JP2007015858A - Sheet conveyance device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet conveyance device capable of preventing a belt wrapped around between a plurality of conveyance rollers from being worn and damaged due to rubbing of members caused by its bias to one side and meandering during circulating running and having high reliability and to provide an image forming device. <P>SOLUTION: A belt control roller is displaced in the direction for correcting a running position of the endless belt using a support shaft in a central part as a fulcrum by friction force given to a belt abutting detection part by the belt when the belt runs biased to one side and meanders and is abutted on the belt abutting detection part in both end parts of the belt control roller to return the belt to a proper position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for guiding a belt, and more particularly to a belt guiding apparatus having a belt deviation prevention control mechanism. The present invention also relates to a belt driving device using a belt guide device provided with a belt deviation prevention control mechanism, a transport device using the belt guide device, and an image forming apparatus having the transport device.

  In the case of an image forming apparatus that outputs a color image, a belt driving device that drives an endless flat belt called an intermediate transfer belt is used. Before a toner image is carried on a plurality of photosensitive drums that are image bearing members of a plurality of colors and this toner image is transferred onto a sheet that is a recording paper, the toner image is temporarily transferred from the photosensitive drum to the surface of the intermediate transfer belt. An apparatus is known in which the transferred image is collectively transferred to a sheet.

  Conventionally, the belt driving device is also used in a sheet conveying device that conveys a sheet as a recording medium.

  12 and 13 show a conventional example of an image forming apparatus using a belt driving device as a sheet conveying device. In this case, the conveying belt 131 is stretched between the driven roller 132, the driving roller 134, and the belt adjusting roller 135 and rotates in the direction of the arrow. The belt adjusting roller 135 is a rotating roller that has a function of applying a predetermined tension to the conveyor belt 131 and is equipped for correcting belt meandering. The conveying belt 131 is provided with comb-like electrodes parallel to the belt width direction perpendicular to the conveying direction, and an intermediate resistance layer that generates an attractive force in the contact area with the sheet. . Furthermore, power feeding means 136 and static elimination means 137 are provided at both ends of the belt width of the conveyor belt 131, and an electrostatic attraction force is generated by applying a high voltage in contact with the comb-shaped electrodes. That is, the sheet is sucked onto the conveying belt 131 so as not to be shaken, and is fed to an appropriate position corresponding to the recording head 107 of the image forming unit. That is, if the sheet is misaligned on the belt, it causes image unevenness and the like, and the sheet is conveyed by being electrostatically adsorbed onto the transport belt 131 to prevent such misalignment.

  Further, in order to monitor the lateral movement of the conveyor belt 131, optical belt detection sensors 138 such as photo interrupters are installed at both ends of the belt width, and based on the detection signal from the belt detection sensor 138, as shown in FIG. The control device 156 controls the amount of belt deviation (meandering amount). The belt adjustment roller 135 is rotatably supported by a roller bearing 155, and the roller bearing 155 is changed by driving a motor 157. A drive signal for turning on and off the motor 157 is transmitted from the control device 156.

  In the case of this belt shift prevention control mechanism, as shown in FIG. 15, the front other end is rotated with the back one end of the belt adjustment roller 135 as a fulcrum, and the rotation axis C-C is set with respect to the conveying direction. It is designed to be displaced. When the belt adjustment roller 135 is not shaken and is parallel to the rotation axis of the other rollers, the conveying belt 131 moves from the point A0 to the point B0 in the drawing and shifts in the roller thrust direction (shift shift amount). Does not occur. When the rotation axis C-C of the belt adjustment roller 135 is deviated, the conveyor belt 131 moves from A1 to B1 to generate a shift amount ΔX1, or when moving from A2 to B2, a shift amount ΔX2 is generated. Then, the conveyor belt 131 is corrected and moved to the front side. The belt detection sensor 138 detects such a shift amount, and moves the belt adjustment roller 135 by the set shift amount by the control device 156, thereby appropriately correcting the running posture of the transport belt 131.

