JP7059613B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

The following Patent Document 1 discloses an image forming apparatus including a heat transport roll that heats a toner image from the back surface side of a surface on which a toner image is formed on a continuous film.

Japanese Unexamined Patent Publication No. 2016-157007

In the present invention, in a configuration in which the surface opposite to the toner image forming surface of the continuous recording medium is heated and then the surface opposite to the toner image forming surface is cooled, the contact width between the cooling unit and the continuous recording medium is the heating unit and the continuous recording medium. It is an object of the present invention to obtain an image forming apparatus that suppresses unevenness of gloss (that is, glossiness) as compared with the case where the contact width is less than or equal to the contact width with.

The image forming apparatus according to the first aspect is a heating unit that heats in contact with a surface opposite to the toner image forming surface of the continuous recording medium, and a downstream side of the heating unit in the transport direction of the continuous recording medium. It is a cooling unit that first contacts and cools the surface of the continuous recording medium opposite to the toner image forming surface, and the contact width with the continuous recording medium in the transport direction of the continuous recording medium is the continuous between the heating unit and the heating unit. It has the cooling unit, which is larger than the contact width with the recording medium.

The image forming apparatus according to the second aspect is the image forming apparatus according to the first aspect , wherein the cooling portion does not have a nip forming portion for forming a nip.

The image forming apparatus according to the third aspect is the image forming apparatus according to the first aspect or the second aspect , in which the heating part and the cooling part are made of rolls, and the outer diameter of the cooling part is outside the heating part. Larger than the diameter.

The image forming apparatus according to the fourth aspect is the image forming apparatus according to any one of the first to third aspects , wherein the heating part and the cooling part are made of rolls, and the continuous recording medium is of the continuous recording medium. The winding angle around the cooling portion is larger than the winding angle of the continuous recording medium around the heating portion.

The image forming apparatus according to the fifth aspect is the image forming apparatus according to any one of the first to fourth aspects , wherein at least the thermal conductivity of the surface of the cooling portion is the surface of the heating portion. Greater than the thermal conductivity of.

The image forming apparatus according to the sixth aspect is the image forming apparatus according to any one of the first to fourth aspects , wherein at least the surface roughness of the cooling portion is higher than the surface roughness of the heating portion. rough.

The image forming apparatus according to the seventh aspect is the toner image forming surface of the continuous recording medium at a position facing the heating portion in the image forming apparatus according to any one of the first to sixth aspects. The other heating unit is provided in contact with and heats the continuous recording medium, and the other heating unit is arranged on the downstream side of the center of the contact portion between the heating unit and the continuous recording medium in the transport direction of the continuous recording medium. The heating unit constitutes a fixing unit for fixing the toner image on the continuous recording medium.

The image forming apparatus according to the eighth aspect has no peeling member at the outlet of the nip portion between the heating portion and the other heating portion in the image forming apparatus according to the seventh aspect .

In the image forming apparatus according to the seventh or eighth aspect , the image forming apparatus according to the ninth aspect is the toner of the continuous recording medium first on the downstream side of the cooling unit in the transport direction of the continuous recording medium. It has another cooling unit that contacts and cools the image forming surface.

The image forming apparatus according to a tenth aspect is the continuous recording medium between the heating unit and the cooling unit in the image forming apparatus according to any one of the first to ninth aspects . The length is smaller than the total length of the contact width between the heating unit and the continuous recording medium in the transport direction of the continuous recording medium and the contact width between the cooling unit and the continuous recording medium.

In the image forming apparatus according to the tenth aspect , the length of the continuous recording medium between the heating unit and the cooling unit is the length of the continuous recording medium in the image forming apparatus according to the eleventh aspect . It is smaller than the contact width between the cooling unit and the continuous recording medium in.

According to the image forming apparatus according to the first aspect , in a configuration in which the surface opposite to the toner image forming surface of the continuous recording medium is heated and then the surface opposite to the toner image forming surface is cooled, the cooling unit and the continuous recording medium are used. Compared with the case where the contact width is equal to or less than the contact width between the heated portion and the continuous recording medium, unevenness in the gloss of the image is suppressed.

According to the image forming apparatus according to the second aspect , unevenness in gloss of an image is suppressed as compared with a configuration in which a cooling portion has a nip forming portion.

According to the image forming apparatus according to the third aspect , the continuous recording medium can be cooled with a simple configuration as compared with a configuration in which the outer diameter of the cooling portion is equal to or smaller than the outer diameter of the heating portion.

According to the image forming apparatus according to the fourth aspect , the continuous recording medium has a simple configuration as compared with the configuration in which the winding angle of the continuous recording medium around the cooling portion is equal to or less than the winding angle of the continuous recording medium around the heating portion. Can be cooled.

According to the image forming apparatus according to the fifth aspect , the continuous recording medium is more likely to be cooled as compared with the case where the thermal conductivity of the surface of the cooling portion is equal to or lower than the thermal conductivity of the surface of the heating portion.

According to the image forming apparatus according to the sixth aspect , the continuous recording medium is more likely to be cooled as compared with the case where the surface roughness of the cooling portion is equal to or less than the surface roughness of the heating portion.

According to the image forming apparatus according to the seventh aspect , the generation of image blister is compared with the configuration in which the other heating portion is arranged on the upstream side of the center of the contact portion between the heating portion and the continuous recording medium. Fixability is improved while suppressing.

According to the image forming apparatus according to the eighth aspect , unevenness in gloss of the image is suppressed as compared with a configuration in which a peeling member is provided at the outlet of the nip portion between the heating portion and the other heating portion.

According to the image forming apparatus according to the ninth aspect , unevenness in gloss of an image is suppressed as compared with a configuration in which the toner image forming surface of the continuous recording medium is not cooled on the downstream side of the cooling unit.

According to the image forming apparatus according to the tenth aspect , the length of the continuous recording medium between the heating part and the cooling part is the contact width between the heating part and the continuous recording medium and the contact between the cooling part and the continuous recording medium. The expansion and contraction of the continuous recording medium is suppressed particularly when the continuous recording medium is a resin film, as compared with the configuration in which the length is equal to or larger than the total length of the width.

According to the image forming apparatus according to the eleventh aspect , the length of the continuous recording medium between the heating unit and the cooling unit is particularly larger than the contact width between the cooling unit and the cooling unit. When the continuous recording medium is a resin film, the expansion and contraction of the continuous recording medium is suppressed.

It is a schematic block diagram which shows the image forming apparatus which concerns on 1st Embodiment. It is a schematic block diagram which shows the toner image forming part used in the image forming apparatus which concerns on 1st Embodiment. It is a front view which shows the fixing device and the cooling device used in the image forming apparatus which concerns on 1st Embodiment. It is a schematic perspective view which shows an example of the 1st cooling roll of the cooling apparatus used in the image forming apparatus which concerns on 1st Embodiment. It is a front view which shows the fixing device and the cooling device used in the image forming apparatus which concerns on 2nd Embodiment. It is a front view which shows the fixing device and the cooling device used in the image forming apparatus which concerns on 3rd Embodiment. It is a schematic enlarged cross-sectional view which shows the toner image before fixing on the paper when the continuous paper is paper in the image forming apparatus of the comparative example. It is a schematic enlarged cross-sectional view which shows the process of fixing a toner image on a paper by a fixing roll in the image forming apparatus of a comparative example, when a continuous paper is a paper. It is a schematic enlarged cross-sectional view which shows the state which the toner image on the paper is fixed in the image forming apparatus of the comparative example, when a continuous paper is a paper. FIG. 5 is a schematic enlarged cross-sectional view showing a state in which a toner image on a resin film is fixed by a fixing roll when the continuous paper is a resin film in the image forming apparatus of the comparative example. It is a schematic enlarged cross-sectional view which shows the state which the toner image on the resin film is fixed when the continuous paper is a resin film in the image forming apparatus of a comparative example.

