JP2007033767A - Fixing device and method, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device in which improved image quality and miniaturization are realized. <P>SOLUTION: The fixing device includes: a fixing part 10 that comes into contact with one side of a sheet S; a plurality of driving parts 50 that come into contact with the other side of the sheet S and sandwich the sheet S between the fixing part 10 and themselves; and a control section that drives the driving parts 50. The plurality of driving parts 50 are arranged in a direction perpendicular to the direction of conveyance of the sheet S. The control section controls the drive of each of the driving parts 50 such that differences in the conveyance speed of the sheet S are made in the direction perpendicular to the direction of conveyance of the sheet S. Thereby, the passing position of the sheet S can be stabilized. This reduces wrinkles or image defects, which result from the passing position of the sheet S. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing device used in an electrophotographic image forming apparatus such as a copying machine, a laser printer, and a facsimile, an image forming apparatus using the fixing device, and a fixing method.

  Conventionally, as a fixing device mounted on an electrophotographic color printer or color copier, as shown in FIG. 10, a heating roller 102, a fixing roller 103, and the heating roller 102 and the fixing roller 103 are wound. In some cases, the fixing belt 101 and the pressure roller 104 that contacts the fixing roller 103 via the fixing belt 101 to form a nip portion are provided.

  The heating roller 102 is heated by a halogen lamp 121 inside. The halogen lamp 121 is controlled by a thermistor 122 that detects the temperature of the heating roller 102.

  Then, the fixing belt 101 is heated by the heating roller 102, and the toner t adhering to the sheet S is melted and fixed while the sheet S is conveyed while being sandwiched by the nip portion.

  Another fixing device includes a heating roller 102 and a pressure roller 104 that forms a nip portion in contact with the heating roller 102 as shown in FIG.

  The heating roller 102 is heated by a halogen lamp 121 inside. The halogen lamp 121 is controlled by a thermistor 122 that detects the temperature of the heating roller 102.

  Then, the heating roller 102 is heated, and the toner t adhering to the sheet S is melted and fixed while being conveyed with the sheet S sandwiched between the nip portions.

  In the fixing device shown in FIGS. 10 and 11, when the sheet S passes through the nip portion, the sheet S needs to be kept in a state that is not strictly loosened, and the fixing belt 101 of FIG. If the sheet S is slightly slack in the axial direction of the heating roller 102, the sheet S is wrinkled as it passes through the nip portion.

  Therefore, in order to guide the sheet S to the nip portion while the sheet S is pulled in the axial direction, the conveying speed applied to the sheet S at the nip portion is set to both ends of the fixing belt 101 and the heating roller 102. The speed difference is given between the center and the center.

  The fixing device shown in FIG. 10 will be described in detail. As shown in FIG. 12, the outer diameter of both ends of the heating roller 102 is set to be smaller than the outer diameter of the central portion of the heating roller 102 by 0.1 mm. Degree) is larger. The conveyance speed applied to the sheet S at the nip portion increases as the elastic layer of the heating roller 102 at the nip portion increases in distortion. A faster conveying speed can be given to the sheet S than the central portion of the roller 102 having a small outer diameter.

  On the other hand, as another problem, in the image forming apparatus using the fixing device, the conveying force that the fixing device gives to the sheet S is extremely larger than the conveying force that other processes give to the sheet S. When the fluctuation of the conveying force applied to the sheet S by the fixing device is transmitted upstream from the transfer device of the image forming apparatus, a problem of image displacement occurs.

  Therefore, in order to prevent fluctuations in the conveying force of the fixing device from being transmitted upstream from the transfer device, generally, a slack called a loop is formed in the sheet S between the fixing device and the transfer device. .

  Also, as shown in FIG. 13, a sheet conveying apparatus that interrupts transmission of fluctuations in conveying force is provided (see Japanese Patent Application Laid-Open No. 9-127745: Patent Document 1).

  The sheet conveying device is disposed between the fixing device and the transfer device, and includes suction belts 71 and 71 at both ends and suction belts 75 and 75 at the center. In this apparatus, the sheet S is conveyed by the suction belts 71 and 75 while being sucked to the suction belts 71 and 75 side by evacuation.

  By making the feeding speed of the central suction belts 75 and 75 slower than the feeding speed of the suction belts 71 and 71 at both ends, the fluctuation of the conveying force by the fixing device is not transmitted.

