WO2012102380A1

WO2012102380A1 - Fixing device, electronic printer and fixing method

Info

Publication number: WO2012102380A1
Application number: PCT/JP2012/051810
Authority: WO
Inventors: 将一青木; 妹尾　慎一郎; 恵一藤木
Original assignee: 三菱重工印刷紙工機械株式会社
Priority date: 2011-01-28
Filing date: 2012-01-27
Publication date: 2012-08-02
Also published as: JP2012155280A

Abstract

A final fixing device is provided with: a heating roller (71) and a driving roller (72) that are provided on an upper side and a lower side respectively with a printing sheet therebetween, the printing sheet conveyed in a state where a transfer surface onto which toner is transferred faces the upper side; a support roller (73) that is provided on an upstream side in the conveying direction of the printing sheet with respect to the driving roller (72); a conveying belt (74) that is bridged between the driving roller (72) and the support roller (73); and a heater (75) that is provided inside the heating roller (71) and is capable of heating the heating roller (71), wherein the printing sheet passes a first nip region (E1) to which the driving roller (72) disposed between the heating roller (71) and the conveying belt (74) is not opposed, and a second nip region (E2) that is located on a downstream side in the conveying direction of the first nip region (E1) and is disposed between the heating roller (71) and the driving roller (72) via the conveying belt (74).

Description

Fixing device, electronic printer and fixing method

The present invention relates to a fixing device, an electronic printer, and a fixing method for fixing toner transferred to a printing material.

Conventionally, the fixing device has a heating roller, a fixing roller, a fixing belt stretched between the heating roller and the fixing roller, and a pressure roller provided to face the fixing roller via the fixing belt, A belt fixing device that fixes a toner image on a material to be fixed (printed material) conveyed between a pressure roller and a fixing belt is known (for example, see Patent Document 1). In this belt fixing device, a first fixing process and a second fixing process are performed on a material to be fixed. In the first fixing step, the pressure roller applies pressure to the material to be fixed (pressing pressure) without pressing the fixing roller via the fixing belt, and in the second fixing step, the pressure roller is fixed to the fixing belt. Then, the fixing roller is pressed to apply a fixing pressure to the fixing material. Thereby, in the first fixing step, it is possible to apply a fixing pressure to the material to be fixed without causing wrinkles in the material to be fixed.

Further, as another fixing device, a device including a primary heating unit and a secondary heating unit is known (for example, see Patent Document 2). In this fixing device, the primary heating unit is constituted by a non-contact type such as a flash lamp or a warm air machine, a contact type consisting of a fixing roller and a pressure roller, or a contact type using a belt. Yes. Further, the secondary heating unit is configured as a contact type composed of a pair of fixing rollers, and this fixing roller is a silicon sponge roller or the like with a built-in heater.

JP-A-2005-202441 JP 2010-72371 A

By the way, at the time of toner fixing, it is preferable that the member that comes into contact with the transfer surface of the substrate to which the toner is transferred has a configuration that has elasticity so as to improve followability to the transfer surface. In other words, when a highly rigid member comes into contact with the transfer surface of the printing material during toner fixing, the followability to the transfer surface is reduced, and rubbing occurs between the member and the transfer surface. In addition, in order to fix the toner so as to have gloss when the toner is fixed, it is preferable to improve the nipping pressure of the printing material. Of course, in order to fix the toner, it is necessary to heat the toner. Therefore, it is preferable that the member in contact with the transfer surface of the printing material is heated well.

In these respects, in the belt fixing device described in Patent Document 1, the toner image of the fixing material is in contact with the fixing belt, and in the first fixing step, the fixing material includes the fixing belt, the pressure roller, and the fixing belt. In the second fixing step, the material to be fixed is sandwiched between the pressure roller and the fixing roller via the fixing belt. From the above, the fixing belt is composed of a thin base and a release layer formed on the base so as to have a high thermal response, and silicon rubber can be applied as the release layer.

However, in the belt fixing device described in Patent Document 1, when the clamping pressure is increased by increasing the tension of the fixing belt in order to increase glossiness in the first fixing step, the fixing belt is thin. The fixing belt may be broken. On the other hand, if the thickness of the fixing belt is increased in order to increase the clamping pressure in the first fixing step, the heat responsiveness is lowered, so that the heating roller can suitably transfer heat to the fixing belt. Therefore, it becomes difficult to suitably heat the toner. Naturally, in order to withstand the increased tension while keeping the thickness of the fixing belt thin, it is necessary to make the fixing belt highly rigid. In this case, the followability to the transfer surface is deteriorated. It will be. The clamping pressure in the first fixing step is 1 kgf / cm ² (≈100 KPa = 0.1 MPa) or less.

In this regard, Patent Document 2 describes a contact-type fixing device using a belt in the primary heating unit, but does not disclose a specific configuration.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a fixing device, an electronic printer, and a fixing method that can suitably fix toner transferred to a printing material so as to have gloss without causing rubbing. And

In the fixing device of the present invention, the toner transferred to the printing material is heated by sandwiching the printing material conveyed with the transfer surface onto which the toner is transferred facing upward in the vertical direction from both upper and lower sides. In the fixing device for fixing the substrate, the elastic roller provided on the upper side in the vertical direction across the substrate to be conveyed and the lower side in the vertical direction with the elastic roller in contact with the transfer surface of the substrate to be printed in between A first roller that is opposed to the elastic roller, a second roller that is provided upstream of the first roller in the conveyance direction of the substrate, and a span between the first roller and the second roller. And a heating belt provided inside the elastic roller and capable of heating the elastic roller, wherein the printing material is interposed between the elastic roller and the hard belt. The first b Passes through a first nip region that is not opposed to the first nip region and a second nip region that is located downstream of the first nip region in the conveying direction and is sandwiched between the elastic roller and the first roller via a hard belt. It is characterized by that.

According to this configuration, the elastic roller heated by the heating means can be brought into contact with the transfer surface of the printing material onto which the toner has been transferred in the first nip region and the second nip region. Thereby, heat can be suitably applied to the transfer surface in the first nip region and the second nip region. Further, in the first nip region, the printed material can be sandwiched between the elastic roller and the hard belt. At this time, since the transfer surface can be heated by the elastic roller, it is not necessary to consider the thermal responsiveness of the hard belt, so that the hard belt can be made highly rigid. The clamping pressure can be increased. Naturally, since the elastic roller is in contact with the transfer surface, it is possible to ensure followability to the transfer surface. Therefore, in the first nip region, heat can be suitably applied to the transfer surface of the printing material while ensuring followability, and the clamping pressure can be increased. For this reason, the toner transferred to the printing material can be suitably fixed so as to have gloss without causing rubbing.

In this case, the second clamping pressure between the elastic roller and the first roller in the second nip region is preferably higher than the first clamping pressure between the elastic roller and the hard belt in the first nip region. .