Hereinafter, an example of the embodiment according to the present invention will be described with reference to the drawings. The arrow H shown in each figure is the vertical direction and indicates the vertical direction of the device, and the arrow W is the horizontal direction and indicates the width direction of the device.

<< First Embodiment >>
<Overall configuration of image forming apparatus 10>
First, the configuration of the image forming apparatus 10 of the first embodiment will be described. FIG. 1 shows a configuration in which the image forming apparatus 10 is viewed from the front side.

The image forming apparatus 10 is an apparatus that conveys the continuous book paper P arranged in advance in the transport path in a predetermined transport direction (direction of arrow B in FIG. 1) and forms an image on the continuous book paper P. .. That is, the continuous paper P, which is the image forming target of the image forming apparatus 10, is an example of a continuous recording medium that is conveyed from a state in which it is previously arranged in the conveying path. The continuous paper P has a length along the transport direction.

Further, for the continuous paper P, for example, the front surface is an image surface on which an image is formed, and the back surface is a non-image surface on which an image is not formed. As the continuous book paper P, for example, plain paper, a resin film, a metal foil (for example, aluminum foil, etc.), a recording medium in which a resin film and a metal foil are laminated, and the like are used. As a recording medium in which a resin film and a metal foil are laminated, for example, there is a recording medium having a metal foil on one surface of an image surface and a non-image surface and a resin film on the other surface.

Specifically, as shown in FIG. 1, the image forming apparatus 10 includes a conveying unit 50, an image forming unit 12, a fixing device 60, a cooling device 80, and a control unit 100. ..

(Transport section 50)
The transport unit 50 is a portion having a function of transporting the continuous book paper P previously arranged in the transport path. Specifically, as shown in FIG. 1, the transport unit 50 includes a winding roll 51 (an example of a supply unit), a winding roll 53, a driving unit 55, and winding rolls 52, 54, 56 (an example of a supply unit). An example of a winding member) and.

The unwinding roll 51 is a roll that unwinds the continuous paper P, and functions as an example of a supply unit that supplies the continuous paper P toward the transfer unit 35 (secondary transfer position NT) described later. A rear end side portion (upstream side portion in the transport direction) of the continuous paper P is wound around the unwinding roll 51. The take-up roll 53 is a roll for winding the continuous paper P, and functions as a collection unit for collecting the continuous paper P conveyed from the transfer unit 35 (secondary transfer position NT) described later. A portion on the tip end side (a portion on the downstream side in the transport direction) of the continuous paper P is wound around the take-up roll 53.

The drive unit 55 rotationally drives the take-up roll 53 in the direction in which the take-up roll 53 winds up the continuous paper P (counterclockwise in FIG. 1). Then, the winding roll 53 winds up the continuous book paper P by the rotational drive of the drive unit 55, so that the continuous book paper P is pulled and the unwinding roll 51 unwinds the continuous book paper P. In this way, the rotary drive of the drive unit 55 causes the take-up roll 53 to wind up the continuous paper P, and the unwinding roll 51 unwinds the continuous paper P, so that the continuous paper P is conveyed in the transport direction. Will be done.

The winding rolls 52, 54, 56 are on the transport path between the unwinding roll 51 and the transfer unit 35 (secondary transfer position NT) described later, and the winding rolls 52, 54, 56 are in this order. It is arranged along the transport direction. Therefore, the winding roll 52 is arranged at the position closest to the unwinding roll 51 among the winding rolls 52, 54, and 56. Further, the winding roll 54 is arranged above the winding rolls 52 and 56. The winding rolls 52 and 56 are wound with the continuous paper P so that the outer peripheral surface of the rolls 52 and 56 is in contact with the image surface of the continuous paper P. The roll 54 is wound with the continuous paper P so that the outer peripheral surface of the roll 54 is in contact with the non-image surface of the continuous paper P (the surface 2B opposite to the toner image forming surface 2A in FIG. 3). .. For example, the winding roll 54 is configured to change its position relative to the winding rolls 52 and 56, and is designed to correct the transport path of the continuous paper P.

(Image forming unit 12)
The image forming unit 12 is a portion having a function of forming an image on the continuous paper P by an electrophotographic method. Specifically, the image forming unit 12 includes a toner image forming unit 20 that forms a toner image, and a transfer device 30 that transfers the toner image formed by the toner image forming unit 20 to the continuous paper P. ing.

A plurality of toner image forming units 20 are provided so as to form a toner image for each color. In this embodiment, a toner image forming unit 20 having a total of four colors of yellow (Y), magenta (M), cyan (C), and black (K) is provided. (Y), (M), (C), and (K) shown in FIG. 1 indicate components corresponding to the above colors. In the image forming apparatus 10, when it is necessary to distinguish between yellow (Y), magenta (M), cyan (C), and black (K), Y, M, C, and K are added after the reference numerals of the respective members. If it is not necessary to distinguish each color, Y, M, C, and K may be omitted.

[Toner image forming unit 20]
The toner image forming unit 20 of each color is basically configured in the same manner except for the toner to be used. Specifically, as shown in FIG. 2, the toner image forming unit 20 of each color has a photoconductor drum 21 (photoreceptor) that rotates clockwise in FIG. 2 and a charger that charges the photoconductor drum 21. 22 and an exposure device 23 that exposes the photoconductor drum 21 charged by the charger 22 to form an electrostatic latent image on the photoconductor drum 21. Further, the toner image forming unit 20 of each color develops the electrostatic latent image formed on the photoconductor drum 21 by the exposure device 23 to form the toner image, and the toner image on the transfer belt 31 described later. It has a blade 25 as a remover for removing the toner remaining on the surface of the photoconductor drum 21 after the transfer.

The charger 22 charges the surface (photosensitive layer) of the photoconductor drum 21 negatively, for example. On the surface of the photoconductor drum 21 charged with a negative electrode property, a portion irradiated with the exposure light L by the exposure apparatus 23 exhibits a positive electrode property, and an electrostatic latent image is formed on the surface of the photoconductor drum 21. Then, the toner triboelectrically charged in the developing apparatus 24 adheres to the electrostatic latent image exhibiting the positive electrode property, and the electrostatic latent image is developed. In this way, a toner image is formed on the surface (outer peripheral surface) of the photoconductor drum 21. The blade 25 comes into contact with the surface of the photoconductor drum 21 and scrapes off the toner remaining on the surface of the photoconductor drum 21.

[Transfer device 30]
The transfer device 30 superimposes the toner image of the photoconductor drum 21 of each color on the transfer belt 31 as an intermediate transfer body for primary transfer, and the superimposed toner image is connected at the secondary transfer position NT (nip portion). Secondary transfer to the toner P. Specifically, as shown in FIG. 1, the transfer device 30 includes a transfer belt 31, a primary transfer roll 33, and a secondary transfer roll 34.

[Transfer belt 31]
As shown in FIG. 1, the transfer belt 31 has an endless shape and is wound around a plurality of rolls 32 to determine its posture. In this embodiment, the transfer belt 31 has an inverted obtuse triangular posture that is long in the width direction of the device when viewed from the front. Of the plurality of rolls 32, the roll 32D shown in FIG. 1 functions as a drive roll that rotates the transfer belt 31 in the direction of arrow A by the power of a motor (not shown). The transfer belt 31 rotates in the direction of arrow A to convey the primary transferred image to the secondary transfer position NT.

Further, among the plurality of rolls 32, the roll 32T shown in FIG. 1 functions as a tension applying roll that applies tension to the transfer belt 31. Of the plurality of rolls 32, the roll 32B shown in FIG. 1 functions as an opposed roll 32B of the secondary transfer roll 34. As described above, the facing roll 32B is wound with the top of the lower end side of the transfer belt 31 having an obtuse-angled triangular posture. The transfer belt 31 is in contact with the photoconductor drum 21 of each color from below at the upper side portion extending in the width direction of the device in the above-mentioned posture.

