JP2009173420A - Belt conveying device and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt conveying device capable of correcting a skew during delivery without abutting a tip of a recording medium to be delivered regardless of thickness of a recording medium and a degree of the skew, and a recording device. <P>SOLUTION: This belt conveying device has a shrinkable conveyor belt 2 extended on a plurality of conveyor rollers, and loads and conveys a sheet-like recording medium P on a top face of the conveyor belt 2. The means comprises pressing rollers 10A, 10B provided to press a vicinity of a width end of the recording medium toward the conveyor belt 2 from a top face; skew detection means 13A, 13B for detecting a skew by detecting an inclining degree of an end of a recording medium P; and control means for correcting the skew of the recording medium P while the recording medium P is conveyed by pressing a vicinity of one width end of the recording medium P with the pressing rollers 10A, 10B according to a skew direction, when the skew of the recording medium P is detected by the skew detection means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a belt conveyance device and a recording device, and more particularly to a belt conveyance device capable of correcting skew of a recording medium supplied on a conveyance belt during conveyance and a recording device including the belt conveyance device.

  As a recording apparatus including a belt conveyance device that conveys a recording medium by a conveyance belt, for example, an ink jet printer that performs recording by ejecting ink droplets from a recording head and landing on a recording medium conveyed on the conveyance belt, An image forming apparatus that forms a toner image or an exposure image by light exposure on a recording medium is known.

  In such a recording apparatus, if the recording medium is placed on the upper surface of the conveying belt obliquely with respect to the conveying direction, the recording medium is conveyed while being skewed, and an image is recorded obliquely with respect to the recording medium. Therefore, there is a problem that the recording quality is impaired.

Conventionally, in Patent Document 1, a gate member that is rotatably supported in the vicinity of a position where the recording medium first contacts the conveyance belt is a first position that prevents the recording medium from passing and a first position that allows the passage. A technique has been proposed in which skew feeding correction is performed by being provided so as to be movable to the position 2 and abutting the leading end of the recording medium against the gate member at the first position.
JP 2007-238199 A

  When skew correction is performed by abutting the leading edge of the recording medium as in the technique described in Patent Document 1, skew correction can be performed when the skew of the recording medium is relatively small. However, when the skew of the recording medium increases, the corner of the recording medium that skews against the gate member comes into contact with the gate member. Therefore, the recording medium is easily buckled from the corner, and skew correction is effective. In addition to disappearing, there are problems that cause damage to the recording medium and occurrence of JAM.

  Further, since the skew is corrected by abutting the leading edge of the recording medium to be conveyed, if the recording medium itself is not somewhat stiff, the middle portion of the recording medium is bent by the conveying force when the leading edge abuts. However, the recording medium may become wrinkled, which may cause damage to the recording medium and occurrence of JAM. Therefore, there is a problem that skew correction cannot be performed when a thin recording medium having no stiffness is used as the recording medium itself.

  Therefore, the present invention includes a belt conveyance device capable of correcting skew feeding in the middle of conveyance without hitting the leading end of the conveyed recording medium regardless of the thickness of the recording medium and the degree of skew, and the belt conveyance device including the belt conveyance device. It is an object to provide a recording device.

  The other subject of this invention becomes clear by the following description.

  The above problems are solved by the following inventions.

  The invention according to claim 1 is a belt conveying apparatus having an extendable and contractible conveying belt stretched around a plurality of conveying rollers, and carrying and transporting a sheet-like recording medium on the upper surface of the conveying belt. A pressing roller provided so as to be able to press the vicinity of the width direction end of the medium from its upper surface toward the conveying belt, and a skew detection means for detecting skew by detecting the inclination of the end of the recording medium. If the skew of the recording medium is detected by the skew detection means, the pressing roller presses the vicinity of one end in the width direction of the recording medium according to the direction of the skew. Thus, the belt conveying apparatus includes a control unit that corrects the skew of the recording medium during the conveyance of the recording medium.

  According to a second aspect of the present invention, the pressing roller is disposed at an interval in the width direction of the conveying belt, and the vicinity of the end in the width direction of the recording medium conveyed by the belt conveying unit is conveyed from the upper surface thereof. 2. The belt conveying device according to claim 1, comprising two pressing rollers provided so as to be independently pressed toward the belt.

  The invention according to claim 3 is characterized in that the pressing roller is composed of a single pressing roller that is movable along the width direction of the conveying belt and is capable of being pressed toward the conveying belt. 1. The belt device according to 1.

