JP6891004B2 - Transport device, recording device and transport method - Google Patents

Description

The present invention includes a conveying device capable of detecting the skew amount of the sheet to be conveyed, and a recording apparatus using the transfer apparatus and a method feeding transportable that put on the conveying device.

A recording device such as a copier or an inkjet recording device holds and conveys a sheet, which is a recording medium, by a conveying unit such as a conveying roller, and in conjunction with this, forms an image by a recording unit such as a liquid discharge head. Recording is performed on, for example, the entire surface of the sheet. At this time, if the sheet conveyed by the conveying unit is tilted obliquely with respect to the recording unit, the image recorded on the sheet is also tilted, resulting in an image defect. Therefore, a technology has been proposed in which detection sensors are provided at two locations in the width direction of the sheet to detect the sheet, detect the inclination of the sheet from the detection timing difference, and correct the inclination of the sheet by mechanical operation before recording. Has been done. The width direction of the sheet is a direction orthogonal to the transport direction of the sheet toward the recording unit. From the viewpoint of detection accuracy, the sensor is generally arranged at two positions near both ends in the width direction of the sheet from the viewpoint of detection accuracy. At this time, if the detection sensor is a fixed type, it cannot handle sheets of a plurality of sizes.

Patent Document 1 discloses a paper transport device in which a sensor moving means for moving a sensor according to both end positions in the width direction of a sheet to be passed is provided, and the position of the sensor is changed according to the sheet size. By using the apparatus of Patent Document 1, even if the size of the sheet to be passed is changed, the two sensors can be arranged at advantageous positions in terms of detection accuracy, and the inclination detection accuracy can be improved.

Japanese Unexamined Patent Publication No. 2009-234691

However, in the technique described in Patent Document 1, the position accuracy of the sensor is lowered due to the distortion of the guide portion for guiding the movement of the sensor, the rattling between the mounting portion of the sensor and the guide portion, and the tilt detection accuracy is sufficiently sufficient. There is a problem that it cannot be secured. Further, there is a problem that the recording device is increased in size by providing the mechanism for moving the sensor, and the cost of the device is increased due to the increase in the number of parts associated with the moving mechanism.

Therefore, an object of the present invention is a transport device capable of detecting skewing of a sheet with an accurate and simple configuration while transporting the sheet without depending on the size of the sheet, a recording device using such a transport device, and transport. and to provide a method Carriage transportable that put the device.

The transport device according to one aspect of the present invention includes a transport roller that transports the sheet and a pinch roller that is arranged at a position facing the transport roller and sandwiches the sheet between the transport rollers at a plurality of positions in the width direction of the sheet. , An encoder that detects the rotation speed or the amount of rotation of the transfer roller as a detection value , and when the transfer roller is controlled to have a predetermined rotation speed, the transfer roller and the pinch roller a nip portion formed between the based on the variation amount of the detection value encoder detects when the end of the conveying direction of the sheet passes, and wherein the Turkey to calculate the skew amount of the sheet.
The recording device of one aspect of the present invention is a recording device that records on a sheet based on image data, the transport device of the present invention, a direction determining means for determining the skew direction of the sheet, and an image on the sheet. The recording head is provided with a recording head for recording the image and an image rotating means for rotating image data based on the skew amount of the sheet and the skew direction determined by the direction determining means to generate a rotated image. Is recorded on a sheet .
The transport method of one aspect of the present invention includes a transport roller for transporting the sheet and a pinch roller provided facing the transport roller and sandwiching the sheet between the transport rollers at a plurality of positions in the width direction of the sheet. , A transport method in a transport device having a feed roller provided on the upstream side of the transport roller with respect to the sheet transport direction and transporting the sheet, wherein the rotation speed or the rotation amount of the transfer roller is detected from the encoder. detecting, when the conveying roller is controlled to a predetermined rotational speed, based on the variation amount of the test detection value when a nip portion formed through the tip of the sheet between the conveying roller and the pinch roller , characterized Rukoto issuing calculate the skew amount of the sheet.

According to the present invention, since the amount of skew of the sheet can be calculated from the fluctuation of the amount related to the rotation of the transport roller, it is not necessary to provide a sensor for detecting both ends that moves according to the size of the sheet, and deterioration of detection accuracy is suppressed. However, highly accurate tilt detection can be realized.

It is a perspective view which shows the mechanical part of the recording apparatus of 1st Embodiment. It is sectional drawing which shows the feeding part and the transporting part. It is a schematic cross-sectional view explaining the correction operation. It is a block diagram which shows the control structure of the recording apparatus shown in FIG. It is a schematic cross-sectional view explaining the transporting force required for the tip of a sheet. It is explanatory drawing which shows that the required transport force changes according to the amount of skew. It is a graph which shows the relationship between the transport force and the rotation speed of a roller. It is a graph which shows the relationship between the amount of skew and the amount of fluctuation of the rotation speed of a roller. It is a figure explaining the method of calculating the fluctuation amount of the rotation speed. It is a flowchart which shows the process up to the calculation of the fluctuation amount of a rotation speed. It is a figure explaining the correlation table. It is a schematic cross-sectional view which shows the relationship between the sheet and the operating state of each part. It is a flowchart explaining a series of recording operations. It is a block diagram which shows the control structure of the recording apparatus of 2nd Embodiment. It is a conceptual diagram which shows that an image is rotated and recorded. It is a conceptual diagram explaining the detection of the tilt direction of a sheet. It is a flowchart explaining a series of recording operations. It is a block diagram which shows the control structure of the recording apparatus of 2nd Embodiment. It is a flowchart explaining a series of recording operations.

