JP7131108B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Patent Literature 1 listed below discloses a film stretching method in which an engaging portion is provided on a cooling roll after heating during film production to suppress thermal shrinkage.

Japanese Unexamined Patent Application Publication No. 2002-200000 discloses an image forming apparatus in which an expander roll is provided between a preheating section and a main fixing section, and the temperature of the film on the expander roll is controlled by a fan.

JP-A-02-048924 JP 2017-167340 A

For example, when the cooling unit first comes into contact with the fixing unit downstream of the fixing unit in the conveying direction of the continuous recording medium, the continuous recording medium may be wrinkled due to deformation of the continuous recording medium.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus that suppresses wrinkling of a continuous recording medium compared to an image forming apparatus in which a cooling section contacts first downstream of a fixing section in the conveying direction of the continuous recording medium.

The image forming apparatus according to the first aspect includes : a fixing unit that fixes a toner image formed on a continuous recording medium; a contact member for pulling the continuous recording medium outward in the width direction; a cooling unit for cooling the continuous recording medium by contacting the continuous recording medium first on the downstream side of the contact member in the conveying direction of the continuous recording medium; have

The image forming apparatus according to the second aspect is the image forming apparatus according to the first aspect , wherein the contact member does not contact the toner image forming area of the continuous recording medium.

The image forming apparatus according to a third aspect is the image forming apparatus according to the second aspect , wherein the contact member contacts only the surface of the continuous recording medium opposite to the toner image forming surface.

The image forming apparatus according to a fourth aspect is the image forming apparatus according to any one of the first to third aspects , wherein a heating roll provided in the fixing section and a heating roll provided in the cooling section and a cooling roll, wherein the contact member is a contact roll, and the diameter of the contact roll is smaller than both the diameter of the heating roll and the diameter of the cooling roll.

The image forming apparatus according to a fifth aspect is the image forming apparatus according to any one of the first to fourth aspects , wherein the contact member is positioned closer to the cooling section than to the fixing section. .

The image forming apparatus according to a sixth aspect is the image forming apparatus according to the fourth aspect , wherein the contact member is positioned closer to the fixing section than to the cooling section.

The image forming apparatus according to a seventh aspect is the image forming apparatus according to any one of the first to sixth aspects , wherein the contact member adjusts the degree of pulling the continuous recording medium outward in the width direction. It is adjustable.

The image forming apparatus according to the eighth aspect is characterized in that, in the image forming apparatus according to the seventh aspect , when the continuous recording medium is a film, the contact member is the continuous recording medium compared to when the continuous recording medium is paper. Increase the degree of tension with which the recording medium is contacted.

The image forming apparatus according to a ninth aspect is the image forming apparatus according to the seventh aspect or the eighth aspect , wherein the contact member is an extractor having a plurality of rolls arranged along a shaft portion capable of changing the amount of bending. It's a panda roll.

According to the image forming apparatus of the first aspect , wrinkling of the continuous recording medium is suppressed compared to the case where the cooling section comes into first contact downstream of the fixing section in the conveying direction of the continuous recording medium.

According to the image forming apparatus of the second aspect , compared with the configuration in which the contact member contacts the toner image forming area of the continuous recording medium, the change in the surface shape of the image is suppressed before cooling.

According to the image forming apparatus according to the third aspect , compared with the configuration in which the contact member contacts the toner image forming surface of the continuous recording medium, the change in surface shape of the image is suppressed before cooling.

According to the image forming apparatus of the fourth aspect , the temperature difference before and after the contact roll on the continuous recording medium is smaller than when the diameter of the contact roll is equal to or larger than the diameter of the heating roll or the cooling roll. Become.

According to the image forming apparatus of the fifth aspect , wrinkling of the continuous recording medium is suppressed as compared with the case where the contact member is positioned closer to the fixing section than to the cooling section.

According to the image forming apparatus of the sixth aspect , the temperature difference before and after the contact roll on the continuous recording medium is smaller than when the contact member is positioned closer to the cooling section than to the fixing section.

According to the image forming apparatus of the seventh aspect , the occurrence of wrinkles in the continuous recording medium is suppressed as compared with the case where the contact member pulls the continuous recording medium outward in the width direction at a constant pulling degree.

According to the image forming apparatus according to the eighth aspect , the occurrence of wrinkles is suppressed even in the case of the film of the continuous recording medium, compared to the case where the contact amount of the contact member to the continuous recording medium does not change. In addition, when the continuous recording medium is paper, the change in the surface shape of the image before cooling is suppressed compared to when the contact amount of the contact member with the continuous recording medium does not change.

According to the image forming apparatus of the ninth aspect , the degree of tension of the contact member can be easily adjusted as compared with the structure in which the contact member is an inverted crown-shaped roll.

1 is a schematic configuration diagram showing an image forming apparatus according to a first embodiment; FIG. 2 is a schematic configuration diagram showing a toner image forming unit used in the image forming apparatus according to the first embodiment; FIG. 2 is a schematic configuration diagram showing an expander roll between a fixing device and a cooling device used in the image forming apparatus according to the first embodiment; FIG. FIG. 2 is a bottom view seen from the continuous recording medium side showing the positional relationship among a fixing device, an expander roll, and a cooling device used in the image forming apparatus according to the first embodiment; 2 is a front view showing the positional relationship among a fixing device, an expander roll, and a cooling device used in the image forming apparatus according to the first embodiment; FIG. 2 is a partially cut plan view showing an expander roll used in the image forming apparatus according to the first embodiment; FIG. (A) is a front view showing a wrap amount of an expander roll on a continuous recording medium and a bending amount of the expander roll used in the image forming apparatus according to the first embodiment; FIG. 4 is a bottom view seen from the continuous recording medium side showing a contact state of an expander roll to the continuous recording medium used in the image forming apparatus according to the embodiment; 2 is a configuration diagram showing a wrap amount changing device and a bending amount changing device used in the image forming apparatus according to the first embodiment; FIG. 2 is a front view showing a state in which an expander roll used in the image forming apparatus according to the first embodiment is separated from the continuous recording medium; FIG. FIG. 10 is a diagram showing wrinkle generation states of a continuous recording medium when an expander roll is used and when no countermeasure is taken; FIG. 8 is a plan view showing a contact roll used in an image forming apparatus according to a second embodiment; FIG. 11 is a plan view showing straight rolls and nip rolls used in an image forming apparatus according to a third embodiment; FIG. 11 is a schematic configuration diagram showing an expander roll between a fixing device and a cooling device used in an image forming apparatus according to a fourth embodiment;

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

<Overall Configuration of Image Forming Apparatus 10>
First, the configuration of the image forming apparatus 10 will be described. FIG. 1 shows the configuration of the image forming apparatus 10 viewed from the front side.

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

The continuous paper P has, for example, an image surface on which an image is formed on the front surface, and a non-image surface on which an image is not formed on the back surface. Examples of the continuous form paper P include plain paper, film (resin film), metal foil (such as aluminum foil), and a recording medium in which a film (resin film) and metal foil are laminated. Recording media in which a film and a metal foil are laminated include, for example, a recording medium having a metal foil on one of an image surface and a non-image surface and a film (resin film) on the other surface. In this embodiment, the continuous paper P is, for example, a thermoplastic OPP (oriented polypropylene) or PET (polyethylene terephthalate) film.

Specifically, as shown in FIG. 1, the image forming apparatus 10 includes a conveying section 50, an image forming section 12, a fixing device 60, an expander roll 110, a cooling device 80, and a control section 100. ,have.

(Conveyor 50)
The transport unit 50 is a part that has a function of transporting the continuous paper P that has been arranged in advance on the transport path. Specifically, as shown in FIG. 1, the conveying unit 50 includes an unwinding 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 winding member).

