JP6722330B2 - Recording device, control method and program - Google Patents

Description

The present invention relates to a recording device.

As a method of improving the recording speed of a recording apparatus, sheet continuous feeding has been proposed. Overlapped feeding is a conveyance method in which, when images are continuously recorded on a plurality of sheets, the trailing edge of the preceding sheet and the leading edge of the succeeding sheet are overlapped and are conveyed. (For example, patent document 1). Overlapped feeding has a higher printing speed than the feeding method in which feeding of the succeeding sheets is started after the recording of the preceding sheet is completed or the feeding method of continuously feeding these while reducing the gap between the sheets. It enables further improvement.

JP, 2000-15881, A

As one of conventional recording apparatuses, a recording apparatus having a function of recording both sides of a sheet has been proposed. When recording on both sides of a sheet, the recording speed tends to be slow as a whole because the sheet is recorded on each side. The apparatus of Patent Document 1 does not consider the improvement of the recording speed in recording on both sides of the sheet.

The present invention provides a technique for improving the recording speed when performing continuous double-sided recording on a plurality of sheets.

According to the present invention, for example, a feeding unit that feeds a sheet, a conveying unit that conveys the sheet fed by the feeding unit, and first and second surfaces of the sheet conveyed by the conveying unit. A recording means capable of performing a recording operation on the surface based on the recording data; a reversing means for performing a reversing operation for reversing the front and back of the sheet on which the first surface has been recorded; A recording device that includes a preceding sheet that has been recorded and then reversed by the reversing unit, and a conveyance control unit that can perform a stacking operation for stacking the leading end of the succeeding sheet that is fed next to the preceding sheet by the feeding unit. In the apparatus, the conveyance control unit executes the superimposing operation when the recording density on the first surface of the preceding sheet is less than a first threshold value, and when the recording density is equal to or higher than the first threshold value, the superimposing operation is performed. There is provided a recording device characterized by not performing an operation.

According to the present invention, it is possible to provide a technique for improving the recording speed when continuously performing double-sided recording on a plurality of sheets.

FIG. 3 is an operation explanatory diagram of the recording apparatus according to the embodiment of the invention. FIG. 3 is an operation explanatory diagram of the recording apparatus of FIG. 1. FIG. 3 is an operation explanatory diagram of the recording apparatus of FIG. 1. FIG. 3 is an operation explanatory diagram of the recording apparatus of FIG. 1. FIG. 3 is an operation explanatory diagram of the recording apparatus of FIG. 1. FIG. 2 is a block diagram of a control unit of the recording device in FIG. 1. 3 is a flowchart showing an example of processing executed by a control unit of the recording apparatus of FIG. 3 is a flowchart showing an example of processing executed by a control unit of the recording apparatus of FIG. 3 is a flowchart showing an example of processing executed by a control unit of the recording apparatus of FIG. 3 is a flowchart showing an example of processing executed by a control unit of the recording apparatus of FIG. 3 is a flowchart showing an example of processing executed by a control unit of the recording apparatus of FIG. (A) And (B) is explanatory drawing of the area|region which refers to recording data.

1 to 5 are operation explanatory diagrams of a recording apparatus 100 according to an embodiment of the present invention, and particularly, are operation explanatory diagrams of double-sided recording and lap continuous feeding. 1 to 5 schematically show the cross-sectional structure of the recording apparatus 100. In the present embodiment, the case where the present invention is applied to a serial type ink jet recording apparatus will be described, but the present invention can also be applied to other types of recording apparatuses.

The "recording" is not limited to the case of forming significant information such as characters and figures, but also forming a wide range of images, patterns, patterns, etc. on the recording medium or processing the medium irrespective of significant insignificance. This includes cases and does not matter whether or not it is manifested so that it can be visually perceived by humans. Further, in the present embodiment, sheet-shaped paper is assumed as the recording medium, but cloth, plastic film or the like may be used. The sheet-shaped recording medium is referred to as a recording sheet here.

Before describing the operation of the recording apparatus 100, its configuration will be described mainly with reference to the state ST1 of FIG. The recording apparatus 100 includes a feeding tray 11 (stacking unit) on which a plurality of recording sheets 1 can be stacked, a recording unit that records on the recording sheets 1, and recording from the feeding tray 11 to a discharge tray 23 (discharging unit). A transport device that transports the sheet 1.

The recording unit includes a recording head 7 and a carriage 10. The recording head 7 records on the recording sheet 1. In this embodiment, the recording head 7 is an inkjet recording head that ejects ink to record on the recording sheet 1. A platen 8 that supports the back surface of the recording sheet 1 is arranged at a position facing the recording head 7. The carriage 10 carries the recording head 7 and moves in a direction intersecting the transport direction.