Next, a preferred embodiment of the present invention will be described.
The transfer device based on the present invention includes a transfer roller that conveys a sheet, and a pinch roller that is provided so as to face the transfer roller and sandwiches the sheet between the transfer rollers, and further detects an amount related to the rotation of the transfer roller. It is something that I tried to do. Then, based on the amount of change in the detected value of the amount related to rotation when the end portion (front end or rear end) of the sheet in the transport direction passes through the nip portion formed between the transfer roller and the pinch roller. , Calculate the skew amount of the sheet. The amount related to the rotation of the transfer roller is, for example, the rotation speed or the amount of rotation of the transfer roller. If the rotation speed of the transfer roller changes, the transfer speed of the sheet also changes, so the transfer speed of the sheet is also included in the amount related to the rotation of the transfer roller. Once the amount of skew of the sheet is calculated, it is possible to correct the skew of the sheet and correct the recorded data based on the skew. The principle of calculating the skew amount of the sheet will be described later. Hereinafter, a case where the transport device based on the present invention is applied to a recording device that records an image (including characters and the like) on a sheet will be described, but the application target of the present invention is not limited to the recording device. .. The present invention can be applied to various devices that require correction of sheet skew. For example, the transport device of the present invention can be applied to a scanner that reads a document that is a sheet, a perforator that punches holes in a sheet, and the like.

(First Embodiment)
In the first embodiment, the amount of skew is calculated when the sheet is bitten into the nip portion, and then the operation parameters used for the straightening operation to correct the tilted sheet are based on the calculated value of the amount of skew. An example of the recording device to be changed will be described. The correction operation for correcting the skew of the sheet is also called the registration operation. First, the main mechanical parts of the recording device described in the present embodiment will be described with reference to FIGS. 1 to 4. The recording device 100 is roughly divided into a recording unit that records on the sheet 50, a feeding unit that takes out the sheet 50 one by one from the accommodating unit (not shown) and supplies the sheet 50 to the recording unit, and a sheet being recorded. It is composed of a transport unit that transports 50 and a control system that controls the operation of these mechanisms. FIG. 1 shows the entire mechanical unit (recording unit, feeding unit, and transporting unit) of the recording device 100, and FIG. 2 shows the feeding unit and transporting unit in the recording device 100. FIG. 3 shows the state of the sheet 50 in the straightening operation, and FIG. 4 shows the configuration of the control system. The control system controls all the mechanical parts of the recording device 100, but is not shown in FIG. Hereinafter, these mechanical units and control systems will be described.

(A) Recording unit The recording unit records an image on the sheet 50 by a recording head (not shown) mounted on the carriage 1. The sheet 50 transported by the transport unit is supported from below by the platen 30 in the recording unit, and the recording liquid is discharged from the recording head located above the platen 30, so that the sheet 50 is based on the recorded image information, that is, the image data. The image is recorded. The carriage 1 is movable in a carriage scanning direction (Y direction in the drawing) that intersects the transport direction (X direction in the drawing) of the seat 50, and records an image in the seat width direction while moving in the scanning direction. Hereinafter, the transport direction of the sheet 50 is simply referred to as a transport direction.

(B) Feeding unit The feeding unit is provided upstream in the transport direction of the recording unit, separates the sheets 50 one by one from the bundle of sheets accommodated in the accommodating unit (not shown), and supplies the sheets to the transport unit. It is a thing. The feeding section is divided into a separation mechanism section (not shown) that separates the sheets and a feeding section that is arranged on the downstream side thereof and transports the separated sheets to the transport section. As will be described in detail later, in addition to transporting the sheet to the transport section, the feeding section is configured to perform a straightening operation for correcting the tilted sheet in cooperation with the transport section. The feeding portion includes a feeding roller 2 in which a rubber roller is inserted through a metal shaft, and a pinch roller 3 which is urged by a spring toward the feeding roller 2 and can be driven to rotate according to the rotation of the feeding roller 2. Is provided. The feeding roller 2 and the pinch roller 3 form a roller nip on the feeding side in which the sheet 50 is sandwiched and conveyed between them. The feed unit includes a feed motor 4 that drives the feed roller 2, a gear 5 and a motor gear 6 that transmit drive from the feed motor 4 to the feed roller 2, and a code that detects the amount of rotation of the feed roller 2. A wheel 7 is provided. The chord wheel 7 is formed with slits at a pitch of 150 lines per 25.4 mm, for example. The number and timing of passage through the slit are read by the encoder sensor 8, and the rotation speed and rotation amount of the feeding roller 2 are detected from the number of times and timing of reading. As shown in FIG. 2, a pinch roller holder 9 for guiding the sheet and a feeding guide 10 are provided facing each other in the sheet conveying path from the feeding portion to the conveying portion. Further, in the transport path, a rotary lever 11 for detecting the passage of the front and rear ends of the seat and a PE sensor 12 for detecting the rotation of the lever 11 are provided.

(C) Transport section The transport section is provided downstream in the transport direction when viewed from the feed section, transports the sheet sent from the feed section with high accuracy, and forms an image in collaboration with the above-mentioned recording section. Is. The main mechanism of the transport unit is attached to a main side plate 13 extending in the scanning direction of the carriage 1 and a right side plate 14 and a left side plate 15 connected to both ends of the main side plate 13 and extending in the transport direction, respectively. The sheet is transported by the transport section by the transport roller 16 and the discharge roller 17. The transport roller 16 has a structure in which the surface of a metal shaft is coated with fine ceramic particles, and the metal portions at both ends thereof are supported by the right side plate 14 and the left side plate 15, respectively. A plurality of pinch rollers 18 are provided, and these pinch rollers 18 are mounted on the pinch roller holder 9. The pinch roller holder 9 receives a force by the pinch roller spring 19 and presses the pinch roller 18 against the transport roller 16 so as to be driven. As described above, the transport roller 16 and the pinch roller 18 form a nip portion that is a roller nip on the transport side.