According to this configuration, the toner can be fixed with a high second clamping pressure in the second nip region after the toner is fixed with a low first clamping pressure in the first nip region. The toner can be fixed stepwise, and the toner can be fixed satisfactorily.

In this case, the first clamping pressure is preferably between 0.1 MPa and 0.3 MPa, and the second clamping pressure is preferably between 0.4 MPa and 0.7 MPa.

According to this configuration, the first clamping pressure can be increased as compared with the conventional one, and the second clamping pressure can be higher than the first clamping pressure. It can be fixed.

In this case, the first nip region is preferably longer in the transport direction than the second nip region.

According to this configuration, the first nip region can hold the printed material longer than the second nip region. Therefore, in the first nip region, the temperature of the printed material is quickly increased and transferred to the printed material. A sufficient time until the toner melts can be secured. The first nip region preferably has a length in the transport direction of 30 mm or more. The second nip region preferably has a length in the transport direction of 10 mm or more.

In this case, it is preferable that the passing time of the printing material passing through the first nip region is 0.044 seconds or more.

According to this configuration, since the toner can be quickly fixed to the printed material, the printed material can be fixed efficiently.

In this case, it is preferable that the hard belt has a base layer made of metal and an outer peripheral surface layer made of a non-adhesive material covering the outer peripheral surface of the base layer.

According to this configuration, since the base layer is made of metal, the rigidity can be increased, so that the hard belt can withstand the increasing tension. Further, by constituting the outer peripheral surface layer with a non-adhesive material, it is possible to prevent toner from adhering to the hard belt.

In this case, the elastic roller is formed of a body portion made of a heat transfer material, a buffer layer formed of an elastic material formed on the outer peripheral side of the body portion, and a non-adhesive material covering the outer peripheral surface of the buffer layer. It is preferable to have a configured outer peripheral surface layer.

According to this configuration, it is possible to suitably transfer the heat from the heating means toward the outer peripheral surface layer by configuring the body portion with the heat transfer material. Moreover, the followability with respect to the transfer surface of to-be-printed material can be ensured by comprising a buffer layer with an elastic material. Furthermore, by forming the outer peripheral surface layer from a non-adhesive material, it is possible to suppress toner from adhering to the elastic roller.

In this case, the second roller is preferably a crown roller.

According to this configuration, blurring in the width direction of the hard belt in contact with the transfer surface can be suppressed. As a result, the hard belt can be transported without causing the printed material to be displaced in the width direction, so that the toner is suitably fixed to the printed material without causing uneven fixing on the transfer surface of the printed material. Can be made.

An electronic printer according to the present invention includes a paper feeding device capable of supplying a printing material, a printing device that transfers toner to the printing material supplied from the paper feeding device, and heating the toner transferred to the printing material. A hypothetical landing device that is presupposed, a main fixing device that is provided downstream of the hypothetical landing device in the conveyance direction of the substrate, heats the hypothetically adhered substrate and fixes the toner, and the fixing device fixes the toner. A paper discharge device for discharging the printed material, and the main fixing device is provided on the upper side in the vertical direction across the material to be conveyed, and is used for main fixing that is in contact with the transfer surface of the material to be printed. The first roller for main fixing that is provided on the lower side in the vertical direction across the elastic roller and the substrate to be conveyed and faces the elastic roller, and the upstream side in the conveyance direction of the substrate with respect to the first roller A second roller for main fixing provided in the A main fixing hard belt which is stretched between the roller and the second roller and is in contact with the surface opposite to the transfer surface of the printing material, and a heating for main fixing which is provided inside the elastic roller and can heat the elastic roller. A first fixing nip region where the first roller sandwiched between the elastic roller and the hard belt does not oppose, and a downstream side of the first nip region in the transport direction. And a second nip region for main fixing that is sandwiched between the elastic roller and the first roller via a hard belt.

According to this configuration, in the first nip region for main fixing, heat can be suitably applied to the transfer surface of the printing material while ensuring followability, and the pinching pressure can be increased. The toner transferred to the toner can be preferably permanently fixed so as to have gloss without causing rubbing.

In this case, the hypothetical landing apparatus is provided on the upper side in the vertical direction across the substrate to be transported, and is assumed to be in contact with the transfer surface of the substrate to be printed, and the vertical roller sandwiched between the substrate to be transported. A first roller for hypothetical wear that is provided on the lower side in the direction and faces the elastic roller; a second roller for hypothetical wear that is provided upstream of the first roller in the conveyance direction of the substrate; and the first roller A hypothetical wearing hard belt that is stretched between the second roller and the second roller, and is in contact with the opposite surface of the transfer surface of the printed material; and a hypothetical wearing heating means that is provided inside the elastic roller and can heat the elastic roller; And the printed material is located on the downstream side in the transport direction of the first nip region and the first nip region where the first roller sandwiched between the elastic roller and the rigid belt is not opposed to the first roller. The elastic roller and the first b It is preferred to pass and a second nip region assumptions wearing sandwiched between La.

According to this configuration, in the assumed first nip region, heat can be appropriately applied to the transfer surface of the printing material while ensuring followability, and the holding pressure can be increased. The transferred toner can be suitably presupposed without causing rubbing. In addition, since the printing material is sandwiched for a long time in the first nip region and the second nip region that are assumed to be worn, the printing material can be suitably heated, and the heated printing material is conveyed to the fixing device. Can do. For this reason, the heating of the printing material in the fixing device can be suppressed by the amount raised by the hypothetical landing device.

Another electronic printing machine of the present invention includes a paper feeding device capable of supplying a printing material, a printing device that transfers toner to the printing material supplied from the paper feeding device, and heating the toner transferred to the printing material. A fixing device that fixes the toner and a paper discharge device that discharges the printed material on which the toner is fixed by the fixing device. The fixing device is provided on the upper side in the vertical direction with the conveyed printed material interposed therebetween. The first roller opposite to the elastic roller is provided on the lower side in the vertical direction with the elastic roller in contact with the transfer surface of the printed material sandwiched between the conveyed printed material and the first roller. A second roller provided on the upstream side in the transport direction, a hard belt that is stretched between the first roller and the second roller and is in contact with the surface opposite to the transfer surface of the substrate, and an elastic roller. Heating means that can heat the elastic roller The printed material is positioned on the downstream side in the transport direction of the first nip region where the first roller sandwiched between the elastic roller and the hard belt does not face the first nip region. And passing through a second nip region sandwiched between the elastic roller and the first roller.

According to this configuration, in the first nip region, heat can be suitably applied to the transfer surface of the printed material while ensuring followability, and the clamping pressure can be increased, so that the transferred material is transferred to the printed material. The toner can be suitably fixed so as to have gloss without causing rubbing.