  By the way, when the conveyor belt 131 travels at a high speed, the speed at which the conveyor belt 131 moves is increased, which is likely to cause damage. FIGS. 14A and 14B show an example of a conventional structure proposed for such a problem. Detection members 140 are rotatably provided at both ends of the belt adjustment roller 135, and a gear 144 provided on the rotation axis is integrally formed so as to move in synchronization with the detection member 140. The belt adjustment roller 135 is supported by the support bracket 143. A rack gear 143 is provided on the support bracket 143, and the rack gear 143 is engaged with the gear 144 on the roller rotation axis. The support bracket 143 is attached to the frame via a tension spring 145 to apply tension to the belt, and applies a certain tension to the belt 131 by applying a spring force in the X direction.

In addition to this, there is also one disclosed in Patent Document 1 as a belt driving device having a function of correcting the meandering of the belt.
Japanese Patent Publication No. 6-99055

  However, in the case of such a conventional belt deviation prevention mechanism, there are the following problems to be solved. As shown in FIG. 14, when the rotational axis C-C of the belt adjustment roller 135 is angularly displaced and the deviation control of the intermediate transfer belt 131 is performed, the belt adjustment roller 135 receives a force in the thrust direction. Wear occurs due to the frictional force in the thrust direction between the adjusting roller 135 and the bearing.

  Therefore, an object of the present invention is to prevent the endless belt wound between a plurality of rollers from being worn or damaged by being rubbed against each other by being offset or meandering during rotation. It is in.

  In order to achieve the above object, a sheet conveying apparatus of the present invention is at least one of an endless belt that conveys a sheet of a recording medium and a plurality of rotating rollers that stretch the belt. The belt has run improperly, a belt control roller for correcting improper running due to side running and meandering, a roller support member that supports the rotation axis of the belt control roller with a variable angle at the center of the roller length, and a variable fulcrum. First and second belt contact detection units provided at both ends of the belt control roller so that the belt main body sometimes contacts and rubs, and the first belt contact detection unit and the second belt contact detection unit The belt control roller is configured to vary the rotation axis by angularly displacing the roller support member as a fulcrum due to a difference in frictional force between the belt contact detection unit and the belt main body.

  According to another aspect of the present invention, there is provided an image forming apparatus including the sheet conveying apparatus having the above-described configuration, and an image forming unit configured to record an image on a sheet conveyed from the sheet conveying apparatus. To do.

  According to the present invention, it is possible to correct the belt body that travels illegally so as to travel back to the appropriate position. Thereby, it is possible to prevent wear due to friction between members such as the belt main body and the roller bearing.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a sheet conveying apparatus and an image forming apparatus according to the invention will be described in detail with reference to the drawings. As specific examples of the image forming apparatus that can remarkably reflect the gist of the present invention, each embodiment of an ink jet recording apparatus and a sheet conveying apparatus installed therein will be described.

  As shown in FIG. 1, a sheet conveying apparatus including a sheet feeding unit 2, a conveying belt 3 and a sheet discharging unit 4 is provided inside the main body of the inkjet recording apparatus 1. A color image is formed on a sheet P, which is a recording medium conveyed by the conveying belt 3, by a recording head 7 as recording means. In this case, an example in which the sheet conveying device further includes a manual sheet feeding device in addition to the automatic sheet feeding device including the above-described members and devices is shown.

  The sheet feeding unit 2 is provided with a pressure plate 21 for storing a bundle of sheets P inside the cassette body 23, and a sheet feeding roller for picking up the sheets P with rotational friction and feeding them one by one out of the cassette. A shaft 22 is rotatably supported. The pressure plate 21 is pivotally supported by the cassette body 23 via a rotation spindle at the rear end portion in the sheet feeding direction. A pressure plate spring 24 mounted on the back side of the thick plate 21 urges the uppermost sheet P in a direction to press the sheet feeding roller 22. In addition, a separation pad made of a material having a high coefficient of friction such as an artificial skin is provided at a portion of the pressure plate 21 facing the sheet feeding roller 22 in order to prevent so-called multi-feeding in which several sheets P are overlapped and conveyed at a time. Is provided.

