Conveyance device, fixation device and image formation apparatus

Abstract

To suppress the generation of wrinkles on a conveyance object material.SOLUTION: A conveyance device comprises: a first conveyance body; a second conveyance body which is movable between the contact position and the separation position with respect to the first conveyance body and sandwiches a conveyance object material with the first conveyance body at the contact position; and a conveyance part which has a holding part for holding the tip of the conveyance object material, and conveys the conveyance object material toward a region where the first conveyance body and the second conveyance body sandwich the conveyance object material in such a state that the second conveyance body is located at the separation position. The second conveyance body sandwiches the conveyance object material with the first conveyance body after holding of the tip by the holding part for the conveyance object material conveyed by the conveyance part is released, and conveys the conveyance object material.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a conveying device, a fixing device, and an image forming device.

Background Art

[0002] Patent Document 1 discloses a fixing device that fixes an image drawn on a recording medium using particles containing at least resin on the recording medium, comprising a first fixing roll and a second fixing roll arranged to be paired with the first fixing roll, at least one of which is a heating roll, and a fixing roll pair in which the surface layer of at least one fixing roll is replaceable, a sticking means including a sticking member for sticking the recording medium, a charging means for charging at least one of the recording medium and the sticking means, and a fixing means for physically fixing the leading end portion of the recording medium in the conveying direction to a predetermined position of the sticking member by a gripping portion. By the charging means, the sticking member and the recording medium on which the image is drawn are electrostatically adsorbed, and after the leading end portion of the recording medium on which the image is drawn is fixed to a predetermined position of the sticking member by the fixing means, the recording medium is sandwiched and conveyed together with the sticking means by the fixing roll pair to fix the image on the recording medium.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration where a conveying unit that holds and conveys the leading end portion of the conveyed material conveys the conveyed material while sandwiching it between a first conveying body and a second conveying body while holding the leading end portion, wrinkles may occur in the conveyed material.

[0005] Compared to a configuration in which the conveying unit holds the leading edge of the conveyed material while conveying it by sandwiching the material between a first conveying body and a second conveying body while holding the leading edge, this configuration suppresses the occurrence of wrinkles in the conveyed material. [Means for solving the problem]

[0006] The first embodiment comprises a first conveyor, a second conveyor that is movable between a contact position and a separation position with respect to the first conveyor and sandwiches a material to be conveyed between itself and the first conveyor at the contact position, and a conveying unit having a holding part that holds the leading edge of the material to be conveyed, and when the second conveyor is in the separation position, the conveying unit conveys the material to be conveyed toward a clamping area where the first conveyor and the second conveyor are sandwiching the material to be conveyed, wherein the second conveyor, after the holding part has released the holding of the leading edge of the material to be conveyed by the conveying unit, sandwiches the material to be conveyed between itself and the first conveyor and conveys the material to be conveyed.

[0007] In the second embodiment, the second conveyor moves from the separated position to the contact position after the holding portion has passed the clamping region and the holding portion has released the holding of the tip portion, and then clamps the material to be conveyed between itself and the first conveyor and conveys it.

[0008] In the third embodiment, the transport unit transports the material to be transported to the clamping area while the holding unit holds the tip when the second transport unit is positioned at the separated position, and the second transport unit moves from the separated position to the contact position after the holding unit has passed the clamping area and the holding unit has released the tip, and clamps the material to be transported to the clamping area by the transport unit with the first transport unit, thereby transporting the material to be transported.

[0009] In the fourth embodiment, the first conveyor body comes into contact with the conveyed material while it is rotating, as the holding portion releases the tip portion from being held by the holding portion.

[0010] The fifth embodiment includes a support portion that supports the rear end portion of the material to be conveyed, which is supported by the first conveyor body when the holding portion releases the holding portion of the front end portion of the material to be conveyed.

[0011] In the sixth embodiment, the second conveyor moves from the separated position to the contact position and sandwiches the conveyed material between itself and the first conveyor after a predetermined time has elapsed since the holding portion released its grip on the tip of the material being conveyed by the conveying portion.

[0012] In the seventh embodiment, the first conveyor has a recess in which the holding portion is housed, the recess having an upstream corner of the conveying path, and the second conveyor sandwiches the material to be conveyed between itself and the corner of the first conveyor.

[0013] In the eighth embodiment, the first moving speed of the second transporter as it moves from the separated position to the contact position is faster than the second moving speed as it moves from the contact position to the separated position.

[0014] In the ninth embodiment, at least one of the first conveyor and the second conveyor is made of an elastic material that elastically deforms under the load when the second conveyor sandwiches the material to be conveyed between the first conveyor and the second conveyor.

[0015] In the tenth embodiment, with both the first conveyor and the second conveyor rotating, the second conveyor sandwiches the material to be conveyed between itself and the first conveyor.

[0016] In the eleventh embodiment, the first conveyor and the second conveyor, while rotating, have the same peripheral speed.

[0017] The twelfth embodiment is a fixing device as a conveying device in which the first conveying body is one of the heating member and the pressurizing member, and the second conveying body is the other of the heating member and the pressurizing member.

[0018] In the 13th embodiment, the second conveyor clamps the material to be conveyed between itself and the first conveyor with a first load when the material to be conveyed is plain paper, and clamps the material to be conveyed between itself and the first conveyor with a second load greater than the first load when the material to be conveyed is coated paper.

[0019] In the 14th embodiment, the second conveyor clamps the material to be conveyed between itself and the first conveyor with a first load when the basis weight of the material to be conveyed is less than a predetermined standard value, and clamps the material to be conveyed between itself and the first conveyor with a second load greater than the first load when the basis weight of the material to be conveyed is equal to or greater than the standard value.

[0020] The 15th embodiment comprises an image forming unit for forming an image on a recording medium, a first transport body which is one of a heating member and a pressurizing member, a second transport body which is the other of the heating member and the pressurizing member and is movable between a contact position and a separation position with respect to the first transport body, and at the contact position, sandwiches the recording medium with the first transport body, and a transport unit which has a holding part that holds the leading edge of a material to be transported, and when the second transport body is in the separation position, the first transport body and the second transport body transport the recording medium toward a sandwiching area where the recording medium is sandwiched, with the holding part holding the leading edge, wherein the second transport body moves from the separation position to the contact position after the holding part has released the holding of the leading edge of the recording medium that has been transported by the transport unit, and a fixing device which fixes the image formed on the recording medium by the image forming unit to the recording medium, wherein the second transport body sandwiches the recording medium with the first transport body after the rear end of the recording medium has passed through the image forming unit. [Effects of the Invention]

[0021] According to the configuration of the first embodiment, the transport unit that holds and transports the leading edge of the transported material suppresses the occurrence of wrinkles in the transported material compared to a configuration in which the transported material is sandwiched between a first transport body and a second transport body while holding the leading edge.

[0022] According to the configuration of the second aspect, compared with the configuration in which the second carrier moves from the separated position to the contact position before the holding part passes through the clamping area, the contact between the holding part and the second carrier is suppressed.

[0023] According to the configuration of the third aspect, compared with the configuration in which the conveyed material is sandwiched and conveyed by the first carrier and the second carrier after the holding of the tip by the holding part is released in front of the clamping area and the conveyed material is conveyed to the clamping area by another conveying part, the generation of wrinkles in the conveyed material is suppressed.

[0024] According to the configuration of the fourth aspect, compared with the configuration in which the first carrier contacts the conveyed material in a state where the first carrier is not rotating with respect to the conveyed material whose holding of the tip by the holding part is released, the decrease in the speed in the downstream direction of the tip of the conveyed material whose holding of the tip by the holding part is released is suppressed.

[0025] According to the configuration of the fifth aspect, compared with the configuration in which only the tip side of the conveyed material is supported when the holding of the tip by the holding part is released, the drooping of the rear end side of the conveyed material whose holding of the tip by the holding part is released is suppressed.

