Conveying device, fixing device and image forming 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 apparatus. [Background technology]

[0002] Patent Document 1 discloses a fixing device that fixes an image drawn on a recording medium using particles containing at least a resin, the fixing device comprising a pair of fixing rolls consisting of a first fixing roll and a second fixing roll arranged in a pair with the first fixing roll, at least one of which is a heating roll and the surface layer of at least one of the fixing rolls is replaceable, an adhering means including an adhering member that adheres the recording medium, a charging means that charges at least one of the recording medium and the adhering means, and a fixing means that physically fixes the leading end of the recording medium in the transport direction to a predetermined position on the adhering member using a gripping portion, the charging means electrostatically adsorbing the adhering member and the recording medium on which the image is drawn, and the fixing means fixes the leading end of the recording medium on which the image is drawn to a predetermined position on the adhering member, and then the fixing device conveys the recording medium while sandwiching it together with the adhering means, thereby fixing the image on the recording medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-259223 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which a conveying section that holds the tip of the material to be conveyed and conveys the material by sandwiching the material between a first conveying body and a second conveying body while holding the tip, wrinkles may occur in the material to be conveyed.

[0005] The conveying section, which holds and conveys the leading end of the material to be conveyed, suppresses the occurrence of wrinkles in the material to be conveyed compared to a configuration in which the material to be conveyed is sandwiched between a first conveying body and a second conveying body while the leading end is still being held. [Means for solving the problem]

[0006] The first aspect comprises a first conveying body, a second conveying body that is movable between a contact position with the first conveying body and a separation position with respect to the first conveying body and that sandwiches the material to be conveyed with the first conveying body at the contact position, and a conveying section that has a holding section that holds the tip of the material to be conveyed, and that, when the second conveying body is positioned at the separation position, conveys the material to be conveyed toward a clamping area where the first conveying body and the second conveying body sandwich the material to be conveyed, and after the holding section releases the hold on the tip of the material to be conveyed by the conveying section, the second conveying body clamps the material to be conveyed with the first conveying body and conveys the material to be conveyed.

[0007] In a second aspect, after the holding portion has passed through the clamping area and the holding portion has released its hold on the tip portion, the second conveying body moves from the separation position to the contact position and conveys the material by clamping it between itself and the first conveying body.

[0008] In a third aspect, when the second conveying body is positioned at the separation position, the conveying section conveys the conveyed material to the clamping area while the holding section holds the tip portion, and after the holding section passes through the clamping area and the holding section releases the hold on the tip portion, the second conveying body moves from the separation position to the contact position, clamps the conveyed material conveyed to the clamping area by the conveying section between itself and the first conveying body, and conveys the conveyed material.

[0009] In a fourth aspect, the first conveying body comes into contact with the conveyed material, the leading end of which is released from the holding portion, in a rotating state.

[0010] The fifth aspect includes a support portion that supports the rear end side of the transported material whose front end side is supported by the first transport body when the holding portion releases the holding of the front end.

[0011] In a sixth aspect, after a predetermined time has elapsed since the holding section releases the hold of the tip portion of the transported material transported by the transport section, the second transport body moves from the separation position to the contact position and clamps the transported material between itself and the first transport body.

[0012] In a seventh aspect, the first conveying body has a recess in which the holding portion is accommodated, the recess having a corner on the upstream side of the conveying path, and the second conveying body clamps the material to be conveyed between the corner of the first conveying body.

[0013] In an eighth aspect, a first movement speed at which the second conveying body moves from the separated position to the contact position is faster than a second movement speed at which the second conveying body moves from the contact position to the separated position.

[0014] In a ninth aspect, at least one of the first conveying body and the second conveying body is formed of an elastic body that elastically deforms due to the load when the second conveying body sandwiches the material to be conveyed between the first conveying body and the second conveying body.

[0015] In a tenth aspect, in a state in which both the first conveying body and the second conveying body are rotating, the second conveying body sandwiches the conveyed material between itself and the first conveying body.

[0016] In an eleventh aspect, the first conveying body and the second conveying body in a rotating state have the same peripheral speed.

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

[0018] In a thirteenth aspect, when the material to be transported is plain paper, the second transport body clamps the material to be transported between itself and the first transport body at a first load, and when the material to be transported is coated paper, the second transport body clamps the material to be transported between itself and the first transport body at a second load greater than the first load.

[0019] In a fourteenth aspect, when the basis weight of the material to be transported is less than a predetermined standard value, the second transport body clamps the material to be transported between itself and the first transport body with a first load, and when the basis weight of the material to be transported is equal to or greater than the standard value, the second transport body clamps the material to be transported between itself and the first transport body with a second load greater than the first load.

[0020] a first conveying body that is one of a heating member and a pressure member; a second conveying body that is the other of the heating member and the pressure member and is movable between a contact position with the first conveying body and a separation position with respect to the first conveying body, and at the contact position, sandwiches the recording medium with the first conveying body; and a conveying section that has a holding section that holds the leading end of the material to be conveyed, and when the second conveying body is positioned at the separation position, conveys the recording medium while the holding section holds the leading end toward a sandwiching area where the first conveying body and the second conveying body sandwich the recording medium, and after the holding section releases the hold on the leading end of the recording medium conveyed by the conveying section, the second conveying body moves from the separation position to the contact position to sandwich the material to be conveyed with the first conveying body, and a fixing device that fixes the image formed on the recording medium by the image forming section to the recording medium, and the second conveying body sandwiches the recording medium with the first conveying body after the trailing end of the recording medium has passed through the image forming section. [Effects of the Invention]

[0021] According to the configuration of the first aspect, the conveying section that holds the leading end of the material to be conveyed and conveys it suppresses the occurrence of wrinkles in the material to be conveyed compared to a configuration in which the material to be conveyed is sandwiched between the first conveying body and the second conveying body while holding the leading end.

[0022] According to the configuration of the second aspect, contact between the holding portion and the second conveying body is suppressed compared to a configuration in which the second conveying body moves from the separation position to the contact position before the holding portion passes through the pinching region.

[0023] According to the configuration of the third aspect, the holding of the tip portion by the holding section is released just before the clamping area, and the transported material is then transported to the clamping area by another transport section, after which the transported material is sandwiched between the first transport body and the second transport body and transported, thereby suppressing the occurrence of wrinkles in the transported material.