  Further, the cassette body 23 covers a corner in one direction of the sheet P, a separation claw for separating the sheets P one by one, and a release cam for releasing the contact between the pressure plate 21 and the paper feed roller 22 (both are (Not shown) is provided. In the standby state, the release cam pushes down the pressure plate 21 to a predetermined position, and the pressure plate 21 is separated to a position where it does not contact the paper feed roller 22. In this state, the driving force from the driving roller 34 is transmitted to the paper feeding roller 22 and the release cam via a gear or the like. As a result, when the release cam moves away from the pressure plate 21, the pressure plate 21 rises, the paper feed roller 22 and the sheet P come into contact with each other, and the paper feed roller 2 rotates to pick up the uppermost sheet P and start feeding. Then, the sheets P are separated one by one by the separation claw and conveyed to the conveyance belt 3. The sheet feeding roller 22 rotates until the sheet P is fed to the conveyance belt 3, and the sheet P is separated from the sheet feeding roller 22 again, and the driving force from the driving roller 34 is turned off. The paper feed roller 90 provided in the manual paper feed device feeds the sheet P set on the manual feed tray 91 in accordance with a recording command signal, and transports the sheet P to the transport belt 3.

  The sheet P conveyed from the sheet feeding unit 2 stops in a state in which a tip is brought into contact with a nip portion of a pair of registration rollers 44 positioned in front of the conveyance belt 3 to form a fixed loop shape, and is skewed. Is corrected. When the registration roller 44 is rotated by a print start instruction signal output from a main control device (not shown) built in the apparatus main body, the sheet P is sent to the conveyance belt 3.

  Further, the platen 30 supports the belt body 31 of the conveyor belt 3 from the inside and holds it flat to restrict downward displacement. The platen 30 is a member that assists the sheet P on the belt body 31 to be fed to an appropriate position corresponding to each color recording head 7 (Y, M, C, K) of the image recording unit (image forming unit). Further, at a position facing the driven roller 32, a suction roller 33 that is driven and rotated by the belt main body 31 is provided in contact with the belt main body 31. The suction roller 33 is pressed against the belt main body 31 by a spring (not shown) to guide the sheet P to the recording head unit. Further, an upper guide 27 and a lower guide 28 for guiding the sheet P to the registration roller 44 are provided on the upstream side of the conveyance belt 3. A recording head 7 is provided on the downstream side of the driven roller 32 in the recording paper conveyance direction as recording means for recording an image based on image information.

  The sheet P sent out by the registration roller 44 is conveyed by the driven roller 32 and the suction roller 33. At that time, the recording position on the sheet P can be calculated by detecting the leading edge of the conveyed sheet P with a PE sensor lever (not shown).

  As the recording head 7, a line type ink jet recording head in which a plurality of nozzles are arranged in a direction orthogonal to the conveyance direction of the sheet P is used. The recording heads for each color are arranged at predetermined intervals in the order of 7K (black), 7C (cyan), 7M (magenta), and 7Y (yellow) from the upstream side in the conveyance direction of the sheet P. Each of the recording heads 7K, 7C, 7M, and 7Y is attached to the head holder 7A. These recording heads heat the ink with a heater to cause film boiling, and ink is ejected from the nozzles of the recording head due to pressure changes caused by bubble growth or contraction due to film boiling to form an image on the sheet P. The recording head 7 can set the distance (between sheets) between the nozzle surface and the sheet P during the recording operation. The recording head 7 rises when stopped, and the cap 8 slides to cap the nozzle surface of the recording head 7 to prevent ink sticking.

  The paper discharge unit 4 includes a paper discharge roller 41 and a spur 42, and the sheet P on which an image has been recorded by the recording head 7 is conveyed between the paper discharge roller 41 and the spur 42 and is transferred to the paper discharge tray 43. And discharged. The paper discharge roller 41 is driven by rotation from the drive roller 34 via the transmission means. Since the spur 42 rolls on the printing surface after recording, the contact area with the sheet P is small, and even if the spur 42 contacts the printing surface after recording, the recorded image on the sheet P is not disturbed by blurring. It is.