  However, as shown in FIG. 12, when the outer diameter of both ends of the heating roller 102 is larger than the outer diameter of the central portion of the heating roller 102, the width dimension of the nip portion or the nip portion Is different in the axial direction of the heating roller 102, and a quality difference occurs in the fixing quality of the sheet S in the width direction.

  In addition, when forming a slack called a loop on the sheet S between the fixing device and the transfer device, there is no effect unless a sufficient loop amount can be secured. More specifically, if there is a difference in the loop amount at both ends in the width direction of the sheet S due to variations in the transport posture of the sheet S, and the loop amount on one side becomes extremely large, Deviation occurs. For this reason, the effect cannot be expected in a small image forming apparatus.

Further, in the sheet conveying apparatus shown in FIG. 13, it is necessary to keep the conveying path from the transfer apparatus to the fixing apparatus horizontal, and since the apparatus itself has a size, the configuration as an image forming apparatus can be freely set. The degree is too low to achieve miniaturization. Further, in order to give the sheet S a conveying force by friction caused by the suction force of the suction belts 71 and 75, an aggressive restraining force that controls the conveying posture of the sheet S by a difference in conveying speed is used. Can not give to.
JP-A-9-127745

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device that can improve image quality and can be downsized.

In order to solve the above problems, the fixing device of the present invention is:
A fixing unit that contacts one surface of the sheet;
The drive unit has a plurality of drive units that are in contact with the other surface of the sheet and sandwich the sheet together with the fixing unit, and are driven in an independent manner from each other. A conveying unit that conveys the sheet by driving;
And a control unit that independently controls the driving of the plurality of driving units.

  Here, the fixing unit is, for example, a fixing roller, a fixing belt, or a fixing sheet.

  According to the fixing device of the present invention, since the driving of the plurality of driving units is independently controlled by the control unit, the speed difference is set in the direction crossing the sheet conveying direction. Can be given.

  As described above, the width of the nip formed by the contact between the fixing unit and the conveyance unit and the pressure of the nip can be affected without affecting the sheet conveyance speed. In addition, the posture of the sheet when the sheet passes through the nip portion can be controlled without affecting the fixing quality.

  Further, since the speed difference is given by a strong conveying force at the nip portion, the sheet passing posture can be positively controlled, and the loop amount necessary on the upstream side of the nip portion can be reduced.

  Therefore, the sheet passing posture can be stabilized in a small space, and a fixing device in which the occurrence of wrinkles and image defects due to the sheet passing posture can be reduced can be provided.

  In the fixing device according to the embodiment, the control unit has a conveyance speed at both ends in a direction orthogonal to the sheet conveyance direction higher than a conveyance speed at a center in the direction orthogonal to the sheet conveyance direction. As described above, the driving of the plurality of driving units is controlled.

  According to the fixing device of this embodiment, the sheet is spread in a direction intersecting the sheet conveying direction by making the conveying speed of both ends of the sheet faster than the conveying speed of the central part of the sheet. The sheet can be guided to the nip portion while being urged to prevent wrinkling of the sheet.

  In the fixing device according to the embodiment, a setting unit that sets a speed difference between a conveyance speed at both ends in a direction orthogonal to the conveyance direction of the sheet and a conveyance speed at a central portion in a direction orthogonal to the conveyance direction of the sheet. Is provided.

  According to the fixing device of this embodiment, since the setting unit that sets the speed difference between the conveyance speed at both ends of the sheet and the conveyance speed at the center of the sheet is provided, the type (material, thickness, etc.) of the sheet Accordingly, the speed difference between the conveyance speed at both ends of the sheet and the conveyance speed at the center of the sheet can be set, and the application range is wide.

  The fixing device according to an embodiment further includes a detection unit that detects an attitude of the sheet on the upstream side in the sheet conveyance direction of the fixing unit and the conveyance unit. Controls driving of a plurality of driving units.

  Here, “detecting the posture of the sheet” means detecting, for example, the amount of looseness (loop amount) of the sheet, the inclination of the sheet with respect to the sheet conveyance direction, and the like.

  According to the fixing device of this embodiment, the control unit controls the driving of the plurality of driving units based on the output of the detection unit, so that the posture of the sheet passing through the nip portion is further stabilized. This prevents wrinkles and image defects.