  According to a fourth aspect of the present invention, the skew detection means is disposed on the downstream side of the pressing roller, and the control means detects the inclination of the leading edge of the recording medium detected by the skew detection means. When the skew is detected, the conveyance belt is rotated in the reverse direction so that the leading edge of the recording medium is once fed back to the upstream side of the pressure roller, and then the conveyance belt is rotated in the normal direction again to 4. The belt conveyance according to claim 1, wherein the skew of the recording medium is corrected by operating a roller, and the inclination of the leading end of the recording medium is detected again by the skew detection means. Device.

  According to a fifth aspect of the present invention, the skew detection means is disposed upstream of the pressing roller, and the control means is configured to determine the inclination of the leading edge of the recording medium detected by the skew detection means. When the skew is detected, the pressing roller is operated to correct the skew of the recording medium, and then the conveying belt is rotated in the reverse direction so that the leading edge of the recording medium is positioned more than the skew detecting means. 4. The head of the recording medium according to claim 1, wherein the belt is once rotated backward to the upstream side, and then the conveyor belt is rotated forward again to detect the inclination of the leading edge of the recording medium by the skew detection means. This is a belt conveying device.

  According to a sixth aspect of the present invention, the skew detection means is disposed on the upstream side of the pressing roller, and the control means detects the inclination of the leading edge of the recording medium detected by the skew detection means. When the skew is detected from the head, the pressure roller is operated to correct the skew of the recording medium, and then the skew detecting means detects the inclination of the trailing edge of the recording medium. The belt conveying device according to claim 1, 2 or 3.

  According to a seventh aspect of the present invention, the skew detection means is disposed on the upstream side of the recording means and on the upstream side and the downstream side of the pressing roller, and the control means is configured by the pressing roller. When the skew is detected from the inclination of the leading edge of the recording medium detected by the upstream skew detection means, the pressing roller is operated to correct the skew of the recording medium, and 4. The belt conveying device according to claim 1, wherein the inclination detecting means on the downstream side of the pressing roller redetects the inclination of the leading edge of the recording medium.

  According to an eighth aspect of the present invention, the skew detection means includes an end detection means for transmitting a detection signal to the control means when detecting an end of the recording medium, along the width direction of the conveyance belt. The control unit detects a skew amount of the recording medium based on a time difference between detection signals from the plurality of edge detection units, and the control unit detects the skew amount of the recording medium according to the skew amount. The belt conveying device according to claim 1, wherein the pressing roller controls a pressing force that presses the upper surface of the recording medium toward the conveying belt.

  A ninth aspect of the present invention includes slip imparting means for imparting slip between the recording medium on the upstream side of the pressing roller and the conveyor belt, and the control means operates the pressing roller to perform the recording. The belt conveying device according to any one of claims 1 to 8, wherein the slip imparting means is operated when correcting the skew of the medium.

  According to a tenth aspect of the present invention, the conveying belt has a plurality of through holes extending in the length direction, and the slip-applying means is provided on the back side of the recording medium mounting surface of the conveying belt. The belt conveying device according to claim 9, comprising a blower, and means for blowing the wind force on the blowing side of the fan blower from the through hole on the upstream side of the pressing roller.

  An eleventh aspect of the invention includes the belt conveyance device according to any one of the first to tenth aspects, and a recording unit that performs recording on the recording medium conveyed by the belt conveyance device. It is a recording device.

  According to the present invention, there is provided a belt conveyance device capable of correcting skew feeding in the middle of conveyance without hitting the leading end of the conveyed recording medium regardless of the thickness of the recording medium and the degree of skew, and the belt conveyance device including the belt conveyance device. A recording apparatus can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view showing a schematic configuration of a recording apparatus including a belt conveying device according to the present invention, FIG. 2 is a plan view, and FIG. 3 is a block diagram showing an internal configuration.

  In the figure, reference numeral 100 denotes a recording apparatus, and 1 denotes a belt conveying apparatus provided in the recording apparatus 100. In the belt conveyance device 1, a stretchable conveyance belt 2 formed of a material such as polyurethane is stretched over a plurality of rollers 3 to 6.

  The drive roller 3 of the plurality of rollers is coaxially provided with a conveyance motor 7 as a drive source, and is driven and controlled by the control unit 101 so that the driving force is transmitted to the conveyance belt 2 to be conveyed. The belt 2 is rotated. The transport motor 7 can rotate forward and backward, and rotates forward to rotate the transport belt 2 in the A direction, which is counterclockwise in FIG. 1, and rotates backward in the B direction, which is clockwise. The other rollers 4 to 6 are driven rollers that apply a predetermined tension to the transport belt 2 and rotate in accordance with the rotation of the transport belt 2.