  As shown in FIGS. 2 and 3, the conveyance belt 3 has an endless belt main body 31 that adsorbs and conveys the sheet P on the upper surface, and the belt main body 31 includes a driven roller 32, a drive roller 34, and a belt control roller 35. These are wound around a plurality of rollers and rotated by receiving rotational power from the driving roller 34. The driven roller 32 and the driving roller 34 are rotatably supported on the apparatus frame 39.

  The belt control roller 35 is a main member of the belt traveling adjustment mechanism that is the gist of the present invention, and has a tension roller function that rotates while being in contact with the belt main body 35 and applies an appropriate tension to the belt main body 31. At the same time, the belt control roller 35 has a function of correcting an improper traveling such as a deviation traveling or a meandering traveling of the belt main body 31. Both ends of the belt control roller 35 are rotatably supported by a control roller frame 71 as a support member provided on the apparatus frame 39 so as to be swingable.

  5 (a) to 5 (c), cylindrical first and second belt contact detection portions 70a and 70b are rotated as friction members on the side of the belt control roller 35 at both ends of the control roller frame 71. It is immovable. The belt control roller 35 is rotatably supported by the control roller frame 71 via the belt contact detection units 70a and 70b. The belt control roller 35 is rotated by being driven by the belt body 31 rotating. The belt contact detection portions 70a and 70b have a cylindrical shape with the same curvature as a roller that contacts the belt main body 31 and generates a frictional force. One of the contact detection units 70a and 70b is brought into contact. The area of the surface of the belt contact detection unit 70a, 70b that can contact the belt main body 31 is sufficient to generate a force necessary for moving the belt control roller 35 for the deviation control of the belt main body 31 described later. The coefficient of friction is In the present embodiment, the belt control roller 35 is formed of wear-resistant rubber, and the friction coefficient k with the belt body 31 is 0.2 to 0.5.

  Further, as shown in FIG. 5C, the shaft 35a at the end of the belt control roller 35 protruding outward from the belt contact detection portions 70a and 70b is rotatably supported by a bearing formed on the movable piece 35b. Has been. The movable piece 35b is supported so as to be movable in the arrow B direction along a bifurcated guide portion provided at both ends of the control roller frame 71. The spring 72 urges the movable piece 35B in the direction of arrow B to apply tension (1.0 kgf to 15 kgf (9.8 N to 147 N)) to the belt body 31. In the present embodiment, stable high-precision conveyance is realized by applying a tension of 4.0 kgf (39.2 N). The control roller frame 71 is provided with a support shaft 73 at the center portion of the roller width in the thrust direction of the belt control roller 35 (the center portion in the longitudinal direction of the belt control roller 35). The support shaft 73 is rotatably supported by a bearing provided on the bracket 74 so as to support the belt control roller 35 with a variable angle. The control roller frame 71 is rotatable about the support shaft 73 as a rotation center. The distance from the rotation center of the control roller frame 71 to one end of the belt control roller 35 is equal to the distance from the rotation center of the control roller frame 71 to the other end of the belt control roller 35. A shaft 73 is arranged. The belt contact detection units 70 a and 70 b can rotate integrally with the control roller frame 71. The bracket 74 is attached to the device frame 39. The belt control roller 35 can swing in the directions indicated by reference numerals X1 and X2 in FIG. The first and second contact detectors 70 a and 70 b are arranged at an equal distance from the axis of the support shaft 73.

  Further, compression springs 75 as urging means are attached to both ends of the control roller frame 71 between the frame 39 and the rotation axis of the belt control roller 35 is parallel to the rotation axes of the driving roller 34 and the driven roller 32. It is energized in the direction to return to the steady position (return position). The compression spring 75 adjusts the magnitude of the frictional force generated in the belt contact detection units 70a and 70b necessary for moving the belt control roller 35 in meandering control to be described later. Even if the compression spring 75 is not particularly arranged, there is no problem in meandering control.

  Each figure shows a structure example in which the winding angle of the belt main body 31 is in contact with the belt control roller 35 at about 180 °. However, the present invention is not limited to such a wrapping angle, and there is no difference in control theory even when the wrapping angle is about 90 ° as shown in FIGS. 10 (a) and 10 (b). However, because the generated frictional force is different, adjustment of the friction coefficient is necessary.