  Further, when there is an image forming device that forms an image by attaching unfixed toner to the sheet on the upstream side of the fixing device, the fluctuation in the conveying force of the fixing device is upstream of the image forming device. It is possible to prevent transmission to the process and to prevent image displacement.

  In the fixing device according to an embodiment, the detection unit detects a slack amount at both ends in a direction orthogonal to the conveyance direction of the sheet, and the control unit detects the sheet of the sheet detected by the detection unit. The driving of the plurality of driving units is controlled so that the slack amounts at both ends in the direction orthogonal to the transport direction are equal.

  According to the fixing device of this embodiment, the control unit controls the driving of the plurality of driving units so that the slack amounts at the both ends of the sheet are equal. Therefore, the slack amounts at the both ends of the sheet. Therefore, it is possible to fix the above-mentioned sheet and prevent image displacement.

  In the fixing device according to the embodiment, the detection unit may determine a slack amount at both ends in a direction orthogonal to the sheet conveyance direction and a slack amount at a center portion in a direction orthogonal to the sheet conveyance direction. The control unit detects the amount of slack at both ends in the direction orthogonal to the sheet conveyance direction and the amount of slack at the center in the direction orthogonal to the sheet conveyance direction detected by the detection unit. The driving of the plurality of driving units is controlled so as to be substantially equal.

  According to the fixing device of this embodiment, the control unit controls the driving of the plurality of driving units so that the amount of slack at both ends of the sheet is substantially equal to the amount of slack at the center of the sheet. Therefore, the passing posture of the sheet can be controlled so that unevenness does not occur in the central portion of the sheet, and wrinkling of the sheet can be prevented.

  In the fixing device according to the embodiment, the fixing unit contacts a surface on which the image of the sheet is recorded.

  The fixing device according to an embodiment includes a heat generating unit that heats the sheet through the fixing unit.

The image forming apparatus of the present invention is
An image forming apparatus for forming an image by attaching unfixed toner to a sheet;
And a fixing device that melts and fixes the toner onto the sheet.

  According to the image forming apparatus of the present invention, since the fixing device is provided, the image quality can be improved and the size can be reduced.

  The image forming apparatus according to an embodiment further includes a detection unit that detects a posture of the sheet between the image forming device and the fixing device, and the control unit of the fixing device is based on an output of the detection unit. Then, the driving of the plurality of driving units of the fixing device is controlled.

  According to the image forming apparatus of this embodiment, the control unit of the fixing device controls driving of the plurality of driving units of the fixing device based on the output of the detection unit. Can be prevented from being transmitted to a process upstream of the image forming apparatus, and image displacement can be prevented.

  According to the fixing method of the present invention, the plurality of driving units arranged in a direction intersecting the sheet conveying direction and the fixing unit sandwich the sheet, and the plurality of driving units are driven independently. The sheet is heated by the fixing unit while the sheet is conveyed.

  According to the fixing method of the present invention, since the plurality of driving units are driven independently to convey the sheet, a speed difference is generated between the sheet conveyance speed and the direction intersecting the sheet conveyance direction. Can be given.

  In this way, the width of the nip formed by the contact between the fixing unit and the driving unit and the pressure of the nip can be affected without affecting the sheet conveyance speed. In addition, the posture of the sheet when the sheet passes through the nip portion can be controlled without affecting the fixing quality.

  Further, since the speed difference is given by a strong conveying force at the nip portion, the sheet passing posture can be positively controlled, and the loop amount necessary on the upstream side of the nip portion can be reduced.

  Therefore, the sheet passing posture can be stabilized in a small space, and wrinkles and image defects caused by the sheet passing posture can be reduced.

  According to the fixing device of the present invention, since the driving of the plurality of driving units is independently controlled by the control unit, the speed difference is set in the direction crossing the sheet conveying direction. The image quality can be improved and the size can be reduced.

  Also, according to the image forming apparatus of the present invention, since the fixing device is provided, the image quality can be improved and the size can be reduced.