In the fixing method of the present invention, the toner transferred to the printing material is heated by being sandwiched and heated from both the upper and lower sides of the printing material conveyed with the transfer surface onto which the toner is transferred facing upward in the vertical direction. In the fixing method for fixing the printed material, an elastic roller that is in contact with the transfer surface of the printed material is provided on the upper side in the vertical direction across the substrate to be conveyed. A first roller facing the elastic roller is provided on the side, and a second roller is provided on the upstream side of the first roller in the conveyance direction of the printed material, between the first roller and the second roller. Is covered with a hard belt that is in contact with the surface opposite to the transfer surface of the substrate, and heating means capable of heating the elastic roller is provided inside the elastic roller, and the first roller is not opposed to the elastic roller. With hard belt In a first nip step sandwiching the substrate, between the elastic roller and the first roller via a rigid belt, characterized by comprising a second nip step sandwiching the substrate.

According to this configuration, in the first nip step, heat can be suitably applied to the transfer surface of the printed material while ensuring followability, and the clamping pressure can be increased, so that the transferred surface is transferred to the printed material. The toner can be suitably fixed so as to have gloss without causing rubbing.

In this case, it is preferable that the first nip process takes a longer time to sandwich the substrate to be printed than the second nip process.

According to this configuration, the first nip step can hold the printed material longer than the second nip step. Therefore, in the first nip step, the temperature of the printed material is quickly increased and transferred to the printed material. A sufficient time until the toner melts can be secured.

According to the fixing device, the electronic printer, and the fixing method of the present invention, it is possible to suitably fix the toner transferred to the printing material so as to have gloss without causing rubbing.

FIG. 1 is a schematic configuration diagram of an electronic printing machine according to the present embodiment. FIG. 2 is a schematic configuration diagram of the fixing device according to the present exemplary embodiment. FIG. 3 is a graph of the clamping pressure applied to the print sheet in the fixing device. FIG. 4 is a graph of the temperature change of the print sheet in the fixing device. FIG. 5 is a graph of the temperature change of the printed sheet from the hypothetical fixing device to the fixing device. FIG. 6 is a graph of glossiness during duplex printing.

Hereinafter, a fixing device, an electronic printer, and a fixing method according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following examples. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

FIG. 1 is a schematic configuration diagram of an electronic printing machine according to the present embodiment. As shown in FIG. 1, the electronic printing machine 1 is a liquid development electrophotographic double-sided and single-sided printing machine, and includes a paper feeding device 11, a printing device 12, a hypothetical landing device 13, a main fixing device 14, and a conveying device 15. , And a paper discharge device 16.

The sheet feeding device 11 has a pair of upper and lower sheet feeding units 11a and 11b. Each of the sheet feeding units 11a and 11b includes a sheet feeding table 21a and 21b and a

separator device

22a and 22b as a sheet feeding mechanism. And have. The

paper feed bases

21a and 21b are for stacking and placing print sheets (substrates) S up and down, and the

separator devices

22a and 22b are a large number of print sheets S stacked on the

paper feed bases

21a and 21b. Are picked up one by one in order from the top and sent forward. In this case, the

paper feed bases

21a and 21b can be moved up and down in response to the supply of the print sheet S so that the

separator devices

22a and 22b can maintain a substantially constant positional relationship with the print sheet S. ing.

The printing device 12 can perform process color printing of K (black), C (indigo), M (red), and Y (yellow). In this case, as shown in FIG. 1, the printing device 12 transfers a toner image developed by transferring the liquid toner to the electrostatic latent image on the photosensitive drum 41 with respect to the printing sheet S supplied from the paper feeding device 11. Transcript. That is, the printing apparatus 12 includes a backup roller 31, an intermediate transfer body 32, and four developing

units

33, 34, 35, and 36 corresponding to the respective colors.

The backup roller 31 and the intermediate transfer body 32 are rollers having the same outer diameter, and can be synchronously driven in the direction of the arrow in a state of contact with each other, and a nip portion set at a predetermined pressure is provided at the contact portion. Is set. The backup roller 31 is provided with grippers 31a on the outer peripheral portion at equal intervals in the circumferential direction. The gripper 31a can grip the leading end portion of the print sheet S supplied from the paper feeding device 11, and the gripped print sheet S can be guided to the nip portion by rotating the backup roller 31. On the other hand, the intermediate transfer body 32 is configured by mounting a blanket made of, for example, urethane conductive rubber on the outer peripheral surface, and a bias voltage of about −200 to −300 V, for example, is applied.

The backup roller 31 is disposed so as to apply pressure to the intermediate transfer member 32 at a predetermined pressure, for example, about 1 to 13 kg / cm, at the nip portion described above. Therefore, when the print sheet S is conveyed by the backup roller 31, a predetermined nip pressure is applied when passing through the nip portion formed between the print sheet S and the intermediate transfer body 32. The backup roller 31 is applied with a transfer bias of about -800V, for example. Therefore, due to the difference between the bias voltage (about −800 V) of the backup roller 31 and the bias voltage (−200 to −300 V) of the intermediate transfer body 32, a force for attracting liquid toner, which will be described later, to the backup roller 31 side is given. The electrostatic transfer of the liquid toner from the intermediate transfer body 32 to the print sheet S can be promoted.

The developing

units

33, 34, 35, and 36 are arranged around the intermediate transfer body 32 along the rotation direction, and the configuration is the same except that the color of the liquid toner to be used is different. ing. Therefore, hereinafter, the developing unit 33 will be described.

The developing unit 33 includes a photosensitive drum 41 that is in rolling contact with the intermediate transfer member 32, and forms an electrostatic latent image on the photosensitive drum 41 based on image data transmitted from a control device (not shown). Liquid toner is supplied to a position corresponding to the image, and the liquid toner image formed on the photosensitive drum 41 is transferred to the intermediate transfer member 32.

Here, the liquid toner is obtained by dispersing and blending a particulate toner formed of a thermoplastic material and a pigment (pigment or dye) in a liquid carrier. A liquid toner containing about 10 to 40 percent by weight of particulate toner having an average particle diameter of about 1 to 2 μm in a non-polar solvent (for example, nonpolar, paraffinic solvent, mineral oil, etc.) ing.

The hypothetical attachment device 13 presupposes the liquid toner layer (toner image) transferred on the upper surface of the print sheet S by sandwiching (niping) the print sheet S to which the toner image has been transferred. . The fixing device 14 fixes the liquid toner layer (toner image) transferred onto the upper surface of the print sheet S by sandwiching the print sheet S to which the toner image has been transferred while being heated. The assumption landing device 13 and the fixing device 14 will be described later.

