JP2018193200A - Recording device - Google Patents

Abstract

To suppress decrease of accuracy of a thrust amount to a carrier roller due to a backlash of a drive mechanism of the carrier roller when conducting skew correction to realize skew correction with high accuracy.SOLUTION: Power transmission means 30 has a configuration that rotates both a first carrier roller pair 15 and a second carrier roller pair 16 in a normal direction when rotationally driving a drive motor 22 in a first direction, and rotates the first carrier roller pair 15 in the normal direction and the second carrier roller pair 16 in an inverse direction when rotationally driving the drive motor 22 in a second direction opposite to the first direction, a control unit 23 comprises a first skew correction mode that maintains a driving direction of the drive motor 22 in the second direction when a tip of a sheet reaches a conveyance target position S between a nip position N1 of the sheet in the first carrier roller pair 15 and a detection position of a first medium sensor 18 until at least the tip of the sheet strikes the second carrier roller pair 16.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a recording apparatus that performs recording on a conveyed medium.

  In a recording apparatus typified by a printer, a plurality of sheets as a medium are set, and the plurality of sheets are fed one by one by a feeding means such as a feeding roller, and a recording unit that performs recording is used. It is comprised so that it may convey toward.

By the way, in the printer, there is a case where a so-called skew (also referred to as skew) occurs in which the sheet is conveyed in an inclined state.
In order to avoid the sheet from being obliquely sent to the recording unit, a technique for correcting the skew by hitting the sheet against a conveyance roller on the upstream side of the recording unit has been conventionally used (for example, Patent Document 1 and Patent Document 2).

Specifically, in the skew correction operation, the leading end of the sheet is abutted against the transport roller to form a bend in the sheet. Due to this bending, the leading edge of the sheet follows the conveying roller, and the skew is corrected.
When the skew correction operation is performed, that is, when the paper is abutted against the transport roller, the transport roller is switched from the normal rotation drive for transporting the paper to the reverse drive.

JP, 2006-078388, A Japanese Patent Laid-Open No. 2006-150826

By the way, in a printer, some conveyance rollers may be driven by the same drive source (motor etc.). Accordingly, a conveyance roller (hereinafter referred to as a correction conveyance roller) on which paper is abutted for skew correction operation, and an upstream conveyance roller that is provided on the upstream side of the paper and that feeds the paper to the correction conveyance roller. May be driven by the same drive source.
In this case, in order to achieve both the normal paper conveyance operation and the skew correction operation, both the correction conveyance roller and the upstream conveyance roller rotate in the normal direction when the motor as the drive source is driven in the normal direction. In addition, when the motor is driven in reverse, the correction conveyance roller is reversed, but a power transmission mechanism is configured to transmit power from the motor to each roller so that the upstream conveyance roller is maintained in normal rotation. There is a need.

Conventionally, when the skew correction operation is performed, the motor is switched from the forward drive to the reverse drive using a detection of paper by a sensor provided near the upstream side of the correction conveyance roller as a trigger. It was.

In this case, when the skew correction operation is performed, the paper is brought into contact with the correction transport roller by the upstream transport roller due to the backlash of the power transmission mechanism when the motor is switched from the forward drive to the reverse drive. In some cases, the accuracy of the amount decreases, and as a result, the accuracy of correcting the skew decreases.

In particular, if the device is downsized, it may not be possible to sufficiently secure the space necessary for the formation of the deflection required for skew correction. When the amount of abutment is small, the influence of the backlash becomes larger, so that it becomes more difficult to maintain the skew correction accuracy.

  Therefore, an object of the present invention is to suppress a decrease in the accuracy of the amount of abutting of the sheet against the conveyance roller due to backlash of the driving mechanism of the conveyance roller, and to realize a highly accurate skew correction.

  In order to solve the above-described problem, a recording apparatus according to a first aspect of the present invention includes a first transport roller pair that transports the medium toward a recording unit that records on the medium, and a downstream of the first transport roller pair. And a second transport roller pair provided on the upstream side of the recording unit, and the second transport roller pair from the first transport roller pair between the first transport roller pair and the second transport roller pair. A first medium sensor that detects at least the passage of the front end of the medium, a drive motor that is a drive source of the first transport roller pair and the second transport roller pair, and power of the drive motor By controlling the power transmission means for transmitting to the first transport roller pair and the second transport roller pair and the drive motor, the medium is abutted against the second transport roller pair, And a controller that performs a skew correction operation for correcting the skew of the medium, and the power transmission means rotates the drive motor in the first direction when the drive motor rotates in the first direction. When both of the roller pairs are rotated in the forward direction to send the medium toward the recording unit and the drive motor is driven to rotate in a second direction opposite to the first direction, the first transport roller pair In the forward direction and the second transport roller pair is rotated in the reverse direction, and the control unit includes a nip position of the medium in the first transport roller pair, and the first medium sensor. When the leading edge of the medium reaches a transport target position between the detection position by the above, the driving direction of the drive motor is changed until at least the leading edge of the medium hits the second transport roller pair. Comprising a first skew correction mode to maintain the two directions, characterized in that.

When executing the first skew correction mode, the drive direction of the drive motor is changed from the first direction (both the first transport roller pair and the second transport roller pair rotate in the forward direction) to the second direction (first When the transport roller pair rotates in the forward direction and the second transport roller pair rotates in the reverse direction), that is, when the rotational drive of the drive motor is reversed, the components constituting the power transmission means (for example, gears, cams, belts, etc.) ) Due to play (gap) in) may occur.
Conventionally, when correcting the skew, the driving is performed when the leading edge of the medium reaches a detection position by the first medium sensor, that is, when the leading edge of the medium reaches a position closer to the second conveyance roller pair. The rotation drive of the motor was reversed. Therefore, at the time of reversing the rotational drive of the drive motor, play-related deviation, rattling, etc. occur in the components of the power transmission means, and the medium is abutted against the second transport roller pair in the skew correction operation. In some cases, the accuracy of the quantity was affected.