  According to the fixing method of the present invention, the plurality of driving units are driven independently to convey the sheet. Therefore, in the direction intersecting the sheet conveyance direction with the sheet conveyance speed, A speed difference can be given, image quality can be improved, and miniaturization can be achieved.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a simplified configuration diagram showing a first embodiment of a fixing device according to the present invention. The fixing device includes a fixing unit 10 that contacts one surface on which an image of the sheet S is recorded, a conveyance unit 11 that contacts the other surface of the sheet S and conveys the sheet S together with the fixing unit 10; A control unit 12 that controls the conveyance unit 11 and a heat generation unit 13 that heats the sheet S via the fixing unit 10 are provided.

  The sheet S is, for example, a sheet such as paper or an OHP sheet. A toner t is attached to one surface of the sheet S, and the toner t is made of a material having heat melting properties such as a resin, a magnetic material, or a colorant.

  The fixing unit 10 is a fixing belt, and includes a base material layer 41, an elastic layer 42, and a release layer 44 from the inside to the outside, as shown in the sectional view of FIG. The base material layer 41 is made of a material having strength such as aluminum or iron. The elastic layer 42 is made of a material having heat resistance and elasticity such as rubber or resin. The release layer 44 is made of a material having release properties and heat resistance, such as silicon rubber, fluorine rubber, PFA, PTFE, FEP, or PFEP.

  As shown in FIG. 3, the transport unit 11 includes a plurality (three) of drive units 50 arranged in a direction intersecting the transport direction of the sheet S. The plurality of driving units 50 are arranged in a direction orthogonal to the conveying direction of the sheet S (in the axial direction of the fixing belt). The plurality of driving units 50 are driven independently of each other. The driving unit 50 contacts the other surface of the sheet S, and conveys the sheet S by the driving of the driving unit 50. The drive unit 50 is, for example, a vibrating body such as an ultrasonic vibrator or a piezoelectric element, or a roller.

  The control unit 12 drives the drive unit 50 by energizing the drive unit 50. When the driving unit 50 is a vibrating body, the control unit 12 may vibrate the driving unit 50 using an electrical signal, pressure fluctuation, acoustic signal, mechanical vibration, or the like.

  The control unit 12 controls the driving of the plurality of driving units 50 independently. That is, the control unit 12 controls the conveyance speed of the sheet S by the plurality of driving units 50 by changing the voltage or frequency of the driving power source that drives the plurality of driving units 50.

  The heat generating unit 13 is, for example, a ceramic heater, and is disposed inside the fixing unit 10 and holds the fixing unit 10 by pressing it against the conveying unit 11 side.

  A guide plate 5 is provided inside the fixing unit 10, and the guide plate 5 rotatably supports the fixing unit 10. Further, guide plates 6 are provided on the upstream side and the downstream side of the driving unit 50 in the conveyance direction of the sheet S, and the guide plate 6 smoothly conveys the sheet S.

  The control unit 12 is configured so that the conveyance speed at both ends in the width direction of the sheet S (the direction orthogonal to the conveyance direction of the sheet S) is faster than the conveyance speed at the center in the width direction of the sheet S. The drive of the some drive part 50 is controlled. That is, the conveyance speed of the sheet S by the driving units 50 and 50 at both ends is faster than the conveyance speed of the sheet S by the central driving unit 50. For example, the conveyance speed at both ends of the sheet S is set to be about 0.1 to 1% higher.

  In this way, by energizing the conveying speed at both ends of the sheet S faster than the conveying speed at the center of the sheet S, the sheet S is urged so as to spread in the direction orthogonal to the conveying direction of the sheet S. However, the sheet S can be guided to the nip formed by the contact between the fixing unit 10 and the driving unit 50, and the generation of wrinkles of the sheet S can be prevented.

  A setting unit 16 that sets a speed difference between the conveyance speed at both ends in the width direction of the sheet S and the conveyance speed at the center in the width direction of the sheet S is provided. Specifically, the setting unit 16 receives an input of the set value of the speed difference from the user, and inputs the set value to the control unit 12. The setting unit 16 includes, for example, an operation panel of an image forming apparatus including the fixing device.

  Thus, since the user can set the speed difference between the conveyance speeds at both ends and the center of the sheet S by the setting unit 16, the sheet can be set according to the type (material, thickness, etc.) of the sheet S. The speed difference between the conveying speeds at both ends and the center of S can be varied, and the application range is wide.