[0024] According to the configuration of the fourth aspect, the decrease in the downstream speed of the tip of the transported material whose tip has been released from the holding section is suppressed compared to a configuration in which the first transport body contacts the transported material while not rotating, and the tip of the transported material whose tip has been released from the holding section is released from the holding section.

[0025] According to the configuration of the fifth aspect, when the holding portion releases the tip end portion, the rear end portion of the transported material whose holding portion has been released is prevented from sagging, compared to a configuration in which only the tip end side of the transported material is supported.

[0026] According to the configuration of the sixth aspect, the occurrence of wrinkles in the transported material is suppressed compared to a configuration in which the second transport body clamps the transported material between itself and the first transport body at the same time that the holding portion releases the holding of the tip of the transported material.

[0027] According to the configuration of the seventh aspect, the second conveying body can begin to clamp the material held by the holding portion near the tip thereof, compared to a configuration in which the second conveying body clamps the material past the corner of the first conveying body.

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

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

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

[0031] According to the configuration of the eleventh aspect, the occurrence of wrinkles in the conveyed material is suppressed compared to a configuration in which the first conveying body and the second conveying body rotate at different peripheral speeds.

[0032] According to the configuration of the 12th aspect, the conveying section that holds the tip of the material to be conveyed and conveys it suppresses the occurrence of wrinkles in the material to be conveyed compared to a configuration in which the material to be conveyed is sandwiched between the first conveying body and the second conveying body while holding the tip.

[0033] According to the configuration of the thirteenth aspect, 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 conveying body sandwiches the material to be conveyed between itself and the first conveying body at the first load.

[0034] According to the configuration of the 14th aspect, when the basis weight of the material being transported is equal to or greater than the standard value, poor fixing of the material being transported is suppressed compared to a configuration in which the second transport body clamps the material being transported between itself and the first transport body at a first load.

[0035] According to the configuration of the 15th aspect, the transport section that holds and transports the leading edge of the recording medium suppresses the occurrence of wrinkles in the recording medium compared to a configuration in which the recording medium is sandwiched between a first transport body and a second transport body and transported while the leading edge is still held. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing the configuration of a transfer body according to the first embodiment. [Figure 3] FIG. 2 is a perspective view illustrating a configuration of the fixing device according to the first embodiment. [Figure 4] FIG. 2 is a perspective view showing a gripper according to the first embodiment. [Figure 5] FIG. 2 is a schematic diagram showing the configuration of a pressure roll and a heating roll according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a state in which the heating roll is positioned at a distance from the pressure roll in the configuration shown in FIG. 5. [Figure 7] 7 is a schematic diagram showing a state in which the conveying unit has conveyed the recording medium up to just before the pinch area in the configuration shown in FIG. 6. FIG. [Figure 8] 7 is a schematic diagram showing a state in which the conveying unit conveys the recording medium to a pinch area in the configuration shown in FIG. 6. FIG. [Figure 9] 9 is a schematic diagram showing a state in which the gripper of the transport unit releases the grip on the leading edge of the recording medium in the configuration shown in FIG. 8. FIG. [Figure 10] FIG. 10 is a schematic diagram showing a state in which the recording medium, whose leading edge has been released from the holding, is sandwiched between the heating roll and the pressure roll in the configuration shown in FIG. 9. [Figure 11] 11 is a schematic diagram showing a state in which a recording medium sandwiched between a heating roll and a pressure roll is being transported in the configuration shown in FIG. 10. FIG. [Figure 12] FIG. 10 is a schematic diagram showing a state (comparative example) in which a recording medium is sandwiched between a heating roll and a pressure roll while a gripper holds the leading edge of the recording medium. [Figure 13] 13 is a schematic diagram showing a state in which wrinkles occur in a recording medium conveyed by the configuration shown in FIG. 12. FIG. [Figure 14] 10 is a schematic diagram showing a modified example in which the gripper releases the grip on the leading edge of the recording medium before the pinching area. FIG. [Figure 15] FIG. 10 is a schematic diagram showing the configuration of an image forming apparatus according to a second embodiment. [Figure 16] FIG. 10 is a schematic diagram showing a state in which a recording medium, the leading edge of which has been released from the holding state, is sandwiched between a heating roll and a pressure roll in a configuration of a modified example. DETAILED DESCRIPTION OF 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 device 10) First, the configuration of an image forming apparatus 10 according to the first embodiment will be described. Fig. 1 is a schematic diagram showing the configuration of an image forming apparatus 10 according to this embodiment. Note that arrow H shown in each figure indicates the vertical direction, i.e., the up-down direction of the apparatus, arrow W indicates the horizontal direction, i.e., the width direction of the apparatus, and arrow D indicates the front-rear direction of the apparatus (depth direction of the apparatus). The dimensional ratios of the parts shown in each figure in the H direction, W direction, and D direction may differ from the actual dimensional ratios.

[0039] 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 conveyed, and the ink image is an example of an image.

[0040] More specifically, the image forming apparatus 10 includes an image forming section 14 and a fixing device 60. Each section of the image forming apparatus 10 (the image forming section 14 and the fixing device 60) will be described below.

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

[0042] 1, the transfer belt 31 is endless and is wound around a plurality of rolls 32 and an opposing roll 34 so as to assume an inverted triangular shape when viewed from the front (i.e., when viewed from the depth direction of the device). The transfer belt 31 rotates in the direction of arrow A when at least one of the plurality of rolls 32 is driven to rotate.

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

[0044] Specifically, the adhesive layer forming device 24 is disposed at one end of the horizontal portion of the transfer belt 31, which is shaped like an inverted triangle, in the device width direction (left side in the drawing). The adhesive layer forming device 24 contains an adhesive inside, and forms an adhesive layer (not shown) by applying the adhesive to the outer peripheral surface of the rotating transfer belt 31. For example, glue, organic solvent, etc. are used as the adhesive.