Incidentally, a first sheet conveyance path S1 for the print sheet S is provided between the paper feeding device 11 and the printing device 12 described above. The first sheet conveyance path S1 has a base end portion branched into two and connected to the paper feeding units 11a and 11b, and a front end portion connected to a nip portion between the backup roller 31 and the intermediate transfer member 32. ing. In the first sheet transport path S1, a plurality of upper and lower driveable transport rollers 81 are provided at a predetermined interval between the paper feeding device 11 and the printing device 12. In this case, the intervals between the conveyance rollers 81 are shorter than the length of the print sheet S in the conveyance direction, and at least two sets of the conveyance rollers 81 can hold and convey the print sheet S.

The path from the hypothetical landing device 13 to the paper discharge device 16 via the main fixing device 14 is a second sheet conveyance route S2 for conveying the print sheet S. A conveying device 15 is provided in the second sheet conveying path S2 between the two. The second sheet transport path S2 has a base end side connected to the hypothetical landing device 13 and a front end side connected to the paper discharge device 16 via the fixing device 14 and the transport device 15. In the second sheet conveyance path S2, a plurality of upper and lower drive rollers 82 that can be driven are provided at predetermined intervals between the hypothetical landing device 13 and the paper discharge device 16. In this case, the interval between the conveying rollers 82 is shorter than the length of the printing sheet S in the conveying direction, like the conveying rollers 81, and at least two sets of conveying rollers 82 can convey and hold the printing sheet S. It has become.

A reversing device 91 for reversing the front and back of the printing sheet S is provided between the first sheet conveying path S1 and the front side of the conveying apparatus 15 in the second sheet conveying path S2. The reversing device 91 includes a switch mechanism 92, a sheet switching path 93, a conveying roller 94, a sheet reversing path 95, a switchback roller 96, a sheet return path 97, and a conveying roller 98. The reversing device 91 is used for duplex printing.

The switch mechanism 92 switches and conveys the print sheet S conveyed through the first sheet conveyance path S <b> 1 to the fixing device 14 or the sheet switching path 93, and the conveyance roller 94 is supplied to the sheet switching path 93. S can be supplied to the sheet reversing path 95. The sheet reversing path 95 is for reversing the printing sheet S, and the switchback roller 96 is capable of normal rotation and reverse rotation. The printing sheet S supplied to the sheet switching path 93 is guided to the sheet reversing path 95, Thereafter, the sheet can be supplied to the sheet return path 97. The printing sheet S supplied to the sheet return path 97 is returned to the first sheet conveyance path S1 by the conveyance roller 98 and is supplied to the printing apparatus 12 again.

The transport device 15 transports the printed print sheet S being transported through the second sheet transport path S2 to the paper discharge device 16, and supports the lower surface of the print sheet S by a belt member that can be circulated and transports horizontally. It is possible.

The paper discharge device 16 includes a paper discharge tray 101, front and rear direction

position adjusting members

102 and 103, and a left and right direction position adjusting member 104. That is, when the printed print sheet S is transported along the second sheet transport path S2, the transport device 15 releases the held print sheet S above the paper discharge device 16 and discharges it. At this time, the front position adjustment member 103 operates to position the front position of the print sheet S, and the rear position adjustment member 102 positions the rear position of the print sheet S. Further, the left-right position adjusting member 104 positions the left-right position of the print sheet S.

When double-sided printing is performed on the print sheet S in the electronic printing machine 1 configured as described above, as shown in FIG. 1, first, in the paper feeding device 11, one of the two paper feeding units 11a and 11b is Operates and feeds the printing sheets S one by one. The print sheet S sent out from the paper feeding device 11 is conveyed to the printing device 12 by a plurality of conveyance rollers 81 in the first sheet conveyance path S1. In the printing apparatus 12, the backup roller 31 receives the leading end portion of the printing sheet S with the gripper 31a open, holds the leading end portion of the printing sheet S by closing the gripper 31a, and holds it by rotating. The print sheet S is conveyed.

On the other hand, in the intermediate transfer body 32, K (black) corresponding to the peripheral surface of the photosensitive drum 41 on which the electrostatic image to be transferred to the surface of the print sheet S is formed by the developing

units

33, 34, 35, and 36. ), C (Indigo), M (Red), and Y (Yellow) liquid toners are transferred, an image is developed on the photosensitive drum 41, and the liquid toner transferred to the peripheral surface of the photosensitive drum 41 is intermediate. Transferred to the transfer body 32.

Thereafter, when the print sheet S held by the backup roller 31 reaches the nip portion with the intermediate transfer body 32, the surface of the print sheet S on the side in contact with the intermediate transfer body 32 from the peripheral surface of the intermediate transfer body 32 here. Liquid toner is transferred to (surface: transfer surface).

Then, the printing sheet S on which the liquid toner is transferred is conveyed to the hypothetical landing device 13 and heated while the printing sheet S is sandwiched, thereby assuming the liquid toner transferred to the surface of the printing sheet S. Put on.

The print sheet S with the liquid toner fixed on the surface is conveyed by a plurality of conveyance rollers 82 in the second sheet conveyance path S2. Then, the front and back are reversed by the reversing device 91 and conveyed again to the printing device 12 via the first sheet conveying path S1.

Again, the printing sheet S conveyed to the printing apparatus 12 is gripped at the leading end by the gripper 31 a of the backup roller 31 and conveyed by the backup roller 31 as described above. In the intermediate transfer body 32, K (black) corresponding to the peripheral surface of the photosensitive drum 41 on which the electrostatic image to be transferred to the back surface of the print sheet S is formed by the developing

units

33, 34, 35, and 36. C (blue), M (red), and Y (yellow) liquid toners are transferred, an image is developed on the photosensitive drum 41, and the liquid toner transferred onto the peripheral surface of the photosensitive drum 41 is an intermediate transfer member. 32 is transferred. When the printing sheet S held by the backup roller 31 reaches the nip portion with the intermediate transfer body 32, the surface of the printing sheet S on the side in contact with the intermediate transfer body 32 (from the peripheral surface of the intermediate transfer body 32 ( Liquid toner (toner image) is transferred to the back surface (transfer surface).

Then, the printing sheet S on which the liquid toner is transferred to the back surface is transported to the hypothetical landing device 13 and heated while the printing sheet S is sandwiched, so that the liquid toner transferred to the back surface of the printing sheet S is assumed. Put on.

Thereafter, the assumed print sheet S is conveyed to the main fixing device 14 and heated while the print sheet S is sandwiched, thereby fixing the liquid toner assumed on the front and back of the print sheet S.

The printing sheet S, on which the liquid toner is permanently fixed on the front and back surfaces, is conveyed to the conveying device 15 by the plurality of conveying rollers 82 in the second sheet conveying path S2, and is conveyed to the paper discharge device 16 by the conveying device 15. The paper is discharged by the paper discharge device 16.

Next, with reference to FIG. 2, the assumption fixing device 13 and the fixing device 14 will be described in detail. Note that the assumption landing device 13 and the main fixing device 14 have substantially the same configuration. Therefore, hereinafter, the configuration of the fixing device 14 will be described, and only the different parts of the configuration of the hypothetical landing device 13 will be described.