The rotational force of the transfer roller 16 is transmitted to the pulley gear 23 provided on the shaft of the transfer roller 16 via the motor pulley 21 and the timing belt 22 as the driving force of the transfer motor 20 which is a drive means composed of a DC motor. Obtained by A chord wheel 24 similar to the chord wheel 7 of the feeding portion is directly connected on the same axis as the transport roller 16, and the slit provided in the chord wheel 24 is detected by the encoder sensor 25 provided in the left plate 15. Wheel. The code wheel 24 and the encoder sensor 25 constitute a detecting means for detecting an amount related to the rotation of the transport roller 16. The pulley gear 23 includes a pulley portion and a gear portion, and the discharge roller 17 is driven by transmitting the drive from the gear portion to the discharge roller gear 27 via the idler gear 26. The discharge roller 17 is composed of a metal shaft and a rubber roller inserted through the metal shaft, and both ends of the metal shaft are supported by the right side plate 14 and the left side plate 15, respectively. A plurality of spurs 28 are attached to a spur holder (not shown) provided at a position facing the discharge roller 17, and these spurs 28 are connected to the discharge roller 17 by a spur spring 29 provided with a coil spring in a rod shape. It is being pressed. After the recording operation in the recording device 100 is completed, the seat is discharged to the outside of the machine by the discharge roller 17.

In the present embodiment, the straightening operation for correcting the inclination of the conveyed sheet is performed by the feeding roller 2 in a state where the conveying roller 16 is rotating in the direction opposite to the conveying direction, as shown in FIG. It is carried out by abutting the tip of the tip against the nip. Along with the abutting operation of the sheet, a loop of the sheet is formed in the sheet transport path composed of the pinch roller holder 9 and the feeding guide 10, and twisting occurs in this loop to align the tip of the sheet, that is, to correct the operation. Will be done.

(D) Control system FIG. 4 shows the configuration of the control system. The control system 400 controls the operation of all the mechanical units provided in the recording device 100, and is configured as an electronic circuit attached to a housing (not shown) of the recording device 100. Here, regarding the control system 400, only the parts related to the present invention will be described.

The control system 400 includes a memory 401, a controller 403, and a motor driver 404 that drives the feed motor 4 and the transfer motor 20. The memory 401 stores a correlation table 402 that describes the correlation between the amount of variation in the rotation speed and the amount of skew, which will be described later. The controller 403 controls the rotational speed and position of the feed motor 4 and the transfer motor 20 via the motor driver 404, thereby driving the rotation of each roller. Specifically, the controller 403 includes a motor control unit 410, and the motor control unit 410, which is a control means, controls each motor by, for example, PID control based on the information from the encoder sensors 8 and 25. The transfer roller 16 controls the transfer motor 20 based on the information from the encoder sensor 25 of the transfer unit, and the feed roller 2 is operated by the feed motor 4 based on the information of the encoder sensor 8 of the feed unit. By being controlled, it is controlled to a predetermined rotation speed and a predetermined position. Information from the PE sensor 12 is also input to the controller 403, and the motor control unit 410 determines the sheet transport position based on the information from the PE sensor input to the controller 403, and rotationally drives each roller. Control the timing of.

Further, the controller 403 includes a skew amount calculation unit 405 which is a skew amount calculation means and a correction control unit 406 which is a correction control means in order to execute the correction operation described in detail later. The skew amount calculation unit 405 calculates the skew amount of the sheet 50 from the rotation speed data of the transfer roller 16 detected by the encoder sensor 25 on the transfer motor 20 side and the correlation table 402 in the memory 401. The specific calculation method of the skew amount will be described later. The correction control unit 406 executes a correction operation by controlling the transfer motor 16 and the feed motor 4 via the motor driver 404 based on the skew amount calculated by the skew amount calculation unit 405.

In the present embodiment, the amount of skew of the sheet 50 is calculated when the tip of the sheet 50 in the transport direction passes through the nip portion of the transport roller 16 and the pinch roller 18. Hereinafter, a mechanism for calculating the skew amount of the sheet 50 will be described with reference to FIGS. 5 to 8. FIG. 5 shows the conveying force required to bite the tip of the sheet 50 in the nip portion. As shown in FIG. 5, when the tip of the sheet 50 is bitten into the nip portion, the pinch roller pressure P _pr generated by the pinch roller spring 19 is pressed against the sheet 50 via the pinch roller 18. _Acts as a force F c. Here, it is assumed that the pinch roller 18 can be driven and rotated without resistance in the direction of rotation. In order to bite the sheet 50 into the nip portion, the other transfer roller 16 in contact with the sheet 10 generates a pressure contact reaction force F _r and a bite transfer force F _{nc so as to balance the paper pressure contact force F c.} I need to let you. The pressure contact force F _r is a force generated from the surface of the transport roller 16 outward in the radial direction as a reaction force with respect to the paper pressure contact force F _c. Further, the biting transfer force F _nc is a transfer force required to bite the sheet 50 into the nip portion in the tangential direction of the surface of the transfer roller 16, and is a transfer motor 20 or the like that drives the transfer roller 16. It is a force that is both a load and a disturbance for the drive system of. Here, the biting transfer force F _nc can be theoretically calculated from the geometrical positional relationship between the pinch roller 18, the LF roller 16 and the sheet 50 and the pinch roller pressure P _pr. Further, the biting transfer force F _nc changes depending on the amount of skew of the sheet 50. In the present embodiment, the amount of skew of the sheet 50 is the amount of deviation of both ends of the sheet 50 in the transport direction at the tip end side of the sheet 50.

FIG. 6 shows that the _{biting transfer force F nc} changes depending on the difference in the amount of skew of the sheet 50. FIG. 6A shows a state in which the sheet 50 is conveyed without skewing, and FIG. 6B shows the position (transport position) of the sheet 50 in the conveying direction and the biting conveying force F at that time. _{The relationship with nc} (hereinafter, also simply referred to as transport capacity) is shown. As shown in FIG. 6B, when there is no skew, the tip of the sheet 50 is simultaneously bitten into the nip portion over the entire width thereof, so that the transport force momentarily increases, and then the transport force linearly increases. As it decreases, the graph showing the carrying force becomes a right-angled triangle. On the other hand, FIG. 6 (c) shows a state in which the sheet 50 is transported in an oblique manner, and FIG. 6 (d) shows the relationship between the transport position of the sheet 50 and the transport force at that time. In FIG. 6 (d), as compared with FIG. 6 (b), the graph showing the change in the carrying force has a flat shape and fine fluctuations appear. This is because when a plurality of pinch rollers 18 arranged in the sheet width direction individually _{generate pinch roller pressure P pr} as shown in FIG. 6 (c), these pinches are obtained in the case of the sheet 50 which is oblique. This is because the seat 50 is bitten at a timing different from that of the roller 18. As a result, the timings of the transport forces are deviated and integrated, resulting in a graph as shown in FIG. 6 (d).