[Primary transfer roll 33]
The primary transfer roll 33 is a roll that transfers the toner image of each photoconductor drum 21 to the transfer belt 31, and is arranged inside the transfer belt 31 as shown in FIG. Each primary transfer roll 33 is arranged so as to face the photoconductor drum 21 of the corresponding color with the transfer belt 31 interposed therebetween. Further, a primary transfer voltage is applied between the primary transfer roll 33 and the photoconductor drum 21 by a feeding unit 37 (see FIG. 2). As a result, the toner image formed on the photoconductor drum 21 is transferred to the transfer belt 31 at the primary transfer position T (see FIG. 2) between the photoconductor drum 21 and the primary transfer roll 33.

[Secondary transfer roll 34]
The secondary transfer roll 34 is a roll that transfers the toner image superimposed on the transfer belt 31 to the continuous paper P. As shown in FIG. 1, the secondary transfer roll 34 is arranged so as to sandwich the transfer belt 31 with the opposed roll 32B, and the secondary transfer roll 34 and the transfer belt 31 have a predetermined load. Are in contact with. The area between the secondary transfer roll 34 and the transfer belt 31 that are in contact with each other in this way is defined as the secondary transfer position NT (nip portion). The continuous paper P is supplied from the unwinding roll 51 to the secondary transfer position NT. The secondary transfer roll 34 is rotationally driven in the clockwise direction in FIG.

Further, a secondary transfer voltage is applied between the secondary transfer roll 34 and the counter roll 32B by the application unit 39. As a result, a potential difference is generated between the toner image transferred to the transfer belt 31 and the continuous paper P conveyed to the secondary transfer position NT. That is, at the secondary transfer position NT, a voltage is applied between the continuous paper P and the toner image along the thickness direction of the continuous paper P. As a result, an electrostatic force acts on the toner image of the transfer belt 31, and the toner image is transferred from the transfer belt 31 to the continuous paper P passing through the secondary transfer position NT. As described above, in the present embodiment, the secondary transfer roll 34 and the opposed roll 32B apply a voltage between the continuous paper P and the toner image along the thickness direction of the continuous paper P to connect the toner images. A transfer unit 35 for transferring to the book paper P is configured.

(Overview of fixing device 60)
As shown in FIG. 1, the fixing device 60 is arranged on the downstream side of the secondary transfer position NT in the transport direction of the continuous paper P. Support rolls 58 and 59 that support the continuous paper P in a defined transport path are arranged between the secondary transfer position NT and the fixing device 60. The support rolls 58 and 59 rotate in accordance with the movement of the continuous paper P. The support roll 59 is moved in a direction (in the direction of arrow H) intersecting the paper surface of the continuous paper P by a moving mechanism (not shown) to apply tension to the continuous paper P.

As shown in FIG. 3, the fixing device 60 contacts the first heating roll 62 that contacts the surface 2B opposite to the toner image forming surface 2A of the continuous paper P, and the continuous book paper P contacts the first heating roll 62. A second heating roll 64 that comes into contact with the toner image forming surface 2A of the continuous paper P on the downstream side of the region is provided. Here, the first heating roll 62 is an example of a heating unit, and the second heating roll 64 is an example of another heating unit. Further, the first heating roll 62 and the second heating roll 64 constitute an example of the fixing portion. The fixing device 60 will be described in detail later. In the fixing device 60, the continuous paper P and the toner image G (see FIG. 3) are heated by bringing the first heating roll 62 into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. Further, the second heating roll 64 is brought into contact with the toner image forming surface 2A of the continuous paper P on the downstream side in the transport direction of the first heating roll 62 to heat the continuous paper P and the toner image G. As a result, the toner image G formed on the continuous paper P is heated and pressurized to be fixed on the continuous paper P. Note that FIG. 3 illustrates only a part of the toner image G formed on the continuous paper P.

(Outline of cooling device 80)
As shown in FIG. 3, the cooling device 80 comes into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P on the downstream side of the second heating roll 64 in the transport direction of the continuous paper P. A cooling roll 82 is provided. Further, the cooling device 80 includes a second cooling roll 84 that comes into contact with the toner image forming surface 2A of the continuous paper P on the downstream side of the first cooling roll 82 in the transport direction of the continuous paper P. Here, the first cooling roll 82 is an example of a cooling unit, and the second cooling roll 84 is an example of another cooling unit. The cooling device 80 will be described in detail later. In the cooling device 80, the continuous book paper P and the toner image G are brought into contact with the first cooling roll 82 from the surface 2B opposite to the toner image forming surface 2A of the continuous book paper P, so that the continuous book paper P and the toner image G are brought into contact with each other from the side opposite to the toner image forming surface 2A. Cooling. Further, by bringing the second cooling roll 84 into contact with the toner image forming surface 2A of the continuous book paper P on the downstream side in the transport direction of the first cooling roll 82, the continuous book paper P and the toner image are brought into contact with the toner image forming surface 2A. Cool G.

(Control unit 100)
The control unit 100 is a part having a function of controlling the operation of each part of the image forming apparatus 10. Each unit of the image forming apparatus 10 including the application unit 39 and the drive unit 55 is connected to the control unit 100.

<Image formation operation>
Next, the outline of the image forming process on the continuous paper P by the image forming apparatus 10 will be described.

In the present embodiment, first, for example, the continuous paper P is preliminarily arranged in the transport path of the image forming apparatus 10 by the manual work of the user of the image forming apparatus 10. The continuous paper P is, for example, unwound from the unwinding roll 51 and arranged from the unwinding roll 51 to the winding roll 53 along the transport path.

In the image forming apparatus 10 shown in FIG. 1, the control unit 100 that receives the image forming command operates each toner image forming unit 20 and the like. As shown in FIG. 2 and the like, the photoconductor drum 21 of each color is charged by the charger 22 while being rotated. Further, the control unit 100 sends the image data processed by the image signal processing unit to each exposure apparatus 23. Each exposure apparatus 23 emits each exposure light L according to the image data to expose each charged photoconductor drum 21. As a result, an electrostatic latent image is formed on the outer peripheral surface of each photoconductor drum 21. The electrostatic latent image formed on each photoconductor drum 21 is developed by the developing device 24, and the photoconductor drum 21 of each color has yellow (Y), magenta (M), cyan (C), and black (K). Toner image is formed.

The toner image of each color formed on the photoconductor drum 21 of each color is sequentially primary-transferred to the orbiting transfer belt 31 by the primary transfer roll 33 of each color at each primary transfer position T. As a result, a toner image on which toner images for four colors are superimposed is formed on the transfer belt 31. The superimposed toner image is conveyed to the secondary transfer position NT by the circulation of the transfer belt 31. At the secondary transfer position NT, the toner image G (see FIG. 3) superimposed from the transfer belt 31 is transferred to the continuous paper P.

The continuous paper P on which the toner image G is secondarily transferred is conveyed toward the fixing device 60. In the fixing device 60, the surface 2B opposite to the toner image forming surface 2A of the continuous paper P is heated by the first heating roll 62. Further, when the second heating roll 64 comes into contact with the toner image forming surface 2A of the continuous paper P on the downstream side in the transport direction of the first heating roll 62, the toner image G is heated and pressed to be the continuous paper. It is fixed to P.

Further, the continuous paper P is conveyed toward the cooling device 80 on the downstream side of the fixing device 60. In the cooling device 80, the surface 2B opposite to the toner image forming surface 2A of the continuous paper P is cooled by the first cooling roll 82. Further, the toner image G is cooled by the contact of the second cooling roll 84 with the toner image forming surface 2A of the continuous paper P on the downstream side in the transport direction of the first cooling roll 82. Then, on the downstream side of the cooling device 80 in the transport direction, the continuous paper P is wound on the take-up roll 53.