[0045] The particle supply device 18 is disposed on the horizontal portion of the transfer belt 31, downstream of the adhesive layer forming device 24 in the belt rotation direction (on the right side in the drawing). The particle supply device 18 contains ink receptive particles 16 capable of receiving ink droplets inside, and supplies the ink receptive particles 16 to the transfer belt 31 on which the adhesive layer has been formed. As a result, the ink receptive particles 16 supplied to the transfer belt 31 by the particle supply device 18 are adhered to the adhesive layer by the adhesive force of the adhesive layer, and an ink receptive particle layer 16A is formed on the transfer belt 31.

[0046] The ejection head 20 is disposed on the horizontal portion of the transfer belt 31, downstream of the particle supply device 18 in the belt rotation direction (on the right side in the drawing). A plurality of ejection heads 20 are provided so as to form ink images for each color. In this embodiment, ejection heads 20 are provided for a total of four colors: yellow (Y), magenta (M), cyan (C), and black (K). (Y), (M), (C), and (K) shown in FIG. 1 indicate components corresponding to the above colors.

[0047] The ejection head 20 of each color ejects ink droplets from a nozzle (not shown) onto the ink receptive 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 the ejection head 20 of each color are received by the ink receptive particle layer 16A to form an ink image.

[0048] The transfer body 36 is disposed below the transfer belt 31. Specifically, as shown in Fig. 2, the transfer body 36 has a transfer cylinder 37 and a pair of sprockets 38. The transfer cylinder 37 is disposed opposite the transfer belt 31, and forms a nip region 37T (see Fig. 1) where the transfer belt 31 is sandwiched between the transfer cylinder 37 and the opposing roll 34.

[0049] In this embodiment, the ink image formed on the ink receiving particle layer 16A is transported to the sandwich region 37T by the rotation of the transfer belt 31, and the recording medium P is transported to the sandwich 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 onto the recording medium P by sandwiching and pressurizing the recording medium P and the ink image conveyed to the pinch region 37T between the transfer cylinder 37 and the transfer belt 31.

[0051] In addition, when the recording medium P and the ink image are sandwiched and pressed between the transfer belt 31 in the sandwiching region 37T, the recording medium P and the ink image may be heated by the transfer cylinder 37. In addition, the outer periphery of the transfer cylinder 37 is formed with a recess 37D in which a gripper 54 and an attachment member 55, which will be described later, are housed.

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

[0053] 1, cleaner 28 is disposed downstream of pinch region 37T in the belt rotation direction and upstream of adhesive layer forming device 24 in the belt rotation direction. Cleaner 28 has blade 28a that contacts the outer peripheral surface of transfer belt 31. As transfer belt 31 rotates, cleaner 28 uses blade 28a to remove the adhesive layer, ink receptive particles 16, ink, and other foreign matter (for example, paper dust when recording medium P is paper) remaining on the portion of transfer belt 31 that has passed through pinch region 37T.

[0054] (fixing device 60) 1 is an example of a conveying device, and is a device that fixes an ink image transferred onto a recording medium P to the recording medium P. Specifically, as shown in FIG. 1, the fixing device 60 has a pressure member 67, a heating roll 62, a heating unit 70, a blower unit 80, and a conveying unit 15.

[0055] (Pressure body 67 and heating roll 62) 3, the pressure body 67 has a pressure roll 61 and a pair of sprockets 69. The pair of sprockets 69 are arranged on both axial ends of the pressure roll 61. The pair of sprockets 69 are arranged coaxially with the pressure roll 61 and are configured to rotate integrally with the pressure roll 61. A chain 52, which will be described later, is wound around the pair of sprockets 69.

[0056] 1 and 5, the pressure roll 61 and the heating roll 62 are arranged vertically side by side. Specifically, the heating roll 62 is arranged above the pressure roll 61. The heating roll 62 has a heat source 62A (see FIG. 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, and the other of the pressure roll 61 and the heating roll 62 is rotated. Note that a configuration in which both the pressure roll 61 and the heating roll 62 are rotationally driven may also be used.

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

[0059] As shown in Fig. 10, this heating roll 62 sandwiches the recording medium P with the pressure roll 61 at the contact position. 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 that has a width in the conveying direction X. Furthermore, as will be described later, the recording medium P conveyed 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 between the pressure roll 61 and the heating roll 62 is planned.

[0060] Further, a recess 61D is formed on the outer periphery of the pressure roll 61 to accommodate a gripper 54 and a mounting member 55, which will be described later. This recess 61D opens to the outside in the radial direction of the pressure roll 61. A corner 61R (hereinafter referred to as a rear edge 61R) is formed at the upstream end of the recess 61D of the pressure roll 61 in the rotation direction. This rear edge 61R is formed in a shape with rounded corners (so-called a radiused shape).

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

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

[0063] The heater 72 is a heating element that heats the recording medium P without contacting the recording medium P being transported in the transport direction X by the transport unit 15. More specifically, the heater 72 is configured as follows. That is, as shown in FIG. 1, a plurality of heaters 72 are arranged at intervals along the transport direction X. The heater 72 is configured as a cylindrical infrared heater having a length in the device depth direction D. The heater 72 generates heat from a filament (not shown) provided inside, and heats the recording medium P by the radiant heat. Note that in this embodiment, four heaters 72 are provided as shown in FIG. 1, but the number of heaters 72 is not limited to four.

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

[0065] (Blower section 80) 1 faces the heating unit 70 on the opposite side (i.e., lower side) from the heating unit 70 side (i.e., upper side) of the recording medium P transported by the transport unit 15. The air blowing unit 80 is an example of a support unit.

[0066] The air blowing section 80 has a function of blowing air to the underside of the recording medium P being transported by the transport section 15. Specifically, the air blowing section 80 has a function of blowing air to the recording medium P to float the recording medium P and maintain the non-contact state so that the recording medium P is transported by the transport section 15 with the back surface opposite to the front surface on which the unfixed image is formed in a non-contact state.

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

[0068] The blower 84 is provided at the bottom of the main body 82. The blower 84 sends air into 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. Note that a centrifugal blower that blows air in a centrifugal direction, such as a multi-blade blower (for example, a sirocco fan), may also be used as the blower 84.