As mentioned earlier, the biting transfer force is a disturbance for the drive system. In general, it is known that when a sudden disturbance is applied to a drive system that performs rotation speed control and position control by PID control as in the present embodiment, the rotation speed of the rollers temporarily decreases. Since this decrease in rotation speed occurs in proportion to the amount of disturbance generated, it is significant in the detection result of rotation speed with and without skew as shown in FIGS. 7 (a) and 7 (b). Make a difference. 7 (a) and 7 (b) show the relationship between the transfer position and the rotation speed of the transfer roller 16 when the sheet 50 is not skewed and when it is present, respectively. Since the rotation speed of the transport roller 16 is a value that can be detected via the encoder sensor 25, it is possible to estimate the amount of skew of the sheet 50 by detecting the rotation speed. In the present embodiment, the difference between the stable rotation speed before biting and the peak value at the rotation speed during biting is calculated as the fluctuation amount ΔV of the rotation speed, and the skew amount is calculated using ΔV. doing. As described above, since there is a correlation between the rotation speed and the skew amount, the relationship between the fluctuation amount ΔV and the skew amount S is as shown in the graph of FIG. 8 as an example. This relationship varies depending on the type and size of the sheet, but can be determined in advance. Therefore, if the fluctuation amounts ΔV1 and ΔV2 can be calculated in two states in which the skew amounts are different as shown in FIGS. 7 (a) and 7 (b), the difference in the skew amount S1 is obtained by using the relationship diagram shown in FIG. , S2 can be calculated quantitatively.
The above description relates to a state when the front end of the sheet 50 passes through the nip portion, but a change in the rotation speed also occurs when the rear end of the sheet 50 passes, and skewing is performed based on this change. The amount can be calculated. However, when the rear end of the seat 50 passes through the nip portion, the direction of change in the conveying force is opposite to that in the case where the front end passes, and the direction of change in the rotational speed is also opposite.

Next, in the transport device of the present embodiment, a specific procedure for the skew amount calculation unit 405 to calculate the skew amount S of the sheet 50 will be described with reference to FIGS. 9 to 11. FIG. 9 describes a method of calculating the fluctuation amount ΔV of the rotation speed from the rotation speed data, and FIG. 10 shows a procedure (steps 501 to 505) for calculating the fluctuation amount ΔV from the rotation speed data. FIG. 11 shows an example of the contents of the correlation table 402 showing the relationship between the fluctuation amount ΔV and the skew amount S. As shown in FIG. 9, the skew amount calculation unit 405 determines the rotation speed information of the transfer roller 16, that is, the transfer speed, at the timing when the sheet 50 reaches the predetermined position d1 during a series of operations involving the sheet biting operation. Start collecting (step 501). The rotation speed information is collected from the predetermined position d1 until the sheet transport amount reaches the predetermined transport amount D. Here, the predetermined position d1 and the predetermined transfer amount D are parameters that are set so that the nip bite is surely performed during the data acquisition of the rotation speed. For example, when the diameter of the transport roller 16 and the diameter of the pinch roller 18 are 10 mm and 5 mm, respectively, and the thickness of the sheet 50 is 0.3 mm, the region where the rotation speed fluctuates is about 1 mm. In this case, for example, set the predetermined position d1 and the predetermined transport amount D so that the collection starts from 5 mm before the ideal biting position in the design and ends when the transport amount reaches 10 mm. Just do it. After the rotation speed information of the transport roller 16 is collected, the skew amount calculation unit 405 calculates and determines the minimum speed Vp shown in FIG. 9 based on the acquired data (step 502). The minimum speed Vp referred to here is the minimum value of the rotation speed during the biting operation at the nip portion. In determining the minimum speed Vp, specific noise may be removed by obtaining a moving average in the speed data in advance, and then the minimum speed Vp may be determined.

Next, the skew amount calculation unit 405 calculates and determines the rotation speed of the transport position retroactively by a predetermined distance L from the detection position dp where the minimum speed Vp is detected as the reference rotation speed Vd (step 503). The reference rotation speed Vd is a reference for the rotation speed of the transport roller 16 in the non-engaged state. The reference rotation speed Vd may be calculated by averaging the data regions that do not bite into the nip portion, or may use design values without using actual measurement values.
Next, the skew amount calculation unit 405 calculates the fluctuation amount ΔV of the rotation speed according to the equation (1) in order to calculate the skew amount S of the sheet 50 (step 504).
ΔV = Vd-Vp (1)

After that, the skew amount calculation unit 405 calculates the skew amount S of the sheet using the correlation table 402 shown in FIG. 11 based on the calculated fluctuation amount ΔV (step 505). The correlation table 402 is a table in which the fluctuation amount ΔV with respect to the predetermined skew amount S is discretely recorded, and is prepared for each type and size of the sheet 50 as shown in FIGS. 11A to 11D. It is stored in the memory 401 of the control system 400 of the recording device 100. The reason why the correlation table 402 is prepared for each type and size of the sheet 50 is that the carrying force required for biting differs depending on the thickness and width of the sheet 50 even under the condition that the amount of skew is the same. is there. The skew amount calculation unit 405 refers to a table corresponding to a predetermined sheet type and size from a plurality of correlation tables 402 shown in FIG. 11, and calculates the amount of fluctuation of the rotation speed closest to the calculated ΔV. It is calculated and the skew amount S stored in the table is determined as the skew amount. The amount of skew may be calculated by interpolation using a plurality of data in the correlation table 402. Further, the correlation table 402 may be based on a value theoretically calculated based on the above-mentioned theoretically obtained biting carrying force, or may be based on a value determined in advance by an experiment. Instead of using the correlation table 402, a function representing the relationship between the fluctuation amount ΔV and the skew amount S may be prepared, and the skew amount calculation unit 405 may calculate the skew amount S using this function.
According to the skew amount calculation unit 405 configured as described above, the skew amount S can be calculated from the fluctuation amount of the load when the tip of the sheet 50 passes through the nip portion of the transport roller 16. It is not necessary to provide both end detection sensors that can move according to the seat size. Therefore, it is possible to suppress deterioration of the tilt detection accuracy due to making the sensor movable, and to realize highly accurate tilt detection regardless of the seat size.