According to this aspect, in the first skew correction mode performed by the control unit, the conveyance target position between the nip position of the medium in the first conveyance roller pair and the detection position by the first medium sensor is set to the conveyance target position. When the leading edge of the medium reaches, the drive direction of the drive motor is maintained in the second direction until at least the leading edge of the medium hits the second conveying roller pair. The skew correction operation can be executed with less influence of rattling and the like. Accordingly, the accuracy of the skew correction of the medium can be improved.
In addition, the position of the first medium sensor can be arranged closer to the second transport roller pair. Thus, the apparatus can be reduced in size.

  According to a second aspect of the present invention, in the first aspect, the power transmission means has a configuration in which the power of the drive motor is transmitted by a plurality of gears engaged with each other.

When the power transmission means has a configuration in which the power of the drive motor is transmitted by a plurality of gears engaged with each other, the first transport roller pair or the A deviation may occur in the conveyance accuracy of the medium by the second conveyance roller pair.
According to this aspect, in the recording apparatus having the configuration in which the power transmission means transmits the power of the drive motor by using a plurality of gears that are engaged with each other, it is possible to obtain the same operational effects as those of the first aspect. That is, it is possible to correct the skew of the medium by reducing the influence of the deviation of the medium conveyance accuracy due to the backlash.

  According to a third aspect of the present invention, in the first aspect or the second aspect, the control unit separates from the first skew correction mode until the leading edge of the medium is detected by the first medium sensor. When the drive motor is driven to rotate in the first direction and the first medium sensor detects the leading edge of the medium, the driving direction of the driving motor is switched from the first direction to the second direction, and the leading edge of the medium is moved. A second skew correction mode that abuts against the second conveying roller pair is provided.

  According to this aspect, for example, the first skew correction according to the type of the medium and the recording setting (whether continuous recording is performed continuously on a plurality of media or single recording is performed only on one sheet). The mode and the second skew correction mode can be switched. Therefore, it is possible to improve the throughput while improving the recording quality. This point will be described in detail later.

  According to a fourth aspect of the present invention, in the third aspect, the fourth aspect includes a feeding roller that feeds the medium from a medium accommodating portion that accommodates a plurality of media, and the feeding roller is a pair of the first conveying rollers. And it is driven by the drive motor common to the second transport roller pair.

  According to this aspect, the feeding roller that feeds the medium from the medium accommodating unit that accommodates a plurality of media is driven by the drive motor that is common to the first conveying roller pair and the second conveying roller pair. Therefore, the size of the apparatus can be reduced by reducing the number of parts.

  According to a fifth aspect of the present invention, in the fourth aspect, the power transmission means rotates the feeding roller in the positive direction when the drive motor is rotationally driven in the first direction, and the drive When the motor is driven to rotate in the second direction, the power of the driving motor is not transmitted to the feeding roller.

  According to this aspect, the power transmission means rotates the feeding roller in the forward direction and rotationally drives the drive motor in the second direction when the drive motor is rotationally driven in the first direction. Since the power of the drive motor is not transmitted to the feeding roller when performing the recording, when performing continuous recording on a plurality of media, after performing skew correction on the preceding medium, the feeding roller Subsequent feeding of the subsequent medium is started. Accordingly, it is possible to appropriately secure an interval between the preceding medium and the succeeding medium.

  According to a sixth aspect of the present invention, in the fifth aspect, the control unit is configured to reduce the first feeding mode and the second feeding for reducing the interval between the medium preceding and following the first feeding mode. The first skew correction mode is selected when the first feeding mode is executed, and the second skew correction mode is selected when the second feeding mode is executed. It is characterized by.

When the feeding roller is driven by the drive motor that is common to the first transport roller pair and the second transport roller pair, and the power transmission unit rotationally drives the drive motor in the first direction, When the feed roller is rotated in the forward direction and the drive motor is driven to rotate in the second direction, the first skew correction is performed when the power of the drive motor is not transmitted to the feed roller. During the execution of the mode or the second skew correction mode, the feeding by the feeding roller is not performed while the driving direction of the driving motor is set to the second direction.
In the first skew correction mode, the timing of switching the drive direction of the drive motor from the first direction to the second direction is earlier than that in the second skew correction mode. The period that is not performed becomes longer. That is, the first skew correction mode is a mode in which the interval between the preceding medium (hereinafter referred to as the preceding medium) and the subsequent medium (hereinafter referred to as the subsequent medium) is wider than that of the second skew correction mode. . When the interval between the preceding medium and the succeeding medium increases, the recording throughput decreases.

  According to this aspect, when the first feeding mode is executed, the first skew correction mode is selected, and when the second feeding mode is executed, the second skew correction mode (first skew correction is performed). Therefore, it is possible to suppress a decrease in throughput in the second feeding mode in which the interval between the preceding medium and the succeeding medium is narrower than that in the first feeding mode.

  According to a seventh aspect of the present invention, in the fifth aspect, the control unit selects the first skew correction mode when the length of the medium to be conveyed is longer than a predetermined length, and the first control mode when the medium is short. 2 skew correction mode is selected.

As described above, when the first skew correction mode or the second skew correction mode is performed, feeding by the feeding roller is not performed while the drive direction of the drive motor is set to the second direction. In this case, the interval between the preceding medium and the succeeding medium is widened. For example, when a skew correction operation is performed on the preceding medium, the trailing end side of the preceding medium is in a position in contact with the feeding roller. In the case of a long medium, there is no problem that the distance between the preceding medium and the succeeding medium increases in the first skew correction mode.
Therefore, the control unit selects the first skew correction mode when the length of the conveyed medium is longer than a predetermined length, and selects the second skew correction mode when the length is shorter than the predetermined length. Through improvement, throughput can be improved.