[0069] The air 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. The air blower plate 83 faces the heating unit 70 on the opposite side (i.e., lower side) from the heating unit 70 side (i.e., upper side) of the recording medium P transported by the transport unit 15. The air blower plate 83 is a plate-shaped plate made of metal or resin, and has a plurality of air blowing holes 83A that penetrate in the up-down direction H. The air blower plate 83 causes air sent from the air blower 84 into the space 82A of the main body 82 to pass upward through the plurality of air blowing holes 83A and hit the underside of the recording medium P, thereby floating the recording medium P and supporting the recording medium P.

[0070] (Transport unit 15) The transport unit 15 shown in Fig. 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 Figs. 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 unit that holds the leading end of the recording medium P. Note that the chains 52 and the gripper 54 are shown in a simplified form in Fig. 1.

[0071] As shown in Fig. 1, the pair of chains 52 are formed in a loop. As shown in Figs. 2 and 3, the pair of chains 52 are arranged at a distance from each other in the device depth direction (direction D in the drawings). The pair of chains 52 are respectively wound around a pair of sprockets 38 (see Fig. 2) of the transfer body 36 and a pair of sprockets 69 (see Fig. 3) of the pressure body 67. When the transfer body 36 having the pair of sprockets 38 and the pressure body 67 having the pair of sprockets 69 rotate, the chains 52 rotate in a circumferential direction C (the direction of arrow C in Figs. 1, 2, and 3).

[0072] 2 and 3, mounting members 55 to which grippers 54 are attached are hung across the pair of chains 52 in the depth direction of the device. A plurality of mounting members 55 are fixed to the pair of chains 52 at predetermined intervals along the circumferential direction of the chains 52 (circumferential direction C).

[0073] As shown in Figures 2 and 3, a plurality of grippers 54 are attached to mounting members 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 members 55. The grippers 54 have the function of holding the leading end of the recording medium P. Specifically, as shown in Figure 4, the grippers 54 have claws 54A and claw bases 54B. The grippers 54 are configured to hold the recording medium P by pinching the leading end of the recording medium P between the claws 54A and the claw bases 54B. In other words, the grippers 54 can be said to be an example of a pinching portion that pinches the recording medium P in the thickness direction.

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

[0075] 4, the leading edge of the recording medium P sent from a storage unit (not shown) in which the recording medium P is stored is held by gripper 54. Furthermore, in conveyance unit 15, chain 52 rotates in circumferential direction C with gripper 54 holding the leading edge of the recording medium P, thereby moving gripper 54 to convey the recording medium P, and passing the recording medium P together with gripper 54 through pinching region 37T while holding the recording medium P with gripper 54. Furthermore, in conveyance unit 15, the recording medium P is conveyed, and passing the recording medium P together with gripper 54 between heating unit 70 and blower unit 80 while holding the recording medium P with gripper 54.

[0076] In the portion where the chain 52 is wound around the sprocket 38, the gripper 54 moves integrally with the transfer cylinder 37 in the rotation direction of the transfer cylinder 37 while being housed in the recess 37D of the transfer cylinder 37.

[0077] 7 and 8, in the present embodiment, the conveying unit 15 conveys the recording medium P toward the pinching region NP with the gripper 54 holding the leading end of the recording medium P when the heating roll 62 is in the separated position. In the portion where the chain 52 is wound around the sprocket 69, the gripper 54 moves integrally with the pressure roll 61 in the rotation direction of the pressure roll 61 while being accommodated in the recess 61D of the pressure roll 61. When the gripper 54 is accommodated in the recess 61D, the recording medium P is positioned on the outer circumferential surface of the pressure roll 61 from the rear end edge 61R of the pressure roll 61 toward the upstream side in the rotation direction.

[0078] Furthermore, as shown in FIG. 9 , the conveying unit 15 releases the grip on the leading edge of the recording medium P when the recording medium P is conveyed to the clamping region NP. That is, the conveying unit 15 releases the grip on the leading edge of the recording medium P after the gripper 54 passes through the clamping region NP. The recording medium P, whose leading edge has been released from the gripper 54, moves in the conveying direction X due to inertia. Then, the leading edge side of the recording medium P, whose leading edge has been released from the gripper 54, rests on the pressure roll 61. In other words, the pressure roll 61 supports the leading edge side of the recording medium P, whose leading edge has been released from the gripper 54, from below. Furthermore, the air blowing unit 80 (see FIG. 1 ) blows air toward the rear edge side of the recording medium P, whose leading edge has been released from the gripper 54, thereby supporting the recording medium P from below. In this way, in this embodiment, the leading edge side and the rear edge side of the recording medium P, whose leading edge has been released from the gripper 54, are supported.

[0079] Furthermore, the pressure roll 61 in contact with the recording medium P is maintained in a rotating state, and the chain 52 is maintained in a circling state. That is, in this embodiment, the pressure roll 61 rotates with the heating roll 62 positioned at the separated position, and generates a frictional force that causes the recording medium P, whose leading edge has been released from the gripper 54, to move downstream in the conveyance direction.

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

[0081] As shown in FIG. 10 , after the gripper 54 has passed through the pinch region NP and the gripper 54 has released its hold on the leading edge of the recording medium P, the heating roll 62 moves from the separation position to the contact position and sandwiches the recording medium P, which has been transported to the pinch region NP by the transport unit 15, with the pressure roll 61. In this embodiment, the heating roll 62 starts moving from the separation position after a predetermined time has elapsed since the gripper 54 released its hold on the leading edge of the recording medium P, after the gripper 54 has passed through the pinch region NP, and sandwiches the recording medium P, which has been transported to the pinch region NP, with the pressure roll 61. At this time, the trailing edge 61R of the pressure roll 61 has also passed through the pinch region NP. That is, the heating roll 62 sandwiches the recording medium P with the pressure roll 61 after the trailing edge 61R of the pressure roll 61 has also passed through the pinch region NP.

[0082] Furthermore, in this embodiment, while both the heating roll 62 and the pressure roll 61 are rotating, the heating roll 62 moves from the separated position to the contact position to sandwich the recording medium P between the heating roll 62 and the pressure roll 61. The heating roll 62 and the pressure roll 61 are configured to be rotated by, for example, a driving force transmitted to their respective rotation shafts via a transmission member such as a gear. Note that at least one of the heating roll 62 and the pressure roll 61 may be configured to contact a different drive roll and be driven to rotate, thereby allowing the heating roll 62 and the pressure roll 61 to rotate independently. In this case, instead of or in addition to the heat source 62A, heat may be transmitted to the heating roll 62 from a drive roll in contact with the heating roll 62. Note that 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 the leading edge of the heating roll 62.