[0026] According to the configuration of the sixth aspect, compared with the configuration in which the second carrier sandwiches the conveyed material with the first carrier simultaneously with the release of the holding of the tip of the conveyed material by the holding part, the generation of wrinkles in the conveyed material is suppressed.

[0027] According to the configuration of the seventh aspect, compared with the configuration in which the second carrier sandwiches the conveyed material at a position past the corner of the first carrier, the second carrier can start sandwiching from near the tip of the conveyed material held by the holding part.

[0028] According to the configuration of the eighth aspect, compared with the configuration in which the first moving speed is slower than the second moving speed, the generation of wrinkles in the conveyed material is suppressed.

[0029] According to the configuration of the ninth aspect, compared with the configuration in which both the first carrier and the second carrier are rigid bodies that do not elastically deform, the impact when the second carrier sandwiches the conveyed material with the first carrier is absorbed.

[0030] According to the configuration of the 10th embodiment, when at least one of the first and second conveyors is stopped, the occurrence of wrinkles in the conveyed material is suppressed compared to a configuration in which the second conveyor sandwiches the conveyed material between the first conveyor and the first conveyor.

[0031] According to the configuration of the 11th embodiment, the occurrence of wrinkles in the conveyed material is suppressed compared to a configuration in which the peripheral speeds of the first and second conveyors are different while they are rotating.

[0032] According to the configuration of the 12th embodiment, the transport unit that holds and transports the leading edge of the transported material suppresses the occurrence of wrinkles in the transported material compared to a configuration in which the transported material is sandwiched between a first transport body and a second transport body while the leading edge is being held.

[0033] According to the configuration of the 13th embodiment, when the material to be conveyed is coated paper, the gloss of the material to be conveyed is improved compared to a configuration in which the second conveyor body sandwiches the material to be conveyed between the first conveyor body and the first conveyor body with the first load.

[0034] According to the configuration of the 14th embodiment, when the basis weight of the material to be conveyed is equal to or greater than the standard value, poor fixing of the material to be conveyed is suppressed compared to a configuration in which the second conveyor body sandwiches the material to be conveyed between the first conveyor body and the first conveyor body with the first load.

[0035] According to the configuration of the 15th embodiment, the transport unit that holds and transports the leading edge of the recording medium suppresses the occurrence of wrinkles on the recording medium compared to a configuration in which the recording medium is transported by sandwiching it between a first transport body and a second transport body while holding the leading edge. [Brief explanation of the drawing]

[0036] [Figure 1] This is a schematic diagram showing the configuration of an image forming apparatus according to the first embodiment. [Figure 2] This is a perspective view showing the configuration of the transfer body according to the first embodiment. [Figure 3] This is a perspective view showing the configuration of the fixing device according to the first embodiment. [Figure 4] This is a perspective view showing a gripper according to the first embodiment. [Figure 5] This is a schematic diagram showing the configuration of the pressure roll and heating roll according to the first embodiment. [Figure 6] Figure 5 is a schematic diagram showing the configuration in which the heating roll is positioned at a distance from the pressure roll. [Figure 7] Figure 6 is a schematic diagram showing the configuration in which the transport unit has transported the recording medium to just before the clamping area. [Figure 8] Figure 6 is a schematic diagram showing the state in which the transport unit has transported the recording medium to the clamping area in the configuration shown. [Figure 9] Figure 8 is a schematic diagram showing the configuration in which the gripper of the transport unit has released its grip on the tip of the recording medium. [Figure 10] Figure 9 is a schematic diagram showing the configuration in which the recording medium, whose tip has been released from being held, is sandwiched between the heating roll and the pressure roll. [Figure 11] Figure 10 is a schematic diagram showing the state in which the recording medium held between the heating roll and the pressure roll is transported in the configuration shown. [Figure 12] This is a schematic diagram showing a state (comparative example) in which the recording medium is sandwiched between a heating roll and a pressure roll while the gripper is holding the tip of the recording medium. [Figure 13] This is a schematic diagram showing the state in which wrinkles have formed on a recording medium that has been transported in the configuration shown in Figure 12. [Figure 14] This is a schematic diagram showing a modified example in which the gripper releases its grip on the leading edge of the recording medium before reaching the gripping area. [Figure 15] This is a schematic diagram showing the configuration of an image forming apparatus according to the second embodiment. [Figure 16] This is a schematic diagram showing a modified configuration in which a recording medium, whose tip has been released from being held, is sandwiched between a heating roll and a pressure roll. [Modes for carrying out the invention]

[0037] An example of an embodiment of the present invention will be described below with reference to the drawings.

[0038] <First Embodiment> (Image forming apparatus 10) First, the configuration of the image forming apparatus 10 according to the first embodiment will be described. Figure 1 is a schematic diagram showing the configuration of the image forming apparatus 10 according to this embodiment. In each figure, arrow H is in the vertical direction and indicates the up-down direction of the apparatus, arrow W is in the horizontal direction and indicates the width direction of the apparatus, and arrow D indicates the front-to-back direction of the apparatus (depth direction of the apparatus). The dimensional ratios in the H, W, and D directions of each part shown in each figure may differ from the actual dimensional ratios.

[0039] The image forming apparatus 10 shown in Figure 1 is an example of an image forming apparatus that forms an image on a recording medium. Specifically, the image forming apparatus 10 is an inkjet type image forming apparatus that forms an ink image on a recording medium P. The recording medium P is an example of a material to be transported, and the ink image is an example of an image.

[0040] More specifically, the image forming apparatus 10 comprises an image forming unit 14 and a fixing device 60. The parts of the image forming apparatus 10 (image forming unit 14 and fixing device 60) will be described below.

[0041] (Image forming unit 14) The image forming unit 14 has the function of forming an ink image on the recording medium P. Specifically, the image forming unit 14 includes a transfer belt 31 as an intermediate transfer body, a plurality of rolls 32, opposing rolls 34, an adhesive layer forming device 24, a particle supply device 18, a discharge head 20, a transfer body 36, and a cleaner 28.

[0042] As shown in Figure 1, the transfer belt 31 is endless and is wrapped around multiple rolls 32 and opposing rolls 34 such that it is in an inverted triangular shape when viewed from the front (i.e., in the direction of the depth of the device). The transfer belt 31 rotates in the direction of arrow A when at least one of the multiple rolls 32 is driven to rotate.

[0043] The adhesive layer forming device 24, particle supply device 18, discharge head 20, transfer body 36, and cleaner 28 are arranged in this order on the outer circumference of the transfer belt 31, along the circumferential direction of the transfer belt 31 (hereinafter referred to as the "belt circumferential direction").

[0044] Specifically, the adhesive layer forming device 24 is positioned at one end (left side in the figure) in the width direction of the device on the horizontal portion of the transfer belt 31, which is in an inverted triangular orientation. The adhesive layer forming device 24 contains an adhesive inside and forms an adhesive layer (not shown) by applying the adhesive to the outer surface of the circulating transfer belt 31. For example, glue, organic solvents, etc., can be used as the adhesive.

[0045] The particle supply device 18 is located on the horizontal portion of the transfer belt 31, downstream of the adhesive layer forming device 24 in the belt circumferential direction (right side in the figure). The particle supply device 18 contains ink-receiving particles 16 capable of receiving ink droplets, and supplies the ink-receiving particles 16 to the transfer belt 31 on which the adhesive layer is formed. As a result, the ink-receiving particles 16 supplied to the transfer belt 31 by the particle supply device 18 adhere to the adhesive layer due to the adhesive force of the adhesive layer, and an ink-receiving particle layer 16A is formed on the transfer belt 31.

[0046] The ejection head 20 is located on the horizontal portion of the transfer belt 31, downstream of the particle supply device 18 in the belt circumference direction (right side in the figure). Multiple ejection heads 20 are provided to form an ink image for each color. In this embodiment, there are four ejection heads 20 for yellow (Y), magenta (M), cyan (C), and black (K). (Y), (M), (C), and (K) shown in Figure 1 represent the components corresponding to each of the above colors.