  According to an eighth aspect of the present invention, there is provided a discharge roller pair provided on the downstream side of the recording unit in any one of the first to seventh aspects, and configured to discharge the medium after recording. The roller pair is driven by the drive motor common to the first transport roller pair and the second transport roller pair.

  According to this aspect, the discharge roller pair that is provided on the downstream side of the recording unit and discharges the medium after recording is driven by the drive motor that is common to the first transport roller pair and the second transport roller pair. Therefore, the size of the apparatus can be reduced by reducing the number of parts.

  According to a ninth aspect of the present invention, in the eighth aspect, the power transmission means rotates the discharge roller pair in the positive direction when the drive motor is rotationally driven in the first direction, and the drive When the motor is driven to rotate in the second direction, the discharge roller pair is rotated in the opposite direction.

  According to this aspect, when the power transmission means rotationally drives the drive motor in the first direction, the discharge roller pair is rotated in the forward direction, and the drive motor is rotationally driven in the second direction. In this case, in the recording apparatus having a configuration in which the discharge roller pair is rotated in the reverse direction, the same effect as the eighth aspect is obtained.

FIG. 3 is an external perspective view illustrating an example of a printer according to the invention. The side sectional view of a device main part. FIG. 3 is a schematic diagram illustrating a sheet conveyance path. The figure explaining 2nd skew correction mode. The flowchart which shows the flow of 2nd skew correction mode. The figure explaining 1st skew correction mode. The flowchart which shows the flow of 1st skew correction mode. The perspective view which shows the state which removed the exterior of the apparatus main body. The top view of the power transmission means provided in the flame | frame assembly. The perspective view of the power transmission means provided in the flame | frame assembly. The perspective view which shows the part connected with a feed roller in a power transmission means.

[Example 1]
As an example of the recording apparatus according to the present invention, an ink jet printer is taken as an example. Hereinafter, an outline of the inkjet printer 1 (hereinafter referred to as the printer 1) will be described. FIG. 1 is an external perspective view showing an example of a printer according to the present invention. FIG. 2 is a side sectional view of the apparatus main body. FIG. 3 is a schematic diagram showing a paper conveyance path. FIG. 4 is a diagram illustrating the second skew correction mode. FIG. 5 is a flowchart showing the flow of the second skew correction mode. FIG. 6 is a diagram illustrating the first skew correction mode. FIG. 7 is a flowchart showing the flow of the first skew correction mode. FIG. 8 is a perspective view showing a state in which the exterior of the apparatus main body is removed. FIG. 9 is a plan view of power transmission means provided in the frame assembly. FIG. 10 is a perspective view of power transmission means provided in the frame assembly. FIG. 11 is a perspective view showing a portion connected to the feeding roller in the power transmission means.

In the XYZ coordinate system shown in each figure, the X direction is the width direction of the recording apparatus and the scanning direction of the recording head. The Y direction is the depth direction of the recording apparatus and is the paper transport direction. The Z direction is the direction of gravity and indicates the height direction of the recording apparatus.
Further, the + Y direction is the front side of the apparatus, and the −Y direction side is the back side of the apparatus. Further, the + Z direction is referred to as the upper side (including the upper part and the upper surface), and the −Z direction is referred to as the lower side (including the lower part and the lower surface).
The direction in which the sheet as the “medium” is conveyed in the printer 1 is called “downstream”, and the opposite direction is called “upstream”.

■■■ Overview of the printer ■■■
First, an outline of the printer 1 will be described mainly with reference to FIG.
The printer 1 shown in FIG. 1 includes an apparatus main body 2 including a recording head 20 (FIG. 2) as a “recording unit” that performs recording on a sheet, and a scanner unit 3. The scanner unit 3 includes a scanner body 3a and an ADF (auto document feeder) 3b. An operation unit 4 and a discharge port 5 are provided on the front side of the apparatus main body 2, and a medium receiving tray 6 is provided below the discharge port 5. Below the medium receiving tray 6, a medium accommodation cassette 7 that can be inserted into and removed from the apparatus main body 2 from the front side of the apparatus main body 2 is provided.

■■■ Printer paper transport path ■■■
Next, the paper conveyance path of the printer 1 will be described mainly with reference to FIG. In FIG. 2, the conveyance path of the paper P is indicated by a one-dot chain line. On the −Y direction side of the apparatus main body 2, a feeding roller 10 is disposed above the medium accommodation cassette 7. The feeding roller 10 is configured to be swingable about a swing shaft 11 as a fulcrum. The feeding roller 10 rotates in contact with the medium accommodated in the medium accommodating cassette 7, thereby conveying the uppermost medium of the medium accommodated in the medium accommodating cassette 7 to the downstream side along the sheet conveying path. The feed roller 10 is driven by a drive motor 22 (FIG. 3).

An intermediate roller 12 is provided on the downstream side of the feeding roller 10 in the medium conveyance direction. The intermediate roller 12 is driven by a drive motor 22 (FIG. 3). Driven rollers 13 a, 13 b, 13 c, and 13 d are provided around the intermediate roller 12 so as to be driven to rotate with respect to the intermediate roller 12.
In this embodiment, four driven rollers 13a, 13b, 13c, and 13d are provided for one intermediate roller 12. However, each driven roller 13a, 13b, 13c, and 13d is provided with an individual driving roller. be able to. In the present embodiment, a roller pair constituted by a combination of the intermediate roller 12 and the driven roller 13c is referred to as a “first transport roller pair 15”. The first transport roller pair 15 transports the paper P toward the recording head 20.