[0083] Furthermore, the pressure roll 61 and the heating roll 62 are rotated at the same peripheral speed. The peripheral speeds of the pressure roll 61 and the heating roll 62 do not need to be completely the same, and a difference in the peripheral speeds of the pressure roll 61 and the heating roll 62 is allowed within a range in which wrinkles do not occur in the recording medium P.

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

[0085] Then, as shown in FIG. 11, the pressure roll 61 and the heating roll 62 sandwich the recording medium P therebetween, and the heating roll 62 starts to rotate to transport the recording medium P.

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

[0087] After conveying the recording medium P, the heating roll 62 moves from the contact position (the position shown in FIG. 5) to the separation position (the position shown in FIG. 6). Specifically, the heating roll 62 moves from the contact position to the separation position after conveying the recording medium P is completed (in other words, after fixing of the image on the recording medium P is completed) and before the leading edge of the recording medium P to be next conveyed to the pinch region NP enters the pinch region NP.

[0088] As described above, in this embodiment, the heating roll 62 moves from the separation position to the contact position when the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61, and then moves from the contact position to the separation position when the conveyance of the recording medium P is completed. The first movement speed at which the heating roll 62 moves from the separation position to the contact position is faster than the second movement speed at which the heating roll 62 moves from the contact position to the separation position. That is, the heating roll 62 moves from the separation position to the contact position by the movement mechanism A at the first movement speed that is faster than the second movement speed. In other words, the movement time of the heating roll 62 from the separation position to the contact position is shorter than the movement time from the contact position to the separation 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 in the radial direction from the center of rotation is longer than the minor axis portion. In the moving mechanism A, for example, the heating roll 62 is moved from the contact position to the separation position by contacting the cam follower in a range from the minor axis portion to the major axis portion of the outer peripheral surface of the cam (hereinafter referred to as range X) as the cam rotates in a predetermined rotation direction. Furthermore, in the moving mechanism A, the heating roll 62 is moved from the separation position to the contact position by contacting the cam follower in a range from the major axis portion to the minor axis portion of the outer peripheral surface of the cam (hereinafter referred to as range Y) as the cam rotates in the rotation direction. In this configuration, for example, range X is formed longer than range Y on the outer peripheral 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. This causes the heating roll 62 to move from the separated position to the contact position at a first movement speed that is faster than the second movement speed.

[0090] Note that the configuration may also be such that the range X and the range Y on the outer peripheral surface of the cam have the same length, and the change in radial length from the short diameter portion to the long diameter portion in range X is the same as the change in radial length from the long diameter portion to the short diameter portion in range Y. In this configuration, for example, the rotational speed of the cam when range Y contacts the cam follower is made faster than the rotational speed of the cam when range X contacts the cam follower, thereby causing the heating roll 62 to move from the separation position to the contact position at a first movement speed that is faster than the second movement speed.

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

[0092] In this embodiment, for example, whether the recording medium P is coated paper is determined by input from the user of the fixing device 60 or by detecting the presence or absence of a coating layer on the recording medium P using a detection unit such as an optical sensor. Then, in this embodiment, based on this determination, the first load or the second load is selected as the load of the heating roll 62.

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

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

[0095] In this embodiment, the movement mechanism A adjusts the load on the heating roll 62 by changing the contact position of the cam follower on the short diameter portion of the cam depending on the rotation angle of the cam. Specifically, the movement mechanism A generates a second load as the load on the heating roll 62 by bringing the cam follower into contact with the shortest radial position, which has the shortest radial length, on the short diameter portion of the cam. Furthermore, the movement mechanism A generates a first load as the load on the heating roll 62 by bringing the cam follower into contact with the cam follower at a position on the short diameter portion of the cam that is longer in radial length than the shortest radial position.

[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 pinches the recording medium P between the heating roll 62 and the pressure roll 61 at a second load, regardless of the size of the recording medium P. When the recording medium P is plain paper and the basis weight of the recording medium P is equal to or greater than a predetermined reference value, the heating roll 62 pinches the recording medium P between the heating roll 62 and the pressure roll 61 at a second load, regardless of the size of the recording medium P. When the recording medium P is plain paper and the basis weight of the recording medium P is less than the predetermined reference value, the heating roll 62 pinches the recording medium P between the heating roll 62 and the pressure roll 61 at a first load, regardless of the size of the recording medium P. When the basis weight is equal to or greater than the reference value, the recording medium P is thicker than when the basis weight of the recording medium P is less than the predetermined reference value, and therefore the heating roll 62 comes into contact with the surface faster by the thickness of the recording medium P. This shortens the time it takes for waviness and other issues caused by the recording medium P being restrained by the gripper 54 to disappear, but since a thicker recording medium P is less likely to wrinkle, the impact of the heating roll 62 coming into contact with the surface more quickly is smaller.

[0097] At least one of the pressure roll 61 and the heating roll 62 is formed of an elastic body that elastically deforms due to 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 formed of, for example, a rubber roll (an example of an elastic body) having a rubber layer on the outer periphery of the roll.

[0098] (Action of this embodiment) 1, in the image forming apparatus 10, an adhesive layer forming device 24 forms an adhesive layer (not shown) by applying an adhesive to the outer peripheral surface of the rotating transfer belt 31. Next, a particle supplying device 18 supplies ink receptive particles 16 to the transfer belt 31, and an ink receptive 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 receptive particle layer 16A to form an ink image. The ink image formed on the ink receptive particle layer 16A is transported to the nip region 37T by the rotation of the transfer belt 31, and the recording medium P is transported to the nip region 37T by the transport unit 15.

[0100] The transfer body 36 transfers the ink image onto the recording medium P by sandwiching and pressurizing the recording medium P and the ink image conveyed to the pinch region 37T between the transfer body 36 and the transfer belt 31.