<Main part composition>
Next, the configuration of the main part of the present embodiment will be described.

(Fixing device 60)
As shown in FIG. 3, the fixing device 60 includes a first heating roll 62 and a second heating roll 64 as described above. A surface 2B opposite to the toner image forming surface 2A of the continuous paper P is wound (wound) around the first heating roll 62 within a predetermined range. In the present embodiment, for example, the contact width L1 between the first heating roll 62 and the continuous book paper P in the transport direction (arrow B direction) of the continuous book paper P is 1/4 or more of the outer peripheral surface of the first heating roll 62. The range is 2 or less. For example, the winding angle of the continuous paper P around the first heating roll 62 is preferably 90 ° or more and 180 ° or less, more preferably 110 ° or more and 170 ° or less, and further preferably 120 ° or more and 160 ° or less.

As an example, the first heating roll 62 includes a cylindrical roll 62A and a heating source 62B arranged inside the roll 62A. The heating source 62B is composed of, for example, a single or a plurality of halogen lamps. The temperature sensor 66 is arranged at a position facing the outer peripheral surface of the first heating roll 62 (the facing portion through which the continuous paper P does not pass). The control unit 100 controls the first heating roll 62 to a predetermined temperature based on the temperature detected by the temperature sensor 66. For example, the temperature of the first heating roll 62 detected by the temperature sensor 66 is controlled to be 120 ° C. or higher and 200 ° C. or lower. The first heating roll 62 is configured to rotate in accordance with the movement of the continuous paper P.

The second heating roll 64 and the toner image forming surface 2A of the continuous book paper P are located downstream of the range in which the first heating roll 62 comes into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. Are in contact. For example, the second heating roll 64 is arranged on the downstream side from the center of the contact portion between the first heating roll 62 and the continuous book paper P in the transport direction (arrow B direction) of the continuous book paper P. At this time, the second heating roll 64 is preferably arranged in a range of 1/3 from the most downstream of the contact portion between the first heating roll 62 and the continuous book paper P in the transport direction of the continuous paper P. It is more preferable that the first heating roll 62 and the continuous book paper P are arranged in a range of 1/4 from the most downstream of the contact portion in the transport direction of the book paper P. Further, it is more preferable that the second heating roll 64 is arranged in a range of 1/5 from the most downstream of the contact portion between the first heating roll 62 and the continuous paper P in the transport direction of the continuous paper P. In the present embodiment, the second heating roll 64 is located at the most downstream position in the range where the first heating roll 62 comes into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous book paper P, and the toner of the continuous book paper P. It is in contact with the image forming surface 2A.

As an example, the second heating roll 64 includes a cylindrical roll 64A formed of a material having elasticity on the surface side, and a heating source 64B arranged inside the roll 64A. The roll 64A is, for example, a soft roll whose surface is made of silicone rubber or the like. The heating source 64B is composed of, for example, a single or a plurality of halogen lamps. A temperature sensor 68 is arranged at a position facing the outer peripheral surface of the second heating roll 64. The control unit 100 controls the first heating roll 62 to a predetermined temperature based on the temperature detected by the temperature sensor 68. The second heating roll 64 is configured to rotate in accordance with the movement of the continuous paper P.

Further, an external heating roll 70 in contact with the second heating roll 64 is arranged at a position opposite to the first heating roll 62 of the second heating roll 64. As an example, the external heating roll 70 includes a cylindrical roll 70A made of metal and a heating source 70B such as a halogen lamp arranged inside the roll 70A. A temperature sensor 72 is arranged at a position facing the outer peripheral surface of the external heating roll 70. The control unit 100 controls the external heating roll 70 to a predetermined temperature based on the temperature detected by the temperature sensor 72. The external heating roll 70 is configured to rotate in accordance with the rotation of the second heating roll 64.

Further, a cleaning roll 74 for removing deposits on the surface of the second heating roll 64 is provided at a position where the second heating roll 64 comes into contact with the outer peripheral surface. The roll 78 is in contact with the side of the cleaning roll 74 opposite to the second heating roll 64 via the cleaning web 76. Although not shown, the cleaning web 76 is configured to move along the circumferential direction of the cleaning roll 74 so that a new surface is supplied.

No peeling member is provided at the outlet of the fixing device 60, that is, the outlet of the nip portion between the first heating roll 62 and the second heating roll 64 that come into contact with each other via the continuous paper P. In other words, the outlet of the fixing device 60 is not provided with a peeling member (for example, a claw or a baffle) that comes into contact with the continuous paper P.

(Cooling device 80)
As shown in FIG. 3, the cooling device 80 includes a first cooling roll 82 and a second cooling roll 84 as described above. The first cooling roll 82 first contacts and cools the surface 2B opposite to the toner image forming surface 2A of the continuous paper P on the downstream side of the fixing device 60 in the transport direction (arrow B direction) of the continuous paper P. It is said to be composed. Here, "first" means that on the downstream side of the fixing device 60, the first cooling roll 82 comes into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P on the most upstream side. It means to take heat from P and the toner image G, that is, to positively cool the continuous paper P and the toner image G. That is, the first cooling roll 82 positively cools the continuous paper P and the toner image G by having a cooling function, and the one that does not have the cooling function and simply comes into contact with the continuous paper P is Not included in the "cooling section". A surface 2B opposite to the toner image forming surface 2A of the continuous paper P is wound (wound) around the first cooling roll 82 within a predetermined range. In the present embodiment, for example, the contact width L2 between the first cooling roll 82 and the continuous book paper P in the transport direction (arrow B direction) of the continuous book paper P is 1/4 or more of the outer peripheral surface of the first cooling roll 82. The range is 2 or less. For example, the winding angle of the continuous paper P around the first cooling roll 82 is preferably 90 ° or more and 180 ° or less, more preferably 110 ° or more and 170 ° or less, and further preferably 120 ° or more and 160 ° or less.

At this time, the contact width L2 between the first cooling roll 82 and the continuous book paper P in the transport direction of the continuous book paper P is from the contact width L1 between the first heating roll 62 and the continuous book paper P in the transport direction of the continuous book paper P. big. In the present embodiment, the outer diameter of the first cooling roll 82 is equal to the outer diameter of the first heating roll 62, and the winding angle θ2 of the continuous paper P around the first cooling roll 82 is set around the first heating roll 62. The winding angle θ1 of the continuous paper P is larger. That is, the cooling time of the surface 2B opposite to the toner image forming surface 2A of the continuous paper P by the first cooling roll 82 is the surface 2B opposite to the toner image forming surface 2A of the continuous paper P by the first heating roll 62. It will be longer than the heating time.

As shown in FIG. 4, the first cooling roll 82 includes, as an example, a cylindrical roll 82A made of metal or the like, and a duct 82B is provided inside the roll 82A. A fan 88 is provided at one end of the first cooling roll 82 in the axial direction via an introduction portion 86 connected to the duct 82B. The first cooling roll 82 causes the continuous paper P in contact with the first cooling roll 82 to flow in the duct 82B through the introduction portion 86 by the rotation of the fan 88, so that the continuous paper P is opposite to the toner image forming surface 2A. It is designed to cool from the surface 2B. In addition, in FIG. 4, in order to make it easy to understand the structure of the first cooling roll 82, it is schematically shown in a state where a part of the first cooling roll 82 in the axial direction is cut off. Further, although not shown, the first cooling roll 82 is provided with shaft portions extending on both sides in the axial direction, and is configured to rotate in accordance with the movement of the continuous paper P. The first cooling roll 82 is not limited to the above configuration, and may be configured to cool the continuous paper P from the surface 2B opposite to the toner image forming surface 2A by passing water inside, for example. In addition, even if the duct and the fan are not provided inside the first cooling roll 82, the temperature of the first cooling roll 82 is lowered by the rotation of the fan 94 around the first cooling roll 82 to lower the temperature of the first cooling roll 82. The 82 may be configured to cool the continuous paper P and the toner image G.