  The width dimension of the fixing unit 10, the heat generating unit 13, and the plurality of driving units 50 (the dimension in the depth direction from the front side of FIG. 1) is larger than the width dimension of the sheet S.

  Next, the operation of this fixing device will be described.

  The sheet S is fed into a nip formed by contact between the fixing unit 10 and the plurality of driving units 50. On the one surface of the sheet S, the unfixed toner t adheres.

  The fixing unit 10 is heated by the heat generating unit 13 and heated while pressing one surface of the sheet S at the nip portion to melt and fix the unfixed toner t.

  At the same time, the sheet S is transported by applying a transport force to the other surface of the sheet S by driving the plurality of driving units 50. The fixing unit 10 rotates following the conveyance of the sheet S.

  At this time, the plurality of driving units 50 are independently driven so that the conveyance speed at both ends of the sheet S is faster than the conveyance speed at the center of the sheet S. The sheet S is urged so as to spread in the direction orthogonal to the conveying direction.

  According to the fixing device having the above configuration, since the driving of the plurality of driving units 50 is independently controlled by the control unit 12, the conveyance speed of the sheet S is orthogonal to the conveyance direction of the sheet S. Speed difference can be given.

  Thus, the speed difference of the sheet S can be given without affecting the width dimension of the nip part and the pressure of the nip part, and without affecting the fixing quality. The posture of the sheet S when the sheet S passes through the nip portion can be controlled.

  Further, since the speed difference is given by the strong conveyance force at the nip portion, the passing posture of the sheet S can be positively controlled, and the loop amount necessary on the upstream side of the nip portion can be reduced.

  Therefore, it is possible to stabilize the passing posture of the sheet S in a small space, and to provide a fixing device with less occurrence of wrinkles and image defects due to the passing posture of the sheet S.

  Further, according to this fixing method, the plurality of driving units 50 are driven independently to convey the sheet S, so that the conveyance speed of the sheet S is set in a direction orthogonal to the conveyance direction of the sheet S. Can give speed difference. Thus, the passing posture of the sheet S can be stabilized, and wrinkles and image defects caused by the passing posture of the sheet S can be reduced. Further, since the conveying force is applied to the other surface of the sheet S by driving the driving unit 50, it is possible to prevent image rubbing.

(Second Embodiment)
FIG. 4 shows a second embodiment of the fixing device of the present invention. The difference from the first embodiment will be described. In the second embodiment, a detection unit 17 that detects the posture of the sheet S on the upstream side of the fixing unit 10 and the conveyance unit 11 is provided.

  The detection unit 17 is disposed between the fixing unit 10 and a secondary transfer unit 64 (described later). Three detection units 17 are provided in a direction orthogonal to the conveyance direction of the sheet S, and each detection unit 17 detects a slack amount (loop amount) formed on the sheet S being conveyed. The detection unit 17 may have any configuration as long as it can detect a difference in the loop amount of the sheet S in the width direction of the sheet S. For example, a plurality of distance sensors are integrated in a line shape. The configuration may be either a contact type sensor or a non-contact type sensor.

  In the present embodiment, since the control unit 12 controls the driving of each driving unit 50 based on the output of the detection unit 17, the posture of the sheet S passing through the nip portion can be further stabilized. Prevents wrinkles and image defects.

  Here, correction control for correcting the passing posture of the sheet S will be described so that the loop amount on one side of the sheet S does not become extremely large.

  The detection unit 17 detects the amount of slack at both ends in the width direction of the sheet S, and the control unit 12 equalizes the amount of slack at both ends in the width direction of the sheet S detected by the detection unit 17. Thus, the drive of each drive part 50 is controlled.

  Specifically, among the three detection units 17, those provided at positions corresponding to both end portions A and B of the sheet S are referred to as A detection unit 17 and B detection unit 17, respectively. The both ends A and B of the sheet S are detected by the A detector 17 and the B detector 17.

  Then, as shown in FIG. 5, the control is started with the sheet S entering the nip portion, and the loop amount of the end portion A detected by the A detection portion 17 and the B detection portion 17 are detected. A difference K from the loop amount at the end B is obtained.

  Here, when the speed is increased with respect to the reference conveyance speed, the loop amount decreases, but when the speed is decreased, the loop amount decreases. Therefore, when the end A side loop amount is large, the end A side speed is set to the loop. In proportion to the amount difference K, the speed is made KΔV faster than the reference speed, and the speed on the end B side is made KΔV slower than the reference speed.