  The driving roller 3 and the driven roller 4 are arranged in parallel at a predetermined distance in the horizontal direction, and the upper surface of the conveying belt 2 therebetween is a conveying surface on which the recording medium P is placed and conveyed. In the present embodiment, the downstream side in the conveyance direction (A direction) of the recording medium P is the driving roller 3, and the upstream side is the driven roller 4. At both ends of the driving roller 3 and the driven roller 4, flanges 3a and 4a are provided, respectively, to restrict the movement of the conveying belt 2 in the width direction to prevent the separation.

  The recording medium P has a sheet-like shape that has been cut into a predetermined size in advance, and is accommodated in a paper feed tray 8 that is disposed in proximity to the driven roller 4, and is fed one by one on the transport surface of the transport belt 2 by the paper feed roller 9. To be supplied. The feed roller 9 can be rotated forward and backward by a feed motor 9 a provided coaxially and controlled by the control unit 101, and the recording medium P is supplied onto the transport surface of the transport belt 2 by rotating forward. To do.

  In the present invention, the conveyance direction of the recording medium P means the A direction in which the recording medium P is conveyed when the conveyance belt 2 rotates forward. Further, the upstream side and the downstream side are referred to as the upstream side or the downstream side with reference to the A direction in which the recording medium P is transported when the transport belt 2 rotates in the forward direction. Furthermore, when the leading edge and the trailing edge of the recording medium P are referred to, the leading end at that time is the leading edge and the trailing edge with respect to the A direction in which the recording medium P is conveyed when the conveying belt 2 rotates forward. The end of is called the rear end.

  On the conveyance surface of the conveyance belt 2, a pair of narrow pressure rollers 10 </ b> A and 10 </ b> B (the right pressure roller 10 </ b> A and the left pressure roller 10 </ b> B) for correcting the skew of the recording medium P are spaced at predetermined intervals in the width direction. In each case, they are arranged at positions spaced apart from the upper surface of the conveyor belt 2 by a predetermined distance.

  The right pressure roller 10A and the left pressure roller 10B are disposed in the vicinity of both ends in the width direction of the transport belt 2, and support arms 11A provided so as to be independently swingable with respect to the surface of the transport belt 2. It is rotatably attached to the tip of 11B. Reference numerals 12A and 12B denote driving units for independently pressing the right pressure roller 10A and the left pressure roller 10B toward the transport belt 2 by swinging the front ends of the support arms 11A and 11B, respectively.

  For example, as shown in FIG. 4, each of the drive units 12A and 12B includes tension springs 121A and 121B that urge the ends of the support arms 11A and 11B on the rear end side downward from the rotation shafts 111A and 111B. There are provided pressing motors 122A and 122B for pressing a portion closer to the tip than the rotating shafts 111A and 111B. Reference numerals 123A and 123B denote drive shafts that protrude or retract as the pressing motors 122A and 122B are driven, and their tips are in contact with the upper surfaces of the support arms 11A and 11B closer to the tips than the pivot shafts 111A and 111B. .

  The rotations of the pressing motors 122A and 122B are controlled in the forward and reverse directions by the control unit 101, and the drive shafts 123A and 123B protrude or retract. When the drive shafts 123A and 123B are projected, the distal ends of the support arms 11A and 11B are swung downward against the tension springs 121A and 121B. As a result, the pressure rollers 10A and 10B provided at the tips of the support arms 11A and 11B are lowered, and the vicinity of the end in the width direction of the recording medium P that is placed on the upper surface of the conveying belt 2 and conveyed is viewed from the upper surface. Press toward the conveyor belt 2. On the other hand, when the drive shafts 123A and 123B are retracted, the leading ends of the support arms 11A and 11B are swung upward by the tension springs 121A and 121B, and the conveying belts that do not contact the pressing rollers 10A and 10B with the recording medium P 2 is maintained above.

  The control unit 101 adjusts the amount of protrusion or the amount of retraction of the drive shafts 123A and 123B by controlling the drive amount of each press motor 122A and 122B (drive time, the number of steps in the case of a stepping motor). The pressing force of the pressing rollers 10A and 10B is adjusted.

  Here, the skew correction operation of the recording medium P by the pressing rollers 10A and 10B will be described.