The unwinding roll 51 is a roll for unwinding the continuous paper P, and functions as an example of a supply section that supplies the continuous paper P toward the transfer section 35 (secondary transfer position NT) described later. A trailing end portion (an upstream portion in the conveying direction) of the continuous paper P is wound around the feed roll 51 . The take-up roll 53 is a roll that winds the continuous paper P, and functions as a collection unit that collects the continuous paper P transported from the transfer unit 35 (secondary transfer position NT) described later. A leading end portion (downstream portion in the conveying direction) of the continuous form paper P is wound around the take-up roll 53 .

The drive unit 55 rotates the take-up roll 53 in the direction in which the take-up roll 53 winds the continuous paper P (counterclockwise direction in FIG. 1). Then, the continuous form paper P is wound by the winding roll 53 by the rotational driving of the drive unit 55 , so that the continuous form paper P is pulled and the unwinding roll 51 unwinds the continuous form paper P. In this manner, the driving unit 55 rotates to cause the winding roll 53 to wind the continuous paper P and the unwinding roll 51 to unwind the continuous paper P, thereby conveying the continuous paper P in the conveying direction. be done.

The winding rolls 52, 54, and 56 are on the transport path between the unwinding roll 51 and the transfer section 35 (secondary transfer position NT) described later, and in the order of the winding rolls 52, 54, and 56. are arranged along the conveying direction. Therefore, the winding roll 52 is arranged at a position closest to the unwinding roll 51 among the winding rolls 52 , 54 and 56 . The winding roll 54 is arranged above the winding rolls 52 and 56 . The continuous paper P is wound around the winding rolls 52 and 56 so that the outer peripheral surfaces of the continuous paper P are in contact with the image surface of the continuous paper P. As shown in FIG. The continuous paper P is wound around the winding roll 54 so that the outer peripheral surface of the continuous paper P is in contact with the non-image surface (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 so as to correct the conveying path of the continuous paper P. FIG.

(Image forming unit 12)
The image forming section 12 is a section having a function of forming an image on a continuous form P by an electrophotographic method. Specifically, the image forming section 12 includes a toner image forming section 20 that forms a toner image, and a transfer device 30 that transfers the toner image formed by the toner image forming section 20 onto the continuous form 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 total of four color toner image forming units 20 of yellow (Y), magenta (M), cyan (C), and black (K) are provided. (Y), (M), (C), and (K) shown in FIG. 1 indicate components corresponding to the respective 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 each member code. Y, M, C, and K may be omitted if there is no need to distinguish between colors.

[Toner image forming unit 20]
The toner image forming units 20 for each color are basically configured in the same manner except for the toner used. Specifically, as shown in FIG. 2, the toner image forming unit 20 for each color includes a photoreceptor drum 21 (photoreceptor) that rotates clockwise in FIG. 22 and an exposure device 23 that exposes the photosensitive drum 21 charged by the charger 22 to form an electrostatic latent image on the photosensitive drum 21 . Further, the toner image forming unit 20 for each color includes a developing device 24 that develops the electrostatic latent image formed on the photosensitive drum 21 by the exposure device 23 to form a toner image, and a toner image onto a transfer belt 31, which will be described later. and a blade 25 as a remover for removing toner remaining on the surface of the photosensitive drum 21 after the transfer.

The charger 22 negatively charges the surface (photosensitive layer) of the photosensitive drum 21, for example. The negatively charged surface of the photosensitive drum 21 becomes positive in the portion irradiated with the exposure light L by the exposure device 23 , and an electrostatic latent image is formed on the surface of the photosensitive drum 21 . Then, the toner triboelectrically charged to have a negative polarity in the developing device 24 adheres to the electrostatic latent image exhibiting a positive polarity to develop the electrostatic latent image. Thus, a toner image is formed on the surface (peripheral surface) of the photosensitive drum 21 . The blade 25 contacts the surface of the photoreceptor drum 21 and scrapes off the toner remaining on the surface of the photoreceptor drum 21 .

[Transfer device 30]
The transfer device 30 superimposes and primarily transfers the toner images on the photoreceptor drum 21 of each color onto a transfer belt 31 as an intermediate transfer member, and connects the superimposed toner images at a secondary transfer position NT (nip portion). Secondarily transfer to the book paper P. Specifically, the transfer device 30 includes a transfer belt 31, a primary transfer roll 33, and a secondary transfer roll 34, as shown in FIG.

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

Among the plurality of rolls 32 , the roll 32 T shown in FIG. 1 functions as a tension imparting roll that imparts tension to the transfer belt 31 . Among the plurality of rolls 32, the roll 32B shown in FIG. 1 functions as the opposing roll 32B of the secondary transfer roll 34. As described above, the opposite roll 32B is wrapped around the top of the lower end of the transfer belt 31, which forms an obtuse angle and is in the shape of an inverted obtuse triangle. The transfer belt 31 is in contact with the photoreceptor drums 21 of the respective colors from below at the upper side portion extending in the width direction of the apparatus in the posture described above.

[Primary transfer roll 33]
The primary transfer roll 33 is a roll that transfers the toner image of each photosensitive drum 21 onto the transfer belt 31, and is arranged inside the transfer belt 31 as shown in FIG. Each primary transfer roll 33 is arranged to face the photosensitive drum 21 of the corresponding color with the transfer belt 31 interposed therebetween. A primary transfer voltage is applied between the primary transfer roll 33 and the photoreceptor drum 21 by a power supply section 37 (see FIG. 2). As a result, the toner image formed on the photoreceptor drum 21 is transferred to the transfer belt 31 at the primary transfer position T (see FIG. 2) between the photoreceptor 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 form paper P. As shown in FIG. As shown in FIG. 1, the secondary transfer roll 34 is arranged so as to sandwich the transfer belt 31 between itself and the opposing roll 32B. are in contact with A secondary transfer position NT (nip portion) is defined between the secondary transfer roll 34 and the transfer belt 31 that are in contact with each other in this way. Continuous paper P is supplied from the unwinding roll 51 to the secondary transfer position NT. The secondary transfer roll 34 is rotated clockwise in FIG.

Further, a secondary transfer voltage is applied by the applying section 39 between the secondary transfer roll 34 and the opposing roll 32B. 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, a voltage is applied along the thickness direction of the continuous paper P between the continuous paper P and the toner image at the secondary transfer position NT. As a result, an electrostatic force acts on the toner image on 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 opposing roll 32B apply a voltage between the continuous paper P and the toner image along the thickness direction of the continuous paper P to continuously transfer the toner image. A transfer section 35 for transferring to the paper sheet P is configured.

(Overview of Fixing Device 60)
The fixing device 60 is arranged downstream of the secondary transfer position NT in the conveying direction of the continuous paper P, as shown in FIG. Support rolls 58 and 59 are arranged between the secondary transfer position NT and the fixing device 60 to support the continuous paper P on a predetermined transport path. The support rolls 58 and 59 are designed to rotate as the continuous paper P moves. The support roll 59 is adapted to apply tension to the continuous paper P by moving in a direction intersecting the surface of the continuous paper P (in the direction of arrow H) by a moving mechanism (not shown).

The fixing device 60, as shown in FIG. and a second heating roll 64 that contacts the toner image forming surface 2A of the continuous paper P on the downstream side of the area where the toner image is formed. Here, the fixing device 60 is an example of a fixing section. The fixing device 60 will be detailed 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 of the continuous paper P opposite to the toner image forming surface 2A. Further, the continuous paper P and the toner image G are heated by bringing the second heating roller 64 into contact with the toner image forming surface 2A of the continuous paper P on the downstream side of the first heating roller 62 in the transport direction. As a result, the toner image G formed on the continuous form P is fixed to the continuous form P by heating and pressing. 3, only a part of the toner image G formed on the continuous paper P is illustrated.