  By repeating the above steps until the conveyance of the sheet S is completed, the passing posture of the sheet S can be controlled without being biased toward the loop amount at both ends of the sheet S.

  In this way, the control unit 12 controls the driving of each driving unit 50 so that the slack amounts at both ends of the sheet S are equal, so that the slack amounts at both ends of the sheet S are eliminated. Thus, the sheet S can be fixed, and image displacement can be prevented.

  Next, correction control for correcting the passing posture of the sheet S so as not to cause wrinkles in the sheet S will be described.

  First, the generation of wrinkles of the sheet S will be described. When the sheet S enters the nip portion with the central portion of the sheet S slack, the slackness of the sheet S is pressed at the nip portion. As a result, the sheet S is wrinkled. The slackness of the sheet S can be detected by the difference between the slack amount (loop amount) at the center of the sheet S and the slack amount (loop amount) at both ends of the sheet S. It can be determined that wrinkles occur when the amount of slack at both ends is extremely small.

  The detection unit 17 detects the amount of slack at both ends in the width direction of the sheet S and the amount of slack at the center in the width direction of the sheet S, and the control unit 12 is detected by the detection unit 17. The driving of each driving unit 50 is controlled so that the amount of slack at both ends in the width direction of the sheet S is substantially equal to the amount of slack at the center in the width direction of the sheet S.

  More specifically, if the three detection units 17 are an A detection unit 17, a B detection unit 17, and a C detection unit 17, respectively, both end portions A and B of the sheet S are set to the A detection unit 17 respectively. , B detection unit 17 detects the center C of the sheet S is detected by C detection unit 17.

  Then, as shown in FIG. 6, the control is started in a state where the sheet S enters the nip portion, and the loop amount of the end A detected by the A detection unit 17 and the detection by the B detection unit 17 are detected. The average value with the loop amount of the end B is obtained. A difference D between the average value of the both ends and the loop amount of the center C detected by the C detection unit 17 is obtained.

  When the loop amount at the center C is small, the speed at the center C is proportional to the difference D in the loop amount and is delayed by DΔV from the reference speed, and the speeds at both ends A and B are increased by DΔV from the reference speed. .

  By repeating the above steps until the conveyance of the sheet S is completed, the passing posture of the sheet S can be controlled so that unevenness does not occur in the center of the sheet S.

  Thus, the control unit 12 controls the driving of each driving unit 50 so that the amount of slack at both ends of the sheet S is substantially equal to the amount of slack at the center of the sheet S. The passing posture of the sheet S can be controlled so that no unevenness is generated in the central portion of the S, and the generation of wrinkles of the sheet S can be prevented.

(Third embodiment)
FIG. 7 shows a third embodiment of the fixing device of the present invention. The difference from the first embodiment will be described. In the third embodiment, the configuration of the transport unit is different.

  The transport unit 11 according to the third embodiment includes a vibrating body 51. The vibrating body 51 includes a base portion 51a and a plurality of vibrators 51b attached to the base portion 51a in a direction orthogonal to the conveyance direction of the sheet S (the axial direction of the fixing unit 10). The vibrator 51 has a comb shape in cross section.

  The sheet S is conveyed by the vibrations of the plurality of vibrators 51b. Each of the plurality of vibrators 51b vibrates independently. That is, the vibrator 51 b corresponds to the driving unit 50.

  The speed given to the plurality of vibrators 51b is obtained by the following expression (1) from a reference speed difference (KΔV or DΔV) (determined in FIG. 5 or FIG. 6).

V = Vs × X / L (1)
V indicates a speed difference given to each vibrator.
Vs indicates a reference speed difference.
X indicates the position of the vibrator (distance from the center between the vibrators at both ends).
L indicates half of the length between the vibrators at both ends.

  In this way, since a large number of minute vibrators 51b (drive unit 50) are arranged in a comb shape, the speed difference between the adjacent vibrators 51b and 51b becomes small, and the passing posture of the sheet S is smooth. And the image of the sheet S can be improved.