  As shown in FIG. 5A, for example, when the vicinity of the left end of the recording medium P in the width direction is pressed downward toward the conveying belt 2 only by the left pressing roller 10B, the left end of the pressed conveying belt 2 is moved to the left side. It extends compared to the right end side. For this reason, it reaches | attains late | slow to a predetermined position compared with the right side which is not pressed. As a result, the recording medium P is conveyed while being gradually skewed to the left as shown by the arrow as shown in FIG. In the case of pressing by the right pressing roller 10A, the operation is the reverse of the above.

  The correction amount of the recording medium P is adjusted by the pressing force of each pressing roller 10A, 10B. Therefore, the control unit 101 sets the pressing force corresponding to the skew amount of the recording medium P by adjusting the drive amount of the pressing motors 122A and 122B according to the skew amount (inclination magnitude) of the recording medium P. Is done.

  Two end detection sensors 13A and 13B that constitute the skew detection means are disposed in the width direction of the conveyor belt 2 at the downstream side of the pressing rollers 10A and 10B above the conveyance surface of the conveyor belt 2. And arranged in parallel to the transport direction. The end detection sensors 13 </ b> A and 13 </ b> B irradiate detection light toward the upper surface of the conveyor belt 2 from a light source such as a semiconductor laser or an LED. When the leading end of the recording medium P placed on the transport surface and transported reaches the detection light, the end detection sensors 13A and 13B receive the reflected light and send a detection signal (High signal) to the control unit. Call 101. Therefore, the control unit 101 can detect the leading edge of the recording medium P when the detection signal is switched to the High signal. Further, when the rear end of the recording medium P passes, the end detection sensors 13A and 13B do not transmit detection signals until then (Low signal). Therefore, the control unit 101 can detect the trailing edge of the recording medium P when the detection signal is switched to the Low signal. After the leading edge of the recording medium P has not yet reached or the trailing edge of the recording medium P has passed, the edge detection sensors 13A and 13B do not receive reflected light and thus do not transmit a detection signal. The surface of the conveyor belt 2 has a color that hardly reflects this detection light.

  The skew detection means in the present invention detects the time difference between the input of detection signals (High signals) respectively transmitted from these two end detection sensors 13A and 13B, thereby adjusting the inclination of the end of the recording medium P. Detect and detect skew. For example, as shown in FIG. 6A, when the recording medium P to be conveyed is inclined to the right, the left end detection sensor 13B first detects the leading end of the recording medium P, and then The right end detection sensor 13A detects. The detection signal is as shown in FIG. 6B, and the transmission start time t2 of the detection signal of the end detection sensor 13A is delayed with respect to the transmission start time t1 of the detection signal of the end detection sensor 13B. Occurs. Since this time difference T is proportional to the skew amount of the recording medium P, the skew amount of the recording medium P can be measured from the magnitude of the time difference T. Also, depending on which detection signal transmission start time t1 or t2 of the two end detection sensors 13A and 13B is earlier, the direction of skew of the recording medium P (inclined to the right side or to the left side) ) Can be detected. Accordingly, the control unit 101 detects the transmission start times t1 and t2 of the detection signals from the end detection sensors 13A and 13B, and determines the magnitude of the skew amount from the time difference T according to which detection signal is earlier. Each direction of skew is judged.

  Similarly, the skew amount and skew direction of the recording medium P are detected by the trailing edge of the recording medium P from the time when the detection signals from the two end detection sensors 13A and 13B are switched to the Low signal. You can also

  On the downstream side of these end detection sensors 13A and 13B, a recording head 14 serving as recording means is disposed above the conveying surface of the conveying belt 2 with a predetermined distance. The recording head 14 ejects ink droplets from a number of nozzles provided on the surface opposite to the conveying surface of the conveying belt 2 to land on the recording medium P conveyed to the lower side thereof, thereby recording a predetermined image. An inkjet head. Here, a line type head that is constructed over the entire width of the conveyance belt 2 and that performs recording at the same time across the width of the recording medium P by ejecting ink droplets from nozzles arranged in the width direction is illustrated. However, a shuttle type head that records an image by reciprocating in the width direction of the conveying belt 2 may be used.

  For example, the drive roller 3 is provided with an encoder 15 coaxially with the rotating shaft, whereby the transport amount of the transport belt 2 can be detected. The encoder 15 is configured by a disk having through holes formed in a stripe shape, and transmits an encoder pulse, which is an electric signal, to the control unit 101 by detecting whether or not light is transmitted. Based on the encoder pulse transmitted from the encoder 15, the transport amount of the recording medium P placed on the transport surface of the transport belt 2 and transported is detected. Further, the control unit 101 determines the timing for ejecting ink droplets from the recording head 14 based on the encoder pulse.