(Overview of Expander Roll 110)
The image forming apparatus 10 is provided with an expander roll 110 that contacts the continuous form P downstream of the fixing device 60 in the conveying direction of the continuous form P and pulls the continuous form P outward in the width direction. The expander roll 110 is provided between the fixing device 60 and the cooling device 80 in the continuous paper P transport direction. In this embodiment, the expander roll 110 contacts the surface 2B of the continuous paper P opposite to the toner image forming surface 2A on the downstream side of the first heating roll 62 in the continuous paper P transport direction. Here, the expander roll 110 is an example of a contact member (that is, a contact roll). The expander roll 110 will be detailed later.

(Outline of cooling device 80)
As shown in FIG. 3, the cooling device 80 is a first cooling device that contacts the surface 2B of the continuous paper P opposite to the toner image forming surface 2A on the downstream side of the expander roll 110 in the conveying direction of the continuous paper P. A roll 82 is provided. Further, the cooling device 80 includes a second cooling roll 84 that contacts the toner image forming surface 2A of the continuous form P downstream of the first cooling roll 82 in the continuous form P transport direction. Here, the first cooling roll 82 is an example of a cooling section. The cooling device 80 will be detailed later. In the cooling device 80, the first cooling roll 82 is brought into contact with the surface 2B of the continuous paper P opposite to the toner image forming surface 2A, thereby cooling the continuous paper P and the toner image G from the side opposite to the toner image forming surface 2A. Cooling. Furthermore, by bringing the second cooling roll 84 into contact with the toner image forming surface 2A of the continuous paper P on the downstream side of the conveying direction of the first cooling roll 82, the continuous paper P and the toner image are cooled from the toner image forming surface 2A side. Cool G.

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

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

In the present embodiment, first, for example, the user of the image forming apparatus 10 manually arranges the continuous paper P in the transport path of the image forming apparatus 10 in advance. The continuous form 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 conveying path.

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

The toner images of each color formed on the photosensitive drums 21 of each color are sequentially primary-transferred onto the rotating transfer belt 31 at each primary transfer position T by the primary transfer rollers 33 of each color. As a result, a toner image in which toner images of four colors are superimposed is formed on the transfer belt 31 . This superimposed toner image is conveyed to the secondary transfer position NT by the rotation of the transfer belt 31 . At the secondary transfer position NT, the superimposed toner image G (see FIG. 3) is transferred from the transfer belt 31 to the continuous paper P. As shown in FIG.

The continuous paper P onto which the toner image G has been secondarily transferred is conveyed toward the fixing device 60 . In the fixing device 60 , the continuous paper sheet P is heated by the first heating roll 62 from the surface 2</b>B opposite to the toner image forming surface 2</b>A. 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 of the first heating roll 62 in the conveying direction, thereby heating and pressurizing the toner image G to heat and pressurize the continuous paper. P is fixed.

On the downstream side of the fixing device 60 in the conveying direction of the continuous paper P, the expander roll 110 contacts the surface 2B of the continuous paper P opposite to the toner image forming surface 2A. The expander roll 110 pulls and expands the continuous paper sheet P to the outside in the width direction. This function will be explained later.

Further, the continuous paper P is conveyed toward the cooling device 80 on the downstream side of the expander roll 110 . In the cooling device 80, the continuous paper P and the toner image G are cooled by the first cooling roll 82 from the surface 2B of the continuous paper P opposite to the toner image forming surface 2A. Further, the continuous paper P and the toner image G are cooled by the second cooling roller 84 coming into contact with the toner image forming surface 2A of the continuous paper P on the downstream side of the first cooling roller 82 in the transport direction. As a result, an image is formed on the continuous paper P, and the continuous paper P is taken up by the take-up roll 53 on the downstream side of the cooling device 80 in the conveying direction.

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

(Fixing device 60)
As shown in FIG. 3, the fixing device 60 includes the first heating roll 62 and the second heating roll 64 as described above. Here, the first heating roll 62 and the second heating roll 64 are examples of heating rolls. 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 this embodiment, the continuous paper P is wound around the first heating roll 62 in a range of 1/4 to 1/2 of the outer peripheral surface of the first heating roll 62, for example. 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 even more preferably 112° or more and 160° or less.

The first heating roll 62 includes, for example, a cylindrical roll 62A and a heat source 62B arranged inside the roll 62A. The heating source 62B is composed of, for example, a single or multiple halogen lamps, halogen heaters, or the like. The roll 62A has, for example, a multi-layer structure having an elastic layer and a release layer thereon on the surface of the core metal. A temperature sensor 66 is arranged at a position facing the outer peripheral surface of the first heating roll 62 (a facing portion through which the continuous paper P does not pass). The controller 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 as the continuous paper P moves. The outer diameter of the first heating roll 62 is, for example, φ200 mm.

The second heating roll 64 is located downstream of the range where the first heating roll 62 contacts the surface 2B of the continuous paper P opposite to the toner image forming surface 2A. in contact. In this embodiment, the second heating roll 64 is located at the most downstream position in the range where the first heating roll 62 contacts the surface 2B of the continuous paper P opposite to the toner image forming surface 2A. It is in contact with the image forming surface 2A. The second heating roll 64 includes, for example, a cylindrical roll 64A and a heat source 64B arranged inside the roll 64A. The roll 64A has, for example, a multi-layer structure having an elastic layer and a release layer thereon on the surface of the core metal. The heating source 64B is composed of, for example, a single or multiple halogen lamps, halogen heaters, or the like. A temperature sensor 68 is arranged at a position facing the outer peripheral surface of the second heating roll 64 . The controller 100 controls the first heating roll 62 to a predetermined temperature based on the temperature detected by the temperature sensor 68 . The first heating roll 62 is configured to rotate as the continuous paper P moves. The outer diameter of the second heating roll 64 is, for example, φ150 mm.

An external heating roll 70 that contacts the second heating roll 64 is arranged at a position on the opposite side of the second heating roll 64 from the first heating roll 62 . The external heating roll 70 includes, for example, a cylindrical roll 70A and a heating source 70B such as a halogen lamp or a halogen heater disposed 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 controller 100 controls the temperature of 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 following the rotation of the second heating roll 64 .

A cleaning roll 74 for removing deposits on the surface of the second heating roll 64 is provided at a position in contact with the outer peripheral surface of the second heating roll 64 . A roll 78 is in contact with the side of the cleaning roll 74 opposite to the second heating roll 64 via a 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.

A peeling member is not provided at the exit of the fixing device 60, that is, at the exit of the nip portion between the first heating roll 62 and the second heating roll 64 that come into contact with each other through the continuous paper P. FIG. 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 contacts the continuous paper P.

(Expander roll 110)
The expander roll 110 contacts only the surface 2B of the continuous paper P opposite to the toner image forming surface 2A on the downstream side of the first heating roller 62 in the conveying direction of the continuous paper P, as described above. That is, the expander roll 110 does not come into contact with the toner image forming area of the continuous paper P. As shown in FIG.

As shown in FIGS. 4 and 5, the expander roll 110 has an axial central portion 110A directed toward the downstream side in the conveying direction of the continuous paper P (the arrow B direction) with respect to the axially opposite end portions 110B. It has a curved shape that protrudes from the bottom. As shown in FIG. 6, the expander roll 110 has a shaft portion 112 that is curved so that the central portion in the axial direction protrudes toward the downstream side in the conveying direction of the continuous form paper P with respect to both ends in the axial direction. and a plurality of rolls 114 arranged at intervals in the axial direction of the shaft portion 112 . Further, the expander roll 110 includes an elastic layer 116 that covers (covers) the surfaces of the plurality of rolls 114 . Roll 114 is, for example, a metal roll. For example, the number of rolls 114 is preferably 5 or more, more preferably 10 or more, and even more preferably 15 or more. As an example, the elastic layer 116 is formed endlessly along the circumferential direction of the plurality of rolls 114 and continuously formed in the axial direction so as to straddle all the rolls 114 . The elastic layer 116 is composed of, for example, a rubber tube. Here, FIGS. 4 and 5 are exaggerated for the sake of easy understanding of the configuration.