FIG. 2 is a schematic configuration diagram of the fixing device according to the present embodiment. The printing sheet S conveyed toward the fixing device 14 is introduced with the transfer surface onto which the liquid toner has been transferred by the printing device 12 facing upward in the vertical direction. The fixing device 14 into which the print sheet S is introduced has a configuration capable of performing so-called long nip. The long nip is to sandwich the print sheet S longer than the time for which the print sheet S is sandwiched between the pair of fixing rollers. The fixing device 14 includes a heating roller (elastic roller) 71, a driving roller (first roller) 72, a support roller (second roller) 73, an endless conveying belt (hard belt) 74, and a heater (heating means) 75. It is configured.

The heating roller 71 is provided on the upper side in the vertical direction with respect to the print sheet S, and is provided in contact with the transfer surface of the print sheet S. The heating roller 71 includes a body part 110, a buffer layer 111 formed on the outer peripheral side of the body part 110, and an outer peripheral surface layer 112 that covers the outer peripheral surface of the buffer layer 111. The trunk | drum 110 is comprised, for example with metals, such as aluminum, and is formed in the cylindrical shape with the material with high heat conductivity. The buffer layer 111 is made of an elastic material such as silicon rubber, for example. The outer peripheral surface layer 112 is made of a non-adhesive material such as a fluororesin, for example. That is, the heating roller 71 functions as an elastic roller, and is configured to follow the transfer surface of the print sheet S.

The driving roller 72 is provided on the lower side in the vertical direction with respect to the printing sheet S, and is provided to face the heating roller 71. The drive roller 72 can drive the heating roller 71 in synchronization via a drive transmission mechanism (not shown). Further, the driving roller 72 can drive the support roller 73 in synchronization via the conveyor belt 74.

The support roller 73 is provided upstream of the drive roller 72 in the transport direction of the print sheet S, that is, on the printing apparatus 12 side. The support roller 73 is a crown roller having a diameter in the central portion in the axial direction that is larger than the diameter at both ends in the axial direction, and suppresses deviation in the width direction (axial direction) of the conveyed printing sheet S.

The conveying belt 74 is stretched between the driving roller 72 and the support roller 73 and is provided in contact with the opposite surface of the printing sheet S to the transfer surface. The conveyor belt 74 includes a base layer 115 and an outer peripheral surface layer 116 that covers the outer peripheral surface of the base layer 115. The base layer 115 is made of metal and is formed in an annular shape with a highly rigid material. For this reason, since the base layer 115 has a high thermal conductivity and the temperature is likely to rise, the effect of holding heat is enhanced, whereby the temperature of the transport belt 74 can be suitably held. The outer peripheral surface layer 116 is made of a non-adhesive material such as a fluororesin, for example.

The heater 75 is provided inside the body 110 of the heating roller 71 and heats the heating roller 71. Since the body portion 110 of the heating roller 71 is made of metal, the heater 75 can suitably transmit heat toward the outer peripheral surface layer 112 of the heating roller 71.

Here, the heating roller 71 is provided with a conveyor belt 74 wound around a driving roller 72 and a support roller 73 around the outer peripheral surface thereof. That is, the contact portion where the heating roller 71 and the conveyance belt 74 are in contact with each other is heated via the conveyance belt 74 and the first nip region E1 where the driving roller 72 sandwiched between the heating roller 71 and the conveyance belt 74 is not opposed. A second nip region E <b> 2 sandwiched between the roller 71 and the driving roller 72 is formed. The first nip region E1 is formed on the upstream side in the transport direction, the second nip region E2 is formed on the downstream side in the transport direction, and the first nip region E1 is compared to the second nip region E2. And it is formed long in the conveyance direction.

Here, a fixing method using the fixing device 14 will be described. When the print sheet S is conveyed to the main fixing device 14, the conveyed print sheet S is introduced between the heating roller 71 and the conveyance belt 74. The introduced printing sheet S passes through the first nip region E1, and is thus sandwiched between the heating roller 71 and the conveying belt 74 and heated by the heating roller 71 while applying a first clamping pressure (first 1 nip process). Thereafter, the printing sheet S passes through the second nip region E2, and is sandwiched between the heating roller 71 and the conveyance belt 74 and is heated by the heating roller 71 while applying the second clamping pressure (first 2 nip process). At this time, since the first nip region E1 is formed longer in the transport direction than the second nip region E2, the print sheet S is longer in the first nip region E1 than in the second nip region E2. Sandwiched. In addition, the 1st nip area | region E1 is comprised 30 mm or more, Preferably it is 30 mm or more and 40 mm or less, and the 2nd nip area | region E2 is comprised 10 mm or more, Preferably it is 10 mm or more and 20 mm or less. The print sheet S passes through the first nip region E1 and the second nip region E2, and thereby the liquid toner is fixed. At this time, the printing speed in the first nip region E1 is set to 0.68 m / s or more, and the passing time for the print sheet S to pass through the first nip region E1 is set to be 0.044 seconds or more. is doing.

The assumption fixing device 13 includes a heating roller 71, a driving roller 72, a support roller 73, a conveyance belt 74, and a heater 75, similarly to the main fixing device 14 described above. That is, the main fixing device 14 includes a heating roller 71 for main fixing, a driving roller 72 for main fixing, a support roller 73 for main fixing, a conveyance belt 74 for main fixing, and a heater 75 for main fixing. The hypothetical wearing device 13 includes a hypothetical wearing heating roller 71, a hypothetical wearing driving roller 72, a hypothetical wearing support roller 73, a hypothetical wearing conveyor belt 74, and a hypothetical wearing heater 75. Composed. Note that the configuration of the hypothetical landing device 13 is the same as the configuration of the fixing device 14 and is omitted.

Next, the first clamping pressure applied to the printing sheet S in the first nip region E1 and the second clamping pressure applied to the printing sheet S in the second nip region E2 will be described with reference to FIG. FIG. 3 is a graph of the clamping pressure applied to the print sheet in the fixing device. In the graph shown in FIG. 3, the horizontal axis is the position in the conveyance direction, and the vertical axis is the pressure of the clamping pressure applied to the print sheet.

As shown in FIG. 3, when the printing sheet S passes through the first nip region E1, the printing sheet S is sandwiched at a pressure that becomes the first sandwiching pressure P1. The first clamping pressure P1 is not less than 0.1 MPa and not more than 0.3 MPa. After the print sheet S passes through the first nip region E1, when the print sheet S passes through the second nip region E2, the print sheet S is sandwiched with a pressure that becomes the second sandwiching pressure P2. The second clamping pressure P2 is 0.4 MPa or more and 0.7 MPa or less, and the position L (see FIG. 2) connecting the axis of the heating roller 71 and the axis of the drive roller 72 is the maximum pressure. For this reason, the second clamping pressure P2 is set to a higher pressure than the first clamping pressure P1.