Further, the thermal conductivity (W / m · K) of the surface of the roll 82A of the first cooling roll 82 is larger than the thermal conductivity (W / m · K) of the surface of the roll 62A of the first heating roll 62. For example, the thermal conductivity is made different by changing the material of the surface of the roll 82A of the first cooling roll 82 and the material of the surface of the roll 62A of the first heating roll 62. In the present embodiment, the surface of the roll 82A of the first cooling roll 82 is made of metal, and the surface of the roll 62A of the first heating roll 62 is made of rubber.

Further, in the image forming apparatus 10, the surface roughness (Ra) of the first cooling roll 82 is coarser (larger) than the surface roughness (Ra) of the first heating roll 62. When the surface roughness (Ra) of the first cooling roll 82 is made coarser than the surface roughness (Ra) of the first heating roll 62, the first cooling roll 82 is easier to cool than the first heating roll 62. The surface roughness (Ra) of the first cooling roll 82 and the surface roughness (Ra) of the first heating roll 62 are different, for example, due to differences in materials and mechanical processing. For example, the difference between the surface roughness (Ra) of the first cooling roll 82 and the surface roughness (Ra) of the first heating roll 62 is preferably 0.1 to 0.8 μm, preferably 0.3 to 0. It is more preferably 0.7 μm, and even more preferably 0.5 to 0.6 μm. The surface roughness (arithmetic mean roughness) Ra is based on the JIS B0601 (1994) standard. The measuring device is SURFCOM manufactured by Tokyo Seimitsu Co., Ltd. The measurement length is 4 [mm], the cutoff wavelength is 0.8 [mm], the cutoff type is Gaussian, and the measurement speed is 0.3 [mm / s]. The surface roughness may be measured by Rz in addition to Ra. The surface roughness Rz is the ten-point average roughness Rz of JIS B0601 (1994). The surface roughness Rz has a cutoff wavelength of 0.8 mm, a measurement length of 4.0 mm, and a measurement speed of 0.3 [mm / s]. Measure 3 places) and calculate the average value. For example, the difference between the surface roughness (Rz) of the first cooling roll 82 and the surface roughness (Rz) of the first heating roll 62 is preferably 0.4 to 3.2 μm.

As shown in FIG. 3, the second cooling roll 84 is first on the toner image forming surface 2A of the continuous paper P on the downstream side of the first cooling roll 82 in the transport direction (arrow B direction) of the continuous paper P. It is configured to contact and cool. Here, "first" means that the second cooling roll 84 comes into contact with the toner image forming surface 2A of the continuous book paper P on the most upstream side on the downstream side of the first cooling roll 82, and the continuous book paper P and the toner. It means to take heat from the image G, that is, to positively cool the continuous paper P and the toner image G. That is, the second cooling roll 84 positively cools the continuous paper P and the toner image G by having a cooling function, and the one that simply comes into contact with the continuous paper P without having a cooling function Not included in "other cooling units". The toner image forming surface 2A of the continuous paper P is wound (wound) around the second cooling roll 84 within a predetermined range.

The outer diameter of the second cooling roll 84 is smaller than the outer diameter of the first cooling roll 82. In the present embodiment, the outer diameter of the second cooling roll 84 is ½ or less of the outer diameter of the first cooling roll 82. For example, the continuous paper P is wound around the second cooling roll 84 in a range of 1/2 of the outer peripheral surface of the second cooling roll 84. For example, the winding angle of the continuous paper P around the second cooling roll 84 is preferably 110 ° or more and 200 ° or less, more preferably 120 ° or more and 190 ° or less, and further preferably 130 ° or more and 180 ° or less. In the present embodiment, the winding angle of the continuous book paper P around the second cooling roll 84 is larger than the winding angle of the continuous book paper P around the first cooling roll 82.

In the present embodiment, for example, the winding amount of the continuous book paper P around the second cooling roll 84 (see L2 in FIG. 3) is the winding amount of the continuous book paper P around the first cooling roll 82 (in FIG. 3). See L1). In other words, the contact width between the second cooling roll 84 and the continuous book paper P in the transport direction (arrow B direction) of the continuous book paper P is smaller than the contact width L2 between the first cooling roll 82 and the continuous book paper P. That is, the cooling time of the toner image forming surface 2A of the continuous book paper P by the second cooling roll 84 is shorter than the cooling time of the surface 2B opposite to the toner image forming surface 2A of the continuous book paper P by the first cooling roll 82.

Although not shown, the second cooling roll 84 includes, as an example, a cylindrical roll made of metal or the like, and a duct is provided inside the roll. A fan is provided at the axial end of the second cooling roll 84 via the introduction portion. The first cooling roll 82 cools the toner image forming surface 2A of the continuous paper P in contact with the second cooling roll 84 by allowing air to flow inside the duct by rotating the fan. The second cooling roll 84 is not limited to the above configuration, and may be configured to cool the continuous paper P from the surface 2B opposite to the toner image forming surface 2A by passing water inside, for example. Although not shown, the second cooling roll 84 is provided with shaft portions extending on both sides in the axial direction, and is configured to rotate in accordance with the movement of the continuous paper P. In addition, even if the duct and the fan are not provided inside the second cooling roll 84, the temperature of the second cooling roll 84 is lowered by the rotation of the fan 94 around the second cooling roll 84 to lower the temperature of the second cooling roll 84. The 84 may be configured to cool the continuous paper P and the toner image G.

The length L3 of the continuous paper P between the first heating roll 62 and the first cooling roll 82 (the length of the continuous paper P in the transport direction) is the first heating roll in the transport direction of the continuous paper P. The length is smaller than the total length of the contact width L1 between 62 and the continuous paper P, and the contact width L2 between the first cooling roll 82 and the continuous paper P. As a result, the time for the continuous paper P to pass between the first heating roll 62 and the first cooling roll 82 is on the surface 2B opposite to the toner image forming surface 2A of the continuous paper P by the first heating roll 62. The heating time is shorter than the total time of the heating time and the cooling time of the surface 2B opposite to the toner image forming surface 2A of the continuous paper P by the first cooling roll 82. As a result, cooling by the first cooling roll 82 is started in a short time after the toner image G is fixed. For example, the temperature of the toner image G at the inlet of the first cooling roll 82 is 10 ° C. or more lower than the temperature at the time of fixing the toner image G.

The first cooling roll 82 is configured not to have a nip forming portion that comes into contact with the continuous paper P to form a nip. That is, it is the second cooling roll 84 that first comes into contact with the toner image forming surface 2A of the continuous paper P after fixing. Further, the second cooling roll 84 is configured not to have a nip forming portion for forming a nip in contact with the continuous paper P.

A plurality of (two in this embodiment) fans 94 are provided in a housing of a cooling device 80 (not shown) at a position facing a region of the first cooling roll 82 that does not come into contact with the continuous paper P. Further, a fan 94 is provided in the housing of the cooling device 80 (not shown) at a position facing the area of the second cooling roll 84 that does not come into contact with the continuous paper P. The rotation of the plurality of fans 94 lowers the ambient temperature of the first cooling roll 82 and the second cooling roll 84.