[0047] In each color ejection head 20, ink droplets are ejected from a nozzle (not shown) onto an ink-receiving particle layer 16A using a known method such as a thermal method or a piezoelectric method, thereby forming an ink image based on image data. The ink droplets ejected from each color ejection head 20 are received by the ink-receiving particle layer 16A to form an ink image.

[0048] The transfer body 36 is positioned below the transfer belt 31. Specifically, as shown in Figure 2, the transfer body 36 includes a transfer cylinder 37 and a pair of sprockets 38. The transfer cylinder 37 is positioned opposite the transfer belt 31 and forms a clamping region 37T (see Figure 1) between the transfer belt 31 and the opposing roll 34.

[0049] In this embodiment, the ink image formed on the ink-receiving particle layer 16A is transported to the clamping region 37T by the rotation of the transfer belt 31, and the recording medium P is transported to the clamping region 37T by the transport unit 15. In each figure, the transport direction of the recording medium P is indicated by the arrow X.

[0050] The transfer cylinder 37 then transfers the ink image to the recording medium P by pressing the recording medium P and the ink image, which have been transported to the clamping area 37T, between the transfer belt 31 and the recording medium P.

[0051] Furthermore, when the recording medium P and the ink image are pressed between the transfer belt 31 and the clamping region 37T, the recording medium P and the ink image may be heated by the transfer cylinder 37. In addition, a recess 37D is formed on the outer circumference of the transfer cylinder 37, which accommodates the gripper 54 and mounting member 55 described later.

[0052] As shown in Figure 2, the pair of sprockets 38 are positioned at both axial ends of the transfer cylinder 37. These sprockets 38 are arranged coaxially with the transfer cylinder 37 and are configured to rotate integrally with the transfer cylinder 37. The transfer body 36 is rotationally driven by a drive unit (not shown). A chain 52, described later, is wrapped around the pair of sprockets 38.

[0053] As shown in Figure 1, the cleaner 28 is positioned downstream of the clamping region 37T in the belt circumferential direction and upstream of the adhesive layer forming device 24 in the belt circumferential direction. The cleaner 28 is equipped with a blade 28a that is in contact with the outer circumferential surface of the transfer belt 31. As the transfer belt 31 rotates, the cleaner 28 uses the blade 28a to remove the adhesive layer, ink-receiving particles 16, ink, and other foreign matter (for example, paper dust when the recording medium P is paper) remaining on the portion of the transfer belt 31 that has passed through the clamping region 37T.

[0054] (Fusing device 60) The fixing device 60 shown in Figure 1 is a device that fixes an ink image transferred to a recording medium P onto the recording medium P, and is an example of a transport device. Specifically, as shown in Figure 1, the fixing device 60 includes a pressurizing body 67, a heating roll 62, a heating section 70, an air blowing section 80, and a transport section 15.

[0055] (Pressurizing body 67 and heating roll 62) The pressurizing body 67, as shown in Figure 3, includes a pressurizing roll 61 and a pair of sprockets 69. The pair of sprockets 69 are positioned at both axial ends of the pressurizing roll 61. These sprockets 69 are arranged coaxially with the pressurizing roll 61 and are configured to rotate integrally with the pressurizing roll 61. A chain 52, described later, is wrapped around the pair of sprockets 69.

[0056] As shown in Figures 1 and 5, the pressure roll 61 and the heating roll 62 are arranged vertically. Specifically, the heating roll 62 is positioned above the pressure roll 61. This heating roll 62 has a heating source 62A (see Figure 1), such as a halogen lamp, inside the roll.

[0057] In this embodiment, for example, one of the pressure roll 61 and the heating roll 62 is rotationally driven, while the other of the pressure roll 61 and the heating roll 62 is driven to rotate. Alternatively, both the pressure roll 61 and the heating roll 62 may be rotationally driven.

[0058] The heating roll 62 is movable between a contact position (shown in Figure 5) and a separation position (shown in Figure 6) relative to the pressure roll 61. Specifically, the heating roll 62 moves between the contact position (shown in Figure 5) and the separation position (shown in Figure 6) by a movement mechanism (hereinafter referred to as movement mechanism A) using a cam or the like. That is, the heating roll 62 is pushed or pulled towards the contact position by the elastic force of an elastic member (e.g., a spring) of the movement mechanism A, and moves to the separation position by the cam of the movement mechanism A in opposition to this elastic force.

[0059] As shown in Figure 10, the heating roll 62 sandwiches the recording medium P between the pressure roll 61 and the heating roll 61 at the contact point. In each figure, the sandwiching region where the pressure roll 61 and the heating roll 62 sandwich the recording medium P is indicated by the symbol NP. This sandwiching region NP is a region with a width in the transport direction X. Furthermore, as will be described later, the recording medium P that has been transported to the sandwiching region NP is sandwiched between the pressure roll 61 and the heating roll 62 in the sandwiching region NP, so the sandwiching region NP can also be said to be the place where sandwiching by the pressure roll 61 and the heating roll 62 is planned.

[0060] Furthermore, a recess 61D is formed on the outer circumference of the pressure roll 61, which accommodates the gripper 54 and mounting member 55 described later. This recess 61D opens radially outward from the pressure roll 61. A corner portion 61R (hereinafter referred to as the rear edge 61R) is formed at the upstream end in the rotational direction of the recess 61D of the pressure roll 61. This rear edge 61R is formed in a rounded shape (so-called radius shape).

[0061] In this embodiment, the pressure roll 61 is an example of a first conveyor and an example of a pressure member. The heating roll 62 is an example of a second conveyor and an example of a heating member.

[0062] (Heating section 70) The heating unit 70 shown in Figure 1 has the function of non-contact heating the recording medium P being transported in the transport direction X by the transport unit 15. This heating unit 70 is positioned upstream of the heating roll 62 in the transport direction (to the right in Figure 1). As a result, the heating unit 70 non-contact heats the unfixed toner image formed on the surface of the recording medium P prior to the heating roll 62. Specifically, as shown in Figure 1, the heating unit 70 includes a heater 72 and a reflector 73.

[0063] The heater 72 is a heating element that heats the recording medium P without contact with it as it is transported in the transport direction X by the transport unit 15. More specifically, the heater 72 is configured as follows: As shown in Figure 1, multiple heaters 72 are arranged at intervals along the transport direction X. Each heater 72 is a cylindrical infrared heater with a length in the depth direction D of the device. The heater 72 generates heat from a filament (not shown) located inside, and heats the recording medium P with its radiant heat. In this embodiment, as shown in Figure 1, four heaters 72 are provided, but the number of heaters 72 is not limited to four.

[0064] The reflector 73 has the function of reflecting infrared rays from the heater 72 toward the lower side of the device (i.e., toward the recording medium P being transported by the transport unit 15). Specifically, the reflector 73 is formed in the shape of a box with the lower side of the device open. This reflector 73 is formed using a metal plate such as an aluminum plate.

[0065] (Air blower unit 80) The air blower 80 shown in Figure 1 is located on the opposite side (i.e., the lower side) from the heating unit 70 (i.e., the upper side) to the recording medium P being transported by the transport unit 15, and faces the heating unit 70. Note that the air blower 80 is an example of a support unit.

[0066] The blower unit 80 has the function of blowing air onto the lower surface of the recording medium P being transported by the transport unit 15. Specifically, the blower unit 80 has the function of lifting the recording medium P by blowing air onto it so that the back surface opposite to the surface on which the unfixed image is formed remains in a non-contact state while the recording medium P is being transported by the transport unit 15.

[0067] In this embodiment, the blower unit 80 includes a main body 82, a blower plate 83, and a blower 84. The main body 82 has an internal space 82A that opens upward.

[0068] The blower 84 is located at the bottom of the main body 82. The blower 84 supplies air to the space 82A of the main body 82. As an example, an axial flow blower that blows air in the axial direction is used as the blower 84. Alternatively, a centrifugal blower that blows air in the centrifugal direction, such as a multi-blade blower (for example, a sirocco fan), may also be used as the blower 84.