The sheet P sent by the feeding roller 10 passes through the intermediate roller 12 and the driven rollers 13a and 13b, and then passes through the first conveying roller pair 15 (the intermediate roller 12 and the driven roller 13c) to the downstream second conveying roller pair. 16 is sent. The second transport roller pair 16 is a roller pair provided on the downstream side of the first transport roller pair 15 and on the upstream side of the recording head 20.
The second transport roller pair 16 sends the paper P to a recording area (FIG. 3) below the recording head 20, and recording is performed by the recording head 20. The recording head 20 is provided below the carriage 21 that moves in the width direction (X-axis direction) intersecting the medium conveyance direction.

  A first position that detects at least the passage of the leading edge of the paper P is located between the first conveyance roller pair 15 and the second conveyance roller pair 16 at a position closer to the second conveyance roller pair 16 than the first conveyance roller pair 15. A medium sensor 18 (FIG. 3) is arranged.

The paper P after recording by the recording head 20 is discharged to the medium receiving tray 6 through the discharge port 5 by the discharge roller pair 17. The second transport roller pair 16 and the discharge roller pair 17 are driven by a drive motor 22 (FIG. 3).
That is, the feed roller 10, the first transport roller pair 15 (the intermediate roller 12 and the driven roller 13c), the second transport roller pair 16, and the discharge roller pair 17 are a drive motor 22 (FIG. 3) that is a common drive source. Driven by. As a result, the number of parts can be reduced and the apparatus can be downsized. In addition, it is comprised so that operation | movement of each roller pair may change with the rotation directions of the drive motor 22. FIG.

Incidentally, there may be a skew (skew) in which the paper P sent from the medium storage cassette 7 is transported obliquely in the transport process. In order to correct the skew of the paper P before recording, a skew correction operation for correcting the skew of the paper P is executed before the second transport roller pair 16 sends the paper P toward the recording area by the recording head 20. As shown in FIG. 3, the skew correction operation is performed by the control unit 23 controlling the drive motor 22 to abut the leading end of the paper P against the nip portion N <b> 2 of the second transport roller pair 16. In the present embodiment, when the leading edge of the paper P abuts against the nip portion N2, the second transport roller pair 16 rotates in the direction opposite to the medium transport direction.
In the following, after explaining the rotation direction of the drive motor 22 and the operation of each roller pair, the skew correction operation will be explained.

■■■ About the rotation direction of the drive motor and the operation of each roller ■■■
The power of the drive motor 22 is transmitted to each roller by the power transmission means 30. The drive motor 22 is configured to be rotatable in a first direction that is one rotation direction and a second direction that is the opposite direction.
The drive motor 22 transmits driving force to the feed roller 10, the first transport roller pair 15, the second transport roller pair 16, and the discharge roller pair 17 via the power transmission means 30.

  More specifically, when the drive motor 22 is rotationally driven in the first direction, the power transmission means 30 directs both the first conveyance roller pair 15 and the second conveyance roller pair 16 to the recording head 20. When the drive motor 22 is driven to rotate in the second direction opposite to the first direction, the first transport roller pair 15 is rotated in the forward direction and the second transport roller pair is rotated. 16 is rotated in the reverse direction.

  The power transmission means 30 rotates the feeding roller 10 in the forward direction and rotationally drives the driving motor 22 in the second direction when the driving motor 22 rotates in the first direction. The power of the drive motor 22 is not transmitted to the roller 10. That is, when the drive motor 22 is rotationally driven in the second direction, power is not transmitted to the feeding roller 10 and the sheet P is not picked up by the feeding roller 10.

Further, the power transmission means 30 rotates the discharge roller pair 17 in the positive direction when the drive motor 22 rotates in the first direction, and rotates the drive motor 22 in the second direction. The discharge roller pair 17 is configured to rotate in the reverse direction. That is, the discharge roller pair 17 rotates in the same direction as the second transport roller pair 16.
Table 1 shown below shows the rotation direction of each roller pair according to the rotation drive direction (first direction and second direction) of the drive motor 22. The detailed configuration of the power transmission means 30 will be described later.

■■■ Skew correction operation ■■■
As described above, the skew correction operation is executed by the control unit 23 controlling the drive motor 22 to abut the leading edge of the paper P against the second transport roller pair 16.
The control unit 23 includes two modes of a “first skew correction mode” and a “second skew correction mode”, which are modes different from the “first skew correction mode”, as modes for executing the skew correction operation. ing. In the following, the “second skew correction mode” will be described first, and then the “first skew correction mode” will be described.

<<< Second Skew Correction Mode >>>
In the “second skew correction mode”, the control unit 23 rotates the drive motor 22 in the first direction until the first medium sensor 18 detects the leading edge of the paper P, and the first medium sensor 18 moves the paper P in the first direction. In this mode, when the leading edge is detected, the driving direction of the drive motor 22 is switched from the first direction to the second direction, and the leading edge of the paper P is abutted against the second transport roller pair 16.
The “second skew correction mode” corresponds to a conventional skew correction operation.
Details of the “second skew correction mode” will be described with reference to FIGS. 4 and 5.

  When performing the “second skew correction mode”, the control unit 23 rotationally drives the drive motor 22 in the first direction until the first medium sensor 18 detects the leading edge of the paper P (the upper diagram of FIG. 4). And step S1) of FIG. The upper diagram of FIG. 4 shows a normal conveyance state. That is, the first transport roller pair 15, the second transport roller pair 16, and the feed roller 10 rotate in the positive direction that is the medium transport direction, and transport the paper P in the direction toward the recording head 20.