Next, the temperature change of the print sheet S in the first nip region E1 and the temperature change of the print sheet S in the second nip region E2 will be described with reference to FIG. FIG. 4 is a graph of the temperature change of the print sheet in the fixing device. In the graph shown in FIG. 4, the horizontal axis represents time, and the vertical axis represents the temperature of the print sheet S. Here, T1 is the temperature on the transfer surface of the print sheet S, that is, the temperature of the surface with which the heating roller 71 contacts. T2 is the temperature of the surface opposite to the transfer surface of the printing sheet S, that is, the temperature of the surface with which the conveyor belt 74 contacts. T3 is an intermediate temperature between the transfer surface of the printing sheet S and the opposite surface. R is a boundary before and after the melting of the toner. The lower side in the drawing is before the melting of the toner, and the upper side in the drawing is after the melting of the toner.

As shown in FIG. 4, when the printing sheet S is introduced into the first nip region E1, first, the temperatures T1 and T2 of the transfer surface and the opposite surface of the printing sheet S rise transiently, and the temperatures T1 and T2 are increased. As the temperature rises, the intermediate temperature T3 of the print sheet S rises so as to follow the temperatures T1 and T2. Thereafter, the intermediate temperature T3 of the rising print sheet S becomes a temperature between the temperature T1 of the transfer surface of the print sheet S and the temperature T2 of the opposite surface of the print sheet S, and reaches the boundary R in this state. As a result, the particulate toner contained in the liquid toner is melted. The temperatures T1, T2, and T3 of the printing sheet S at the boundary R gradually increase until the printing sheet S passes through the first nip region E1, and printing is performed in a state where the relationship between the temperatures T1, T2, and T3 is maintained. The sheet S is introduced into the second nip region E2. When the print sheet S is introduced into the second nip region E2, the print sheet S temperature T1, T2, T3 maintains the relationship between the temperatures T1, T2, T3, and the print sheet S passes through the second nip region E2. Gradually rise until passing.

For this reason, when the print sheet S passes through the first nip region E1, the liquid toner transferred to the print sheet S is melted, and in a state where the liquid toner is melted, the print sheet S is introduced into the second nip region E2. Is done.

By the way, the print sheet S passes through the hypothetical fixing device 13 and presupposes the toner, and then passes through the fixing device 14 to fix the toner. At this time, the assumed fixing device 13 has substantially the same configuration as that of the main fixing device 14, and therefore the assumed fixing device 13 and the main fixing device 14 have a configuration in which the print sheet S can be nipped long.

Here, with reference to FIG. 5, the temperature change of the print sheet S from the assumed fixing device 13 of the present embodiment to the fixing device 14 of the present embodiment, and the conventional fixing device of the present embodiment to the present fixing device of the present embodiment. Comparison is made with respect to the temperature change of the printing sheet S up to 14. FIG. 5 is a graph of the temperature change of the printed sheet from the hypothetical fixing device to the fixing device. In the graph shown in FIG. 5, the horizontal axis is the position in the transport direction, and the vertical axis is the temperature of the print sheet S. Here, the temperature Ta is the temperature of the print sheet S from the assumed fixing device 13 of the present embodiment to the fixing device 14 of the present embodiment, and the temperature Tb is the conventional fixing device of the present embodiment from the conventional assumed fixing device. This is the temperature of the printing sheet S up to the apparatus 14. Note that the conventional assumption fixing device has a configuration in which the print sheet S is sandwiched between a pair of fixing rollers, and corresponds to a configuration in which the print sheet S is sandwiched only in the second nip region E2. The temperature range TE is an optimum temperature range for suitably fixing the liquid toner to the print sheet S.

As shown in FIG. 5, in the hypothetical dressing device 13 of this embodiment, the temperature Ta of the print sheet S is set by passing the print sheet S between the presumably worn heating roller 71 and the hypothetical wear belt 74. Raise. For this reason, in the hypothetical landing device 13, the temperature of the print sheet S can be raised in the first nip region E1 and the second nip region E2. At this time, since the base layer 115 of the conveyance belt 74 is made of metal as described above, the temperature of the conveyance belt 74 can be suitably maintained even when the printing sheets S sequentially pass. On the other hand, in the conventional hypothetical landing apparatus, the temperature Tb of the print sheet S is raised by passing the print sheet S between the pair of fixing rollers. For this reason, in the conventional hypothetical landing apparatus, this corresponds to heating the print sheet S only in the second nip region E2, and therefore, the temperature Tb is the temperature that cannot be increased in the first nip region E1. Lower than Ta.

Thereafter, the temperature Ta gradually decreases while being transported from the hypothetical fixing device 13 to the fixing device 14. Similarly, the temperature Tb gradually decreases while being conveyed from the conventional hypothetical landing device to the fixing device 14. The temperature Ta immediately before being introduced into the fixing device 14 is higher than the temperature Tb immediately before being introduced into the fixing device 14. Subsequently, in the main fixing device 14, the temperatures Ta and Tb of the print sheet S are increased by passing the print sheet S between the main fixing heating roller 71 and the main fixing conveyance belt 74. Therefore, in the fixing device 14, the temperature of the print sheet S can be raised in the first nip region E1 and the second nip region E2. At this time, since the temperature Ta is higher than the temperature Tb immediately before being introduced into the fixing device 14, the fixing device 14 can set the temperature Ta to a temperature within the temperature range TE. In other words, since the temperature Tb is lower than the temperature Ta immediately before being introduced into the fixing device 14, the fixing device 14 has difficulty in setting the temperature Tb to a temperature within the temperature range TE. Therefore, in order to set the temperature Tb within the temperature range TE, the temperature of the heating roller 71 in the fixing device 14 is set higher than the temperature of the heating roller 71 of the fixing device 14 related to the temperature Ta. It is necessary to do.

Next, referring to FIG. 6, the glossiness of the print sheet S when using the assumed fixing device 13 of the present embodiment and the fixing device 14 of the present embodiment, and the conventional configuration having the same configuration as FIG. The glossiness of the printed sheet S when using the assumed fixing device and the fixing device 14 of this embodiment will be compared. FIG. 6 is a graph of glossiness during duplex printing. In the graph shown in FIG. 6, the glossiness of the liquid toner corresponding to each color of K, C, M, and Y is expressed numerically. Note that H is the target gloss level. If the gloss level of the liquid toner after fixing exceeds the target gloss level H, the liquid toner on the print sheet S is fixed with sufficient gloss. It becomes.