[0069] The blower plate 83 is provided on the upper part of the main body 82 so as to close the opening of the main body 82. This blower plate 83 faces the heating unit 70 on the opposite side (i.e., the lower side) from the heating unit 70 side (i.e., the upper side) of the recording medium P being transported by the transport unit 15. Furthermore, the blower plate 83 is made of metal or resin and is plate-shaped, and has a plurality of air holes 83A that penetrate in the vertical direction H. The blower plate 83 supports the recording medium P by allowing air sent from the blower 84 to the space 82A of the main body 82 to pass upward through the plurality of air holes 83A and strike the lower surface of the recording medium P, thereby levitating the recording medium P.

[0070] (Conveying section 15) The transport unit 15 shown in Figure 1 has the function of transporting the recording medium P and passing it through the clamping area 37T and the clamping area NP. As shown in Figures 1, 2, and 3, the transport unit 15 has a pair of chains 52 and a gripper 54. The gripper 54 is an example of a holding part that holds the leading edge of the recording medium P. Note that in Figure 1, the chains 52 and gripper 54 are shown in a simplified manner.

[0071] The pair of chains 52 are formed in an annular shape, as shown in Figure 1. These chains 52 are spaced apart in the depth direction of the device (direction D in the figures), as shown in Figures 2 and 3. Each of these chains 52 is wrapped around a pair of sprockets 38 on the transfer body 36 (see Figure 2) and a pair of sprockets 69 on the pressurizing body 67 (see Figure 3). The chains 52 are configured to rotate in the circumferential direction C (direction of arrow C in Figures 1, 2, and 3) as the transfer body 36 with the pair of sprockets 38 and the pressurizing body 67 with the pair of sprockets 69 rotate.

[0072] As shown in Figures 2 and 3, mounting members 55 to which grippers 54 are attached are stretched along the depth direction of the device on a pair of chains 52. Multiple mounting members 55 are fixed to the pair of chains 52 at predetermined intervals along the circumferential direction (circumferential direction C) of the chains 52.

[0073] As shown in Figures 2 and 3, multiple grippers 54 are attached to a mounting member 55 at predetermined intervals along the depth direction of the device. In other words, the grippers 54 are attached to the chain 52 via the mounting member 55. These grippers 54 have the function of holding the tip of the recording medium P. Specifically, as shown in Figure 4, the gripper 54 has claws 54A and claw bases 54B. The gripper 54 is configured to hold the recording medium P by sandwiching its tip between the claws 54A and claw bases 54B. In other words, the gripper 54 can be considered an example of a clamping part that clamps the recording medium P in the thickness direction.

[0074] More specifically, the gripper 54 is positioned downstream of the recording medium P in the transport direction, and holds the leading edge of the recording medium P from the downstream side in the transport direction of the recording medium P. In the gripper 54, for example, the claws 54A are pressed against the claw base 54B by a spring or the like, and the claws 54A are opened and closed relative to the claw base 54B by the action of a cam or the like.

[0075] Then, in the transport unit 15, the leading edge of the recording medium P, which has been transported from the storage unit (not shown) containing the recording medium P, is held by the gripper 54 as shown in Figure 4. Furthermore, in the transport unit 15, the chain 52 rotates in the circumferential direction C while the gripper 54 holds the leading edge of the recording medium P, thereby moving the gripper 54 and transporting the recording medium P, and passing the recording medium P through the gripping region 37T together with the gripper 54 while still holding it. Furthermore, in the transport unit 15, the recording medium P is transported and, while still being held by the gripper 54, passes between the heating unit 70 and the blowing unit 80 together with the gripper 54.

[0076] Furthermore, in the portion where the chain 52 is wrapped around the sprocket 38, the gripper 54 is housed in the recess 37D of the transfer cylinder 37 and moves together with the transfer cylinder 37 in the direction of rotation of the transfer cylinder 37.

[0077] In this embodiment, as shown in Figures 7 and 8, the transport unit 15 transports the recording medium P toward the gripping region NP with the gripper 54 holding the leading edge of the recording medium P while the heating roll 62 is positioned at a distance from the other side. In the portion where the chain 52 is wrapped around the sprocket 69, the gripper 54 is housed in the recess 61D of the pressure roll 61 and moves integrally with the pressure roll 61 in the rotational direction of the pressure roll 61. When the gripper 54 is housed in the recess 61D, the recording medium P is positioned on the outer circumferential surface of the pressure roll 61 toward the upstream side in the rotational direction from the rear end edge 61R of the pressure roll 61.

[0078] Furthermore, as shown in Figure 9, when the transport unit 15 transports the recording medium P to the gripping region NP, it releases its grip on the leading edge of the recording medium P. That is, the transport unit 15 releases its grip on the leading edge of the recording medium P after the gripper 54 has passed through the gripping region NP. The recording medium P, whose leading edge has been released from the gripper 54, moves in the transport direction X due to inertia. The leading edge of the recording medium P, whose leading edge has been released from the gripper 54, then rests on the pressure roll 61. In other words, the pressure roll 61 supports the leading edge of the recording medium P, whose leading edge has been released from the gripper 54, from below. Furthermore, the air blowing unit 80 (see Figure 1) supports the recording medium P from below by blowing air onto the rear end of the recording medium P, whose leading edge has been released from the gripper 54. Thus, in this embodiment, the recording medium P, whose leading edge has been released from the gripper 54, is supported on both its leading edge and rear end.

[0079] Furthermore, the state in which the pressure roll 61 in contact with the recording medium P is rotated, and the state in which the chain 52 is circulating is maintained. In other words, in this embodiment, the pressure roll 61 rotates when the heating roll 62 is in a separated position, generating a frictional force that causes the recording medium P, whose tip is released from being held by the gripper 54, to move downstream in the conveying direction.

[0080] Furthermore, the fact that the recording medium P has been transported to the clamping area NP is detected by the time elapsed since the detection unit (specifically, the sensor) on the upstream side of the transport direction in the clamping area NP detected the leading edge of the recording medium P. The object detected by the detection unit may not be the leading edge of the recording medium P, but rather the mounting member 55 or the gripper 54.

[0081] As shown in Figure 10, the heating roll 62 moves from a separated position to a contact position after the gripper 54 has passed the clamping region NP and the gripper 54 has released its grip on the leading edge of the recording medium P, and clamps the recording medium P, which has been conveyed to the clamping region NP by the conveying unit 15, with the pressure roll 61. In this embodiment, the heating roll 62 starts moving from a separated position after a predetermined time has elapsed after the gripper 54 has passed the clamping region NP and the gripper 54 has released its grip on the leading edge of the recording medium P, and clamps the recording medium P, which has been conveyed to the clamping region NP, with the pressure roll 61. At this time, the rear end edge 61R of the pressure roll 61 has also passed the clamping region NP. That is, the heating roll 62 clamps the recording medium P with the pressure roll 61 after the rear end edge 61R of the pressure roll 61 has also passed the clamping region NP.

[0082] Furthermore, in this embodiment, when both the heating roll 62 and the pressure roll 61 are rotating, the heating roll 62 moves from a separated position to a contact position, sandwiching the recording medium P between it and the pressure roll 61. The heating roll 62 and the pressure roll 61 are configured to be rotationally driven, for example, by a driving force transmitted to their own rotation axis via a transmission member such as a gear. Alternatively, at least one of the heating roll 62 and the pressure roll 61 may be configured to rotate independently by contacting and being driven by a different drive roll. In this case, the heating roll 62 may be configured to receive heat from a drive roll in contact with it, instead of or in addition to the heating source 62A. In this embodiment, the heating roll 62 and the pressure roll 61 each rotate at a constant speed, for example. That is, the heating roll 62 and the pressure roll 61 each rotate at the same speed before and after the gripper 54 releases its gripping of the tip.

[0083] Furthermore, the peripheral speeds of the rotating pressure roll 61 and heating roll 62 are the same. However, the peripheral speeds of the pressure roll 61 and heating roll 62 do not need to be perfectly identical; a difference in peripheral speed between the pressure roll 61 and heating roll 62 is acceptable as long as no wrinkles are generated on the recording medium P.