If the skew amount S of the sheet 50 can be calculated as described above, the skew of the sheet 50 can be corrected with high accuracy. Hereinafter, in a series of recording operations from the start of feeding to the end of discharging, the process of changing the skewing amount calculation and the correction operation based on the calculation result will be described with reference to FIGS. 12 and 13. FIG. 12 shows the relationship between the operating states of each part of the sheet 50 and the recording device 100 in the main operation in the series of recording operations as a schematic cross-sectional view, and FIG. 13 shows a series of control operations from the start of feeding to the end of discharging. (Steps 511 to 519) are shown. In the present embodiment, the loop amount of the sheet 50 is changed as a change in the correction operation. The straightening operation by loop formation has the effect of correcting the inclination of the seat, but if an excessive loop is formed and the seat is pressed against the nip portion too strongly, the tip of the seat may be scratched. Therefore, in the present embodiment, the amount of skew is calculated, the inclination of the sheet is detected, and the minimum necessary loop is generated based on the calculation, so that the correction operation is performed and the quality of the recorded sheet is improved.

When the recording device 100 receives the signal of the image recording operation, the separation mechanism unit (not shown) separates the sheets 50 loaded in a plurality of bundles in the accommodating unit (not shown) into one sheet in the feeding unit, and supplies the sheets 50. It is conveyed toward the feed roller 2. As a feeding operation, the feeding roller 2 receives the sheet 50 from the separation mechanism unit and conveys the sheet 50 toward the conveying roller 16 (step 511). At this point, the transport roller 16 is not rotating. The sheet 50 is conveyed in the conveying path of the conveying section, and as shown in FIG. 12A, the tip of the sheet 50 reaches the lever 11 provided in the conveying path, and the lever 11 is rotated by the sheet 50. To do. As a result, the PE sensor 12 detects that the tip of the sheet 50 has reached (step 512).
When the tip of the sheet 50 is detected, the skew amount detection operation is started (step 513). Specifically, as shown in FIG. 12B, in addition to the rotation of the feeding roller 2, the transport roller 16 starts rotating in the transport direction. When the skew amount calculation unit 405 detects that the sheet transport position has reached the predetermined position d1 based on the information of the PE sensor 12, the encoder sensor 25 starts collecting the rotation speed information. Then, the skew amount calculation unit 405 calculates the skew amount S based on the skew amount calculation procedure described with reference to FIG. 10 (step 514).

When the calculation of the skew amount is completed, in order to move to the next correction operation, as the completion operation of the skew amount detection, the work of returning the sheet 50 bitten into the nip portion to the outside of the nip portion is performed (step 515). ). When the calculation of the skew amount is completed, the tip of the sheet 50 is located on the downstream side in the transport direction with respect to the transport roller 16. Specifically, in the operation of completing the skew amount detection, the rotation directions of the transfer roller 16 and the feed roller 2 are switched, and as shown in FIG. 12 (c), rotation in the direction opposite to the transfer direction is started. As shown in FIG. 12D, due to the reverse rotation of the transport roller 16 and the feed roller 2, the tip of the sheet 50 escapes from the nip portion of the transport roller 16 and moves upstream in the transport direction, and retracts from the nip portion. That's what I did. This process is performed until the tip of the sheet 50 reaches a predetermined distance k from the position of the nip portion. The evacuation distance k is an arbitrary parameter that is set so that the tip of the sheet 50 surely passes through the nip portion of the transport roller 16. For example, a value of about the predetermined transport amount D used when calculating the skew amount is set. do it. This completes the skewing amount detection completion operation, and then starts the correction operation (step 516).

The correction operation is performed by switching the rotation direction of the feed roller 2 to the transport direction. As a result, the sheet 50 resumes traveling in the transport direction. At this time, the transport roller 16 remains rotating in the direction opposite to the transport direction. The rotation of the feeding roller 2 in the transport direction and the reverse rotation of the transport roller 16 are performed by the amount of rotation R calculated by the equation (2).
R = k + 1.5 × S (2)
When such a rotation operation is performed, the tip of the sheet 50 reaches the nip portion of the transfer roller 16 due to the rotation of the PF roller 2 in the transfer direction, and then the sheet with respect to the nip portion in which the transfer roller 16 rotates in the reverse direction. It will be pushed in by 1.5 times the amount of inclination (amount of skew S). As a result, a loop is formed on the sheet 50 as shown in FIG. 12 (e), and the tip of the sheet 50 is aligned.
Next, in order to shift to the image recording operation, as a biting operation, the sheet 50 is bitten into the nip portion again, and the sheet 50 is conveyed below the recording head mounted on the carriage 1 (step 517). .. Specifically, as shown in FIG. 12 (f), the rotation direction of the transfer roller 16 is switched to start the rotation in the transfer direction. As a result, the sheet 50 resumes traveling in the transport direction. The sheet 50 is transported until it reaches the position of the recording head on the downstream side of the nip portion of the transport roller 16 in the transport direction. With the above, the correction of the skew of the sheet 50 is completed.

Next, image recording is performed. After the tip of the sheet 50 reaches the position of the recording head, the sheet 50 is formed by repeating high-precision transfer by the transfer unit composed of the transfer roller 16 and the discharge roller 17 and image recording by the recording unit. An image is formed (step 518). When the image recording on the sheet 50 is completed, the sheet 50 is discharged from the transport unit by the discharge roller 17, and a series of recording operations is completed (step 519).