  Next, an example of the skew correction operation of the recording medium P in the recording apparatus 100 will be described with reference to the flowchart shown in FIG.

  First, the control unit 101 drives the paper feed motor 9a to rotate the paper feed roller 9 forward, and supplies the recording medium P on the paper feed tray 8 onto the transport surface of the transport belt 2 (S1).

  The supply of the recording medium P onto the conveyance surface of the conveyance belt 2 is detected by an end detection sensor (not shown) disposed near the driven roller 4. Eventually, when the leading edge of the recording medium P passes below the end detection sensors 13A and 13B by the rotational driving of the transport belt 2 in the A direction, a detection signal (High signal) is transmitted to the control unit 101 (S2).

  Here, when skew has occurred in the recording medium P, a difference occurs in the transmission start times t1 and t2 of the detection signals of the end detection sensors 13A and 13B. The control unit 101 detects the time difference T from the transmission start times t1 and t2, and based on the detection result, whether or not there is skew, the skew amount when there is skew, and which of t1 and t2 is earlier Is determined (S3).

  As a result, when the recording medium P is properly conveyed, the time difference T does not occur, and the control unit 101 determines that no skew has occurred in the recording medium P (NO in S4). Then, the control unit 101 conveys the recording medium P as it is to the recording head 14 to perform recording, and does not perform the skew correction operation. Note that the time difference T at which it is determined that no skew has occurred is not limited to 0 (t1 = t2), and a predetermined allowable range may be provided for plus and minus.

  On the other hand, when the recording medium P is skewed as shown in FIG. 8, for example, a large time difference T occurs. Thereby, the control unit 101 determines that the skew to be corrected has occurred in the recording medium P (YES in S4). Then, the control unit 101 rotates the transport motor 7 in the reverse direction to rotate the transport belt 2 in the reverse direction B. As shown in FIG. 9, the leading end of the recording medium P is more than the pressure rollers 10A and 10B. Reverse feed is performed until it is positioned upstream (S5). The reverse feed amount at this time is detected by the encoder 15, and the drive of the carry motor 7 is controlled by the control unit 101.

  Here, as shown in FIG. 8, the recording medium P is skewed in a state of being inclined toward the right end detection sensor 13A, and therefore, from each of the end detection sensors 13A and 13B detected in step S3. The comparison result of the reception start times t1 and t2 is t1> t2. Therefore, the control unit 101 determines that the recording medium P is skewed in a state of being tilted to the right (YES in S6). Then, the control unit 101 forwardly rotates the transport motor 7 again to transport the recording medium P in the direction A, and presses the left drive unit 12B disposed on the side opposite to the right end detection sensor 13A. The motor 122B is driven and the left pressing roller 10B is moved downward to press the vicinity of the left end in the width direction of the recording medium P from its upper surface toward the conveying belt 2, and the recording medium P is conveyed while being skewed. Correction is performed (S7).

  At this time, the control unit 101 adjusts the driving amount of the pressing motor 122B according to the skew amount of the recording medium P obtained in step S3, and sets the pressing force of the left pressing roller 10B to the skew amount of the recording medium P. Set the corresponding pressing force.

  The correction amount (pressing force) in the control unit 101 is determined according to the time difference T between the transmission start times t1 and t2 of the detection signals from the end detection sensors 13A and 13B. It is preferable to prepare a table that defines the relationship between the time difference T and the driving amount of the pressing motor 122A or 122B, and to make a determination based on this table because it is possible to quickly determine the correction amount.

  On the other hand, when the comparison result of the reception start times t1 and t2 from the end detection sensors 13A and 13B detected in step S3 is t1 <t2 (NO in S6), the recording medium P is contrary to the above. Since the left end detection sensor 13B is inclined and skewed, the control unit 101 causes the transport motor 7 to rotate forward again to transport the recording medium P in the A direction, and the drive disposed on the right side. The pressing motor 122A of the section 12A is driven, the right pressing roller 10A is moved downward to press the vicinity of the right end of the recording medium P in the width direction from its upper surface toward the conveying belt 2, and the recording medium P is conveyed. The skew is corrected (S8).

  After step S7 or S8, the leading edge of the recording medium P passes through the end detection sensors 13A and 13B again by the rotation driving of the transport belt 2 in the A direction. Accordingly, the processing from the above step S2 is repeated, and again passes below the end detection sensors 13A and 13B to detect again the inclination of the leading edge of the recording medium P, and reexamines the presence and degree of skew. If skew still occurs, the above operation is executed again until it is determined that skew has not occurred. Therefore, reliable skew correction can be performed.