[0084] Furthermore, the heating roll 62 may start moving from the separated position before the gripper 54 releases its hold on the leading edge of the recording medium P, and the clamping of the recording medium P by the heating roll 62 and the pressure roll 61 should be completed after the gripper 54 releases its hold on the leading edge of the recording medium P.

[0085] Then, as shown in Figure 11, the pressure roll 61 and the heating roll 62, with the recording medium P sandwiched between them, begin to rotate as the heating roll 62 starts to transport the recording medium P.

[0086] In the fixing device 60, the ink image transferred to the recording medium P is fixed to the recording medium P by heating and pressurizing the recording medium P while the recording medium P is being transported with the recording medium P sandwiched between the heating roll 62 and the pressure roll 61.

[0087] After transporting the recording medium P, the heating roll 62 moves from the contact position (the position shown in Figure 5) to the separation position (the position shown in Figure 6). Specifically, the heating roll 62 moves from the contact position to the separation position after the transport of the recording medium P is finished (in other words, after the image fixing to the recording medium P is finished) and before the leading edge of the recording medium P that is to be transported to the clamping area NP enters the clamping area NP.

[0088] As described above, in this embodiment, the heating roll 62 moves from a separated position to a contact position when the recording medium P is sandwiched between the pressure roll 61, and moves from the contact position to a separated position when the transport of the recording medium P is completed. The first moving speed at which the heating roll 62 moves from the separated position to the contact position is faster than the second moving speed at which the heating roll 62 moves from the contact position to the separated position. In other words, the heating roll 62 moves from the separated position to the contact position at a first moving speed that is faster than the second moving speed, due to the moving mechanism A. To put it another way, the time it takes for the heating roll 62 to move from the separated position to the contact position is shorter than the time it takes to move from the contact position to the separated position.

[0089] Here, the moving mechanism A includes a support that supports the heating roll 62 or a cam follower (not shown) provided on the heating roll 62, and a cam (not shown) having a minor axis portion and a major axis portion whose length along the radial direction from the center of rotation is longer than that of the minor axis portion. In the moving mechanism A, for example, by rotating the cam in a predetermined rotational direction, the heating roll 62 is moved from the contact position to the separated position by contacting the cam follower in a range from the minor axis portion to the major axis portion on the outer circumferential surface of the cam (hereinafter referred to as range X). Furthermore, in the moving mechanism A, for example, by rotating the cam in the aforementioned rotational direction, the heating roll 62 is moved from the separated position to the contact position by contacting the cam follower in a range from the major axis portion to the minor axis portion on the outer circumferential surface of the cam (hereinafter referred to as range Y). In this configuration, for example, range X is formed to be longer than range Y on the outer surface of the cam, and the change in radial length from the minor axis portion to the major axis portion in range X is made more gradual than the change in radial length from the major axis portion to the minor axis portion in range Y. As a result, the heating roll 62 moves from the separated position to the contact position at a first moving speed that is faster than the second moving speed.

[0090] Furthermore, the cam may be configured such that range X and range Y are the same length on the outer surface of the cam, and the change in radial length from the minor axis portion to the major axis portion in range X is the same as the change in radial length from the major axis portion to the minor axis portion in range Y. In this configuration, for example, by making the rotational speed of the cam when range Y contacts the cam follower faster than the rotational speed of the cam when range X contacts the cam follower, the heating roll 62 moves from the separated position to the contact position at a first moving speed that is faster than the second moving speed.

[0091] Furthermore, in this embodiment, when the recording medium P is plain paper (i.e., not coated paper), the heating roll 62 clamps the recording medium P with the pressure roll 61 with a first load, and when the recording medium P is coated paper, it clamps the recording medium P with the pressure roll 61 with a second load greater than the first load. In this embodiment, when the recording medium P is coated paper, the heating roll 62 clamps the recording medium P with the pressure roll 61 with a second load, regardless of the basis weight of the recording medium P.

[0092] In this embodiment, for example, the presence or absence of a coating layer on the recording medium P is detected by input from the user of the fixing device 60, or by a detection unit such as an optical sensor, to determine whether the recording medium P is coated paper or not. Based on this determination, in this embodiment, either a first load or a second load is selected as the load on the heating roll 62.

[0093] Furthermore, in this embodiment, when the recording medium P is ordinary paper, the heating roll 62 applies a first load to sandwich the recording medium P between itself and the pressure roll 61 when the basis weight of the recording medium P is less than a predetermined standard value, and applies a second load to sandwich the recording medium P between itself and the pressure roll 61 when the basis weight of the recording medium P is equal to or greater than the standard value.

[0094] In this embodiment, for example, the basis weight of the recording medium P is detected by input from the user of the fixing device 60, or by a detection unit such as an ultrasonic sensor, to determine whether the basis weight of the recording medium P is equal to or greater than a standard value. Based on this determination, in this embodiment, either the first load or the second load is selected as the load of the heating roll 62.

[0095] In this embodiment, the moving mechanism A adjusts the load on the heating roll 62 by changing the contact position of the cam's minor diameter portion with the cam follower based on the rotation angle of the cam. Specifically, the moving mechanism A generates a second load on the heating roll 62 when the shortest diameter position, which has the shortest radial length, contacts the cam follower. Furthermore, the moving mechanism A generates a first load on the heating roll 62 when a position with a radial length longer than the shortest diameter position in the cam's minor diameter portion contacts the cam follower.

[0096] In this embodiment, the load of the heating roll 62 is not changed depending on the size of the recording medium P. Therefore, when the recording medium P is coated paper, the heating roll 62 clamps the recording medium P with the pressure roll 61 at the second load, regardless of the size of the recording medium P. Also, when the recording medium P is plain paper and the basis weight of the recording medium P is above a predetermined standard value, the heating roll 62 clamps the recording medium P with the pressure roll 61 at the second load, regardless of the size of the recording medium P. Furthermore, when the recording medium P is plain paper and the basis weight of the recording medium P is below a predetermined standard value, the heating roll 62 clamps the recording medium P with the pressure roll 61 at the first load, regardless of the size of the recording medium P. When the basis weight is above the standard value, the thickness of the recording medium P is greater than when the basis weight of the recording medium P is below the predetermined standard value, so the heating roll 62 makes contact with the surface faster by the thickness of the recording medium P. Therefore, the time required for the waviness and other distortions caused by the restraint of the recording medium P by the gripper 54 to be resolved is shortened. However, since thicker recording mediums P are less prone to wrinkles, the effect of faster contact of the heating roll 62 is smaller.

[0097] At least one of the pressure roll 61 and the heating roll 62 is made of an elastic body that elastically deforms under the load when the heating roll 62 sandwiches the recording medium P between the pressure roll 61. In this embodiment, both the pressure roll 61 and the heating roll 62 are made of rubber rolls (an example of an elastic body) having a rubber layer on the outer circumference of the roll.

[0098] (Operation of this embodiment) In the image forming apparatus 10, as shown in Figure 1, the adhesive layer forming apparatus 24 applies an adhesive to the outer surface of the circulating transfer belt 31, thereby forming an adhesive layer (not shown). Next, the particle supply apparatus 18 supplies ink-receiving particles 16 to the transfer belt 31, and an ink-receiving particle layer 16A is formed on the adhesive layer of the transfer belt 31.

[0099] Next, the ejection head 20 ejects ink droplets onto the ink-receiving particle layer 16A to form an ink image. The ink image formed on the ink-receiving particle layer 16A is transported to the clamping region 37T by the rotation of the transfer belt 31, and the recording medium P is transported to the clamping region 37T by the transport unit 15.

[0100] The transfer unit 36 ​​transfers the ink image to the recording medium P by sandwiching the recording medium P and the ink image, which have been transported to the clamping area 37T, between the transfer belt 31 and applying pressure.