In the case of using the conventional hypothetical fixing device and the fixing device 14 of this embodiment, first, liquid toner is transferred to the surface of the printing sheet S. Thereafter, after the liquid toner on the surface of the print sheet S is presumed to be applied by the conventional hypothetical landing device, the front and back of the print sheet S are reversed by the reversing device 91, and the liquid toner is applied to the back surface of the print sheet S. Transcribed. Thereafter, after the liquid toner on the back surface (and front surface) of the print sheet S is presupposed by the conventional hypothetical deposition device, the liquid on the back surface (and front surface) of the print sheet S is formed by the main fixing device 14 of this embodiment. The toner is permanently fixed. It was recognized that the printed sheet S at this time did not reach the target glossiness H on the front surface, and reached the target glossiness H on the back surface. As a result, it was confirmed that it was difficult to obtain a sufficient glossiness on the surface when the conventional hypothetical fixing device and the fixing device 14 of the present embodiment were used.

On the other hand, when the assumption fixing device 13 of this embodiment and the fixing device 14 of this embodiment are used, first, liquid toner is transferred to the surface of the print sheet S. Thereafter, after the liquid toner on the surface of the print sheet S is presumed by the hypothetical landing device 13, the front and back of the print sheet S are reversed by the reversing device 91, and the liquid toner is transferred to the back surface of the print sheet S. Is done. Thereafter, after the liquid toner on the back surface (and front surface) of the print sheet S is assumed by the hypothetical fixing device 13, the liquid toner on the back surface (and front surface) of the print sheet S is used by the fixing device 14 of this embodiment. Is permanently established. It was recognized that the printed sheet S at this time had the front surface glossiness reaching the target glossiness H and the back surface glossiness reaching the target glossiness H. As a result, it was confirmed that sufficient glossiness was obtained on the front surface and the back surface when the assumed fixing device 13 of the present embodiment and the present fixing device 14 of the present embodiment were used.

As described above, according to the configuration of this embodiment, the transfer of the print sheet S to which the liquid toner has been transferred in the first nip region E1 (first nip step) and the second nip region E2 (second nip step). The heating roller 71 can be brought into contact with the surface. Thereby, the hypothetical fixing device 13 and the main fixing device 14 can suitably apply heat to the transfer surface of the print sheet S in the first nip region E1 and the second nip region E2. Further, in the first nip region E1, the print sheet S can be sandwiched between the heating roller 71 and the conveyance belt 74. At this time, since the transfer surface of the printing sheet S can be heated by the heating roller 71, it is not necessary to consider the thermal responsiveness of the conveyor belt 74, so that the conveyor belt 74 can have high rigidity. In addition, the clamping pressure between the heating roller 71 and the conveyance belt 74 in the first nip region E1 can be increased. In addition, since the heating roller 71 having the buffer layer 111 is in contact with the transfer surface of the print sheet S, it is possible to ensure followability to the transfer surface of the print sheet S. Therefore, in the first nip region E1, heat can be suitably applied to the transfer surface of the printing sheet S while ensuring followability, and the clamping pressure can be increased. For this reason, the liquid toner transferred to the printing sheet S can be suitably fixed so as to have gloss without causing rubbing.

Further, according to the configuration of the present embodiment, in the first nip region E1, after the liquid toner is fixed to the print sheet S at the first nip pressure P1 lower than the second nip pressure P2, in the second nip region E2. The liquid toner can be fixed to the print sheet S at the second clamping pressure P2 higher than the first clamping pressure P1. For this reason, the clamping pressure can be applied to the printing sheet S step by step. At this time, since the liquid toner is melted in the first nip region E1, the molten liquid toner can be sandwiched in the second nip region E2 by applying a high second clamping pressure P2, so that the liquid toner is printed. The sheet S can be fixed satisfactorily.

Moreover, according to the structure of the present Example, the 1st clamping pressure P1 can be 0.1 MPa or more and 0.3 MPa or less, and the 2nd clamping pressure P2 can be 0.4 MPa or more and 0.7 MPa or less. . For this reason, since a higher clamping pressure than before can be applied, the glossiness of the liquid toner fixed on the print sheet S can be improved.

Further, according to the configuration of the present embodiment, the length of the first nip region E1 in the transport direction can be made longer than the length of the second nip region E2 in the transport direction. As a result, the first nip region E1 (first nip step) can hold the print sheet S longer than the second nip region E2 (second nip step). It is possible to secure a sufficient time until the liquid toner transferred to the printing sheet S is melted by quickly raising the temperature of S.

Further, according to the configuration of the present embodiment, in the conveyor belt 74, the base layer 115 can be made of metal, so that the rigidity of the conveyor belt 74 can be increased, and the outer peripheral surface layer 116 is made non-adhesive. Since it can be made of a material, the liquid toner can be prevented from adhering to the transport belt 74.

Further, according to the configuration of the present embodiment, in the heating roller 71, the body portion 110 can be made of metal, so that heat can be suitably transmitted toward the outer peripheral surface layer 112, and the buffer layer 111 can be transmitted. Can be made of an elastic material, so that the followability to the transfer surface of the print sheet S can be secured, and the outer peripheral surface layer 112 can be made of a non-adhesive material, so that the liquid toner is heated. Adhering to the roller 71 can be suppressed.

Further, according to the configuration of the present embodiment, since the support roller 73 can be a crown roller, it is possible to suppress blur in the width direction of the transport belt 74. As a result, the transport belt 74 can transport the print sheet S without shifting its position in the width direction. Therefore, the liquid on the print sheet S without causing uneven fixing on the transfer surface of the print sheet S. The toner can be suitably fixed.

In the electronic printing machine 1 of the present embodiment, the hypothetical fixing device 13 and the main fixing device 14 are provided. However, the present invention is not limited to this configuration, and a single configuration having the same configuration as the hypothetical fixing device 13 and the main fixing device 14 is provided. It may be changed to a fixing device. Specifically, the size of the printing sheet S is A3 size (297 mm × 420 mm), a high-speed electronic printer capable of printing 60 sheets per minute, or a high-speed printing machine with a printing speed of 0.68 m / s or more. In the case of an electronic printing machine, it is preferable to use the assumed fixing device 13 and the fixing device 14 of this embodiment. On the other hand, in the case of a low-speed electronic printer capable of printing 30 sheets per minute, it is preferable to use the hypothetical fixing device 13 and the main fixing device 14 of this embodiment or a single fixing device. At this time, when a single fixing device is used, it is preferable that the single fixing device is provided at a position corresponding to the hypothetical landing device 13 of this embodiment.

