the electric power obtained by the thermoelectric conversion element 70 may be used as electric power when the fixing devices 60 and 90 or the image forming system 1 is started. As described above, the power obtained from the thermoelectric conversion element 70 can be used for various purposes. As described above, the power storage unit 80 may supply the electric power obtained by the thermoelectric conversion element 70 to the cooling unit 66. In this case, the electric power obtained from the thermoelectric conversion element 70 is supplied inside the fixing devices 60 and 90. It can be used effectively.

  As described above, the thermoelectric conversion element 70 may be formed in a sheet shape, and in this case, the degree of freedom of arrangement of the thermoelectric conversion element 70 can be increased. For example, the sheet-like thermoelectric conversion element 70 may be wound around the heating unit 62 or may be attached to the endless belt 61. Note that the thermoelectric conversion element 70 may have a shape other than the sheet shape. Moreover, since the thermoelectric conversion element 70 can be made compact, it becomes possible to arrange the thermoelectric conversion element 70 in various places. As described above, the thermoelectric conversion element 70 may convert the residual heat when the fixing devices 60 and 90 are stopped into electric power. In this case, the waste heat when the fixing devices 60 and 90 are not operating is effectively used without waste. can do.

  It is to be understood that all aspects, advantages, and features described herein are not necessarily achieved or included by any one particular example and embodiment. Indeed, while various examples have been shown herein, it is evident that other examples may be modified in their arrangement and details. For example, at least one of the endless belt 61, the heating unit 62, and the pressing unit 65 need not be a rotating body. Thus, all modifications and variations that come within the spirit and scope of the claimed subject matter are claimed.

  All or a part of the above-described example can be expressed by each closing described below, but is not limited to the following description.

[Close 1]
An endless belt that conveys print media;
A heating unit that heats the endless belt and generates a high-temperature region inside the image forming system,
A cooling unit that cools the endless belt and generates a low-temperature region inside the image forming system,
It has a first end thermally connected to the high temperature region and a second end thermally connected to the low temperature region, and generates electric power from a temperature difference between the first end and the second end. A thermoelectric conversion element,
An image forming system comprising:
[Close 2]
The second end of the thermoelectric conversion element is provided at a position adjacent to the endless belt located inside the low temperature region,
The image forming system according to claim 1.
[Close 3]
The second end of the thermoelectric conversion element is provided at a position adjacent to the cooling unit.
The image forming system according to claim 1.
[Close 4]
The first end of the thermoelectric conversion element is provided at a position adjacent to the heating unit,
The image forming system according to any one of Closes 1 to 3.
[Close 5]
Comprising a power storage unit that stores the power converted by the thermoelectric conversion element,
An image forming system according to any one of claims 1 to 4.
[Close 6]
The power storage unit supplies the power converted by the thermoelectric conversion element to the cooling unit,
6. The image forming system according to Crow 5.
[Close 7]
The cooling unit includes a heat sink and a fan for cooling the endless belt,
The power storage unit supplies power to the fan,
7. The image forming system according to clause 5 or 6.
[Close 8]
A fixing device including the endless belt, the heating unit, the cooling unit, and the thermoelectric conversion element,
The thermoelectric conversion element converts residual heat when the fixing device is stopped into electric power,
The image forming system according to any one of claims 1 to 7.
[Close 9]
The thermoelectric conversion element has a sheet shape,
The image forming system according to any one of claims 1 to 8.
[Close 10]
A temperature difference between the high temperature region and the low temperature region is 30 ° C. or more and 140 ° C. or less;
The image forming system according to any one of claims 1 to 9.

Claims (10)

An endless belt that conveys print media;
A heating unit that heats the endless belt and generates a high-temperature region inside the image forming system,
A cooling unit that cools the endless belt and generates a low-temperature region inside the image forming system,
It has a first end thermally connected to the high temperature region and a second end thermally connected to the low temperature region, and generates electric power from a temperature difference between the first end and the second end. A thermoelectric conversion element,
An image forming system comprising: The second end of the thermoelectric conversion element is provided at a position adjacent to the endless belt located inside the low temperature region,
The image forming system according to claim 1. The second end of the thermoelectric conversion element is provided at a position adjacent to the cooling unit.
The image forming system according to claim 1. The first end of the thermoelectric conversion element is provided at a position adjacent to the heating unit,
The image forming system according to claim 1. Comprising a power storage unit that stores the power converted by the thermoelectric conversion element,
The image forming system according to claim 1. The power storage unit supplies the power converted by the thermoelectric conversion element to the cooling unit,
The image forming system according to claim 5. The cooling unit includes a heat sink and a fan for cooling the endless belt,
The power storage unit supplies power to the fan,
The image forming system according to claim 5. A fixing device including the endless belt, the heating unit, the cooling unit, and the thermoelectric conversion element,
The thermoelectric conversion element converts residual heat when the fixing device is stopped into electric power,
The image forming system according to claim 1. The thermoelectric conversion element has a sheet shape,
The image forming system according to claim 1. A temperature difference between the high temperature region and the low temperature region is 30 ° C. or more and 140 ° C. or less;
The image forming system according to claim 1.

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