Further, on the downstream side of the second cooling roll 84 in the transport direction of the continuous book paper P, a plurality of (three in the present embodiment) support rolls 102 for changing the direction of the continuous book paper P in the intersecting direction are arranged. Has been done. The support roll 102 is configured to rotate in accordance with the movement of the continuous paper P. In the present embodiment, the three support rolls 102 on the downstream side of the second cooling roll 84 arrange the transport path of the continuous paper P so as to surround the lower portion of the cooling device 80 and one side portion of the fixing device 60. It is said to be composed.

<Action and effect>
Next, the operation and effect of this embodiment will be described.

In the image forming apparatus 10, the continuous paper P to which the toner image G is transferred at the secondary transfer position NT is conveyed to the fixing apparatus 60 in a state of being supported by the support rolls 58 and 59. In the fixing device 60, the continuous book paper P and the toner image G are heated by the first heating roll 62 by bringing the first heating roll 62 into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. .. As a result, of the toner image G on the continuous book paper P, the toner melts from the side closer to the continuous book paper P, so that the air in the unfixed toner image G of the continuous book paper P flows from the surface side of the toner image G. It will be easier to escape. For example, if air remains in the toner image G, it causes a so-called blister in which a plurality of concave portions are formed on the surface of the image after fixing. However, when the air escapes into the toner image G, preheating is performed. Blister is less likely to occur compared to a non-fixing device. Further, by bringing the second heating roll 64 into contact with the toner image forming surface 2A of the continuous paper P at the position on the most downstream side of the range in which the first heating roll 62 comes into contact, the continuous book paper P and the toner image G ( (See FIG. 3) is heated. As a result, the toner image G is fixed to the continuous paper P by heating and pressurizing in a state where the air in the toner image G is released.

Further, after fixing by the fixing device 60, the continuous paper P is conveyed to the cooling device 80. The cooling device 80 has a first cooling roll that first contacts the surface 2B opposite to the toner image forming surface 2A of the continuous paper P on the downstream side of the fixing device 60 in the transport direction of the continuous paper P (direction of arrow B). 82 is provided. That is, by bringing the first cooling roll 82 into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous book paper P, the continuous book paper P and the toner image G are cooled from the surface 2B opposite to the toner image forming surface 2A. Will be done. At this time, after the air in the toner image G of the continuous paper P is released by the first heating roll 62, the continuous paper P and the toner image G are cooled by the first cooling roll 82.

Further, in the cooling device 80, a second cooling roll that first contacts the toner image forming surface 2A of the continuous paper P on the downstream side of the first cooling roll 82 in the transport direction (arrow B direction) of the continuous paper P. 84 is provided. That is, by bringing the second cooling roll 84 into contact with the toner image forming surface 2A of the continuous book paper P on the downstream side in the transport direction of the first cooling roll 82, the continuous book paper P and the toner image are brought into contact with the toner image forming surface 2A. G is cooled.

In the image forming apparatus 10, the surface 2B opposite to the toner image forming surface 2A of the continuous paper P is heated by the first heating roll 62, so that the air in the unfixed toner image G of the continuous paper P is heated. Is easy to escape from the surface side of the toner image G. After that, the first cooling roll 82 cools the continuous paper P from the surface 2B opposite to the toner image forming surface 2A, and the continuous paper P and the toner image G are cooled. At this time, the contact width L2 between the first cooling roll 82 and the continuous book paper P in the transport direction of the continuous book paper P is from the contact width L1 between the first heating roll 62 and the continuous book paper P in the transport direction of the continuous book paper P. big. As a result, after the air causing the blister in the toner image G of the continuous paper P is released by the first heating roll 62, the continuous paper P and the toner image G are cooled by the first cooling roll 82. At this time, the cooling from the surface 2B opposite to the toner image forming surface 2A of the continuous paper P by the first cooling roll 82 is more glossy than the cooling from the toner image forming surface 2A of the continuous paper P. It has little effect. Here, the gloss unevenness of the image includes both the gloss unevenness in the same image and the gloss unevenness at different portions in the transport direction of the continuous paper P.

In the above image forming apparatus 10, in a configuration in which the surface opposite to the toner image forming surface of the continuous recording medium is heated and then the surface opposite to the toner image forming surface is cooled, the contact width between the cooling unit and the continuous recording medium is the heating unit. The gloss unevenness of the image is suppressed as compared with the case where the contact width is equal to or less than the contact width with the continuous recording medium.

Further, by heating the first heating roll 62 from the surface 2B opposite to the toner image forming surface 2A of the continuous paper P, the air in the toner image G easily escapes from the surface side of the toner image G. Therefore, in the image forming apparatus 10, the generation of blisters is suppressed as compared with the configuration in which the fixing members are brought into contact with each other from both sides of the continuous paper P to provide the nip portion.

Here, the cause of blister generation will be described using the fixing device of the comparative example.

FIG. 7 shows the state of the toner image G before fixing when the paper P1 is used as the continuous recording medium. As shown in FIG. 7, before fixing, a large number of substantially elliptical toner T particles are placed on the paper P1 in various directions.

FIG. 8 shows a state in which the toner image G on the paper P1 is heated and pressurized by the fixing device 200 without preheating. As shown in FIG. 8, in the fixing device 200 of the comparative example, the fixing roll 202 that heats the toner T on the paper P1 and the pressurizing member 204 arranged on the opposite side of the fixing roll 202 with the paper P1 sandwiched between them. Is provided. In the fixing device 200, a heating portion for preheating the toner image G is not provided on the upstream side of the nip portion between the fixing roll 202 and the pressurizing member 204. The toner image G on the paper P1 is pressed by the nip portion of the fixing roll 202 and the pressure member 204, so that the directions of a large number of substantially elliptical toners T are aligned (the toners T are organized), and in this state. The toner T is heated and pressurized.

FIG. 9 shows a state in which the toner image G is fixed on the paper P1. As shown in FIG. 9, the toner T (see FIG. 8) on the paper P1 melts in a pressurized state, so that the toner image G is fixed on the paper P1. At this time, the air in the toner image G escapes into the paper P1 (between the fibers of the paper P1) as shown by the arrow.

FIG. 10 shows the state of the toner image G at the time of fixing when the resin film P2 is used as the continuous recording medium. The resin film P2 is made of, for example, polyethylene terephthalate (PET) or polypropylene (PP). As shown in FIG. 10, when the toner image G on the resin film P2 is heated and pressed by the nip portion between the fixing roll 202 and the pressure member 204, the air permeability of the resin film P2 is low, so that the toner image The air A1 in G cannot escape into the resin film P2. Therefore, a large amount of air A1 is confined in the molten toner image G.

FIG. 11 shows the state of the toner image G on the resin film P2 after fixing. As shown in FIG. 11, the toner image G on the resin film P2 exits the nip portion between the fixing roll 202 (see FIG. 10) and the pressure member 204 (see FIG. 10), and at the same time the pressure is released. Air A1 (see FIG. 10) pops out of the toner image G. As a result, a plurality of holes 210 such as craters, that is, blister, are generated on the surface of the toner image G.

On the other hand, in the image forming apparatus 10 of the present embodiment, the first heating roll 62 heats the toner image G from the surface 2B opposite to the toner image forming surface 2A of the continuous paper P in a non-pressurized state. The air in the toner image G easily escapes from the surface side of the toner image G. Therefore, in the above image forming apparatus 10, even when a resin film is used as the continuous paper P, blister is generated as compared with a configuration in which the fixing roll 202 and the pressure member 204 are brought into contact with each other to provide a nip portion. Is suppressed.

Further, in the image forming apparatus 10, at least the first cooling roll 82 is configured not to have a nip forming portion for forming a nip. As a result, only the surface 2B opposite to the toner image forming surface 2A of the continuous paper P is independently cooled by the first cooling roll 82. Therefore, in the image forming apparatus 10, the unevenness of the gloss of the image is suppressed as compared with the structure in which the cooling part has the nip forming part.