DESCRIPTION OF SYMBOLS 1 Electronic printer 11 Paper feeder 12 Printing device 13 Assumed landing device 14 This fixing device 15 Conveyance device 16 Paper discharge device 31 Backup roller 32

Intermediate transfer body

33, 34, 35, 36 Development unit 41 Photosensitive drum 71 Heating roller 72 Drive Roller 73 Support roller 74 Conveying belt 75 Heater 91 Reversing device 110 Body 111 Buffer layer 112 Outer peripheral surface layer of heating roller 115 Substrate layer 116 Outer peripheral surface layer of conveying belt S Print sheet E1 First nip region E2 Second nip region P1 First 1 clamping pressure P2 2nd clamping pressure

Claims

In a fixing device for fixing a toner transferred to a printing material by heating the printing material conveyed with the transfer surface onto which the toner is transferred facing upward in a vertical direction sandwiched from both upper and lower sides. ,
An elastic roller provided on the upper side in the vertical direction across the substrate to be conveyed, and in contact with the transfer surface of the substrate;
A first roller provided on the lower side in the vertical direction across the substrate to be conveyed, and facing the elastic roller;
A second roller provided upstream of the first roller in the conveyance direction of the substrate;
A hard belt that is stretched between the first roller and the second roller and is in contact with the surface opposite to the transfer surface of the substrate;
A heating means provided inside the elastic roller and capable of heating the elastic roller;
The printed material is located on a downstream side of the first nip region in the transport direction of the first nip region, the first nip region between which the first roller sandwiched between the elastic roller and the hard belt is not opposed, and the hard belt. And a second nip region sandwiched between the elastic roller and the first roller via a fixing device.
The second clamping pressure between the elastic roller and the first roller in the second nip region is higher than the first clamping pressure between the elastic roller and the hard belt in the first nip region. The fixing device according to claim 1.
The first clamping pressure is between 0.1 MPa and 0.3 MPa, and the second clamping pressure is between 0.4 MPa and 0.7 MPa. Fixing device.
4. The fixing device according to claim 1, wherein the first nip region is longer in the transport direction than the second nip region. 5.
5. The fixing device according to claim 1, wherein the first nip region has a length in the transport direction of 30 mm or more.
The fixing device according to any one of claims 1 to 5, wherein the second nip region has a length in the transport direction of 10 mm or more.
The fixing device according to any one of claims 1 to 6, wherein a passing time of the printing material passing through the first nip region is 0.044 seconds or more.
The said hard belt has the base layer comprised with the metal, and the outer peripheral surface layer comprised with the non-adhesive material which coat | covers the outer peripheral surface of the said base layer, The thru | or 1 characterized by the above-mentioned. 8. The fixing device according to any one of 7 above.
The elastic roller is a body portion made of a heat transfer material, a buffer layer formed on the outer peripheral side of the body portion and made of an elastic material, and a non-adhesive material covering the outer peripheral surface of the buffer layer. The fixing device according to claim 1, further comprising an outer peripheral surface layer.
The fixing device according to claim 1, wherein the second roller is a crown roller.
A paper feeder capable of supplying a substrate;
A printing apparatus that transfers toner to the substrate to be printed supplied from the paper feeding apparatus;
A hypothetical landing device that heats and deposits the toner transferred to the substrate;
A main fixing device that is provided on the downstream side in the transport direction of the substrate with respect to the hypothetical fixing device, and heats and fixes the hypothetically fixed substrate to be fixed;
A paper discharge device for discharging the printed material on which the toner is fixed by the main fixing device;
The fixing device includes:
An elastic roller for main fixing provided on the upper side in the vertical direction across the substrate to be conveyed, and in contact with the transfer surface of the substrate to be printed;
A first fixing roller that is provided on the lower side in the vertical direction across the substrate to be conveyed and faces the elastic roller;
A second roller for main fixing provided on the upstream side in the conveyance direction of the substrate with respect to the first roller;
A main fixing hard belt that is stretched between the first roller and the second roller and is in contact with the opposite surface of the transfer surface of the substrate;
A heating means for main fixing provided inside the elastic roller and capable of heating the elastic roller;
The printed material is positioned on the downstream side of the first nip region for main fixing where the first roller sandwiched between the elastic roller and the hard belt does not face the downstream side in the transport direction of the first nip region. An electronic printing machine that passes through a second nip region for main fixing that is sandwiched between the elastic roller and the first roller via the hard belt.
The hypothetical landing device is
A hypothetical wearing elastic roller provided on the upper side in the vertical direction across the substrate to be conveyed, and in contact with the transfer surface of the substrate,
A first roller that is provided on the lower side in the vertical direction across the substrate to be conveyed, and that is opposed to the elastic roller;
Assumingly worn second roller provided on the upstream side in the transport direction of the substrate with respect to the first roller;
A hypothetical worn hard belt that is spanned between the first roller and the second roller and contacts the opposite surface of the transfer surface of the substrate;
Heating means provided on the inside of the elastic roller and capable of heating the elastic roller;
The printed material is located on the downstream side in the transport direction of the first nip region and the first nip region of the assumed wearing where the first roller sandwiched between the elastic roller and the hard belt does not face, The electronic printing machine according to claim 11, wherein the electronic printing machine passes through a second nip region that is assumed to be sandwiched between the elastic roller and the first roller via the hard belt.
A paper feeder capable of supplying a substrate;
A printing apparatus that transfers toner to the substrate to be printed supplied from the paper feeding apparatus;
A fixing device that heats and fixes the toner transferred to the substrate;
A paper discharge device for discharging the printed material on which the toner is fixed by the fixing device,
The fixing device includes:
An elastic roller provided on the upper side in the vertical direction across the substrate to be conveyed, and in contact with the transfer surface of the substrate;
A first roller provided on the lower side in the vertical direction across the substrate to be conveyed, and facing the elastic roller;
A second roller provided upstream of the first roller in the conveyance direction of the substrate;
A hard belt that is stretched between the first roller and the second roller and is in contact with the surface opposite to the transfer surface of the substrate;
Heating means provided inside the elastic roller and capable of heating the elastic roller;
The printed material is located on a downstream side of the first nip region in the transport direction of the first nip region, the first nip region between which the first roller sandwiched between the elastic roller and the hard belt is not opposed, and the hard belt. And passing through a second nip region sandwiched between the elastic roller and the first roller.
In a fixing method for fixing a toner transferred to a printing material by heating the printing material conveyed with the transfer surface onto which the toner is transferred facing upward in a vertical direction sandwiched from both upper and lower sides. ,
An elastic roller that is in contact with the transfer surface of the substrate is provided on the upper side in the vertical direction across the substrate to be conveyed.
A first roller facing the elastic roller is provided on the lower side in the vertical direction across the substrate to be conveyed,
A second roller is provided upstream of the first roller in the conveyance direction of the substrate,
Between the first roller and the second roller, a hard belt that is in contact with the opposite surface of the transfer surface of the substrate is spanned,
Inside the elastic roller, a heating means capable of heating the elastic roller is provided,
A first nip step of sandwiching the printing material between the elastic roller and the hard belt that are not opposed to the first roller;
A fixing method comprising: a second nip step for sandwiching the printing material between the elastic roller and the first roller via the hard belt.
The fixing method according to claim 14, wherein the first nip step takes a longer time to sandwich the printed material than the second nip step.