In the expander roll 110, for example, a plurality of rolls 114 are rotatably supported with respect to a shaft portion 112, and the rotation of the plurality of rolls 114 causes the elastic layer 116 to rotate following the movement of the continuous paper P. It is designed to The outer diameter of the expander roll 110 (that is, the elastic layer 116) is, for example, φ60 mm.

As shown in FIG. 7, when the image forming apparatus 10 is viewed from the front, the expander roll 110 is set to have a bending amount C1 protruded downstream in the conveying direction of the continuous paper P (FIG. 7 (A )reference). Here, the amount of bending C1 is the distance between the central portion of both ends 110B of the expander roll 110 in the axial direction and the most projected surface of the central portion 11A of the expander roll 110 in the axial direction. The bending amount C1 of the expander roll 110 is preferably 0.5 mm or more and 4.0 mm or less, more preferably 1.5 mm or more and 3.5 mm or less, and even more preferably 2.0 mm or more and 3.0 mm or less. If the bending amount C1 of the expander roll 110 is less than 0.5 mm, the effect of pulling the continuous paper P is reduced. becomes larger. Here, FIG. 7 is exaggerated and illustrated in order to make the configuration easier to understand.

As shown in FIGS. 7A and 7B, when the image forming apparatus 10 is viewed from the front, the expander roll 110 includes a wrap that contacts the continuous paper P in the conveying direction of the continuous paper P. A quantity L1 is set. Here, the wrap amount L1 is the angle between the upstream end of the continuous paper P in the transport direction where the expander roll 110 contacts the continuous paper P and the downstream end of the continuous paper P in the transport direction. is. Note that FIG. 7A shows the overlap amount L1 between the continuous paper P and the end portions 110B on both sides in the width direction of the expander roll 110. As shown in FIG. The overlap amount L1 is the same between both widthwise end portions 110B and the widthwise central portion 110A of the expander roll 110 .

The wrap amount L1 of the expander roll 110 is preferably 30° or more and 70° or less, more preferably 45° or more and 65° or less, and even more preferably 50° or more and 60° or less. If the wrap amount L1 of the expander roll 110 is less than 30°, the effect of pulling the continuous paper P is reduced. Become.

As shown in FIG. 8, the expander roll 110 includes a wrap amount changing device 120 that changes the wrap amount L1, and a bending amount changing device 130 that changes the bending amount C1 (that is, the bending amount). . The overlap amount changing device 120 includes bearings 122 provided at both ends of the shaft portion 112 of the expander roll 110 and latch cams 124 that contact the outer peripheral surface of the bearings 122 . Further, the wrap amount changing device 120 includes a rotary shaft 126 connected to the latch cam 124 and a motor 128 that rotates the rotary shaft 126 . The latch cam 124 has a shape such that the radius of the outer circumference from the rotary shaft 126 gradually changes, and rotates while being in contact with the bearing 122 by an urging means (not shown).

In the overlap amount changing device 120, the overlap amount L1 with respect to the continuous paper P is adjusted by the position at which the latch cam 124 contacts the bearing 122. As shown in FIG. Further, when the portion of the latch cam 124 with the smallest radius from the rotary shaft 126 is in contact with the bearing 122, the expander roll 110 is separated from the continuous paper P (see FIG. 9).

The rotational position of the latch cam 124 is controlled by the amount of rotation of the motor 128 . The control unit 100 refers to a table that defines the correspondence relationship between the optimum wrap amount L1 of the expander roll 110 and the rotation amount of the motor 128 for the material, thickness, and fixing temperature of the continuous form paper P, which will be described later. The amount of rotation of the motor 128 is determined with respect to the material and thickness of the paper P and the fixing temperature. The table is obtained in advance by experiments using the image forming apparatus 10 (see Tables 1 to 7, which will be described later), computer simulations based on design specifications, etc. stored in

The bending amount changing device 130 includes a connecting portion 132 connected to the shaft portion 112 of the expander roll 110 and a motor 134 that changes the bending amount L of the shaft portion 112 via the connecting portion 132 . Although not shown, the shaft portion 112 is provided with a bending amount adjustment dial for adjusting the bending amount of the shaft portion 112 , and a motor 134 is connected to the bending amount adjustment dial via a connecting portion 132 . The rotational position of the bending amount adjustment dial is defined by the amount of rotation of the motor 134 . The control unit 100 refers to a table that defines the correspondence relationship between the optimum amount of bending of the shaft portion 112 and the amount of rotation of the motor 134 with respect to the material, thickness, and fixing temperature of the continuous paper P, which will be described later. The amount of rotation of the motor 134 is determined with respect to the material, thickness, and fixing temperature. The table is obtained in advance by experiments using the image forming apparatus 10 (see Tables 1 to 7, which will be described later), computer simulations based on design specifications, etc. stored in

The bending amount changing device 130 changes the bending amount L of the shaft portion 112 by changing the amount of tension for pulling the both end portions of the shaft portion 112 by the amount of rotation of the motor 134, for example.

The expander roll 110 can adjust the degree of pulling the continuous paper P outward in the width direction by changing both the wrap amount L1 and the bend amount C1, or at least one of the wrap amount L1 and the bend amount C1. ing. Here, the wrap amount L1 includes the case where the expander roll 110 does not come into contact with the continuous form paper P when it is 0. For example, when the continuous paper P is a film (resin film), the wrap amount is set so that the expander roll 110 is pulled to contact the continuous paper P more than when the continuous paper P is paper. It controls the changing device 120 and the bending amount changing device 130 . That is, when the continuous paper P is a film, the wrap amount L1 and the bending amount C1 of the expander roll 110 are made larger than when the continuous paper P is paper, so that the expander roll 110 The degree of pulling the paper P to the outside in the width direction is increased.

For example, when the continuous paper P is a film, the extent to which the expander roll 110 pulls the continuous paper P outward in the width direction may be changed according to the material or thickness of the film. Table 1 shows the relationship between the thickness of the PET film and the amount of bending C1 when a PET film is used as the continuous paper P. Table 2 shows the relationship between the thickness of the PET film and the wrap amount L1 when the PET film is used as the continuous paper P. Here, in the experiments in Tables 1 and 2, the temperature of the second heating roll (heating roll) 64 was set at 180°C, and the temperature of the first heating roll (pressure roll) 62 was set at 120°C. ing. Further, in the experiments of Tables 1 and 2, G3 indicates the case with wrinkles, G2 indicates the case with some wrinkles, and G1 indicates the case without wrinkles. The temperature conditions for the experiments shown in Tables 3 to 5, which will be described later, are the same as those in Tables 1 and 2. In addition, the evaluation of wrinkles in the experiments shown in Tables 3 to 7, which will be described later, is the same as in Tables 1 and 2. Moreover, in the experiment of Table 1, the overlap amount L1 is set to 45 degrees. In the experiment of Table 2, the bending amount C1 is set to 1.5 mm.

As shown in Tables 1 and 2, thicker films are stiffer than thinner films and require more tensile force than thinner films. For this reason, for example, when the film is thick, the wrap amount L1 and the bending amount C1 are increased so that the degree of tension is greater than when the film is thin.

Table 3 shows the relationship between the amount of bending C1 and the difference in the material of the film used as the continuous paper P. Table 4 shows the relationship between the film material used as the continuous form P and the wrap amount L1. In addition, in the experiment of Table 3, the overlap amount L1 is set to 45 degrees. In the experiment of Table 4, the bending amount C1 is set to 1.5 mm.