  When the sheet P is conveyed and the first medium sensor 18 detects the leading edge of the sheet P (YES in step S2 in FIG. 5), as shown in the middle diagram of FIG. 4, the driving direction of the drive motor 22 is changed to the first direction. To step S3 (FIG. 5) for switching to the second direction. The middle diagram of FIG. 4 shows a state when the drive direction of the drive motor 22 is switched to the second direction and the skew correction operation is started. While the first medium sensor 18 does not detect the leading edge of the paper P (NO in step S2 in FIG. 5), the rotation of the drive motor 22 is maintained in the first direction.

  In step S3 of FIG. 5, when the drive direction of the drive motor 22 is switched to the second direction, the second transport roller pair 16 is in the positive direction while the first transport roller pair 15 is rotated in the positive direction. Rotate in the opposite direction. Further, the rotation of the feeding roller 10 is stopped.

Then, the drive direction of the drive motor 22 is switched to the second direction, and the drive motor 22 is driven by a predetermined drive amount (a predetermined number of steps when the drive motor 22 is a step motor). Accordingly, the first transport roller pair 15 feeds the paper P from the detection position of the leading edge of the paper P by the first medium sensor 18 by a predetermined distance (predetermined abutting amount), and the leading edge of the paper P is moved in the reverse direction. It abuts on the nip portion N2 of the rotating second conveying roller pair 16 (the lower diagram in FIG. 4).
The skew of the paper P is corrected by following the nip N2 of the second transport roller pair 16 while the leading edge of the paper P that has hit the nip N2 is bent. The lower diagram of FIG. 4 shows a state in which skew correction is performed.

<<< First Skew Correction Mode >>>
In the “first skew correction mode”, the controller 23 sets the conveyance target position S between the sheet nip position N1 (FIG. 3) in the first conveyance roller pair 15 and the detection position by the first medium sensor 18. In this mode, when the leading edge of the paper P reaches, at least the driving direction of the driving motor 22 is maintained in the second direction until the leading edge of the paper P abuts against the second transport roller pair 16.
Details of the “first skew correction mode” will be described with reference to FIGS. 6 and 7.

In the case of performing the “first skew correction mode”, the control unit 23 performs the conveyance target position between the sheet nip position N1 (FIG. 3) in the first conveyance roller pair 15 and the detection position by the first medium sensor 18. Until the leading edge of the sheet P reaches S, the drive motor 22 is rotationally driven in the first direction (upper view in FIG. 6 and step S11 in FIG. 7). The upper diagram of FIG. 6 shows a normal conveyance state.
In the present embodiment, the paper P is fed by the first transport roller pair 15 by driving the drive motor 22 by a predetermined drive amount (the number of steps counted by a rotary encoder (not shown)) from the start of pickup by the feed roller 10. It is assumed that the paper P has been fed a predetermined distance and the leading edge of the paper P has reached the transport target position S.
For example, another medium sensor is provided in the transport path on the upstream side of the first medium sensor 18, and the drive amount of the drive motor 22 for sending to the transport target position S on the basis of the detection position by the upstream medium sensor. Can also be set.

  When the paper P is transported and the leading edge of the paper P reaches the transport target position S (YES in step S12 in FIG. 7), as shown in the middle diagram of FIG. 6, the drive direction of the drive motor 22 is changed from the first direction. Proceed to step S13 (FIG. 7) for switching to the second direction. The middle diagram of FIG. 6 shows a state when the drive direction of the drive motor 22 is switched to the second direction and the skew correction operation is started. Until the leading edge of the paper P reaches the transport target position S (NO in step S12 in FIG. 7), the drive of the drive motor 22 in the first direction is maintained.

  When the drive direction of the drive motor 22 is switched to the second direction (step S13 in FIG. 7), the second transport roller pair 16 is opposite to the forward direction while the first transport roller pair 15 is rotated in the forward direction. Rotate in the direction. Further, the rotation of the feeding roller 10 is stopped.

When the paper P is sent and the leading edge of the paper P is detected by the first medium sensor 18 (YES in step S14 in FIG. 7), the control unit 23 keeps the drive motor 22 from the second direction in the second direction. Are driven (number of steps counted by a rotary encoder (not shown)) (step S15 in FIG. 7), and the paper P is fed by a predetermined distance by the first transport roller pair 15. By driving the driving motor 22 with the predetermined number of driving steps, the leading edge of the paper P abuts against the nip portion N2 of the second conveying roller pair 16 in which the rotation in the reverse direction is maintained (lower diagram in FIG. 6). The lower diagram of FIG. 6 shows a state in which the skew is corrected.
The skew of the paper P is corrected by following the nip N2 of the second transport roller pair 16 while the leading edge of the paper P that has hit the nip N2 is bent.
That is, in the “first skew correction mode”, when the leading edge of the paper P reaches the transport target position S, the control unit 23 drives the drive motor 22 until at least the leading edge of the paper P hits the second transport roller pair 16. Is maintained in the second direction.

Here, when the “first skew correction mode” or the “second skew correction mode” is executed, the drive direction of the drive motor 22 is changed from the first direction to the second direction, that is, the drive motor 22 is rotated. When the drive is reversed (in the middle diagram of FIG. 4 and the middle diagram of FIG. 6), the play (gap) in the constituent elements (for example, gears, cams, belts, etc.) constituting the power transmission means is displaced and rattled Etc. may occur.
In particular, the power transmission means 30 of the present embodiment, which will be described in detail later, has a configuration in which the power of the drive motor 22 is transmitted by a plurality of gears engaged with each other.
When the power transmission means 30 has a configuration for transmitting the power of the drive motor 22 to a plurality of gears, the medium transport accuracy by the second transport roller pair 16 is increased by backlash when the rotational drive of the drive motor 22 is reversed. Deviation may occur.