In the above description, the biting transfer force is estimated from the rotation speed of the transfer roller 16 and the skew amount S is calculated. However, if the load applied to the transfer roller 16 can be detected, a parameter other than the rotation speed is used. The skew amount S can be calculated. For example, the amount of rotation of the transfer roller 16 can be used instead of the rotation speed of the transfer roller 16. Further, since the transfer roller 16 is driven by the transfer motor 20 via the motor pulley 21, the timing belt 22, and the pulley gear 23, the current and voltage flowing through the transfer motor 20, fluctuations in the pulse width in pulse width modulation (PWM), and the like are taken into consideration. The skew amount S may be obtained. The skew amount S can also be obtained from the fluctuation in the torque of the transfer motor 20. Therefore, a detection means for detecting at least one of the input voltage, the input current, and the torque of the transfer motor 20 which is the drive means is provided, and the skew amount calculation unit 405 sets the skew amount based on the fluctuation of the detected value. Those that calculate S are also included in the category of this embodiment.
In the present embodiment, the amount of variation ΔV of the rotation speed, which is the difference between the reference rotation speed Vd and the peak rotation speed during biting, is calculated to calculate the amount of skew S. Any other method may be used as long as it is a calculation method. For example, the skew amount S may be calculated by obtaining the change in the sheet transport speed due to the change in the rotation speed when the sheet is bitten into the nip portion.

In the present embodiment, the loop amount is changed as the correction operation, but the correction operation itself may be changed according to the skew amount S of the sheet 50. In the present embodiment, as a mode of the straightening operation, that is, a straightening mode, a reverse rotation straightening mode (also referred to as reverse hitting straightening) in which the tip of the sheet 50 is abutted against the nip portion of the reverse rotating transport roller 16 is used. , The correction mode includes other than the reverse rotation correction mode. For example, there is a stop correction mode (also referred to as stop abutting correction) in which the tip of the sheet is abutted against the nip portion of the stopped transfer roller. In addition, after rotating the transport roller in the normal direction and biting the tip of the sheet once, the transfer roller is rotated in the reverse direction while stopping the rotation of the feed roller on the feed side, and the tip of the sheet is abutted against the nip of the transport roller. There is a crowd correction mode. The bite correction mode is also called bite butt correction. Although the stop correction mode and the bite correction mode are inferior in the skew correction ability as compared with the reverse rotation correction mode used in the present embodiment, scratches on the tip of the sheet are less likely to occur. Therefore, the quality of the sheet can be improved by changing the correction mode used for the correction operation according to the skew amount S. As a further modification example, if the skew amount S of the sheet is small as a result of the skew amount calculation, the correction operation itself may not be executed and the recording operation may be started. That is, based on the skew amount S, either the case where the correction operation is performed or the case where the correction operation is not performed may be selected. With this configuration, the recording speed can be improved.

In the above description, a recording device for alternately carrying out a predetermined amount of sheets and scanning an image recording in the recording head in the sheet width direction has been described, but the recording device to which the present invention can be applied is not limited to this. Absent. For example, the present invention can be applied to a recording device that simultaneously transports a sheet and records an image by using a line-type or page-wide type recording head in which discharge ports are arranged in the sheet width direction.

(Second Embodiment)
In the first embodiment described above, the quality of the sheet and the recording speed are improved by changing the correction operation for the sheet based on the detected amount of skew, but the amount of skew is adjusted to the detected amount. The same effect can be obtained by rotating the recorded image itself. In the second embodiment, a recording device that rotates an image according to the detected skew amount of the sheet and records the image on the sheet will be described. The recording device of the present embodiment has the same structure as that of the first embodiment in terms of the configuration of the mechanical unit, and the configuration of the control system and the processing procedure associated therewith are different from those of the first embodiment. Therefore, the second embodiment will be described focusing on the differences from the recording device of the first embodiment.

FIG. 14 shows the configuration of the control system 400 in the recording device of the present embodiment. For the sake of explanation, FIG. 14 shows a motor driver 404 for driving the feed motor 4 and the transfer motor 20, an encoder sensor 8 for controlling PID of each motor, and a motor control unit 410 for the sake of explanation. Absent. The difference between the control system 400 of the present embodiment and the control system of the device of the first embodiment is that the correction control unit is not provided, and instead, the image rotation unit 411 and the direction determination unit 412 are the controller 403. It is provided inside. The image rotation unit 411 and the direction determination unit 412 correspond to the image rotation means and the direction determination means, respectively. The direction determination unit 412 determines the oblique direction of the sheet 50. In the skew amount calculation technique based on the present invention, the load generated at the time of biting into the nip portion appears on the transport roller in an integrated form. Therefore, in principle, the right end or the left end of the sheet precedes. It is not possible to determine the skew direction. Therefore, in the present embodiment, the carriage 1 is newly provided with the detection sensor 413 that detects the seat edge, and the skew direction of the seat 50 is determined based on the information from the detection sensor 413 and the information from the encoder sensor 25. The image rotation unit 411 images a rotation image corresponding to the skew of the sheet 50 based on the skew amount S of the sheet 50 calculated by the skew amount calculation unit 405 and the skew direction determined by the direction determination unit 412. Generate from data. The generated rotation image is output to the recording head 414 mounted on the carriage 1. FIG. 15 is a conceptual diagram showing that an image is rotated and recorded with respect to the oblique sheet 50. FIG. 15A shows an image 51 generated when the sheet 50 has no skew, that is, an image based on the image data itself supplied from the outside to the recording device 100, and FIG. 15B shows the case where there is skew. The image generated in, that is, the rotated image 52 is shown.