  As a result, the skew of the transported recording medium P can be corrected without relying on the conventional abutment, and therefore, the skew correction can be performed even if the recording medium P is thin and has no stiffness. In addition, the thickness of the recording medium P is not selected, and there is no risk of damage due to buckling of the recording medium P or occurrence of JAM, and skew correction can be performed during the conveyance by the conveyance belt 2.

  FIG. 10 is a plan view showing the recording apparatus 200 in which the position of the end detection sensor is different. The belt conveyance device 1 is the same as that shown in FIGS. 1 and 2, and the same reference numerals as those in FIG.

  In this embodiment, the end detection sensors 16A and 16B are located upstream of the pressing rollers 10A and 10B, and are disposed above the conveyance surface in the vicinity of the driven roller 4. Accordingly, since the skew of the recording medium P is detected on the upstream side of the pressure rollers 10A and 10B, when the skew occurs, any one of the pressure rollers 10A as it is without feeding the recording medium P backward. Skew correction can be performed by lowering 10B. Further, in this aspect, each of the end detection sensors 16A and 16B can also be used as an end detection sensor for detecting that the recording medium P is supplied from the paper feed tray 8 onto the transport belt 2.

  In the re-inspection of the recording medium P after the skew correction, the skew of the recording medium P is corrected by the pressing roller 10A or 10B, and then the leading edge of the recording medium P is once sent back to the upstream side of the end detection sensors 16A and 16B, and again. This can be done by transporting in the forward direction and re-detecting the inclination of the leading edge of the recording medium P by the end detection sensors 16A and 16B.

  Further, in this case, after the skew correction, the recording medium P is conveyed in the forward direction as it is without being reversely fed, and the timing at which the rear end of the recording medium P passes through each of the end detection sensors 16A and 16B is detected. In addition, by detecting the inclination of the trailing edge of the recording medium P, the skew correction can be inspected.

  In either case, the skew correction can be surely performed, but in the latter case, the number of times of reverse feeding of the recording medium P can be reduced.

  FIG. 11 is a plan view showing a recording apparatus 300 in which end detection sensors are arranged on the upstream side and the downstream side of the pressure rollers 10A and 10B, respectively. Here, the belt conveying device 1 is the same as that shown in FIGS. 1 and 2, and the same reference numerals as those shown in FIGS. 2 and 10 denote the same components.

  This embodiment is the same as the embodiment shown in FIGS. 1 and 2 in that the end detection sensors 13A and 13B are located on the downstream side of the pressing rollers 10A and 10B. However, the end detection sensors 16A and 16B are further provided. Is also arranged upstream of the pressure rollers 10A and 10B. Accordingly, the skew of the recording medium P is detected by first detecting the leading edge of the recording medium P with the end detection sensors 16A and 16B on the upstream side of the pressure rollers 10A and 10B. In this case, similarly to the embodiment of FIG. 10, the skew correction can be performed by conveying the recording medium P as it is and lowering any one of the pressing rollers 10A and 10B. Each of the end detection sensors 16A and 16B can also be used as an end detection sensor for detecting that the recording medium P is supplied from the paper feed tray 8 onto the transport belt 2.

  And since the front-end | tip of the recording medium P which passed the press rollers 10A and 10B is detected by each edge part detection sensor 13A and 13B next, the recording medium by which skew correction was made | formed by one of the press rollers 10A and 10B The skew correction state of P can be confirmed by transporting the recording medium P as it is and re-detecting the inclination state of the tip by each of the downstream end detection sensors 13A and 13B. Therefore, reliable skew correction can be performed.

  If the skew still occurs due to this re-detection, the recording medium P is transported in the forward direction as it is, and after the rear end passes below the end detection sensors 16A and 16B, the recording medium P is reversed. When feeding, it is also preferable to correct skewing during reverse feeding by moving the pressing roller 10A or 10B downward. The degree of skew correction at the time of reverse feeding can be inspected by detecting the inclination of the rear end of the recording medium P by the end detection sensors 16A and 16B.