[0101] 7 and 8, with the heating roll 62 positioned at the separated position, the recording medium P onto which the ink has been transferred is conveyed to the pinching region NP by the conveying unit 15 with its leading edge held by the gripper 54. Next, as shown in Fig. 9, the gripper 54 releases the leading edge of the recording medium P from its hold. Specifically, after the gripper 54 passes through the pinching region NP, the gripper 54 releases the leading edge of the recording medium P from its hold.

[0102] 10, after the gripper 54 has passed through the pinching region NP and the gripper 54 has released its hold on the leading edge of the recording medium P, the heating roll 62 moves from the separation position to the contact position, and sandwiches the recording medium P, which has been transported to the pinching region NP by the transport unit 15, between the pressure roll 61 and the heating roll 62. Then, as shown in FIG. 11, the heating roll 62 starts to rotate with the recording medium P sandwiched between the pressure roll 61 and the heating roll 62, and transports the recording medium P.

[0103] The recording medium P is conveyed between the heating roll 62 and the pressure roll 61 while being sandwiched between them, and the ink image transferred to the recording medium P is fixed to the recording medium P by applying heat and pressure to the recording medium P.

[0104] 12, in a configuration (hereinafter referred to as a "first configuration") in which the gripper 54 holds the leading edge of the recording medium P transported to the clamping area NP, and the recording medium P is sandwiched between the pressure roll 61 and the heating roll 62 and transported, the leading edge is held by the gripper 54, thereby restricting the orientation of the recording medium P. 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 sandwiched between the pressure roll 61 and the heating roll 62 in that state, which may cause wrinkles in the recording medium P, as shown in FIG. 13. Wrinkles are particularly likely to occur when 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 the leading edge of the recording medium P, so the recording medium P is not constrained to the posture at which it was conveyed to the pinch region NP. Therefore, even if the recording medium P is conveyed to the pinch region NP in a wavy state or tilted with respect to the conveyance direction X, for example, this state of the recording medium P can be resolved. Therefore, according to the configuration of this embodiment, the occurrence of wrinkles in the recording medium P is suppressed compared to the first configuration.

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

[0107] In this embodiment, the conveying unit 15 conveys the recording medium P to the pinch region NP while the gripper 54 holds the leading edge of the recording medium P in a state where the heating roll 62 is located at the separated position.

[0108] Therefore, compared to a configuration in which the gripper 54 releases its grip on the leading edge of the recording medium P just before the clamping region NP, the recording medium P is transported to the clamping region NP by another transport unit, and then the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61, the time from when the gripper 54 releases its grip on the leading edge of the recording medium P to when the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61 is shorter. In this way, the recording medium P is in an unconstrained, free state for a short period of time, and therefore, tilting of the recording medium P due to external forces acting in this free state is suppressed. As a result, poor clamping of the recording medium P between the heating roll 62 and the pressure roll 61 is suppressed, and the occurrence of wrinkles in the recording medium P is suppressed.

[0109] Furthermore, in this embodiment, the pressure roll 61 rotates with the heating roll 62 positioned at the separated position, generating a frictional force that causes the recording medium P, whose leading edge 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, whose leading edge has been released from the gripper 54, while not rotating, the recording medium P, whose leading edge has been released from the gripper 54, is prevented from receding upstream in the transport direction. In this way, the recording medium P, whose leading edge has been released from the gripper 54, is prevented from receding upstream in the transport direction, thereby preventing variations in the position at which image fixing starts on the recording medium P from one recording medium P to another.

[0110] In this embodiment, the pressure roll 61 supports, from below, the leading edge side of the recording medium P whose leading edge has been released from the gripper 54. Furthermore, the air blowing unit 80 supports the recording medium P from below by blowing air toward the rear edge side of the recording medium P whose leading edge has been released from the gripper 54. Therefore, compared to a configuration in which only the leading edge side of the recording medium P is supported, the rear edge side of the recording medium P whose leading edge has been released from the gripper 54 is prevented from sagging.

[0111] Furthermore, in this embodiment, the heating roll 62 starts moving from the separated position after the gripper 54 has passed through the pinching region NP and a predetermined time has elapsed since the gripper 54 released the grip on the leading edge of the recording medium P, and sandwiches the recording medium P transported to the pinching region NP between the heating roll 62 and the pressure roll 61. Therefore, compared to a configuration in which the heating roll 62 sandwiches the recording medium P between the pressure roll 61 at the same time that the gripper 54 releases the grip on the leading edge of the recording medium P, time is ensured for waviness and the like caused by the recording medium P being restrained by the gripper 54 to disappear. As a result, the heating roll 62 sandwiches the recording medium P between the pressure roll 61 after waviness and the like of the recording medium P has disappeared, and thus 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 the separated position to the contact position and sandwiches the recording medium P between itself and the pressure roll 61. Here, in a configuration where the heating roll 62 sandwiches the recording medium P between itself and the pressure roll 61 when only one of the heating roll 62 and the pressure roll 61 is rotating (hereinafter referred to as a first configuration), a conveying force is applied to one side of the recording medium P and a brake acts on the other side, which makes it easy for wrinkles to form in 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 itself and the pressure roll 61, thereby suppressing the occurrence of wrinkles in the recording medium P compared to the first configuration.

[0114] Furthermore, in this embodiment, the pressure roll 61 and the heating roll 62 have the same circumferential speed while rotating. Therefore, the conveying forces acting on one side and the other side of the recording medium P are the same. As a result, the occurrence of wrinkles in the recording medium P is suppressed compared to a configuration in which the pressure roll 61 and the heating roll 62 have different circumferential speeds while rotating (hereinafter referred to as the second configuration). Note that the second configuration is a configuration in which the pressure roll 61 and the heating roll 62 have different circumferential speeds while rotating to the extent that wrinkles are generated in the recording medium P.

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

[0116] Furthermore, in this embodiment, because the second movement speed is slower than the first movement speed, the change in radial length from the minor axis portion to the major axis portion in the range X from the minor axis portion to the major axis portion on the outer peripheral surface of the cam is more gradual than the change in radial length from the minor axis portion to the major axis portion on the outer peripheral surface of the cam in the range Y from the major axis portion to the minor axis portion on the outer peripheral surface of the cam. Therefore, when the heating roll 62 is moved from the contact position to the separation position, noise caused by contact between the cam and the cam follower is suppressed.