[0101] As shown in Figures 7 and 8, the ink-transferred recording medium P is transported by the transport unit 15 to the clamping region NP with its leading edge held by the gripper 54 while the heating roll 62 is in a separated position. Next, as shown in Figure 9, the gripper 54 releases the leading edge of the recording medium P. Specifically, the gripper 54 releases the leading edge of the recording medium P after it has passed through the clamping region NP.

[0102] Next, as shown in Figure 10, the heating roll 62 moves from a separated position to a contact position after the gripper 54 has passed the gripping region NP and the gripper 54 has released its hold on the leading edge of the recording medium P, and grips the recording medium P, which has been conveyed to the gripping region NP by the conveying unit 15, with the pressure roll 61. Then, as shown in Figure 11, with the recording medium P gripped between the pressure roll 61 and the heating roll 62, the heating roll 62 starts to rotate and conveys the recording medium P.

[0103] The heating roll 62 and the pressure roll 61 transport the recording medium P while sandwiching it, and the recording medium P is heated and pressurized to fix the ink image transferred to the recording medium P.

[0104] Here, as shown in Figure 12, in the configuration in which the gripper 54 holds the leading edge of the recording medium P that has been transported to the clamping area NP, and the recording medium P is then clamped and transported by the pressure roll 61 and the heating roll 62 (hereinafter referred to as the "first configuration"), the orientation of the recording medium P is constrained because the leading edge is held by the gripper 54. For example, if the recording medium P is transported to the clamping area NP in a wavy state or tilted with respect to the transport direction X, it will be clamped by the pressure roll 61 and the heating roll 62 in that state, which may cause wrinkles to form on the recording medium P, as shown in Figure 13. Wrinkles are particularly likely to form if the recording medium P is thin paper.

[0105] In contrast, in this embodiment, as described above, the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61 after the gripper 54 releases holding of the leading edge of the recording medium P. Therefore, the recording medium P is not constrained by the orientation it had when it was transported to the sandwiching area NP. For this reason, even if the recording medium P is transported to the sandwiching area NP in a wavy state or tilted with respect to the transport direction X, such state of the recording medium P can be resolved. Accordingly, the configuration of this embodiment suppresses the occurrence of wrinkles on the recording medium P compared to the first configuration.

[0106] Furthermore, in this embodiment, after the gripper 54 has passed through the gripping region NP, the heating roll 62 moves from a separated position to a contact position, gripping the recording medium P with the pressure roll 61. Therefore, compared to a configuration in which the heating roll 62 moves from a separated position to a contact position before the gripper 54 has passed through the gripping region NP, contact between the gripper 54 and the heating roll 62 is suppressed.

[0107] Furthermore, in this embodiment, the transport unit 15 transports the recording medium P to the gripping area NP while the gripper 54 holds the leading edge of the recording medium P, with the heating roll 62 positioned at a distanced position.

[0108] Therefore, compared to a configuration in which the gripper 54 releases its gripping of the recording medium P just before reaching the clamping area NP, and then the recording medium P is transported to the clamping area NP by another transport unit before being clamped by the heating roll 62 and the pressure roll 61, the time from when the gripper 54 releases its gripping of the recording medium P until the recording medium P is clamped by the heating roll 62 and the pressure roll 61 is shorter. In this way, the recording medium P has a shorter free state, so external forces acting on it during this free state can suppress tilting of its posture. As a result, poor clamping of the recording medium P by the heating roll 62 and the pressure roll 61 is suppressed, and the occurrence of wrinkles on the recording medium P is suppressed.

[0109] Furthermore, in this embodiment, the pressure roll 61 rotates when the heating roll 62 is in a separated position, generating a frictional force that causes the recording medium P, whose tip has been released from the gripper 54, to move downstream in the transport direction. Therefore, compared to a configuration in which the pressure roll 61 contacts the recording medium P while it is not rotating, the backward movement of the recording medium P, whose tip has been released from the gripper 54, towards the upstream direction in the transport direction is suppressed. In this way, the backward movement of the recording medium P, whose tip has been released from the gripper 54, towards the upstream direction in the transport direction is suppressed, so that the position at which image fixing begins on the recording medium P does not vary from one recording medium P to another.

[0110] Furthermore, in this embodiment, the pressure roll 61 supports the front end of the recording medium P from below after the gripper 54 has released its grip. In addition, the air blower 80 supports the recording medium P from below by blowing air onto the rear end of the recording medium P after the gripper 54 has released its grip. Therefore, compared to a configuration in which only the front end of the recording medium P is supported, sagging of the rear end of the recording medium P after the gripper 54 has released its grip is suppressed.

[0111] Furthermore, in this embodiment, the heating roll 62 starts moving from a separated position after a predetermined time has elapsed since the gripper 54 has passed through the clamping region NP and the gripper 54 has released its hold on the leading edge of the recording medium P, and clamps the recording medium P, which has been transported to the clamping region NP, with the pressure roll 61. Therefore, compared to a configuration in which the heating roll 62 clamps the recording medium P with the pressure roll 61 at the same time that the gripper 54 releases its hold on the leading edge of the recording medium P, time is ensured for any waviness or other distortions caused by the recording medium P being restrained by the gripper 54 to be resolved. As a result, since the heating roll 62 clamps the recording medium P with the pressure roll 61 after any waviness or other distortions in the recording medium P have been resolved, the occurrence of wrinkles in the recording medium P is suppressed.

[0112] Furthermore, in this embodiment, when both the heating roll 62 and the pressure roll 61 are rotating, the heating roll 62 moves from a separated position to a contact position, sandwiching the recording medium P between itself and the pressure roll 61. In this configuration, where only one of the heating roll 62 or the pressure roll 61 is rotating, and the heating roll 62 sandwiches the recording medium P between itself and the pressure roll 61 (hereinafter referred to as the first configuration), a transporting force is applied to one side of the recording medium P, while a brake acts on the other side, making it easy for wrinkles to occur on the recording medium P.

[0113] In contrast, in this embodiment, when both the heating roll 62 and the pressure roll 61 are rotating, the heating roll 62 sandwiches the recording medium P between the pressure roll 61, thus suppressing the occurrence of wrinkles on the recording medium P compared to the first configuration.

[0114] Furthermore, in this embodiment, the peripheral speeds of the rotating pressure roll 61 and heating roll 62 are the same. As a result, the conveying force acting on one side and the other side of the recording medium P is the same. Consequently, the occurrence of wrinkles on the recording medium P is suppressed compared to a configuration in which the peripheral speeds of the rotating pressure roll 61 and heating roll 62 are different (hereinafter referred to as the second configuration). The second configuration is one in which the peripheral speeds of the rotating pressure roll 61 and heating roll 62 are different to the extent that wrinkles occur on the recording medium P.

[0115] Furthermore, in this embodiment, the first moving speed at which the heating roll 62 moves from the separated position to the contact position is faster than the second moving speed at which the heating roll 62 moves from the contact position to the separated position. Therefore, even if, for example, the heating roll 62 tilts relative to the pressure roll 61, and there is a difference in the contact timing between one end and the other end of the heating roll 62 in the axial direction, the difference will be smaller compared to a configuration where the first moving speed is the same as the second moving speed. As a result, the time during which the load is unevenly applied to one side of the recording medium P is reduced, and the occurrence of wrinkles on the recording medium P is suppressed.

[0116] Furthermore, in this embodiment, since the second moving speed is slower than the first moving speed, the change in radial length from the minor axis to the major axis is more gradual in the range X from the minor axis to the major axis on the outer surface of the cam than in the range Y from the major axis to the minor axis on the outer surface of the cam. As a result, when moving the heating roll 62 from the contact position to the separated position, noise caused by contact between the cam and the cam follower is suppressed.

[0117] Furthermore, in this embodiment, both the pressure roll 61 and the heating roll 62 are formed from, for example, rubber rolls (an example of an elastic body) having a rubber layer on the outer circumference of the roll. Therefore, compared to a configuration in which both the pressure roll 61 and the heating roll 62 are rigid bodies that do not elastically deform, the heating roll 62 absorbs the impact when the recording medium P is sandwiched between the pressure roll 61 and the heating roll 62.