Next, a mechanism in which the direction determination unit 412 determines the skew direction will be described with reference to FIG. FIG. 16A shows a case where the left end of the sheet precedes in the transport direction, and FIG. 16B shows a case where the right end of the sheet precedes. As described in the first embodiment, when the tip of the sheet bites into the nip portion of the transfer roller 16, the rotation speed of the transfer roller 16 depends on the skew of the sheet, FIGS. It changes with the profile as shown in b). The fact that the tip of the sheet is completely caught in the nip portion can be detected by returning the reduced rotation speed of the transport roller 16 to a predetermined rotation speed. This biting completion determination can be determined in both the case of FIG. 7A and the case of FIG. 7B, regardless of the amount of skew of the sheet 50. In FIG. 16, reference numeral 50a indicates a sheet that has reached the biting completion position, and reference numeral 50b indicates a sheet at a position where the end of the sheet is detected by the detection sensor 413. Further, the position where the transfer roller 16 overlaps the rotation axis is the biting position Lj, and the position of the detection sensor 413 is the detection position Ld. The transfer roller 16 is rotated after detecting that the sheet has reached the biting completion position, and the sheet transfer distance until the detection sensor 413 detects the edge of the sheet is measured by the encoder sensor 25. This distance is f1 in the case of the left end leading (FIG. 16 (a)) and f2 in the case of the right end leading (FIG. 16 (b)). If the seat is not skewed, this distance is the ideal distance m, which is the distance between the biting position Lj and the detection position Ld. The direction determination unit 412 determines the skew direction by comparing the sheet transport distance from the bite completion position to the detection position with the ideal distance m. In the present embodiment, since the detection sensor 413 is moved to the right side in the transport direction by the movement of the carriage 1, the detection distance f1 and the ideal distance m are equal to each other in the case of leading the left end shown in FIG. 16A. On the other hand, in the case of leading the right end shown in FIG. 16B, the detection distance f2 is smaller than the ideal distance m.

Next, with reference to FIG. 17, a process of calculating the skew amount in a series of recording operations from the start of feeding to the end of discharging and rotating the recorded image based on the calculation result will be described. First, steps 511 to 514 described with reference to FIG. 13 are carried out. When step 514 is completed and the skew amount S of the sheet 50 is calculated, the direction determination unit 412 then starts the above-described skew direction determination operation (step 525). Specifically, the carriage 1 is moved to a position in the width direction in which the right end of the sheet in the transport direction can be detected, and the transport roller 16 is rotated in the transport direction. The rotation of the transport roller 16 is carried out until the end of the sheet passes the position of the detection sensor 413 and reaches the position below the recording head 414. When the edge of the sheet is detected by the detection sensor 413, the direction determination unit 412 determines the direction of the skew of the sheet according to the above procedure (step 526).
After the skew amount S and the skew direction (right side leading or left leading) are calculated, the image rotation unit 411 generates a rotation image according to the inclination of the sheet based on the calculated value (step 527). After the tip of the sheet reaches the position of the recording head 414 and the rotation image is generated, step 518 described with reference to FIG. 13 is performed. The image recorded at this time is a rotated image generated by the image rotating unit 411 that matches the inclination of the sheet. After that, the sheet is ejected from the transport unit, and a series of recording operations is completed in step 519).

In the present embodiment, the bite completion position is detected from the fluctuation amount ΔV of the rotation speed at the time of biting into the nip portion, and the distance from the bite completion position to the detection sensor 413 detecting the seat edge is measured. The diagonal direction is determined. However, other methods can be used to determine the skew direction. For example, two sensors for detecting the seat edge may be provided in the seat width direction, and the skewing direction can be determined by using the timing difference between the two sensors. In this case, it is not necessary to change the positions of the two sensors, and it is appropriate to arrange the two sensors at positions where the edges can be detected with respect to the minimum size sheet to be recorded.
According to the second embodiment, it is possible to record an image on the sheet according to the skew of the sheet. Therefore, the correction operation for correcting the skew as described in the first embodiment is performed. It is possible to improve the recording speed and the quality of the sheet.

(Third Embodiment)
In the first and second embodiments, the configuration for performing image recording on the skewed sheet without deteriorating the recording quality has been described, but when the skew of the sheet is excessive, the image recording is continued. In some cases, a paper jam may occur and the device may break down. Paper jams occur when the edges of a skewed sheet collide with a component in or near the transport path. In the third embodiment, a recording device that temporarily stops the recording operation when the skew amount exceeds a predetermined amount and notifies the user of a paper jam will be described.
The recording device of the third embodiment can be realized by adding a mechanism for determining the presence or absence of a paper jam and a mechanism for notifying the occurrence of a paper jam in the recording device of each of the above-described embodiments. FIG. 18 shows the control system 400 in the recording device of the third embodiment in which a mechanism for determining the presence or absence of a paper jam and a mechanism for notifying the occurrence of a paper jam are added to the recording device of the first embodiment. The configuration is shown. As shown in FIG. 18, the controller 403 is newly provided with a paper jam determination unit 421, and as a user interface in the recording device 100, a user notification unit 422, which is a notification means and notifies the state of a paper jam, is newly provided. It is provided in. As the user notification unit 422, a monitor (not shown) provided in the recording device 100 or the like can also be used. The paper jam determination unit 421 compares the skew amount S calculated by the skew amount calculation unit 405 with a predetermined paper jam determination value. When the skew amount S is larger than the paper jam determination value, the rotation of the transport roller 16 is interrupted to stop the transport operation, and the user notification unit 422 notifies the user of the paper jam state.

FIG. 19 shows when the skew amount calculation and the paper jam determination are performed in a series of recording operations from the start of feeding to the end of discharge in the recording device of the third embodiment, and it is determined that a paper jam has occurred. Indicates the process of stopping the recording operation and notifying the user. First, steps 511 to 514 described with reference to FIG. 13 are carried out. When step 514 is completed and the skew amount S of the sheet 50 is calculated, the paper jam determination unit 421 then determines the paper jam (step S545). When it is determined that the paper jam is determined, the paper jam determination unit 421 stops the rotation of the feeding roller 2 and the transport roller 16 that are rotating via the motor driver 404 (step 546), and interrupts the transport operation. After that, the paper jam determination unit 421 notifies the user via the user notification unit 422 that the user is in an abnormal state such as a paper jam state (step 547). This completes a series of recording operations. On the other hand, if it is not determined that the paper is jammed in step 545, steps 518 and 519 described with reference to FIG. 13 are executed to record the sheet 50 and eject the sheet 50 after the recording.