  In each of the above aspects, in order to correct the skew of the recording medium P, the pair of pressing rollers 10A and 10B are arranged so as to be independently operable. Instead, as shown in FIG. By providing the width-shaped pressing roller 17 so as to be movable along the width direction of the conveying belt 2 and capable of moving up and down with respect to the surface of the conveying belt 2, the vicinity of one end in the width direction of the recording medium P is selected Alternatively, it can be configured to be pressable. Reference numeral 17a denotes a support shaft that rotatably supports and fixes the pressure roller 17. The support shaft 17a is moved in the width direction of the transport belt 2 by a driving means (not shown), so that the pressure roller 17 is moved in the width of the transport belt 2. Move in the direction.

  According to the pressing roller 17, the position can be arbitrarily changed in the width direction of the conveyor belt 2, so that the vicinity of the end in the width direction can be pressed in correspondence with a plurality of types of recording media P having different widths. it can.

  FIG. 13 is a side view illustrating a schematic configuration of a recording apparatus 400 including a slip imparting unit for the recording medium P. The same reference numerals as those in FIG. 1 denote the same components.

  In this aspect, the conveying belt 2 is formed with a plurality of through holes (not shown) in the length direction. The through holes are formed at intervals along a length direction orthogonal to the width direction of the transport belt 2, and the rows of through holes are arranged in a plurality of rows in the width direction of the transport belt 2.

  A fan blower 18 as a suction means is provided on the back side of the conveyance surface of the conveyance belt 2. The fan blower 18 is provided with a fan 18b in a housing 18a. The fan 18b rotates to generate wind force, thereby sucking air through the through-holes of the transport belt 2 and transporting the recording medium P to the transport belt. The surface of the recording medium P at the time of recording is kept smooth by being in close contact with the transport surface 2.

  A passage 18d is branched in the middle of the passage 18c on the blowout side of the fan 18b, and the tip of the passage 18d faces the back surface of the conveyor belt 2 on the upstream side of the pressing rollers 10A and 10B. A switching valve 18e is provided between the passage 18c and the passage 18d. The switching valve 18e is controlled by the control unit 101 to selectively switch the wind passage on the blowing side of the fan 18b between the passage 18c and the passage 18d. It is like that.

  That is, when the switching valve 18e switches the flow path of the wind force on the blowing side of the fan 18b to the passage 18d side, the wind force blows out toward the back surface of the conveying belt 2 on the upstream side of the pressing rollers 10A and 10B through the passage 18d. It blows out on a conveyance surface through the through-hole of the conveyance belt 2 of this site | part. Thereby, the slip between the recording medium P conveyed to this part and the conveyance belt 2 is promoted. As a result, the suction means for closely attaching the recording medium P during recording to the transport belt 2 also serves as the slip applying means. This slip imparting means improves the slip of the recording medium P so that the skew correction can be performed smoothly, and JAM due to the skew correction is prevented.

  The slip applying means may be provided separately and independently from the suction means. Further, the slip applying means can be similarly applied to the belt conveying device 1 shown in FIGS. 10, 11, and 12 by forming a through hole in the conveying belt 2.

  The above embodiment exemplifies an ink jet recording apparatus as the recording apparatus. However, the present invention can be applied to any recording apparatus that performs recording by conveying the recording medium P using the conveyance belt 2. For example, a toner image on the recording medium P can be applied. Or a recording apparatus such as an image forming apparatus that forms an exposure image by light exposure.

1 is a side view illustrating a schematic configuration of a recording apparatus including a belt conveyance device according to the present invention. FIG. 1 is a plan view of the recording apparatus shown in FIG. The block diagram which shows the internal structure of the recording device shown in FIG. Schematic showing the pressing structure of the pressing roller (A) and (b) are diagrams showing the skew correction operation of the recording medium by the pressing roller. (A) (b) is a figure which shows a mode that skew feeding of a recording medium is detected. A flowchart for explaining an example of the skew correction operation The figure which shows a mode that a recording medium is conveyed diagonally The figure which shows a mode that a recording medium is reversely sent The top view which shows the recording device from which the position of an edge part detection sensor differs The top view which shows the recording device which has arrange | positioned the edge detection sensor in the upstream and downstream of a press roller, respectively. The partial perspective view which shows a mode that one press roller was movable along the width direction of a conveyance belt, and was provided so that it could move up and down with respect to the surface of a conveyance belt. A side view showing a schematic configuration of a recording apparatus provided with a slip applying means for a recording medium