[0118] Furthermore, in this embodiment, when the recording medium P is plain paper, the heating roll 62 clamps the recording medium P with the pressure roll 61 with a first load, and when the recording medium P is coated paper, it clamps the recording medium P with the pressure roll 61 with a second load greater than the first load. As a result, when the recording medium P is coated paper, the amount of heat applied to the recording medium P is increased compared to a configuration in which the heating roll 62 clamps the recording medium P with the pressure roll 61 with a first load, and the gloss of the recording medium P is improved.

[0119] Furthermore, in this embodiment, when the recording medium P is ordinary paper, the heating roll 62 clamps the material to be conveyed between itself and the first conveyor with a first load when the basis weight of the recording medium P is less than a predetermined standard value, and clamps the recording medium P between itself and the pressure roll 61 with a second load when the basis weight of the recording medium P is equal to or greater than the standard value. Therefore, compared to a configuration in which the heating roll 62 clamps the recording medium P between itself and the pressure roll 61 with a first load when the basis weight of the recording medium P is equal to or greater than the standard value, the amount of heat applied to the recording medium P is increased, and poor fixing of the recording medium P is suppressed.

[0120] (A modified example of the timing at which the gripper 54 releases its grip on the tip of the recording medium P) In the above embodiment, the gripper 54 released its grip on the leading edge of the recording medium P after passing through the gripping region NP, but it is not limited to this. In this modified example, the transport unit 15 transports the recording medium P toward the gripping region NP with the gripper 54 holding the leading edge of the recording medium P while the heating roll 62 is in a spaced-out position (see Figure 7). As shown in Figure 14, the transport unit 15 releases its grip on the leading edge of the recording medium P before it reaches the gripping region NP (i.e., before the recording medium P reaches the gripping region NP). Specifically, the gripper 54 releases its grip on the leading edge of the recording medium P before it passes through the gripping region NP. More specifically, the gripper 54 releases its grip on the leading edge of the recording medium P while a part of the gripper 54 is located in the gripping region NP and another part of the gripper 54 is located in front of the gripping region NP. At this time, the state in which the pressure roll 61 is rotating and the state in which the chain 52 is circulating are maintained.

[0121] Subsequently, in this modified example, the recording medium P is adsorbed onto the outer surface of the pressure roll 61 and transported to the clamping region NP. That is, in this modified example, the pressure roll 61 has an adsorption mechanism (not shown) that adsorbs the recording medium P onto its outer surface. The adsorption mechanism has suction holes (not shown) on its outer surface that attract the recording medium P, and by attracting the recording medium P through these suction holes, the recording medium P is adsorbed onto the outer surface of the pressure roll 61. In this way, the adsorption mechanism uses negative pressure to adsorb the recording medium P, but it may also use electrostatic force or the like to adsorb it.

[0122] The heated roll 62 moves from a separated position to a contact position after the gripper 54 has passed through the clamping region NP, and clamps the recording medium P that has been conveyed to the clamping region NP with the pressure roll 61 (see Figure 10). Note that the clamping between the heated roll 62 and the pressure roll 61 may be performed after the suction by the pressure roll 61 is released, or it may be performed while the suction by the pressure roll 61 is maintained.

[0123] Then, with the recording medium P sandwiched between the pressure roll 61 and the heating roll 62, the heating roll 62 starts rotating to transport the recording medium P (see Figure 11).

[0124] In this modified example, similar to the embodiment described above, the recording medium P is transported while sandwiched between the heating roll 62 and the pressure roll 61, and the recording medium P is heated and pressurized to fix the ink image transferred to the recording medium P.

[0125] (Variation in timing of the heating roll 62 inserting the recording medium P) Furthermore, in this embodiment, the heating roll 62 sandwiches the recording medium P with the pressure roll 61 after the rear end edge 61R of the pressure roll 61 has also passed through the sandwiching region NP, but this is not limited to this configuration. For example, as shown in Figure 16, the heating roll 62 may be configured to sandwich the recording medium P with the pressure roll 61 when the rear end edge 61R is located in the sandwiching region NP.

[0126] In this configuration, with the rear edge 61R positioned downstream in the transport direction relative to the clamping region NP, the recording medium P is clamped from a more forward position compared to a configuration where the heating roll 62 clamps the recording medium P between the pressure roll 61. Therefore, even if the image is formed from a more forward position on the recording medium P, the image can be fixed to the recording medium P. As a result, the margin on the leading edge side of the recording medium P is reduced.

[0127] Furthermore, in this embodiment, since the rear edge 61R is formed in a rounded shape (so-called radius shape), even if the heating roll 62 and the rear edge 61R come into contact, the recording medium P is prevented from breaking at the rear edge 61R.

[0128] (Modified form of conveying device) In this embodiment, a fixing device 60 having both a conveying function and a fixing function is given as an example of a conveying device, but it is not limited to this. Examples of conveying devices include, for example, a device having functions other than conveying and fixing functions (e.g., a transfer function), or a conveying device having only a conveying function.

[0129] (Modified versions of the first and second transport units) In this embodiment, a heated roll 62 was used as an example of the second conveying body, but it is not limited to this. As an example of the second conveying body, for example, a heated roll 62 and a heated belt wrapped around the roll may be used.

[0130] Furthermore, the first conveying body may be configured to use a heating element such as a heating roll, and the second conveying body may be configured to use a pressurizing element such as a pressurizing roll and a pressurizing belt.

[0131] As an example of a conveying device, when a device having both a conveying function and a transfer function is used, the first and second conveying bodies may include a transfer member such as a transfer roll and an opposing member such as an opposing roll or opposing belt that faces the transfer member.

[0132] As an example of a conveying device, in the case of a conveying device that has only a conveying function, the first conveying body and the second conveying body may be, for example, a conveying member such as a conveying roll and a conveying member such as a conveying roll or conveying belt facing the conveying member.

[0133] (Modified version of the transport section) In this embodiment, the gripper 54, positioned downstream of the recording medium P in the transport direction, held the leading edge of the recording medium P from the downstream side in the transport direction of the recording medium P. However, this is not limited to this. The gripper 54 may also hold the leading edge portion of the recording medium P from both ends in the width direction of the recording medium P (i.e., the side ends).

[0134] <Second Embodiment> (Image forming apparatus 200) In the first embodiment, the image forming apparatus 10 was an inkjet type image forming apparatus that forms an image on a recording medium P using ink, but the image forming apparatus is not limited to this. For example, an electrophotographic image forming apparatus may be used, or any apparatus that forms an image. In the second embodiment, an electrophotographic image forming apparatus 200 will be described. Figure 15 is a schematic diagram showing the configuration of the image forming apparatus 200 according to this embodiment. Parts having the same function as in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0135] (Image forming unit 214) The image forming apparatus 200 has an image forming unit 214 instead of the image forming unit 14. The image forming unit 214 is an example of an image forming unit that forms an image on a recording medium. Specifically, the image forming unit 214 has the function of forming a toner image (an example of an image) on the recording medium P using an electrophotographic method. More specifically, as shown in Figure 15, the image forming unit 214 has a toner image forming unit 222 that forms a toner image, and a transfer device 217 that transfers the toner image formed by the toner image forming unit 222 to the recording medium P.

[0136] (Toner image forming unit 222) The toner image forming units 222 shown in Figure 15 are provided in multiple units to form toner images for each color. In this embodiment, a total of four toner image forming units 222 are provided for yellow (Y), magenta (M), cyan (C), and black (K). (Y), (M), (C), and (K) shown in Figure 15 indicate the component parts corresponding to each of the above colors.

[0137] Since the toner image forming units 222 for each color are configured similarly except for the toner used, the parts of the toner image forming unit 222(K) in Figure 15 are labeled with reference numerals to represent each color's toner image forming unit 222.

[0138] Each toner image forming unit 222 has, specifically, a photoreceptor 224 that rotates in one direction (for example, counterclockwise in Figure 15). Each toner image forming unit 222 also has a charger 223, an exposure device 240, and a developing device 238.