[0117] In this embodiment, both the pressure roll 61 and the heating roll 62 are formed of, for example, a rubber roll (an example of an elastic body) having a rubber layer on the outer periphery 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 impact when the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61 is absorbed.

[0118] Furthermore, in this embodiment, when the recording medium P is plain paper, the heating roll 62 sandwiches the recording medium P between itself and the pressure roll 61 at a first load, and when the recording medium P is coated paper, the heating roll 62 sandwiches the recording medium P between itself and the pressure roll 61 at a second load that is greater than the first load. Therefore, 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 sandwiches the recording medium P between itself and the pressure roll 61 at the first load, and the gloss of the recording medium P is improved.

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

[0120] (Modification of the timing at which the gripper 54 releases the grip on the leading edge of the recording medium P) In the above embodiment, the gripper 54 releases its hold on the leading edge of the recording medium P after passing through the pinch region NP, but this is not limited to this. In this modified example, the conveying unit 15 conveys the recording medium P toward the pinch region NP while the gripper 54 holds the leading edge of the recording medium P, with the heating roll 62 positioned at the separated position (see FIG. 7). As shown in FIG. 14, the conveying unit 15 releases its hold on the leading edge of the recording medium P just before the pinch region NP (i.e., before the recording medium P reaches the pinch region NP). Specifically, the gripper 54 releases its hold on the leading edge of the recording medium P before passing through the pinch region NP. More specifically, the gripper 54 releases its hold on the leading edge of the recording medium P when a part of the gripper 54 is positioned in the pinch region NP and another part of the gripper 54 is positioned just before the pinch region NP. At this time, the pressure roll 61 is maintained in a rotating state, and the chain 52 is maintained in a rotating state.

[0121] Thereafter, in this modified example, the recording medium P is adsorbed to the outer peripheral surface of the pressure roll 61 and transported to the pinch region NP. That is, in this modified example, the pressure roll 61 has an adsorption mechanism (not shown) that adsorbs the recording medium P to its outer peripheral surface. The adsorption mechanism has suction holes (not shown) that suck the recording medium P into its outer peripheral surface, and by sucking the recording medium P through the suction holes, the recording medium P is adsorbed to the outer peripheral 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 the recording medium P.

[0122] After the gripper 54 passes through the pinching region NP, the heating roll 62 moves from the separation position to the contact position, and sandwiches the recording medium P transported to the pinching region NP between the heating roll 62 and the pressure roll 61 (see FIG. 10). Note that the sandwiching between the heating roll 62 and the pressure roll 61 may be performed after the suction by the pressure roll 61 is released, or 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 to rotate and transports the recording medium P (see FIG. 11).

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

[0125] (Modification of timing for nipping the recording medium P between the heating rolls 62) In this embodiment, the heating roll 62 sandwiches the recording medium P between the pressure roll 61 and the rear end edge 61R of 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. For example, as shown in Fig. 16, the heating roll 62 may be configured to sandwich the recording medium P between the pressure roll 61 and the rear end edge 61R when the rear end edge 61R is located in the sandwiching region NP.

[0126] In this configuration, when the trailing edge 61R is located downstream in the conveying direction relative to the pinch area NP, the recording medium P is pinched closer to the leading edge than in a configuration in which the heating roll 62 pinches the recording medium P between itself and the pressure roll 61. Therefore, even if an image is formed closer to the leading edge of the recording medium P, the image can be fixed to the recording medium P. As a result, the margin on the leading edge of the recording medium P is reduced.

[0127] In addition, in this embodiment, the trailing edge 61R is formed with rounded corners (so-called radiused), so that even if the heating roll 62 comes into contact with the trailing edge 61R, the recording medium P is prevented from folding at the trailing edge 61R.

[0128] (Modification of the conveying device) In the present embodiment, the fixing device 60 having a conveying function and a fixing function is given as an example of the conveying device, but the present invention is not limited to this. Examples of the conveying device may include, for example, a device having a function other than the conveying function and the fixing function (for example, a transfer function), or a conveying device having only the conveying function.

[0129] (Modifications of the first conveyor and the second conveyor) In the present embodiment, the heating roll 62 is used as an example of the second conveyor, but the present invention is not limited to this. For example, the heating roll 62 and a heating belt wrapped around the roll may be used as an example of the second conveyor.

[0130] Furthermore, a heating member such as a heating roll may be used as an example of the first conveyor, and a pressure member such as a pressure roll and a pressure belt may be used as an example of the second conveyor.

[0131] When an apparatus having a conveying function and a transfer function is used as an example of a conveying device, an example of the first conveying body and the second conveying body may be 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, when a conveying device having only a conveying function is used, an example of the first conveying body and the second conveying body may be a conveying member such as a conveying roll, and a conveying member such as a conveying roll or conveying belt that faces the conveying member.

[0133] (Modification of the conveying section) In the present embodiment, the gripper 54 disposed downstream in the transport direction of the recording medium P holds the leading edge of the recording medium P from the downstream side in the transport direction of the recording medium P, but this is not limited to this. The gripper 54 may hold the leading edge portion of the recording medium P from both ends in the width direction of the recording medium P (i.e., from the side edges).

[0134] Second Embodiment (Image forming apparatus 200) In the first embodiment, the image forming apparatus 10 is 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. An example of an image forming apparatus may be, for example, an electrophotographic type image forming apparatus, as long as it is an apparatus that forms an image. In the second embodiment, an electrophotographic type image forming apparatus 200 will be described. FIG. 15 is a schematic diagram showing the configuration of the image forming apparatus 200 according to this embodiment. Note that parts having the same functions as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

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

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

[0137] Since the toner image forming units 222 for each color are configured in the same manner except for the toner used, in Figure 15, the various parts of the toner image forming unit 222(K) are denoted by reference numerals to represent the toner image forming units 222 for each color.

[0138] Specifically, each color toner image forming unit 222 has a photoconductor 224 that rotates in one direction (for example, counterclockwise in FIG. 15). Each color 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 unit 222 for each color, a charger 223 charges a photoconductor 224. Furthermore, an exposure device 240 exposes the photoconductor 224 charged by the charger 223 to light, thereby forming an electrostatic latent image on the photoconductor 224. Furthermore, a development device 238 develops the electrostatic latent image formed on the photoconductor 224 by the exposure device 240, thereby forming a toner image.