  As shown in FIGS. 7A to 7C and FIGS. 8A to 8C, when the belt winding angle is 180 °, the tension t of 4 kgf (39.2 N) is, for example, about 350 mm by the tension spring 72. The belt body 31 is provided. In this case, force N acting on the side that comes into contact with the belt control roller 35 is equal at any position because it is circular, resulting N = t. When the belt main body 31 is driven and moved in this state, the belt control roller 35 rotates following the belt main body 31. Since the belt contact detection units 70a and 70b are fixed so as not to rotate by forming the same surface as the belt control roller 35, a frictional force is generated by friction with the moving belt body 31. The frictional force is expressed as f1 = μN1 when the friction coefficient between the belt back surface and the contact surface of the belt contact detection unit 70a, 70b is μ, and the frictional force is generated in the tangential traveling direction at the contact point. Since the belt contact detection units 70 a and 70 b are attached to both ends of the control roller frame 71 that can rotate around the support shaft 73, the belt contact detection units 70 a and 70 b can move on a rotation plane orthogonal to the shaft 73. By integrating the rotational plane direction component of the frictional force generated at the contact point of the belt contact detection unit in the contact range, a force F for shifting the belt control roller 35 is obtained.

  By using a ball bearing as the bearing 74 of the support shaft 73, a frictional force generated in the belt contact detection portion by the control roller frame 71 that supports the belt main body 31 having a width of 350 mm stretched with a tension of 4 kgf (39.2 N). It is possible to control with a force F of 10 gf (98 N) which is a component of the rotation plane direction. Since the required moving force F varies depending on the tension, the resistance force by the bearing, the belt width, etc., it is important to optimize the frictional force in the belt contact detection unit 70. Considering durability and the like, it is advantageous that the frictional force at the belt contact detection unit 70 is small. Therefore, it is desirable to make the force F necessary for movement as small as possible.

  The case where the effective width L of the belt main body 31 is set to be equal to or less than the length Lμ of the belt control roller 35 as shown in FIG. When the belt does not meander, the belt travels at a predetermined position where the belt does not contact the belt contact detection portions 70a and 70b at both ends of the belt control roller 35, so that no frictional force is generated. On the other hand, when meandering occurs, as shown in FIG. 9B, when the belt main body 31 is displaced from the predetermined position in the left direction in the figure, the belt control roller 35 comes into contact with the detection unit 70a and The belt contact detection unit 70 a receives a frictional force Fa in the traveling direction of the belt body 31 from the belt body 31. The frictional force Fa causes a moment to rotate the belt control roller 35 in the clockwise direction with the central portion corresponding to the support shaft 73 as a fulcrum. When the rotation axis (rotation axis direction) of the belt control roller 35 is angularly displaced clockwise by an angle corresponding to the frictional force Fa, the belt body 31 guided by the belt control roller 35 moves rightward to correct the bias. Is done. When the belt body 31 is biased to the right, the belt contact detection unit 70b on the right side receives the frictional force Fb in the traveling direction of the belt body 31 from the belt body 31. The belt control roller 35 rotates counterclockwise by the frictional force Fb, and the belt main body 31 moves to the left to correct the bias.

  In the embodiment shown in FIG. 7B, the distance Lμ between the effective width L of the belt body 31 and the belt contact detection portions 70a and 70b at both ends of the roller is L ≧ Lμ. When L> Lμ, when the belt does not meander and the belt main body 31 is traveling at a predetermined position, the belt main body 31 comes into contact with each roller at an appropriate position and is in an appropriate position. Because of the relationship, both the belt contact detection units 70 a and 70 b receive the frictional force from the belt main body 31. When the belt main body 31 is traveling at a predetermined position, the difference between the frictional forces received by the belt contact detection units 70a and 70b becomes zero. When the belt body 31 is biased to one side, the contact area of the belt contact detection unit 70 on the biased side increases with the belt body 31, and the frictional force received from the belt body 31 increases in proportion to the shifted distance. On the contrary, the belt contact detection unit 70 on the opposite side has a reduced contact area with the belt body 31, and the frictional force received decreases. As a result, a difference is generated in the frictional force acting on the left and right belt contact detection units 70a and 70b, so that a moment for rotating the control roller frame 17 in a direction to return the bias of the belt main body 31 is generated. FIG. 7C shows a characteristic diagram of the deviation amount of the belt main body 31 and the force F for rotating the control roller frame 17. The inclination of the graph in the characteristic diagram of FIG. 7C varies depending on the frictional force generated between the back surface of the belt main body 31 and the belt contact detection units 70a and 70b.