  In the “second skew correction mode” corresponding to the skew correction mode conventionally performed, when the leading edge of the paper P reaches the detection position by the first medium sensor 18, that is, a position closer to the second transport roller pair 16. When the leading edge of the paper P arrives, the rotational drive of the drive motor 22 is reversed. Therefore, when the rotational drive of the drive motor 22 is reversed (in the middle view of FIG. 4), the backlash of the power transmission means 30 is caused by the skew correction operation shown in the lower diagram of FIG. In some cases, the accuracy of the abutting amount when the leading edge of the paper P is abutted against the paper P may be affected. In particular, if the abutting amount is insufficient, there is a possibility that the skew cannot be corrected sufficiently.

However, in the “first skew correction mode”, the transfer target position S is located upstream of the switching position of the drive motor 22 in the “second skew correction mode” (the detection position by the first medium sensor 18). When the leading edge of the paper P reaches, the drive direction of the drive motor 22 is changed to the second direction. Thereafter, the drive direction of the drive motor 22 is maintained in the second direction until at least the leading edge of the paper P abuts against the second transport roller pair 16.
The abutting amount of the paper P against the second transport roller pair 16 (the feed amount by the first transport roller pair 15, that is, the driving amount of the predetermined number of steps of the drive motor 22) is the leading edge of the paper P by the first medium sensor 18. The detection position can be set as a reference. The influence of the backlash of the power transmission means 30 appears before the leading edge of the paper P moves from the conveyance target position S to the detection position by the first medium sensor 18, but the leading edge of the paper P by the first medium sensor 18. The feed amount from the detected position, that is, the accuracy of the abutting amount is not affected. Accordingly, the accuracy of the “first skew correction mode” of the paper P can be improved as compared with the “second skew correction mode”.

  When executing the “second skew correction mode”, the closer the position of the first medium sensor 18 is to the second conveyance roller pair 16, the ratio of the conveyance error due to the backlash to the amount of abutment against the second conveyance roller pair 16. However, by providing the “first skew correction mode”, the position of the first medium sensor 18 is brought closer to the second transport roller pair 16. It can also be arranged. Thus, the apparatus can be reduced in size.

In this embodiment, when the drive motor 22 is rotationally driven in the first direction, that is, both the first transport roller pair 15 and the second transport roller pair 16 are in the positive direction (normal medium transport direction). When rotating, the feeding roller 10 rotates in the positive direction. On the other hand, when the drive motor 22 is rotationally driven in the second direction, that is, when the second transport roller pair 16 is rotated in the reverse direction in order to perform the skew correction operation, the feed roller 10 has a drive motor. The power of 22 is not transmitted, and the feeding roller 10 does not rotate.
Therefore, when performing continuous recording in which recording is continuously performed on a plurality of sheets, feeding of the succeeding medium by the feeding roller 10 is started after performing skew correction on the preceding medium. Accordingly, it is possible to appropriately secure an interval between the preceding medium and the succeeding medium.

■■■ Selecting the skew correction mode ■■■
By providing the control unit 23 with two modes of “first skew correction mode” and “second skew correction mode”, for example, “first skew correction mode” according to conditions such as paper type and recording settings. And “second skew correction mode” can be switched. In the following, switching between the “first skew correction mode” and the “second skew correction mode” according to conditions such as the type of paper and recording settings will be described.

<<< Switching according to recording settings >>>
The control unit 23 closes the interval between the “single recording mode” as the “first feeding mode” and the sheet preceding the single recording mode (preceding sheet) and the succeeding sheet (following sheet). The “continuous recording mode” as the “feeding mode” can be executed.
Then, when executing the “single recording mode (first feeding mode)”, the control unit 23 selects the “first skew correction mode” and executes the “continuous recording mode (second feeding mode)”. At this time, the “second skew correction mode” is selected.

As described above, in both the “first skew correction mode” and the “second skew correction mode”, a skew correction operation is performed in which the leading edge of the paper P abuts against the second transport roller pair 16 that rotates in the reverse direction. And while the 2nd conveyance roller pair 16 is reversely rotating, the feed roller 10 has stopped (refer Table 1). Accordingly, when the “continuous recording mode (second feeding mode)” is executed, feeding of the succeeding sheet is not performed while the skew correction operation is performed on the preceding sheet.
Therefore, in the “first skew correction mode” in which the second transport roller pair 16 is switched in the reverse direction on the upstream side from the “second skew correction mode”, the feeding roller 10 is stopped because the switching timing is earlier. The period becomes longer, and the interval between the preceding sheet and the succeeding sheet becomes wider than when the “second skew correction mode” is executed. That is, the “first skew correction mode” is a mode in which the interval between the preceding sheet and the subsequent sheet is wider than the “second skew correction mode”. When the interval between the preceding sheet and the succeeding sheet increases, the recording throughput decreases.

In the present embodiment, when the “continuous recording mode (second feeding mode)” is executed, the “second skew correction mode” in which the interval between the preceding sheet and the succeeding sheet is not wider than that in the “first skew correction mode”. By selecting, it is possible to suppress a decrease in throughput in the “continuous recording mode (second feeding mode)”.
Further, when executing the “single recording mode (first feeding mode)” that does not need to worry about the interval between the preceding sheet and the succeeding sheet, the “first skew correcting mode” is selected to correct the skew. Can be improved.