[0140] (Transfer device 217) 15 is a device that transfers the toner image formed in the toner image forming unit 222 onto a recording medium P. Specifically, the transfer device 217 primarily transfers the toner image of each color on the photoconductor 224 onto a transfer belt 213 serving as an intermediate transfer body, superimposing the toner image thereon, and then secondarily transfers the superimposed toner image onto the recording medium P. Specifically, as shown in FIG. 15, the transfer device 217 includes the 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 on the photoconductor 224 to the transfer belt 213 at a primary transfer position T1 between the photoconductor 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 photoconductor 224, so that the toner image formed on the photoconductor 224 is transferred to the transfer belt 213 at the primary transfer position T1.

[0142] Toner images are transferred from the photoconductors 224 of each color onto the outer peripheral surface of the transfer belt 213. As shown in Fig. 15, the transfer belt 213 is endless and is wound around a plurality of rolls 232 and an opposing roll 234 so as to assume an inverted triangular shape when viewed from the front (viewed from the depth direction of the device). The transfer belt 213 rotates in the direction of arrow A when at least one of the plurality of 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 a 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, so that the toner image transferred to the transfer belt 213 is transferred to the recording medium P at the secondary transfer position T2.

[0144] (fixing device 60) In this embodiment, the fixing device 60 functions as a device that fixes the toner image transferred onto 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 conveyed while being sandwiched between a heating roll 62 and a pressure roll 61, and the recording medium P is heated and pressurized, thereby fixing the toner image transferred onto the recording medium P to the recording medium P. The fixing device 60 is configured in the same manner as in the first embodiment, except that the toner image transferred onto the recording medium P is fixed onto the recording medium P.

[0146] (Action of this embodiment) In the image forming apparatus 200, a toner image is formed by a toner image forming unit 222 for each color. The toner images formed by the toner image forming unit 222 for each color are primarily transferred onto the transfer belt 213 in a superimposed manner at the respective primary transfer positions T1, and the superimposed toner images are secondarily transferred onto the recording medium P at the secondary transfer position T2.

[0147] 7 and 8, with the heating roll 62 positioned at the separated position, the recording medium P onto which the toner image has been transferred is conveyed to the pinching region NP by the conveying unit 15 with its leading edge held by the gripper 54. Next, as shown in Fig. 9, the gripper 54 releases the leading edge of the recording medium P from its hold. Specifically, after the gripper 54 passes through the pinching region NP, the gripper 54 releases the leading edge of the recording medium P from its hold.

[0148] 10, after the gripper 54 has passed through the pinching region NP and the gripper 54 has released its hold on the leading edge of the recording medium P, the heating roll 62 moves from the separation position to the contact position, and sandwiches the recording medium P, which has been transported to the pinching region NP by the transport unit 15, between the pressure roll 61 and the heating roll 62. Then, as shown in FIG. 11, the heating roll 62 starts to rotate with the recording medium P sandwiched between the pressure roll 61 and the heating roll 62, and transports the recording medium P.

[0149] The recording medium P is conveyed between the heating roll 62 and the pressure roll 61 while being sandwiched between them, and the ink image transferred to the recording medium P is fixed to the recording medium P by applying heat and pressure to the recording medium P.

[0150] In this way, the recording medium P is sandwiched between the heating roll 62 and the pressure roll 61 after the gripper 54 releases the grip on the leading edge of the recording medium P, so the recording medium P is not constrained to the posture at which it was conveyed to the pinch region NP. Therefore, even if the recording medium P is conveyed to the pinch region NP in a wavy state or tilted with respect to the conveyance direction X, for example, this state of the recording medium P can be resolved. Therefore, according to the configuration of this embodiment, the occurrence of wrinkles in the recording medium P is suppressed compared to the first configuration. In this way, this embodiment also has the same effect as the first embodiment described above.

[0151] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit and scope of the present invention. For example, the above-described modifications may be appropriately combined. Furthermore, the components in the embodiments may be standalone or integrated with peripheral components. [Explanation of symbols]

[0152] 10, 200 Image forming device 14 Image forming unit 15 Conveying section 54 Gripper (an example of a holding part) 60 Fixing device (an example of a conveying device) 61 Pressure roll (an example of a first conveying body, an example of a pressure member) 62 Heating roll (an example of a second conveying body, an example of a heating member) NP pincer 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 for 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 nipping is planned, while the holding means holds the leading end of the recording medium, in a state where 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 conveying means conveys the recording medium to the location where the nipping is planned, 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 between them; the first conveying means and the second conveying means are separated from each other before the next recording medium is conveyed by the third conveying means to the location where the nipping is scheduled; The first conveying means has a recess in which the holding means is housed. Conveying device.

2. a support means for supporting a rear end side of the recording medium whose leading end side is supported by the first transport 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 and nipping the recording medium with the first conveying means after a predetermined time has elapsed since the holding means released the holding of the leading end portion. The conveying device according to any one of claims 1 to 2.

4. The first conveying means has a corner portion upstream of the conveying path of the recess, the second conveying means sandwiches the recording medium between the corner portion of the first conveying means and the second 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 which conveys 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 for 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 nipping is planned, while the holding means holds the leading end of the recording medium, in a state where 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 conveying means conveys the recording medium to the location where the nipping is planned, 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 between them; the first conveying means and the second conveying means are separated from each other before the next recording medium is conveyed by the third conveying means to the location where the nipping is scheduled; The first conveying means has a recess in which the holding means is housed. Image forming device.

7. 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 for 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 nipping is planned, while the holding means holds the leading end of the recording medium, in a state where 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 conveying means conveys the recording medium to the location where the nipping is planned, 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 between them; the first conveying means and the second conveying means are separated from each other before the next recording medium is conveyed by the third conveying means to the location where the nipping is scheduled; The second conveying means is and a recording medium disposed on the side having an unfixed image transferred thereto, After the holding of the leading end portion by the holding means is released, the recording medium is sandwiched between the first conveying means and the first conveying means in a state where the wavy state of the recording medium caused by being restrained by the holding means is eliminated. Conveying device.

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