(Fourth embodiment)
FIG. 8 shows a fourth embodiment of the fixing device of the present invention. The difference from the third embodiment will be described. In the fourth embodiment, a plurality of vibrators 51b are arranged in a staggered manner in a direction orthogonal to the conveyance direction of the sheet S, and adjacent vibrators. The gap between 51b and 51b is made small.

  As described above, since the gap between the adjacent vibrators 51b and 51b is reduced, a sufficient pressing force can be applied to the sheet S, and the occurrence of uneven glossiness and uneven fixing strength can be prevented.

(Fifth embodiment)
FIG. 9 shows a simplified configuration diagram as an embodiment of the image forming apparatus of the present invention. The image forming apparatus includes an image forming device 66 that forms an image by attaching unfixed toner t to a sheet S, and the fixing device according to the first embodiment that melts the toner t and fixes it to the sheet S. 65. This image forming apparatus is an electrophotographic 4-color printer.

  The image forming device 66 includes a photoconductor 60, a charging device that performs a predetermined charging process (not shown) on the photoconductor 60, an exposure device 61 that irradiates the photoconductor 60 with laser light, and the photoconductor 60. A four-color developing device 62 for developing the toner image, an intermediate transfer belt 63 to which an image formed on the photoreceptor 60 is transferred, and an image transferred to the intermediate transfer belt 63 is transferred to the sheet S. A secondary transfer unit 64.

  The developing device 62 is provided with a cartridge having toners of Bk (black), C (cyan), M (magenta), and Y (yellow) in the clockwise direction.

  Next, the operation of this image forming apparatus will be described.

  A constant potential is formed on the surface of the photoreceptor 60 by a charging device (not shown). The surface of the photoreceptor 60 is irradiated with laser light by the exposure device 61 in accordance with the image pattern to be printed. At this time, the potential of the irradiated portion of the surface of the photoconductor 60 is attenuated, and an electrostatic image is formed on the surface of the photoconductor 60.

  In the developing device 62, the toner is in a pre-charged state, and the electrostatic attraction force between the toner and the surface of the photoconductor 60 is used in accordance with the electrostatic image on the surface of the photoconductor 60. Then, toner adheres to the photoreceptor 60.

  The toner adhering to the surface of the photoconductor 60 is transferred onto the intermediate transfer belt 63 by an electric field formed between the photoconductor 60 and the intermediate transfer belt 63. By repeating the above process for four colors, an image in which four color toners are superimposed is formed on the intermediate transfer belt 63.

  The toner image formed on the intermediate transfer belt 63 is transferred to the sheet S by using the electric field and pressure in the secondary transfer unit 64, and finally, by the heat and pressure in the fixing device 65. It is fixed on the sheet S.

  According to the image forming apparatus having the above configuration, since the fixing device 65 is provided, the image quality can be improved and the size can be reduced.

  In this image forming apparatus, as shown in the second embodiment (FIG. 4), the posture of the sheet S between the image forming device 66 (secondary transfer unit 64) and the fixing device 65 is set. You may provide the detection part 17 to detect.

  In this case, since the control unit 12 controls the driving of each driving unit 50 based on the output of the detection unit 17, the variation in the conveyance force of the fixing device 65 is a process upstream of the image forming device 66. It is possible to prevent the image from being transmitted to the image and to prevent image displacement. Note that the fixing device described in the third embodiment or the fourth embodiment may be used as the fixing device of the image forming apparatus.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the fixing unit 10 may be a fixing roller or a fixing sheet. The fixing sheet is configured such that both ends of the sheet main body are wound around rollers, and one end of the sheet main body is wound around one roller.

  The fixing unit 10 may be driven independently according to the conveyance of the sheet S. Further, the fixing unit 10 may be heated by electromagnetic induction by an IH heater.

  Moreover, a pressing force that approaches each other may be applied to at least one of the fixing unit 10 and the transport unit 11.

  The image forming apparatus may be any one of a monochrome / color copying machine, a printer, a FAX, and a complex machine of these.

  Further, the driving units 50 (the vibrators 51b) may be arranged in a line in a direction inclined in the conveyance direction of the sheet S, or arranged in a staggered manner in a direction inclined in the conveyance direction of the sheet S. They may be arranged in a direction crossing the transport direction of the sheet S.

  The “posture of the sheet S” detected by the detection unit 17 may be an inclination of the sheet S with respect to the transport direction of the sheet S.