  As described above, in the meandering control according to the present embodiment, at least one of the belt contact detection units 70 a and 70 b receives a frictional force from the belt body 31 when the position of the belt body 31 is shifted. Then, a force having a magnitude corresponding to the amount of deviation of the position of the belt main body 31 is applied to the belt contact detection unit 70a or 70b to change the axial direction of the belt control roller 35 to correct the deviation of the belt main body 31. can do. Further, when the endurance friction force of the belt main body 31 and the belt contact detection portions 70a and 70b is reduced, the linear inclination of the characteristic diagram is reduced. Therefore, control is not performed unless a force greater than the rotational resistance force of the support shaft 73 is obtained. The impossible area expands. It is possible to cope with this by setting the distance distance Lμ between the belt contact detection units 70a and 70b in anticipation of this.

  Here, with reference to FIG. 11, the behavior at the time of meander correction is reconfirmed. In FIG. 11, reference numeral 35 denotes a belt control roller, and the belt main body moves on the front side with respect to the paper surface of the belt control roller 35.

  In the belt control roller 35 when no meandering occurs, the belt main body contacts the belt control roller 35 at the point A0 and is driven to move away from the point B0. In this case, the force for moving the belt main body in the direction perpendicular to the conveying direction does not act.

  When the belt main body is shifted to the left side, as shown in FIG. 9B, the belt main body 31 travels while sliding on the surface of the belt contact detection unit 70a. Then, the frictional force Fa acts on the belt contact detection unit 70a from the belt main body 31, and the belt control roller 35 moves to the position 35A in FIG. As a result, one point of the belt main body 31 that contacts the belt control roller 35 at point A1 in FIG. 11 is separated from the belt control roller 35 at point B1. At this time, if no slip in the thrust direction occurs, the belt body 31 is moved in the direction perpendicular to the transport direction by the distance L1 in the right direction. Therefore, the deviation of the belt body in the left direction is corrected.

  On the contrary, when the belt body is shifted to the right, the friction force Fb acts on the belt contact detection unit 70b from the belt body 31, and the belt control roller 35 moves to the position 35B in FIG. One point of the belt main body 31 that contacts the belt control roller 35 at point B2 in FIG. 11 is separated from the belt control roller 35 at point B2. Therefore, the belt main body 31 moves to the left by the distance L2, and the right side deviation of the belt main body 31 is corrected.

  Thus, even when the belt body 31 meanders, it can always be returned to the normal position.

  That is, by using the frictional force generated in one of the belt contact detection units 70a and 70b provided at both ends of the belt control roller 35, or the difference in frictional force generated in both, control is performed with a minute difference in frictional force. It becomes possible. The deviation of the intermediate transfer belt 3 is always monitored, and stable transfer of the transfer material sheet P can be realized by the stable rotation of the belt main body 31.

  Here, a partial cross section of the belt main body 31 is shown in FIG. The belt body 31 that rotates while adsorbing and holding the sheet P has electrodes 60a and 60b made of conductive metal arranged in a pattern so as to generate a strong electrostatic attraction force as an attraction force generating means. It is protected by a laminated structure 61. The base layer 62 is formed of a polymer synthetic resin such as polyethylene, polycarbonate, and polyimide, and the surface layer 61 is formed of an endless belt shape using a synthetic resin such as a fluororesin that can be controlled in resistance to generate an optimum electrostatic force. These layers are joined by an adhesive or an adhesive means such as heat welding. As shown in the figure, a plurality of electrodes 60a and 60b form a comb-like pattern, and a plurality of electrodes 60a and 60b are installed on the belt main body 31 so as to face each other in a direction orthogonal to the belt conveying direction. At both ends of the belt main body 31, the surface layer 61 is removed so that a high voltage can be applied to the electrodes 60a and 60b from the power supply brush 36, and the electrodes 60a and 60b are exposed.