As shown in Tables 3 and 4, films made of a material with a relatively large coefficient of linear expansion (OPP, nylon, etc.) are better than films made of a material with a relatively small coefficient of linear expansion ( PET), thermal shrinkage is greater, and wrinkles are more likely to occur. Therefore, in the case of a film made of a material having a relatively large coefficient of linear expansion, the wrap amount L1 and the amount of bending C1 are made larger than in the case of a film made of a material having a relatively small coefficient of linear expansion. .

Further, the tension of the continuous paper P may be changed according to the material or thickness of the film used as the continuous paper P, for example. In the present embodiment, the tension of the continuous paper P is increased by increasing the winding force of the continuous paper P by the winding roll 53 by the drive unit 55 . For example, the thicker the film, the higher the rigidity, and the tighter the adhesion to the expander roll 110 and the wrap amount L1. By increasing the tension of the continuous paper P, the adhesion of the continuous paper P to the expander roll 110 and the wrap amount L1 can be ensured. Further, for example, if the material of the film has a high rigidity even if the thickness is the same, the tension of the continuous form paper P is increased.

Further, the expander roll 110 may be brought into contact with or separated from the continuous paper P depending on the material or thickness of the film used as the continuous paper P. For example, the thicker the film, the less likely it is to wrinkle. Therefore, when the film is less likely to wrinkle, the expander roll 110 is separated from the continuous paper P (see FIG. 9). Table 5 shows how wrinkles are generated depending on the thickness of the PET film.

As shown in Table 5, a PET film with a thickness of 150 μm does not wrinkle even if the expander roll 110 does not come into contact with it. is separated from the continuous paper P. As a result, damage to the film due to slippage between the expander roll 110 and the film is suppressed compared to the case where the expander roll 110 is brought into contact with the continuous paper P.

Further, when the continuous form P is paper, wrinkles are less likely to occur than when the continuous form P is a thin film. Therefore, when the continuous paper P is paper, the wrap amount L1 and the bending amount C1 are made smaller than those of the thin film, or the expander roll 110 is separated from the continuous paper P (see FIG. 9).

Also, the wrap amount L1 and the bending amount C1 may be changed according to the fixing temperature of the fixing device 60 . For example, the fixing temperature may vary depending on the amount of toner per unit area (TMA amount), the material of the film used for the continuous paper P, and the thickness of the film. Table 6 shows the relationship between the bending amounts C1 when the temperatures of the first heating roll (pressure roll) 62 and the second heating roll (heat roll) 64 are changed. Table 7 shows the relationship between the wrap amount L1 when the temperatures of the first heating roll (pressure roll) 62 and the second heating roll (heat roll) 64 are changed. In Tables 6 and 7, a PET film with a thickness of 12 μm is used.

For example, the higher the fixing temperature of the fixing device 60, the greater the amount of heat shrinkage of the film when it comes into contact with the first cooling roll 82, and the greater the trough-like deformation of the film. Therefore, as shown in Tables 6 and 7, for example, when the fixing temperature of the fixing device 60 is high, the wrap amount L1 and the bending amount C1 are made larger than when the fixing temperature of the fixing device 60 is low. There is a need.

In the expander roll 110 as described above, the contact of the expander roll 110 with the continuous paper P pulls the continuous paper P outward in the width direction (see FIG. 7B). As a result, the continuous paper P is widened outward in the width direction toward the downstream side in the transport direction. It is conveyed to the cooling device 80 in a stretched state. Here, the trough-like deformation refers to a recoverable buckling deformation of the continuous paper P due to the tension of the continuous paper P, the misalignment of the winding roll of the continuous paper P, and the eccentricity error. The trough-shaped deformation is, for example, a ship-shaped deformation formed along the transport direction of the film.

(Cooling device 80)
As shown in FIG. 3, the cooling device 80 includes the first cooling roll 82 and the second cooling roll 84 as described above. The first cooling roll 82 first contacts and cools the surface 2B of the continuous paper P opposite to the toner image forming surface 2A on the downstream side of the expander roll 110 in the conveying direction (arrow B direction) of the continuous paper P. It is configured to Here, "first" means that 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 at the downstream side of the expander roll 110, and the continuous paper P and active cooling of 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. Not included in the "cooling section". Here, the first cooling roll 82 is an example of a cooling roll. Also, the outer diameter of the first cooling roll 82 is, for example, φ200 mm.

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 this embodiment, the continuous paper P is wound around the first cooling roll 82 in a range of 1/4 or more and 1/2 or less of the outer peripheral surface of the first cooling roll 82, for example. 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 even more preferably 112° or more and 160° or less.

The first cooling roll 82 includes, for example, a cylindrical roll made of metal or the like, and a duct is provided inside the roll. A fan is provided at one end in the axial direction of the first cooling roll 82 through an introduction portion. The first cooling roll 82 cools the continuous paper P in contact with the first cooling roll 82 from the surface 2B opposite to the toner image forming surface 2A by blowing air inside the duct due to the rotation of the fan. ing. Although not shown, the first cooling roll 82 has shafts extending on both sides in the axial direction, and is configured to rotate following the movement of the continuous paper P. As shown in FIG. The first cooling roll 82 is not limited to the above structure, and for example, may have a structure in which water is passed through the inside of the first cooling roll 82 to cool the continuous paper P from the surface 2B opposite to the toner image forming surface 2A. In addition, even if a duct and a fan are not provided inside the first cooling roll 82, the rotation of the fan 94 around the first cooling roll 82 lowers the temperature of the first cooling roll 82, thereby reducing the temperature of the first cooling roll 82. A configuration in which 82 cools the continuous paper P and the toner image G may be employed.

As shown in FIG. 3, the second cooling roll 84 is positioned downstream of the first cooling roll 82 in the conveying direction of the continuous paper P (the direction of the arrow B), and the toner image forming surface 2A of the continuous paper P is first applied. It is configured to be cooled by contact. Here, "first" means that the second cooling roll 84 comes into contact with the toner image forming surface 2A of the continuous paper P at the downstream side of the first cooling roll 82 and the continuous paper P and the toner image G are formed. active cooling. That is, the second cooling roll 84 positively cools the continuous paper P and the toner image G by having a cooling function. 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 contact width between the second cooling roll 84 and the continuous paper P in the conveying direction of the continuous paper P (direction of arrow B) is smaller than the contact width between the first cooling roll 82 and the continuous paper P.

The outer diameter of the second cooling roll 84 is smaller than the outer diameter of the first cooling roll 82 . In this embodiment, the outer diameter of the second cooling roll 84 is less than or equal to half the outer diameter of the first cooling roll 82 . Continuous paper P, for example, is wound around the second cooling roll 84 over a half range of the outer peripheral surface of the second cooling roll 84 . Further, the amount of continuous paper P wound around the second cooling roll 84 is smaller than the amount of continuous paper P wound around the first cooling roll 82 . 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 even more preferably 130° or more and 180° or less. In this embodiment, the angle at which the continuous paper P is wound around the second cooling roll 84 is greater than the angle at which the continuous paper P is wound around the first cooling roll 82 .

Although not shown, the second cooling roll 84 has, for example, a cylindrical roll made of metal or the like, and a duct is provided inside the roll. A fan is provided at an axial end of the second cooling roll 84 through an 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 blowing air inside the duct due to the rotation of the fan. The second cooling roll 84 is not limited to the above structure, and for example, may have a structure in which water is passed through the inside to cool the continuous paper P from the surface 2B opposite to the toner image forming surface 2A. Although not shown, the second cooling roll 84 has shafts extending on both sides in the axial direction, and is configured to rotate following the movement of the continuous paper P. As shown in FIG. In addition, even if a duct and a fan are not provided inside the second cooling roll 84, the rotation of the fan 94 around the second cooling roll 84 lowers the temperature of the second cooling roll 84, thereby reducing the temperature of the second cooling roll 84. 84 may be configured to cool the continuous paper P and the toner image G. FIG.