  Further, the number of the drive units 50 is arbitrary as long as the conveyance speed of at least the center and both ends of the sheet S can be controlled independently. Moreover, you may arrange | position the press part which presses the said sheet | seat S between the adjacent drive parts 50 and 50. FIG.

1 is a simplified configuration diagram illustrating a first embodiment of a fixing device according to the present invention; It is sectional drawing of a fixing part. 1 is a perspective view showing a fixing device of the present invention. It is a simplified block diagram which shows 2nd Embodiment of the fixing device of this invention. It is a flowchart which correct | amends the deviation of the loop amount of a sheet | seat both ends. 6 is a flowchart for preventing sheet wrinkling. It is a perspective view which shows another conveyance part. It is a perspective view which shows another conveyance part. 1 is a simplified configuration diagram showing an image forming apparatus of the present invention. FIG. 10 is a simplified configuration diagram illustrating a conventional fixing device. FIG. 10 is a simplified configuration diagram illustrating another conventional fixing device. FIG. 10 is a simplified configuration diagram showing another conventional fixing device. It is a perspective view which shows the conventional sheet conveying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixing part 11 Conveying part 12 Control part 13 Heating part 16 Setting part 17 Detection part 50 Drive part 51 Vibrating body 51a Base part 51b Vibrator 60 Photoconductor 61 Exposure apparatus 62 Developing apparatus 63 Intermediate transfer belt 64 Secondary transfer part 65 Fixing device 66 Image forming device S sheet t toner

Claims (11)

A fixing unit that contacts one surface of the sheet;
The drive unit has a plurality of drive units that are in contact with the other surface of the sheet and sandwich the sheet together with the fixing unit, and are driven in an independent manner from each other. A conveying unit that conveys the sheet by driving;
And a control unit that independently controls the driving of the plurality of driving units. The fixing device according to claim 1,
The control unit drives the plurality of drive units so that the conveyance speed at both ends in the direction orthogonal to the sheet conveyance direction is faster than the conveyance speed at the center in the direction orthogonal to the sheet conveyance direction. A fixing device characterized by controlling. The fixing device according to claim 2,
A fixing device, comprising: a setting unit that sets a speed difference between a conveyance speed at both ends in a direction orthogonal to the sheet conveyance direction and a conveyance speed at a center in a direction orthogonal to the sheet conveyance direction. The fixing device according to claim 1,
A detection unit that detects the posture of the sheet on the upstream side in the sheet conveyance direction of the fixing unit and the conveyance unit;
The fixing unit controls the driving of the plurality of driving units based on the output of the detection unit. The fixing device according to claim 4.
The detection unit detects the amount of slack at both ends in the direction orthogonal to the conveyance direction of the sheet,
The control unit controls the driving of the plurality of driving units so that the slack amounts at both ends in the direction orthogonal to the sheet conveyance direction detected by the detection unit are equal to each other. . The fixing device according to claim 4.
The detection unit detects a slack amount at both ends in a direction orthogonal to the sheet conveyance direction, and a slack amount at a center portion in a direction orthogonal to the sheet conveyance direction,
In the control unit, the amount of looseness at both ends in the direction perpendicular to the sheet conveyance direction and the amount of looseness at the center in the direction orthogonal to the sheet conveyance direction detected by the detection unit are substantially equal. As described above, the fixing device controls the driving of the plurality of driving units. The fixing device according to claim 1,
The fixing device, wherein the fixing unit contacts a surface on which the image of the sheet is recorded. The fixing device according to claim 1,
A fixing device comprising: a heat generating unit that heats the sheet via the fixing unit. An image forming apparatus for forming an image by attaching unfixed toner to a sheet;
An image forming apparatus comprising: the fixing device according to claim 1, wherein the toner is melted and fixed to the sheet. The image forming apparatus according to claim 9.
A detection unit for detecting the posture of the sheet between the image forming device and the fixing device;
The image forming apparatus, wherein the control unit of the fixing device controls driving of the plurality of driving units of the fixing device based on an output of the detection unit.   The plurality of driving units arranged in a direction intersecting the sheet conveyance direction and the fixing unit sandwich the sheet, and independently drive the plurality of driving units to convey the sheet. A fixing method, wherein the sheet is heated by a fixing unit.

Images