Explanation of symbols

1: Belt conveying device 2: Conveying belt 3: Driving roller 3a: Flange 4-6: Driven roller 4a: Flange 7: Conveying motor 8: Paper feeding tray 9: Paper feeding roller 9a: Paper feeding motor 10A: Right side pressure roller 10B : Left pressure roller 11A, 11B: Support arm 12A, 12B: Drive unit 111A, 111B: Rotating shaft 121A, 121B: Tension spring 122A, 122B: Press motor 123A, 123B: Drive shaft 13A, 13B: End detection sensor 14 : Recording head 15: Encoder 16A, 16B: End detection sensor 17: Pressure roller 17a: Support shaft 18: Fan blower 18a: Housing 18b: Fan 18c: Passage 18d: Passage 18e: Switching valve

Claims (11)

In a belt conveyance device that has a telescopic conveyance belt stretched around a plurality of conveyance rollers, and conveys a sheet-like recording medium placed on the upper surface of the conveyance belt,
A pressing roller provided to be able to press the vicinity of the widthwise end of the recording medium from its upper surface toward the conveying belt;
Skew detection means for detecting skew by detecting the inclination of the end of the recording medium;
When the skew of the recording medium is detected by the skew detection means, the pressing roller presses the vicinity of one end in the width direction of the recording medium according to the direction of the skew. And a control means for correcting skew of the recording medium during the conveyance of the recording medium.   The pressing rollers are arranged at intervals in the width direction of the conveying belt, and the vicinity of the end in the width direction of the recording medium conveyed by the belt conveying means is independently directed from the upper surface toward the conveying belt. The belt conveying device according to claim 1, comprising two pressing rollers provided so as to be pressed.   The belt device according to claim 1, wherein the pressing roller includes one pressing roller that is movable along a width direction of the conveying belt and is capable of being pressed toward the conveying belt. The skew detection means is disposed on the downstream side of the pressing roller,
When the skew is detected from the inclination of the leading edge of the recording medium detected by the skew detecting means, the control means reversely rotates the conveyance belt so that the leading edge of the recording medium is moved from the pressing roller. Also, the sheet is reversely fed to the upstream side, and then the conveying belt is rotated forward again to operate the pressing roller to correct the skew of the recording medium, and the skew detection means detects the leading edge of the recording medium. 4. The belt conveying device according to claim 1, wherein the inclination degree is detected again. The skew detection means is disposed on the upstream side of the pressing roller,
When the skew is detected from the inclination of the leading edge of the recording medium detected by the skew detection means, the control means corrects the skew of the recording medium by operating the pressing roller; The conveyance belt is rotated in the reverse direction, and the leading edge of the recording medium is once reversely fed to the upstream side of the skew detection means, and then the conveyance belt is rotated in the forward direction again. 4. The belt conveying device according to claim 1, wherein the inclination of the tip of the belt is detected again. The skew detection means is disposed on the upstream side of the pressing roller,
When the skew is detected from the inclination of the leading edge of the recording medium detected by the skew detection means, the control means corrects the skew of the recording medium by operating the pressing roller; 4. A belt conveying apparatus according to claim 1, wherein the skew detecting means detects the inclination of the trailing edge of the recording medium. The skew detection means is disposed upstream of the recording means and upstream and downstream of the pressing roller, respectively.
The control means operates the pressure roller when the skew is detected from the inclination of the leading edge of the recording medium detected by the skew detection means upstream of the pressure roller. 4. The belt conveyance according to claim 1, wherein the inclination of the leading edge of the recording medium is detected again by the skew detection means downstream of the pressing roller. apparatus. In the skew detection means, a plurality of end detection means for transmitting a detection signal to the control means when detecting an end of the recording medium are arranged in parallel at intervals along the width direction of the conveyance belt. Has been
The control unit detects a skew amount of the recording medium based on a time difference between detection signals from the plurality of edge detection units, and the pressing roller moves the upper surface of the recording medium according to the skew amount to the conveying belt. The belt conveying device according to any one of claims 1 to 7, wherein a pressing force to be pressed toward the belt is controlled. Slip imparting means for imparting slip between the recording medium upstream of the pressing roller and the conveying belt,
The belt conveying device according to claim 1, wherein the control unit operates the slip applying unit when the pressing roller is operated to correct the skew of the recording medium. . The conveyor belt has a plurality of through holes in the length direction,
The slip imparting means includes a fan blower on the back side of the recording medium mounting surface of the transport belt, and blows off the wind force on the blowing side of the fan blower from the through hole on the upstream side of the pressing roller. The belt conveying device according to claim 9, wherein the belt conveying device is a means.   11. A recording apparatus comprising: the belt conveyance device according to claim 1; and a recording unit that performs recording on the recording medium conveyed by the belt conveyance device.

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