Also, as an example, the length of the continuous paper P between the first cooling roll 82 and the second cooling roll 84 (the length of the continuous paper P in the transport direction) is equal to that of the first cooling roll 82 and the continuous paper. shorter than the contact width with the paper P; Also, as an example, the length of the continuous paper P between the first cooling roll 82 and the second cooling roll 84 is shorter than the contact width between the second cooling roll 84 and the continuous paper P.

The first cooling roll 82 is configured without a nip forming portion that forms a nip in contact with the continuous paper P. As shown in FIG. That is, it is the second cooling roll 84 that first contacts the toner image forming surface 2A of the continuous paper P after fixing. Further, the second cooling roll 84 is configured without a nip forming portion that forms a nip in contact with the continuous form paper P. As shown in FIG.

A plurality of (two in this embodiment) fans 94 are provided in the casing of the cooling device 80 (not shown) at a position facing the area of the first cooling roll 82 that does not contact the continuous paper P. As shown in FIG. 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 contact the continuous paper P. As shown in FIG. Rotation of the plurality of fans 94 lowers the temperature around the first cooling roll 82 and the second cooling roll 84 .

In addition, in the transport direction of the continuous paper P, the expander roll 110 is positioned closer to the first cooling roll 82 than the installation position of the fixing device 60 (that is, the positions of the first heating roll 62 and the second heating roll 64). be. In other words, the distance D1 between the expander roll 110 and the first cooling roll 82 in the conveying direction of the continuous paper P is smaller than the distance D2 between the expander roll 110 and the installation position of the fixing device 60 . By moving the expander roll 110 closer to the first cooling roll 82 , which is the source of wrinkles in the continuous paper P, the continuous paper P is easily stretched by the expander roll 110 . The distance D1 between the expander roll 110 and the first cooling roll 82 is preferably 1.5 to 3.5 times the outer diameter of the expander roll 110, and preferably 2.0 to 3.0 times. More preferably, 2.2 times or more and 2.8 times or less is even more preferable. In this embodiment, as an example, the distance D1 between the expander roll 110 and the first cooling roll 82 is 2.5 times the outer diameter of the expander roll 110 .

Further, the distance D2 between the expander roll 110 and the installation position of the fixing device 60 in the conveying direction of the continuous paper P is 1.5 times the distance D1 between the expander roll 110 and the first cooling roll 82. 3.5 times or less is preferable, 2.0 times or more and 3.0 times or less is more preferable, and 2.2 times or more and 2.8 times or less is even more preferable.

Further, on the downstream side of the second cooling roll 84 in the conveying direction of the continuous paper P, a plurality of (three in this embodiment) support rollers 102 are arranged for changing the direction of the continuous paper P in the intersecting direction. It is The support roll 102 is configured to rotate as the continuous paper P moves. In this embodiment, the three support rolls 102 on the downstream side of the second cooling roll 84 arrange the conveying 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 configured.

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

In the image forming apparatus 10 , the continuous paper P onto which the toner image G has been transferred at the secondary transfer position NT is conveyed to the fixing device 60 while being supported by the support rolls 58 and 59 . In the fixing device 60, the continuous paper P and the toner image are heated by the first heating roller 62 by bringing the first heating roller 62 into contact with the surface 2B of the continuous paper P opposite to the toner image forming surface 2A. As a result, the air in the unfixed toner image G on the continuous paper sheet P can easily escape from the surface side of the toner image G. As shown in FIG. Further, the continuous paper P and the toner image G ( 3) is heated. As a result, the toner image G is fixed on the continuous paper P by heating and pressing while the air in the toner image G is removed.

Further, after fixing by the fixing device 60, the surface 2B opposite to the toner image forming surface 2A of the continuous paper P contacts the expander roll 110, so that the expander roll 110 moves the continuous paper P outward in the width direction. It is pulled (see FIG. 7(B)). As a result, the continuous paper sheet P is spread outward in the width direction toward the downstream side in the transport direction. is conveyed to the cooling device 80 in a state of being stretched (dissolved or straightened).

The cooling device 80 includes a first cooling roll that first contacts the surface 2B of the continuous paper P opposite to the toner image forming surface 2A on the downstream side of the fixing device 60 in the conveying direction (direction of arrow B) of the continuous paper P. 82 is provided. That is, the continuous paper P and the toner image G are cooled from the surface 2B opposite to the toner image forming surface 2A by bringing the first cooling roll 82 into contact with the surface 2B opposite to the toner image forming surface 2A of the continuous paper P. be done.

Further, the cooling device 80 includes a second cooling roll that first contacts the toner image forming surface 2A of the continuous paper P downstream of the first cooling roll 82 in the conveying direction of the continuous paper P (direction of arrow B). 84 is provided. That is, by bringing the second cooling roll 84 into contact with the toner image forming surface 2A of the continuous paper P on the downstream side of the conveying direction of the first cooling roll 82, the continuous paper P and the toner image are cooled from the toner image forming surface 2A side. G is cooled. As a result, the image on the continuous paper P is stabilized, and the continuous paper P is taken up by the take-up roll 53 .

The image forming apparatus 10 described above is provided with an expander roll 110 that contacts the continuous paper P downstream of the fixing device 60 in the conveying direction of the continuous paper P and pulls the continuous paper P outward in the width direction. . The expander roll 110 expands the continuous paper sheet P toward the downstream side in the conveying direction, and conveys the continuous paper sheet P to the cooling device 80 in a state in which the trough-like deformation of the continuous paper sheet P is extended. . For example, as a comparative example, in a configuration in which the cooling unit first comes into contact with the downstream side of the fixing unit in the conveying direction of the continuous paper P, the trough-like deformation of the continuous paper P is not resolved, and the cooling unit P wrinkles may occur. On the other hand, in the image forming apparatus 10 of the present embodiment, the expander roll 110 extends (eliminates or corrects) the trough-like deformation of the continuous paper P. FIG. Therefore, in the image forming apparatus 10, wrinkling of the continuous paper sheet P is suppressed compared to a configuration in which the cooling section first comes into contact with the cooling section on the downstream side of the fixing section in the conveying direction of the continuous paper sheet P.

FIG. 10 shows how wrinkles are generated in the continuous paper P when the expander roll 110 is present and when no measures are taken (without the expander roll). In FIG. 10, a PET film having a thickness of 12 μm is used as the continuous paper P. As shown in FIG. In addition, in the evaluation of the occurrence of wrinkles in the continuous paper P, G4 is for unacceptable wrinkles, G3 is for wrinkles, G2 is for some wrinkles, and G1 is for no wrinkles. is shown. As shown in FIG. 10, wrinkling of the continuous paper P can be suppressed by providing the expander roll 110 that contacts the continuous paper P downstream of the fixing device 60 in the conveying direction of the continuous paper P. .

Further, in the image forming apparatus 10, the expander roll 110 does not come into contact with the toner image forming area of the continuous paper P. As shown in FIG. Therefore, in the image forming apparatus 10, the change in the surface shape of the image on the continuous paper P before cooling is suppressed compared to the configuration in which the contact member contacts the toner image forming area of the continuous paper P. be. Therefore, in the image forming apparatus 10, the occurrence of gloss unevenness, scratches, and the like on the image on the continuous paper P is suppressed compared to a configuration in which the contact member contacts the toner image forming area of the continuous paper P.