<<< Switching according to paper size >>>
The control unit 23 selects the “first skew correction mode” when the length of the conveyed sheet is longer than a predetermined length, and selects the “second skew correction mode” when the length is shorter.
During the execution of the “first skew correction mode” or the “second skew correction mode”, feeding is performed while the drive direction of the drive motor 22 is set to the second direction and the second transport roller pair 16 is rotated in the reverse direction. In the configuration in which the feeding by the roller 10 is not performed, the interval between the preceding sheet and the succeeding sheet is wider in the “first skew correction mode” than in the “second skew correction mode”. However, for example, when a sheet P as a preceding sheet is abutted against the second conveyance roller pair 16, a long sheet such that the rear end E (FIG. 3) side of the sheet P is in a position in contact with the feeding roller 10. In this case, there is no problem that the interval between the preceding sheet and the succeeding sheet increases in the “first skew correction mode”.
Further, as shown in FIG. 3, when the leading edge of the paper P is abutted against the second transport roller pair 16, even when the trailing edge E is on the downstream side of the feeding roller 10, the paper P is fed from the trailing edge E. Even in the case where the interval L to the pickup position by the feeding roller 10 is narrower than the appropriate interval between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet when executing the “continuous recording mode”, There is no problem that the distance between the preceding sheet and the succeeding sheet increases.
In the case of such a long sheet P, the “first skew correction mode” can be selected even when the “continuous recording mode” is executed. As a result, the accuracy of skew correction can be increased.

On the other hand, if the length of the paper P is short and the interval L in FIG. 3 is wider than the appropriate interval between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet when the “continuous recording mode” is executed, Throughput will be reduced. Accordingly, in the case of such a short sheet P, by selecting the “second skew correction mode”, it is possible to suppress the spread of the interval between the preceding sheet and the succeeding sheet at the time of executing the skew correction operation, and to reduce the recording throughput. Can be improved.
As described above, the control unit 23 selects the “first skew correction mode” or the “second skew correction mode” according to the length of the sheet P to be conveyed, thereby increasing the accuracy of the skew correction and recording. The quality can be improved and the throughput can be improved.

  When performing the “continuous recording mode”, the skew correction operation for the succeeding sheet is started after the preceding sheet is discharged by the discharge roller pair 17. In each skew correction mode, when the second transport roller pair 16 is rotated in the reverse direction, the discharge roller pair 17 is also rotated in the reverse direction. Therefore, before the discharge of the preceding sheet by the discharge roller pair 17, the skew correction for the subsequent sheet is performed. This is because when the operation is started, the discharge of the preceding sheet is delayed and the throughput is lowered, but this can be suppressed.

■■■ Power transmission from the drive motor to each roller ■■■
A frame assembly 8 shown in FIG. 8 is provided inside the exterior of the apparatus main body 2 (FIG. 1). The power transmission means 30 is provided on the right side (−X axis direction) of the frame assembly 8 (FIG. 8).
As shown in FIGS. 9 and 10, the power transmission means 30 has a configuration in which the power of the drive motor 22 is transmitted by a plurality of gears engaged with each other. Hereinafter, mainly referring to FIGS. 9 to 11, the drive motor 22 to the feed roller 10, the intermediate roller 12 that is the drive roller of the first transport roller pair 15, the drive roller of the second transport roller pair, and the discharge roller pair The transmission of power to each roller of the drive roller will be described.

  Referring to FIGS. 9 and 10, the first gear 31, the second gear 32, the third gear 33, and the fourth gear constituting the power transmission means 30 are provided on the side surface on the + X axis direction side of the frame assembly 8. 34, a fifth gear 35, a sixth gear 36, a seventh gear 37, an eighth gear 38, a ninth gear 39, a tenth gear 40, and an eleventh gear 41 are provided.

<<< About transmission of power to intermediate roller >>>
The first gear 31 is a gear provided on the rotation shaft of the drive motor 22 (FIG. 9). The sixth gear 36 is a gear provided on the rotation shaft of the intermediate roller 12. The power of the drive motor 22 is transmitted from the first gear 31 to the sixth gear 36 via the second gear 32, the third gear 33, the fourth gear 34, and the fifth gear 35, and transports the medium through the intermediate roller 12. It is driven to rotate in the positive direction.
As described above, the drive motor 22 has a rotation shaft that rotates in both the first direction and the second direction. That is, when viewed from the front in FIG. 9, the first gear 31 rotates both clockwise (first direction) and counterclockwise (second direction).
Here, the third gear 33 is configured as a planetary gear provided with a one-way clutch (not shown), and the third gear 33 has a first gear 33 regardless of whether the drive motor 22 rotates in the first direction or the second direction. The inner gear 33a engaged with the four gears 34 is rotated in one direction (clockwise as viewed from the front in FIG. 9). As a result, regardless of whether the drive motor 22 rotates in the first direction or the second direction, the intermediate roller 12 rotates in the positive direction.

<<< About the transmission of power to the second conveying roller pair and the discharge roller pair >>>
9 and 10, the ninth gear 39 is a gear provided on the rotation shaft of the drive roller of the second transport roller pair 16. The power of the drive motor 22 is transmitted from the first gear 31 to the ninth gear 39 via the second gear 32, the third gear 33, the seventh gear 37, and the eighth gear 38. The seventh gear 37 is engaged with the outer gear 33 b of the third gear 33. According to the switching of the rotation direction of the driving motor 22 between the first direction and the second direction, the rotation of the outer gear 33b is also switched between clockwise and counterclockwise in a plan view of FIG. Yes.
Accordingly, the rotation direction of the drive motor 22 is also changed so that the rotation direction of the ninth gear 39 is also switched, so that the second transport roller pair 16 can be switched between the forward direction and the reverse direction.

  In addition, transmission of power to the drive roller of the discharge roller pair 17 is performed by a gear train (not shown) that engages with the ninth gear 39, and the second transport roller pair 16 and the discharge roller pair 17 are in the same direction. It is comprised so that it may rotate.

<<<< About transmission of power to feeding roller >>>>
9 and 10, the eleventh gear 41 is a gear provided coaxially with the swing shaft 11 (FIGS. 4 and 11) of the feeding roller 10. The power of the drive motor 22 is transmitted from the first gear 31 to the eleventh gear 41 via the second gear 32, the third gear 33, the seventh gear 37, the eighth gear 38, and the tenth gear 40. .