Further, in the image forming apparatus 10, the first heating roll 62 and the first cooling roll 82 are both rolls, and the winding angle θ2 of the continuous paper P around the first cooling roll 82 is set to the first heating roll 62. The winding angle θ1 of the continuous paper P is larger than that of. Therefore, in the above-mentioned image forming apparatus 10, the continuous book paper P has a simple configuration as compared with a configuration in which the winding angle of the continuous recording medium around the cooling portion is equal to or less than the winding angle of the continuous recording medium around the heating portion. Can be cooled.

Further, in the image forming apparatus 10, the thermal conductivity of the surface of the first cooling roll 82 is larger than the thermal conductivity of the surface of the first heating roll 62. Therefore, in the above-mentioned image forming apparatus 10, the continuous paper P is more likely to be cooled as compared with the case where the thermal conductivity of the surface of the cooling portion is equal to or lower than the thermal conductivity of the surface of the heating portion.

Further, in the image forming apparatus 10, the surface roughness (Ra) of the first cooling roll 82 is coarser (larger) than the surface roughness (Ra) of the first heating roll 62. When the surface roughness (Ra) of the first cooling roll 82 is made coarser than the surface roughness (Ra) of the first heating roll 62, the first cooling roll 82 is easier to cool than the first heating roll 62. In the image forming apparatus 10, the continuous paper P is more likely to be cooled as compared with the case where the surface roughness of the cooling portion is equal to or less than the surface roughness of the heating portion.

Further, in the image forming apparatus 10, the second heating roll 64 is located downstream from the center of the contact portion between the first heating roll 62 and the continuous paper P in the transport direction (arrow B direction) of the continuous paper P. Have been placed. Therefore, in the above-mentioned image forming apparatus 10, the generation of image blister is suppressed as compared with the configuration in which the other heating portion is arranged on the upstream side of the center of the contact portion between the heating portion and the continuous recording medium. However, the fixing property is improved.

Further, in the image forming apparatus 10, there is no peeling member such as a claw or a baffle at the outlet of the nip portion between the first heating roll 62 and the second heating roll 64, and the peeling member comes into contact with the continuous paper P. Never. Therefore, in the image forming apparatus 10, the unevenness of the gloss of the image is suppressed as compared with the configuration in which the peeling member is provided at the outlet of the nip portion between the heating portion and the other heating portion.

Further, in the image forming apparatus 10, a second cooling roll 84 that comes into contact with the toner image forming surface 2A of the continuous book paper P is provided on the downstream side of the first cooling roll 82 in the transport direction of the continuous book paper P. There is. Therefore, in the image forming apparatus 10, the unevenness of the gloss of the image is suppressed as compared with the configuration in which the toner image forming surface of the continuous recording medium is not cooled on the downstream side of the cooling unit.

Further, in the image forming apparatus 10, the length L3 of the continuous paper P (the length of the continuous paper P in the transport direction) between the first heating roll 62 and the first cooling roll 82 is the continuous book. The length is smaller than the total length of the contact width L1 between the first heating roll 62 and the continuous paper P in the transport direction of the paper P and the contact width L2 between the first cooling roll 82 and the continuous paper P. As a result, the continuous paper P is cooled early by the first cooling roll 82. Therefore, in the image forming apparatus 10, the length of the continuous recording medium between the heating unit and the cooling unit is the contact width between the heating unit and the continuous recording medium and the contact width between the cooling unit and the continuous recording medium. Compared with the configuration in which the total length is longer than or equal to the total length, the expansion and contraction due to the residual heat of the continuous paper P is suppressed particularly when the continuous paper P is a resin film.

As a modification of the above image forming apparatus 10, the relationship between the thermal conductivity of the surface of the first cooling roll 82 and the thermal conductivity of the surface of the first heating roll 62, the surface roughness of the first cooling roll 82 ( The relationship between Ra) and the surface roughness (Ra) of the first heating roll 62 may satisfy either one. That is, in the image forming apparatus of the modified example, only the relationship that the thermal conductivity of the surface of the first cooling roll 82 is larger than the thermal conductivity of the surface of the first heating roll 62 may be satisfied, or the first cooling roll 82 may be satisfied. Only the relationship that the surface roughness (Ra) of the first heating roll 62 is coarser (larger) than the surface roughness (Ra) of the first heating roll 62 may be satisfied.

<< Second Embodiment >>
Next, the image forming apparatus as the second embodiment will be described with reference to FIG. The same components as those of the first embodiment described above will be assigned the same number and the description thereof will be omitted.

As shown in FIG. 5, the image forming apparatus 120 includes a fixing device 122. The fixing device 122 includes a first heating roll 124 as an example of a heating portion that comes into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. As an example, the first heating roll 124 includes a cylindrical roll 124A and a heating source 62B arranged inside the roll 124A. The outer diameter of the first cooling roll 82 is larger than the outer diameter of the first heating roll 124 (roll 124A). Further, the contact width L2 between the first cooling roll 82 and the continuous book paper P in the transport direction of the continuous book paper P is larger than the contact width L1 between the first heating roll 124 and the continuous book paper P in the transport direction of the continuous book paper P. ..

Further, the length L3 of the continuous paper P (the length of the continuous paper P in the transport direction) between the first heating roll 124 and the first cooling roll 82 is the first in the transport direction of the continuous paper P. The length is smaller than the total length of the contact width L1 between the heating roll 124 and the continuous paper P and the contact width L2 between the first cooling roll 82 and the continuous paper P.

In the above-mentioned image forming apparatus 120, in addition to the effect having the same configuration as the image forming apparatus 10 of the first embodiment, the following effects can be obtained. The effect of the same configuration as that of the image forming apparatus 10 of the first embodiment will be omitted.

In the image forming apparatus 120, the first cooling roll 82 and the first heating roll 124 are both rolls, and the outer diameter of the first cooling roll 82 is larger than the outer diameter of the first heating roll 124. Therefore, in the image forming apparatus 120 described above, the continuous paper P can be cooled with a simple configuration as compared with a configuration in which the outer diameter of the cooling portion is equal to or smaller than the outer diameter of the heating portion.

<< Third Embodiment >>
Next, the image forming apparatus as the third embodiment will be described with reference to FIG. The same components as those of the first and second embodiments described above will be assigned the same number and the description thereof will be omitted.

As shown in FIG. 6, the image forming apparatus 130 is provided with a fixing apparatus 60 provided with a first heating roll 62 that comes into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. Further, the image forming apparatus 130 is provided with a cooling apparatus 80 provided with a first cooling roll 82 in contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. The contact width L2 between the first cooling roll 82 and the continuous book paper P in the transport direction of the continuous book paper P is larger than the contact width L1 between the first heating roll 62 and the continuous book paper P in the transport direction of the continuous book paper P. Further, the length L4 of the continuous paper P (the length of the continuous paper P in the transport direction) between the first heating roll 62 and the first cooling roll 82 is the first in the transport direction of the continuous paper P. It is smaller than the contact width L2 between the cooling roll 82 and the continuous paper P.

In the above-mentioned image forming apparatus 130, in addition to the effect having the same configuration as the image forming apparatus 10 of the first embodiment, the following effects can be obtained. The effect of the same configuration as that of the image forming apparatus 10 of the first embodiment will be omitted.

In the image forming apparatus 130, the length L4 (the length of the continuous paper P in the transport direction) of the continuous paper P between the first heating roll 62 and the first cooling roll 82 is the continuous paper P. It is smaller than the contact width L2 between the first cooling roll 82 and the continuous paper P in the transport direction of. As a result, the continuous paper P is cooled early by the first cooling roll 82 after the fixing by the fixing device 60. Therefore, in the above-mentioned image forming apparatus 130, the length of the continuous recording medium between the heating unit and the cooling unit is particularly larger than the contact width between the cooling unit and the continuous recording medium. When the paper P is a resin film, the expansion and contraction of the continuous paper P due to the residual heat of the continuous paper P is suppressed.