Further, in the image forming apparatus 10, the expander roll 110 contacts only the surface 2B of the continuous paper P opposite to the toner image forming surface 2A. Therefore, in the image forming apparatus 10, the change in the surface shape of the image on the continuous paper P before cooling is suppressed compared to the configuration in which the contact member contacts the toner image forming surface of the continuous recording medium. . Therefore, in the image forming apparatus 10, the occurrence of gloss unevenness, scratches, and the like on the image on the continuous paper P is suppressed compared to a configuration in which the contact member contacts the toner image forming area of the continuous paper P.

The image forming apparatus 10 also includes a first heating roll 62 and a second heating roll 64 provided in the fixing device 60 and a first cooling roll 82 provided in the cooling device 80 . The diameter of the expander roll 110 is smaller than the diameters of the first heating roll 62 , the second heating roll 64 and the first cooling roll 82 . As a result, the heat capacity of the expander roll 110 becomes smaller than the heat capacities of the first heating roll 62 , the second heating roll 64 , and the first cooling roll 82 . Therefore, in the image forming apparatus 10, the temperature difference before and after the expander roll 110 in the continuous paper P becomes smaller than when the diameter of the expander roll is equal to or larger than the diameter of the heating roll or the cooling roll.

Further, in the image forming apparatus 10 , the expander roll 110 is positioned closer to the cooling device 80 than to the fixing device 60 . For this reason, in the image forming apparatus 10, the continuous paper P is kept stretched in the cooling device 80 compared to the case where the expander roll is located closer to the fixing unit than to the cooling unit. and the occurrence of wrinkles in the continuous form paper P is suppressed.

Further, in the image forming apparatus 10, the expander roll 110 can adjust the degree of pulling the continuous paper P to the outside in the width direction. Therefore, in the image forming apparatus 10, the occurrence of wrinkles in the continuous form P is suppressed compared to the case where the continuous form P is pulled to the outside in the width direction by the contact member at a constant pulling degree. In particular, by adjusting the degree of pulling the continuous paper P to the outside in the width direction according to the material and thickness of the film, wrinkling of the continuous paper P can be suppressed even when the material and thickness of the film are different. be.

Further, in the image forming apparatus 10, when the continuous form P is a film, the degree of pulling by which the expander roll 110 contacts the continuous form P is increased compared to when the continuous form P is paper. Therefore, in the image forming apparatus 10, the occurrence of wrinkles is suppressed even when the continuous paper P is a film, compared to when the contact amount of the expander roll with the continuous paper P does not change. Further, compared to the case where the contact amount of the expander roll to the continuous paper P does not change, when the continuous paper P is paper, the surface shape of the image on the continuous paper P changes before cooling. is suppressed. Therefore, in the image forming apparatus 10, the occurrence of gloss unevenness, scratches, and the like on the image on the continuous paper P is suppressed compared to a configuration in which the contact member contacts the toner image forming area of the continuous paper P.

Further, the image forming apparatus 10 is provided with an expander roll 110 in which a plurality of rolls 114 are arranged along a shaft portion 112 whose bending amount can be changed. Therefore, in the image forming apparatus 10, the degree of tension of the expander roll 110 can be easily adjusted compared to a configuration in which the contact member is an inverted crown-shaped roll.

<<Second embodiment>>
Next, an image forming apparatus as a second embodiment will be described with reference to FIG. In addition, about the same component part as 1st Embodiment mentioned above, the same number is attached and the description is abbreviate|omitted.

FIG. 11 shows a contact roll 152 as an example of a contact member used in the image forming apparatus as the second embodiment. In this embodiment, a contact roll 152 is arranged instead of the expander roll 110 in the image forming apparatus 10 of the first embodiment shown in FIG. As shown in FIG. 11 , the contact roll 152 includes a shaft portion 154 and an outer peripheral portion 156 mounted around the shaft portion 154 . The shaft portion 154 is formed substantially linearly. That is, the shaft portion 154 does not bend. The outer diameter of the outer peripheral portion 156 on both sides in the axial direction is larger than the outer diameter of the central portion in the axial direction. That is, the contact roll 152 is a flare roll formed in an inverted crown shape.

Although not shown, the contact roll 152 is supported by the wrap amount changing device 120 so as to be in contact with or separated from the continuous paper P. The amount of wrap of the contact roll 152 to the continuous paper P is It is modifiable. As a result, the degree of pulling of the continuous form paper P by the contact roll 152 can be changed. The higher the coefficient of friction of the surface of the outer peripheral portion 156, the more effectively the continuous paper P is pulled outward in the width direction.

In the image forming apparatus 10 provided with the contact roll 152, the contact roll 152 contacts the continuous form P downstream of the fixing device 60 (see FIG. 3) in the continuous form P transport direction. The paper P is pulled to the outside in the width direction and expanded to the outside in the width direction. As a result, the continuous form paper P is conveyed to the cooling device 80 (see FIG. 3) in a state in which the deformation is extended.

For this reason, in the image forming apparatus 10 provided with the contact roll 152 , the continuous paper sheet P is more likely to roll over the continuous paper sheet P than in the image forming apparatus 10 in which the cooling section first comes into contact with the downstream side of the fixing section in the conveying direction of the continuous paper sheet P. I am restrained. Further, in the image forming apparatus 10 provided with the contact roll 152, the same effect is obtained by the same configuration except for the effect (adjustment by bending) of the expander roll 110 of the image forming apparatus of the first embodiment. be able to.

<<Third Embodiment>>
Next, an image forming apparatus as a third embodiment will be described with reference to FIG. It should be noted that the same components as those of the above-described first and second embodiments are assigned the same numbers and the description thereof will be omitted.

FIG. 12 shows a straight roll 162 used in the image forming apparatus as the third embodiment, and nip rolls 164 that are pressed against the contact roll 152 via continuous paper P at both ends of the straight roll 162 in the axial direction. I have. In this embodiment, a straight roll 162 and a nip roll 164 are arranged instead of the expander roll 110 in the image forming apparatus 10 of the first embodiment shown in FIG. The straight roll 162 includes a shaft portion 162A and an outer peripheral portion 162B attached around the shaft portion 162A. The outer diameter of the outer peripheral portion 162B does not change along the axial direction. The nip roll 164 includes a shaft portion 164A and an outer peripheral portion 164B attached around the shaft portion 164A. The outer diameter of the outer peripheral portion 164B does not change along the axial direction. The outer diameter of outer peripheral portion 164B is smaller than the outer diameter of outer peripheral portion 162B. A shaft portion 164 A of the nip roll 164 is arranged along the shaft portion 162 A of the straight roll 162 .

A motor (not shown) is connected to the shaft portion 164A of the nip roll 164 and is driven to rotate separately from the straight roll 162 . The straight roll 162 may be driven to rotate by the movement of the continuous paper P, or may be rotationally driven by a motor. Nip roll 164 is driven to rotate faster than straight roll 162 . The straight roll 162 is in contact with the surface opposite to the toner image forming surface 2A. The nip roll 164 is arranged on the side of the toner image forming surface 2A of the continuous paper P, but is arranged so as to contact the outside of the image forming area of the toner image forming surface 2A in the width direction. In other words, the nip roll 164 does not contact the image forming area of the toner image forming surface 2A of the continuous paper P. Here, the straight roll 162 and the nip roll 164 are examples of contact members.

In FIG. 12, the outer diameter of the straight roll 162 is larger than the outer diameter of the nip roll 164, but the outer diameter of the straight roll is approximately the same as the outer diameter of the nip roll, or the outer diameter of the straight roll is larger than the outer diameter of the nip roll. A slightly larger configuration is also possible. As a result, the heat capacity of the straight rolls becomes smaller than when the outer diameter of the straight rolls 162 is large.