  The base layer 62 constituting the belt main body 31 is manufactured by winding a same sheet (20 μm) made of a thermoplastic resin and a thermosetting resin a plurality of times (five times), and heat-welding to manufacture a belt having a thickness of 100 μm. Yes. A belt is completed by wrapping a thermosetting surface layer material on the outside of the laminate and heat-sealing it. In this step, the electrodes 60 are formed on the sheet so as to be disposed at predetermined positions in the form of the base layer sheet, so that each is disposed at a predetermined thickness position of the belt. In arranging, conductive printing may be performed, or conductive resin may be arranged and thermally welded at the same time. By adopting such a laminated structure, uniformization as a belt after molding is promoted, and stable accuracy is ensured.

  By applying a voltage of about 0.5 kV to 10 kV to the power supply brush 36 joined to the belt main body 31, an adsorption force is generated in the belt main body 31 at a recording position below each recording head 7. The power supply brush 36 is connected to a high voltage power source (not shown) that generates a predetermined high voltage. At the time of paper discharge, the electrode 60 is neutralized by the static elimination brush 37, loses the attraction force, and is separated and sent to the paper discharge unit 4.

  The present invention is not limited to the above-described embodiment, and other embodiments and application examples and modifications of each embodiment are possible as long as they do not depart from the gist of the present invention.

1 is a cross-sectional view illustrating an ink jet recording apparatus that is an embodiment of an image forming apparatus according to the present invention. FIG. 3 is a perspective view illustrating a conveyance belt provided in the sheet conveyance apparatus of the embodiment. FIG. 3 is a cross-sectional view showing the engagement between the conveyance belt and the image forming unit according to the present embodiment. The same figure (a), (b) is sectional drawing of the conveyance belt of this embodiment. FIGS. 3A to 3C are a front view, a plan view, and a side view of the belt control roller of the present embodiment. The side view which shows typically operation | movement of the belt control roller of this embodiment. FIGS. 4A to 4C are a front view, a plan view, and a characteristic diagram of the belt control roller of the present embodiment. The same figure (a)-(c) is the operation | movement schematic of meander control in this embodiment. The same figure (a), (b) is the front view and top view of a belt control roller of this embodiment. The figure which shows embodiment in case a belt winding angle is about 90 degrees. The figure which shows belt meandering typically. FIG. 10 is a perspective view showing a conventional intermediate transfer belt and a belt control roller. FIG. 10 is a cross-sectional view showing a connection between an intermediate transfer belt and an image forming unit of a conventional example. (A), (b) is the front view and side view which show the belt shift | offset | difference prevention mechanism of the other conventional example. The figure which shows operation | movement of the belt adjustment roller of the conventional belt deviation prevention control mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 7 Recording head 31 Belt main body 35 Belt control roller 70a Belt contact detection part 70b Belt contact detection part 73 Support shaft (roller support member)
74 Bearing (roller support member)

Claims (16)