<Supplementary explanation>
In the image forming apparatus 10, 120, 130 of the first to third embodiments, the cooling device 80 includes a first cooling roll 82 and a second cooling roll 84, but the present invention is limited to this configuration. is not. For example, the configurations of the first cooling roll 82 and the second cooling roll 84 can be changed. Further, the image forming apparatus includes a cooling unit provided with a member other than the roll (for example, a belt and a cooling member, or a member having a flat plate-shaped cooling surface), and a member other than the roll (for example, a belt and a cooling member). Alternatively, it may be configured to have another cooling unit provided with (such as a member having a flat plate-shaped cooling surface).

In the image forming apparatus 10, 120, 130 of the first to third embodiments, the fixing devices 60, 122 include the first heating rolls 62, 124 and the second heating roll 64. It is not limited to the configuration. For example, the image forming apparatus has a configuration including a heating unit including a member other than the roll (for example, a belt and a heating member) and a second heating unit including a member other than the roll (for example, a belt and a heating member). But it may be. Further, one heating unit may be provided instead of the two heating units. For example, the structure may include only a heating portion for fixing the toner image by heating from the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. Further, the heating unit may be arranged in a non-contact manner with the toner image G of the continuous paper P.

Further, in the image forming apparatus 10, the arrangement relation of each member of the cooling apparatus 80 may be changed. For example, the length of the continuous paper P between the first cooling roll 82 and the second cooling roll 84 may be longer than the contact width between the first cooling roll 82 and the continuous paper P. Further, the length of the continuous paper P between the first cooling roll 82 and the second cooling roll 84 may be longer than the contact width between the second cooling roll 84 and the continuous paper P. Further, the length of the continuous paper P between the first cooling roll 82 and the second cooling roll 84 may be 0.

Further, in the image forming apparatus 10 described above, it is possible to change each member constituting the fixing apparatus 60.

Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is obvious to the trader.

2A Toner image forming surface 2B Surface opposite to the toner image forming surface 10 Image forming apparatus 62 First heating roll (an example of a heating part, an example of a fixing part)
64 Second heating roll (an example of another heating part, an example of a fixing part)
82 First cooling roll (example of cooling unit)
84 Second cooling roll (an example of another cooling unit)
120 Image forming apparatus 124 First heating roll (an example of a heating unit)
130 Image forming device θ1 angle (an example of the winding angle of the continuous recording medium around the heating part)
θ2 angle (an example of the winding angle of the continuous recording medium around the cooling unit)
G Toner image L1 Contact width (an example of contact width between the heating unit and the continuous recording medium)
L2 contact width (an example of contact width between the cooling unit and the continuous recording medium)
L3 length (an example of the length of the continuous recording medium between the heating part and the cooling part)
L4 length (an example of the length of the continuous recording medium between the heating part and the cooling part)
P continuous paper (an example of continuous recording medium)

Claims (11)

A heating unit that heats in contact with the surface opposite to the toner image forming surface of the continuous recording medium,
A cooling unit that first contacts and cools the surface of the continuous recording medium opposite to the toner image forming surface on the downstream side of the heating unit in the transport direction of the continuous recording medium, and is a cooling unit that cools the continuous recording medium in the transport direction. The cooling unit, wherein the contact width with the continuous recording medium is larger than the contact width between the heating unit and the continuous recording medium.
Have,
An image forming apparatus in which the heating unit and the cooling unit are composed of rolls, and the outer diameter of the cooling unit is larger than the outer diameter of the heating unit . A heating unit that heats in contact with the surface opposite to the toner image forming surface of the continuous recording medium,
A cooling unit that first contacts and cools the surface of the continuous recording medium opposite to the toner image forming surface on the downstream side of the heating unit in the transport direction of the continuous recording medium, and is a cooling unit that cools the continuous recording medium in the transport direction. The cooling unit, wherein the contact width with the continuous recording medium is larger than the contact width between the heating unit and the continuous recording medium.
Have,
An image forming apparatus in which the heating unit and the cooling unit are composed of rolls, and the winding angle of the continuous recording medium around the cooling unit is larger than the winding angle of the continuous recording medium around the heating unit . The image forming apparatus according to claim 1 or 2 , wherein at least the surface roughness of the cooling portion is coarser than the surface roughness of the heating portion. A heating unit that heats in contact with the surface opposite to the toner image forming surface of the continuous recording medium,
A cooling unit that first contacts and cools the surface of the continuous recording medium opposite to the toner image forming surface on the downstream side of the heating unit in the transport direction of the continuous recording medium, and is a cooling unit that cools the continuous recording medium in the transport direction. The cooling unit, wherein the contact width with the continuous recording medium is larger than the contact width between the heating unit and the continuous recording medium.
Have,
An image forming apparatus in which at least the surface roughness of the cooling portion is coarser than the surface roughness of the heating portion . Another heating unit is provided at a position facing the heating unit to contact and heat the toner image forming surface of the continuous recording medium.
The other heating unit is arranged on the downstream side of the center of the contact portion between the heating unit and the continuous recording medium in the transport direction of the continuous recording medium, and the heating unit displays a toner image on the continuous recording medium. The image forming apparatus according to any one of claims 1 to 4 , which constitutes a fixing portion to be fixed. A heating unit that heats in contact with the surface opposite to the toner image forming surface of the continuous recording medium,
A cooling unit that first contacts and cools the surface of the continuous recording medium opposite to the toner image forming surface on the downstream side of the heating unit in the transport direction of the continuous recording medium, and is a cooling unit that cools the continuous recording medium in the transport direction. The cooling unit, wherein the contact width with the continuous recording medium is larger than the contact width between the heating unit and the continuous recording medium.
Have,
Another heating unit is provided at a position facing the heating unit to contact and heat the toner image forming surface of the continuous recording medium.
The other heating unit is arranged on the downstream side of the center of the contact portion between the heating unit and the continuous recording medium in the transport direction of the continuous recording medium, and the heating unit displays a toner image on the continuous recording medium. An image forming apparatus that constitutes a fixing portion to be fixed . The image forming apparatus according to claim 5 or 6 , wherein there is no peeling member at the outlet of the nip portion between the heating portion and the other heating portion. Any of claims 5 to 7, which has another cooling unit that first contacts and cools the toner image forming surface of the continuous recording medium on the downstream side of the cooling unit in the transport direction of the continuous recording medium. The image forming apparatus according to item 1 . The length of the continuous recording medium between the heating unit and the cooling unit is the contact width between the heating unit and the continuous recording medium in the transport direction of the continuous recording medium, and the cooling unit and the continuous recording medium. The image forming apparatus according to any one of claims 1 to 8 , which is smaller than the total length of the contact width of the above. A heating unit that heats in contact with the surface opposite to the toner image forming surface of the continuous recording medium,
A cooling unit that first contacts and cools the surface of the continuous recording medium opposite to the toner image forming surface on the downstream side of the heating unit in the transport direction of the continuous recording medium, and is a cooling unit that cools the continuous recording medium in the transport direction. The cooling unit, wherein the contact width with the continuous recording medium is larger than the contact width between the heating unit and the continuous recording medium.
Have,
The length of the continuous recording medium between the heating unit and the cooling unit is the contact width between the heating unit and the continuous recording medium in the transport direction of the continuous recording medium, and the cooling unit and the continuous recording medium. An image forming device smaller than the total length of the contact width of . According to claim 9 or 10 , the length of the continuous recording medium between the heating unit and the cooling unit is smaller than the contact width between the cooling unit and the continuous recording medium in the transport direction of the continuous recording medium. The image forming apparatus according to the description.

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