In the above description, the paper jam determination is performed using a single paper jam determination value. However, since the possibility of a paper jam differs depending on the type and size of the sheet, a determination value may be set for each type and size of the sheet, and the paper jam may be determined for each type and size of the sheet. With this configuration, the burden of confirmation work on the user can be reduced.
In the present embodiment, only the paper jam warning based on the skew amount is given, but since the load collapse of the sheet bundle is the main factor for increasing the skew amount, the accommodating unit (not shown) via the user notification unit 422. ) May be notified to confirm the alignment state of the sheet bundles. With this configuration, the probability of warning occurrence from the next time onward can be reduced.
According to the present embodiment, when there is a possibility that a paper jam may occur due to skewing of the sheet, the user can be notified before the occurrence of the paper jam, so that the possibility of device failure can be reduced. ..

2 Feeding roller 3,18 Pinch roller 8,25 Encoder sensor 16 Conveying roller 405 Diagonal amount calculation unit

Claims (16)

A transport roller that transports the sheet and
A pinch roller arranged at a position facing the transport roller and sandwiching the sheet with the transport roller at a plurality of positions in the width direction of the sheet.
A transport device including an encoder that detects the rotation speed or the amount of rotation of the transport roller as a detection value.
When the end portion of the sheet in the transport direction passes through the nip portion formed between the transport roller and the pinch roller when the transport roller is controlled to have a predetermined rotation speed. A transport device characterized in that the skew amount of the sheet is calculated based on the fluctuation amount of the detected value detected by the encoder. The amount of fluctuation of the detected value is the difference between the peak value of the detected value when the end portion passes through the nip portion and the detected value when the end portion of the sheet does not pass through the nip portion. The transport device according to claim 1, wherein the transport device is characterized by the above. It has a table in which data showing the relationship between the fluctuation amount of the detected value and the skew amount of the sheet is stored in advance.
Before referring to the table based on the variation amount of the dangerous detection value, the transport apparatus according to claim 1 or 2, characterized in that determining the skew amount of the sheet. The table is provided according to the type of sheet and the size of the sheet.
The transport device according to claim 3, wherein the skew amount of the sheet is determined by using the table associated with each type and size of the sheet. The transport device according to any one of claims 1 to 4, wherein a plurality of pinch rollers are provided in the width direction of the sheet. The driving means for driving the transport roller and
A control means for controlling the drive means is further provided.
The transport device according to any one of claims 1 to 5, wherein the control means controls the drive means based on a detection value detected by the encoder. A feeding roller arranged on the upstream side of the transport roller in the transport direction of the sheet and transporting the sheet, and a feeding roller.
The transport according to any one of claims 1 to 6, further comprising a detection sensor provided between the transport roller and the feed roller and detecting the passage of an end portion of the sheet. apparatus. The sheet is based on the detection value detected by the encoder after the tip of the sheet is detected by the detection sensor until the tip of the sheet passes through the nip portion and conveys a predetermined transfer amount. The transport device according to claim 7, wherein the skew amount is calculated. A correction control means for controlling a correction operation for correcting the skew of the sheet performed by the feeding roller and the conveying roller is provided.
The end of the sheet in the transport direction is the tip of the sheet.
The straightening control means calculates the skew amount of the sheet when the tip of the sheet passes through the nip portion, and then reversely rotates the feeding roller and the conveying roller to convey the sheet. The transport device according to claim 7 or 8, wherein the transport device is retracted to the upstream side in the direction, and then the straightening motion is changed based on the calculated skew amount to execute the straightening motion. The straightening operation is an operation in which a sheet conveyed by the feeding roller is abutted against the nip portion to form a loop in the sheet between the feeding roller and the conveying roller.
The transfer device according to claim 9, wherein the change in the correction operation is to change the size of the loop to be formed. The correction operation is changed into a reverse rotation correction mode in which the sheet is abutted against the nip portion while rotating the transfer roller in the reverse direction, and a stop correction mode in which the sheet is abutted against the nip portion while the transfer roller is stopped. , A plurality of correction modes of the bite correction mode in which the sheet is bitten into the nip portion and then the feeding roller is stopped and the transport roller is rotated in the reverse direction to abut the sheet against the nip portion. The transport device according to claim 10, wherein the correction mode is switched between the two. The transport device according to claim 10 or 11, wherein the change of the correction operation includes selecting either a case where the correction operation is performed or a case where the correction operation is not performed. Equipped with a notification means to notify the abnormal status of the transport device
According to any one of claims 1 to 12, the transport operation is stopped when the skew amount of the sheet exceeds a predetermined predetermined amount, and the abnormal state is notified by the notification means. The carrier described. An accommodating unit for accommodating a bundle of sheets composed of a plurality of sheets,
A feeding unit that separates sheets one by one from the sheet bundle and conveys the separated sheets.
It is equipped with a notification means that prompts you to check the alignment status of the sheet bundle.
The invention according to any one of claims 1 to 12, wherein when the skew amount of the sheet exceeds a predetermined predetermined amount, a notification prompting the confirmation of the alignment state is performed by the notification means. Conveyor device. A recording device that records on a sheet based on image data.
The transport device according to any one of claims 1 to 8.
A direction determining means for determining the skewing direction of the sheet, and
A recording head that records an image on the sheet,
An image rotating means that rotates the image data to generate a rotated image based on the skew amount of the sheet and the skew direction determined by the direction determining means, and
The recording head is a recording device for recording a rotated image on the sheet. A transport roller for transporting the sheet, a pinch roller provided facing the transport roller and sandwiching the sheet between the transport rollers at a plurality of positions in the width direction of the sheet, and a transport direction of the sheet. It is a transport method in a transport device having a feed roller provided on the upstream side of the transport roller and transport the sheet.
The rotation speed or the amount of rotation of the transfer roller is detected from the encoder as a detection value, and
Based on the amount of fluctuation of the detected value when the tip of the sheet passes through the nip portion formed between the transfer roller and the pinch roller when the transfer roller is controlled to a predetermined rotation speed. A method of transporting the sheet, which comprises calculating the amount of skew of the sheet.

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