  As shown in FIG. 11, the oscillating shaft 11 of the feeding roller 10 is provided with a twelfth gear 42 and a gear unit 43 that engages with the twelfth gear 42. The gear unit 43 includes a plurality of gears, and the feeding roller 10 is provided at the tip. Power is transmitted from the eleventh gear 41 to the feeding roller 10 via the twelfth gear 42 and the gear unit 43.

Here, the tenth gear 40 is provided with a one-way clutch (not shown), and only when the drive motor 22 rotates in the first direction (clockwise when viewed in plan view in FIG. 9). When power is transmitted to the gear 41 and the drive motor 22 rotates in the second direction (counterclockwise direction in plan view of FIG. 9), the power is not transmitted to the eleventh gear 41. .
Thus, when the driving motor 22 is rotated in the first direction, the feeding roller 10 is rotated to feed the paper, and when the driving motor 22 is rotated in the second direction, the feeding roller is rotated. 10 may be configured to be stopped.

The power transmission means 30 may be configured to include a belt drive mechanism or a cam mechanism including an endless belt wound around a pulley, in addition to a configuration for transmitting the power of the drive motor 22 by a plurality of gears.
Further, the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

1 ... Inkjet printer (recording device), 2 ... Main unit,
3 ... Scanner unit, 3a ... Scanner body, 3b ... ADF, 4 ... Operation part,
5 ... discharge port, 6 ... medium receiving tray, 7 ... medium containing cassette, 8 ... frame assembly,
10 ... feed roller, 11 ... oscillating shaft, 12 ... intermediate roller,
13a, 13b, 13c, 13d ... driven roller, 15 ... first conveying roller pair,
16 ... 2nd conveyance roller pair, 17 ... Discharge roller pair, 18 ... 1st medium sensor,
20 ... recording head, 21 ... carriage, 22 ... drive motor, 23 ... control unit,
30 ... Power transmission means, 31 ... First gear, 32 ... Second gear, 33 ... Third gear,
34 ... 4th gear, 35 ... 5th gear, 36 ... 6th gear, 37 ... 7th gear,
38 ... 8th gear, 39 ... 9th gear, 40 ... 10th gear, 41 ... 11th gear,
42 ... 12th gear, 43 ... Gear unit

Claims (9)

A first conveying roller pair that conveys the medium toward a recording unit that records on the medium;
A second transport roller pair provided downstream of the first transport roller pair and upstream of the recording unit;
A first medium sensor that is disposed between the first transport roller pair and the second transport roller pair at a position closer to the second transport roller pair than the first transport roller pair, and detects at least the passage of the front end of the medium. When,
A drive motor that is a drive source of the first transport roller pair and the second transport roller pair;
Power transmission means for transmitting the power of the drive motor to the first transport roller pair and the second transport roller pair;
A controller that controls the drive motor to perform a skew correction operation for correcting the skew of the medium by causing the medium to abut against the second transport roller pair;
When the drive motor is driven to rotate in the first direction, the power transmission means sends both the first transport roller pair and the second transport roller pair in the forward direction to send the medium toward the recording unit. When rotating and driving the drive motor in a second direction opposite to the first direction, the first transport roller pair is rotated in the forward direction, and the second transport roller pair is rotated in the reverse direction. Having a configuration to rotate,
When the leading edge of the medium reaches a conveyance target position between the nip position of the medium in the first conveyance roller pair and a detection position by the first medium sensor, at least the second conveyance roller A first skew correction mode for maintaining the drive direction of the drive motor in the second direction until the tip of the medium hits the pair;
A recording apparatus. The recording apparatus according to claim 1,
The power transmission means has a configuration for transmitting power of the drive motor by a plurality of gears engaged with each other.
A recording apparatus. The recording apparatus according to claim 1 or 2,
The control unit rotates the drive motor in the first direction until the leading edge of the medium is detected by the first medium sensor, separately from the first skew correction mode, and the first medium sensor A second skew correction mode in which the driving direction of the drive motor is switched from the first direction to the second direction and the front end of the medium is abutted against the second transport roller pair.
A recording apparatus. The recording apparatus according to claim 3,
A feeding roller that feeds the medium from a medium accommodating unit that accommodates a plurality of media;
The feeding roller is driven by the drive motor common to the first transport roller pair and the second transport roller pair,
A recording apparatus. The recording apparatus according to claim 4,
The power transmission means rotates the feed roller in the forward direction when the drive motor is rotated in the first direction, and rotates the feed motor in the second direction. It has a configuration that does not transmit the power of the drive motor to the feed roller,
A recording apparatus. The recording apparatus according to claim 5, wherein the control unit executes a first feeding mode and a second feeding mode that closes a gap between a medium preceding and following the first feeding mode. Is possible,
When executing the first feeding mode, select the first skew correction mode,
Selecting the second skew correction mode when executing the second feeding mode;
A recording apparatus. The recording apparatus according to claim 5, wherein
The control unit selects the first skew correction mode when the length of the medium to be conveyed is longer than a predetermined length, and selects the second skew correction mode when the length is short.
A recording apparatus. The recording apparatus according to any one of claims 1 to 7,
Provided on the downstream side of the recording unit, comprising a pair of discharge rollers for discharging the medium after recording,
The discharge roller pair is driven by the drive motor common to the first transport roller pair and the second transport roller pair,
A recording apparatus. The recording apparatus according to claim 8, wherein
The power transmission means rotates the discharge roller pair in the positive direction when rotating the drive motor in the first direction, and rotates the discharge motor when rotating the drive motor in the second direction. The roller pair is rotated in the opposite direction.
A recording apparatus.

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