An endless belt for conveying a sheet of recording medium;
A belt control roller that is at least one of a plurality of rotating rollers that stretch the belt, and that corrects improper running due to the running and meandering of the belt;
A roller support member that supports the rotation axis of the belt control roller with a variable angle and a central portion of the roller length as a fulcrum;
First and second belt contact detection units provided at both ends of the belt control roller so that the belt main body contacts and rubs when the flat belt travels improperly,
Due to the difference in frictional force between the belt main body of the first belt contact detection unit and the second belt contact detection unit, the belt control roller fluctuates with the roller support member as a fulcrum, and the rotation axis is angularly displaced. A sheet conveying apparatus characterized in that the sheet conveying apparatus is configured to allow the sheet conveying apparatus.   The sheet conveying apparatus according to claim 1, wherein the first and second belt contact detection units are arranged at an equal distance from the roller support member.   3. The sheet conveying apparatus according to claim 1, further comprising an urging unit that urges the rotation axis of the belt control roller toward a steady position parallel to the rotation axis of each of the plurality of rotation rollers. 4. .   An image, comprising: the sheet conveying apparatus according to claim 1; and an image forming unit that records an image on a sheet conveyed from the sheet conveying apparatus. Forming equipment. A roller that rotates following contact with the moving belt;
A support member for rotatably supporting the roller; and a support means for rotatably supporting the support member so that the roller can change a rotation axis direction;
A first friction member provided so as to rotate integrally with the support member, and receiving a large frictional force from the belt as the belt shifts from the predetermined position to the first side;
The second member is provided so as to rotate integrally with the support member, and receives a large frictional force from the belt as the belt shifts from a predetermined position to a second side opposite to the first side. Friction members of
In order to change the direction of the rotation shaft of the roller so as to correct the deviation of the belt, the support member is rotated by a frictional force received from the belt by at least one of the first friction member and the second friction member. A belt guide device characterized by that.   The belt guide device according to claim 5, wherein the first and second friction members are fixed to the support member so as not to rotate.   6. The belt guide device according to claim 5, wherein the first friction member has a larger area in contact with the belt as the belt is displaced from the predetermined position toward the first side.   6. The belt guiding apparatus according to claim 5, wherein the second friction member has a larger area in contact with the belt as the belt is displaced from the predetermined position toward the second side.   The belt guide device according to claim 5, wherein the first and second friction members are arranged on a side of the roller.   The belt guide device according to claim 5, wherein a distance from a rotation center of the support member to both ends of the roller is equal.   The belt according to claim 5, wherein a distance from a rotation center of the support member to the first friction member is equal to a distance from the rotation center of the support member to the second friction member. Guide device.   The belt guide device according to claim 5, wherein a distance from the first friction member to the second friction member is larger than a width of the belt.   The belt guide device according to claim 5, wherein a distance from the first friction member to the second friction member is equal to or less than a width of the belt. A belt for conveying a recording medium;
A plurality of rollers for supporting the belt;
A control roller that is driven and rotated while in contact with the moving belt;
A support member for rotatably supporting the control roller;
Support means for rotatably supporting the support member so that the control roller can change the rotation axis direction;
A first friction member provided so as to rotate integrally with the support member, and receiving a large frictional force from the belt as the belt shifts from the predetermined position to the first side;
The second member is provided so as to rotate integrally with the support member, and receives a large frictional force from the belt as the belt shifts from a predetermined position to a second side opposite to the first side. Friction members of
In order to change the direction of the rotation shaft of the control roller so as to correct the deviation of the belt, the support member is rotated by the frictional force that at least one of the first friction member and the second friction member receives from the belt. A recording medium conveying apparatus. A belt for conveying a recording medium;
A plurality of rollers for supporting the belt;
Recording means for recording an image on a recording medium conveyed by the belt;
A control roller that is driven and rotated while in contact with the moving belt;
A support member for rotatably supporting the control roller;
Support means for rotatably supporting the support member so that the control roller can change the rotation axis direction;
A first friction member provided so as to rotate integrally with the support member, and receiving a large frictional force from the belt as the belt shifts from the predetermined position to the first side;
The second member is provided so as to rotate integrally with the support member, and receives a large frictional force from the belt as the belt shifts from a predetermined position to a second side opposite to the first side. Friction members of
In order to change the direction of the rotation shaft of the control roller so as to correct the deviation of the belt, the support member is rotated by the frictional force that at least one of the first friction member and the second friction member receives from the belt. An image forming apparatus. A drive roller that drives the belt to move;
A roller that rotates following contact with the moving belt;
A support member for rotatably supporting the roller; and a support means for rotatably supporting the support member so that the roller can change a rotation axis direction;
A first friction member provided so as to rotate integrally with the support member, and receiving a large frictional force from the belt as the belt shifts from the predetermined position to the first side;
The second member is provided so as to rotate integrally with the support member, and receives a large frictional force from the belt as the belt shifts from a predetermined position to a second side opposite to the first side. Friction members of
In order to change the direction of the rotation shaft of the roller so as to correct the deviation of the belt, the support member is rotated by a frictional force received from the belt by at least one of the first friction member and the second friction member. A belt drive device characterized by that.

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