In the image forming apparatus 10 described above, the straight roll 162 contacts the surface of the continuous form P opposite to the toner image forming surface 2A downstream of the fixing device 60 (see FIG. 3) in the conveying direction of the continuous form P. The nip roll 164 comes into contact with the outside of the image forming area of the toner image forming surface 2A of the continuous paper P. As shown in FIG. Since the nip roll 164 is driven to rotate faster than the straight roll 162, the continuous form paper P is pulled widthwise outward and expanded widthwise outward. As a result, the continuous form paper P is conveyed to the cooling device 80 (see FIG. 3) in a state in which the deformation is extended.

Therefore, in the image forming apparatus 10 described above, wrinkling of the continuous paper P is suppressed as compared with the case where the cooling unit comes into contact first on the downstream side of the fixing unit in the conveying direction of the continuous paper P. Further, in the image forming apparatus 10 described above, the same effects can be obtained with the same configuration except for the effect (adjustment by bending) of the expander roll 110 of the image forming apparatus of the first embodiment.

<<Fourth Embodiment>>
Next, an image forming apparatus as a fourth embodiment will be described with reference to FIG. The same reference numerals are assigned to the same components as those of the first to third embodiments described above, and the description thereof will be omitted.

As shown in FIG. 13, in the image forming apparatus 170 of the fourth embodiment, a contact member (that is, a contact roll) between the fixing device 60 and the cooling device 80 in the conveying direction of the continuous paper P is provided as an example. An expander roll 110 is arranged.

In the image forming apparatus 170, the expander roll 110 is located at the installation position of the fixing device 60 (that is, the position of the first heating roll 62 and the second heating roll 64) rather than the first cooling roll 82 in the conveying direction of the continuous paper P. is located near the In other words, the distance D1 between the expander roll 110 and the first cooling roll 82 in the conveying direction of the continuous paper P is greater than the distance D2 between the expander roll 110 and the installation position of the fixing device 60 .

Also, the diameter of the expander roll 110 is smaller than the diameters of the first heating roll 62 , the second heating roll 64 , and the first cooling roll 82 . As a result, the heat capacity of the expander roll 110 becomes smaller than the heat capacities of the first heating roll 62 , the second heating roll 64 , and the first cooling roll 82 .

In the image forming apparatus 170 described above, except for the effect of the position of the expander roll 110 between the fixing device 60 and the cooling device 80 of the image forming apparatus of the first embodiment, the same configuration provides the same effect. Obtainable. That is, in the image forming apparatus 170 described above, it is possible to obtain the same effect (adjustment by bending) of the expander roll 110 as in the image forming apparatus of the first embodiment.

Further, in the image forming apparatus 170, the expander roll 110 is positioned closer to the fixing device 60 than the first cooling roll 82 (that is, the first heating roll 62 and the second heating roll 64) in the conveying direction of the continuous paper P. position). This increases the temperature of the expander roll 110 (that is, the expander roll 110 is not heat shielded). Therefore, in the image forming apparatus 170, the temperature difference before and after the expander roll 110 in the continuous paper P is smaller than when the contact member is located closer to the cooling device than to the fixing device.

<Supplementary explanation>
In the image forming apparatus 10 of the third embodiment, the shaft portion 164A of the nip roll 164 is arranged along the shaft portion 162A of the straight roll 162, but the present invention is not limited to this configuration. For example, the nip roll 164 tilts the shaft portion 164A of the nip roll 164 widthwise outward with respect to the shaft portion 162A of the straight roll 162 so that the continuous paper P is pulled widthwise outward at the contact portion with the continuous paper P. can be placed

In the image forming apparatuses 10 and 170 of the first to fourth embodiments, a roll-shaped member is used as a contact member for pulling the continuous paper P outward in the width direction, but the present invention is not limited to this configuration. do not have. For example, as a contact member for pulling the continuous paper P to the outside in the width direction, a support member and an endless belt wound around the support member are provided, and the belt moves as the continuous paper P moves. may be configured.

In the image forming apparatuses 10 and 170 of the first to fourth embodiments, the cooling device 80 includes the first cooling roll 82 and the second cooling roll 84, but the present invention is not limited to this configuration. . For example, the configurations of the first chill roll 82 and the second chill roll 84 can be changed. Further, the image forming apparatus includes a first cooling unit including a member other than the roll (for example, a belt and a cooling member, or a member having a flat cooling surface), and a member other than the roll (for example, the belt and a cooling member, or a member having a flat cooling surface).

In the image forming apparatus 10 described above, the fixing device 60 includes the first heating roll 62 and the second heating roll 64, but the present invention is not limited to this configuration. For example, an image forming apparatus includes a first fixing section including members other than rolls (for example, a belt and a heating member) and a second fixing section including members other than rolls (for example, a belt and a heating member). may be configured to have. Alternatively, one fixing section may be provided instead of two fixing sections. For example, only a fixing section for fixing the toner image by heating from the surface 2B opposite to the toner image forming surface 2A of the continuous paper P may be provided. Furthermore, the fixing section may be configured so as to be arranged in a non-contact manner with the toner image G on the continuous paper sheet P.

Although the present invention has been described in detail with respect to particular embodiments, it should be understood that the invention is not limited to such embodiments and that various other embodiments are possible within the scope of the invention. clear to the trader.

2A toner image forming surface 2B surface opposite to the toner image forming surface 10 image forming device 60 fixing device (an example of a fixing section)
62 First heating roll (an example of a heating roll, an example of a fixing section)
64 Second heating roll (an example of a heating roll, an example of a fixing section)
82 First cooling roll (an example of a cooling roll, an example of a cooling section)
110 expander roll (an example of a contact roll, an example of a contact member)
112 shaft portion 114 roll 152 contact roll (an example of a contact member)
162 straight roll (an example of a contact roll, an example of a contact member)
164 nip roll (an example of a contact roll, an example of a contact member)
170 Image forming apparatus P Continuous paper (an example of continuous recording medium)

Claims (9)

a fixing unit that fixes the toner image formed on the continuous recording medium;
a contact member that contacts the continuous recording medium on the downstream side of the fixing section in the conveying direction of the continuous recording medium and pulls the continuous recording medium outward in the width direction;
a cooling unit that cools the continuous recording medium by first coming into contact with the continuous recording medium on the downstream side of the contact member in the conveying direction of the continuous recording medium;
has
The cooling section includes a first cooling roll that first contacts only the surface of the continuous recording medium opposite to the toner image forming surface on the downstream side of the contact member, and a first cooling roll that first contacts the continuous recording medium on the downstream side of the first cooling roll. and a second cooling roll that contacts the toner image forming surface of the recording medium . 2. The image forming apparatus according to claim 1, wherein said contact member does not contact the toner image forming area of said continuous recording medium. 3. The image forming apparatus according to claim 2, wherein the contact member contacts only the surface opposite to the toner image forming surface of the continuous recording medium. A heating roll provided in the fixing unit ,
4. The contact member according to any one of claims 1 to 3, wherein the contact member is a contact roll, and the diameter of the contact roll is smaller than both the diameter of the heating roll and the diameter of the first cooling roll. image forming device. The image forming apparatus according to any one of claims 1 to 4, wherein the contact member is located closer to the cooling section than to the fixing section. 5. The image forming apparatus according to claim 4, wherein the contact member is located closer to the fixing section than to the cooling section. 7. The image forming apparatus according to any one of claims 1 to 6, wherein the contact member is capable of adjusting a degree of pulling the continuous recording medium outward in the width direction. 8. The image forming apparatus according to claim 7, wherein when said continuous recording medium is a film, the degree of tension with which said contact member contacts said continuous recording medium is made greater than when said continuous recording medium is paper. 9. The image forming apparatus according to claim 7, wherein the contact member is an expander roll having a plurality of rolls arranged along a shaft part capable of changing the amount of bending.

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