[0139] In the toner image forming section 222 for each color, the charger 223 charges the photoreceptor 224. Furthermore, the exposure device 240 exposes the photoreceptor 224, which has been charged by the charger 223, to form an electrostatic latent image on the photoreceptor 224. Then, the developing device 238 develops the electrostatic latent image formed on the photoreceptor 224 by the exposure device 240 to form a toner image.

[0140] (Transfer device 217) The transfer device 217 shown in Figure 15 is a device that transfers the toner image formed in the toner image forming unit 222 to the recording medium P. Specifically, the transfer device 217 performs primary transfer by overlapping the toner images of each color photoreceptor 224 onto a transfer belt 213, which acts as an intermediate transfer body, and then performs secondary transfer of the overlapped toner images to the recording medium P. Specifically, as shown in Figure 15, the transfer device 217 comprises a transfer belt 213, a primary transfer roll 226, and a transfer body 36.

[0141] The primary transfer roll 226 is a roll that transfers the toner image of each color photoreceptor 224 to the transfer belt 213 at the primary transfer position T1 between the photoreceptor 224 and the primary transfer roll 226. In this embodiment, a primary transfer electric field is applied between the primary transfer roll 226 and the photoreceptor 224, so that the toner image formed on the photoreceptor 224 is transferred to the transfer belt 213 at the primary transfer position T1.

[0142] The transfer belt 213 transfers toner images from each color photoreceptor 224 to its outer surface. As shown in Figure 15, the transfer belt 213 is endless and is wrapped around multiple rolls 232 and opposing rolls 234 so that it is in an inverted triangular shape when viewed from the front (in the direction of the depth of the device). The transfer belt 213 rotates in the direction of arrow A as at least one of the multiple rolls 232 is driven to rotate.

[0143] In this embodiment, the transfer cylinder 37 of the transfer body 36 transfers the toner image transferred to the transfer belt 213 to the recording medium P at the secondary transfer position T2 between the opposing roll 234 and the transfer cylinder 37. In this embodiment, a secondary transfer electric field is applied between the opposing roll 234 and the transfer cylinder 37, thereby transferring the toner image transferred to the transfer belt 213 to the recording medium P at the secondary transfer position T2.

[0144] (Fusing device 60) In this embodiment, the fixing device 60 functions as a device that fixes the toner image transferred to the recording medium P by the transfer cylinder 37 onto the recording medium P.

[0145] In the fixing device 60, the recording medium P is transported while being sandwiched between a heating roll 62 and a pressure roll 61, and the recording medium P is heated and pressurized to fix the toner image transferred to the recording medium P. The fixing device 60 is configured the same as in the first embodiment, except that it fixes the toner image transferred to the recording medium P to the recording medium P.

[0146] (Operation of this embodiment) In the image forming apparatus 200, each toner image forming unit 222 forms a toner image for each color. The toner images formed by each toner image forming unit 222 are transferred to the transfer belt 213 at their respective primary transfer positions T1, and these transferred toner images are then transferred to the recording medium P at the secondary transfer position T2.

[0147] As shown in Figures 7 and 8, the recording medium P onto which the toner image has been transferred is transported by the transport unit 15 to the clamping region NP with its leading edge held by the gripper 54 while the heating roll 62 is in a separated position. Next, as shown in Figure 9, the gripper 54 releases its grip on the leading edge of the recording medium P. Specifically, the gripper 54 releases its grip on the leading edge of the recording medium P after it has passed through the clamping region NP.

[0148] Next, as shown in Figure 10, the heating roll 62 moves from a separated position to a contact position after the gripper 54 has passed the gripping region NP and the gripper 54 has released its hold on the leading edge of the recording medium P, and grips the recording medium P, which has been conveyed to the gripping region NP by the conveying unit 15, with the pressure roll 61. Then, as shown in Figure 11, with the recording medium P gripped between the pressure roll 61 and the heating roll 62, the heating roll 62 starts to rotate and conveys the recording medium P.

[0149] The heating roll 62 and the pressure roll 61 transport the recording medium P while sandwiching it, and the recording medium P is heated and pressurized to fix the ink image transferred to the recording medium P.

[0150] Thus, since the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61 after the gripper 54 releases holding of the leading edge of the recording medium P, the recording medium P is not constrained by the orientation it had when it was transported to the sandwiching area NP. For this reason, even if the recording medium P is transported to the sandwiching area NP in a wavy state or tilted with respect to the transport direction X, such state of the recording medium P can be resolved. Therefore, according to the configuration of this embodiment, the occurrence of wrinkles on the recording medium P is suppressed compared to the first configuration. Thus, this embodiment also has the same effect as the first embodiment described above.

[0151] The present invention is not limited to the embodiments described above, and various modifications, changes, and improvements are possible without departing from the spirit of the invention. For example, the modified forms shown above may be combined in any way. In addition, the members in the embodiments may be individual or integrated with surrounding members. [Explanation of Symbols]

[0152] 10,200 Image forming apparatus 14 Image forming unit 15 Conveying section 54. Gripper (an example of a holding mechanism) 60 Fixing device (an example of a conveying device) 61. Pressure Roll (Example of First Conveyor, Example of Pressure Member) 62. Heating Roll (Example of a second conveyor, example of a heating element) NP sandwiched region P Recording medium (an example of a material to be transported)

Claims

1. A first conveying means for conveying a recording medium on which an image is formed; a second conveying means for conveying the recording medium by sandwiching the recording medium between the first conveying means and the second conveying means; a third conveying means having a holding means for holding a leading end of the recording medium in a conveying direction, and conveying the recording medium to a location where the recording medium is to be sandwiched between the first conveying means and the second conveying means; Equipped with the third conveying means conveys the recording medium to a location where the recording medium is to be clamped while the holding means holds the leading end of the recording medium in a state in which the first conveying means and the second conveying means are separated from each other; the holding means releases the holding of the leading end of the recording medium when the third transport means transports the recording medium to a location where the recording medium is to be sandwiched; After the holding means releases the holding of the recording medium, the first conveying means and the second conveying means convey the recording medium while sandwiching it therebetween; The first conveying means and the second conveying means are separated before the next recording medium is conveyed by the third conveying means to a location where the nipping is scheduled. Conveying device.

2. A support means is provided for supporting a rear end side of the recording medium whose leading end side is supported by the first conveying means when the holding of the leading end by the holding means is released. The conveying device according to claim 1 .

3. The second conveying means is After a predetermined time has elapsed since the holding means released the holding of the leading end portion, the recording medium is sandwiched between the first conveying means and the recording medium. The conveying device according to any one of claims 1 to 2.

4. The first conveying means includes a recess in which the holding means is housed, the recess having a corner on an upstream side of the conveying path, The second conveying means sandwiches the recording medium between the corner portion of the first conveying means. The conveying device according to any one of claims 1 to 3.

5. The first conveying means is either a heating member or a pressure member, the second conveying means is the other of the heating member and the pressing member; The fixing device as the conveying device according to any one of claims 1 to 4.

6. An image forming means for forming an image on a recording medium; a first conveying means which is either a heating member or a pressure member; a second conveying means which is the other of the heating member and the pressure member and conveys the recording medium by sandwiching the recording medium with the first conveying means; a third conveying means having a holding means for holding a leading end of the recording medium in a conveying direction, and conveying the recording medium to a location where the recording medium is to be sandwiched between the first conveying means and the second conveying means; Equipped with the third conveying means conveys the recording medium to a location where the recording medium is to be clamped while the holding means holds the leading end of the recording medium in a state in which the first conveying means and the second conveying means are separated from each other; the holding means releases the holding of the leading end of the recording medium when the third transport means transports the recording medium to a location where the recording medium is to be sandwiched; After the holding means releases the holding of the recording medium, the first conveying means and the second conveying means convey the recording medium while sandwiching it therebetween; The first conveying means and the second conveying means are separated before the next recording medium is conveyed by the third conveying means to a location where the nipping is scheduled. Image forming device.

Images