The transport device is roughly classified into a feeding mechanism, a transport mechanism, a discharging mechanism, and a reversing mechanism. The feeding mechanism feeds the recording sheet 1 to the conveying mechanism, and the conveying mechanism conveys the fed recording sheet 1 to the discharging mechanism. The ejection mechanism conveys the recording sheet 1 to the outside of the recording apparatus 100. The conveyance of the recording sheet 1 during recording is mainly performed by the conveyance mechanism. As described above, the recording sheet 1 is sequentially conveyed by the feeding mechanism, the conveying mechanism, and the discharging mechanism. The feeding mechanism side is called the upstream side in the carrying direction, and the discharging mechanism side is called the downstream side in the carrying direction. The reversing mechanism is a mechanism that receives the recording sheet 1 on one side of which is recorded from the conveying mechanism, reverses the front and back of the recording sheet 1 and conveys it to the conveying mechanism, and is a mechanism used for double-sided recording.

The feeding mechanism includes a pickup roller 2, a feeding roller 3, and a feeding driven roller 4. The pickup roller 2 rotates via a drive shaft 19, contacts the uppermost recording sheet 1 stacked on the feeding tray 11, picks up this recording sheet, and conveys it to the feeding roller 3. The feeding roller 3 is a driving roller for feeding the recording sheet 1 picked up by the pickup roller 2 to the downstream side in the conveying direction. The feeding driven roller 4 is pressed against the feeding roller 3 by being urged by the elastic member (for example, a spring) not shown. The feeding roller 3 and the feeding driven roller 4 sandwich the recording sheet 1 and feed it.

Returning to FIG. 1, the transport mechanism includes a transport roller 5 and a pinch roller 6. The transport roller 5 and the pinch roller 6 form a transport roller pair. The conveying roller 5 conveys the recording sheet 1 fed by the feeding roller 3 and the feeding driven roller 4 to a position facing the recording head 7. The pinch roller 6 is urged and pressed against the conveying roller 5 by an elastic member (for example, a spring) (not shown), and the conveying roller 5 and the pinch roller 6 sandwich and convey the recording sheet 1. At the time of recording, for example, the conveyance of the predetermined amount of the recording sheet 1 by the conveying roller 5 and the pinch roller 6 and the movement of the carriage 10 and the ejection of the ink by the recording head 7 are alternately repeated, thereby recording the recording sheet 1 The image is recorded on.

The discharge mechanism includes a discharge roller 9 and spurs 12 and 13. The discharge roller 9 discharges the recording sheet 1 recorded by the recording head 7 to the outside of the apparatus (to the discharge tray 23). The spurs 12 and 13 rotate in contact with the recording surface of the recording sheet 1 on which recording is performed by the recording head 7. The spur 13 on the downstream side is urged and pressed against the discharge roller 9 by an elastic member (not shown) (for example, a spring). The discharge roller 9 is not arranged at a position facing the spur 12 on the upstream side. The spur 12 is for preventing the recording sheet 1 from rising and is also called a presser spur.

The recording device 100 includes a sheet detection sensor 16. The sheet detection sensor 16 is a sensor for detecting the leading edge and the trailing edge of the recording sheet 1, and is, for example, an optical sensor. The sheet detection sensor 16 is provided on the downstream side of the feeding roller 3 in the transport direction.

The sheet pressing lever 17 presses the trailing end of the preceding recording sheet 1 (also referred to as a preceding recording medium or a preceding sheet) and superimposes the leading end of a succeeding recording sheet 1 (also referred to as a succeeding recording medium or a succeeding sheet). It is a lever. The leading end and the trailing end of the recording sheet 1 mean the downstream end and the upstream end in the transport direction, respectively. The sheet pressing lever 17 is biased in the counterclockwise direction in the drawing by a not-shown elastic member (for example, a spring) around the rotating shaft 17b.

The reversing mechanism includes a flapper 20, a reversing roller 21, and a reversing driven roller 22. During double-sided recording, the flapper 20 guides the recording sheet 1, which is fed back from the transport nip portion and whose one side has already been recorded, to the reversing path. The flapper 20 is rotatably or elastically deformable and is lifted by the recording sheet 1 when the recording sheet 1 is fed to the transport nip portion by the feeding roller 3 and the feeding driven roller 4. The conveyance of the recording sheet 1 is not hindered.

The reversing roller 21 conveys the recording sheet 1 having one side already recorded, which is fed back from the conveying roller 5, to the feeding roller 3. The recording sheet 1 is conveyed from the reversing roller 21 to the feeding roller 3, so that the front and back of the recording sheet 1 are reversed. The reversing driven roller 22 is urged against the reversing roller 21 by an unillustrated elastic member (for example, a spring) so as to be pressed against the reversing roller 21, and the reversing roller 21 and the reversing driven roller 22 sandwich and convey the recording sheet.

Between a nip portion formed by the feeding roller 3 and the feeding driven roller 4 (referred to as a feeding nip portion) and a nip portion formed by the conveying roller 5 and the pinch roller 6 (referred to as a conveying nip portion) A conveyance guide 15 that guides the conveyance of the recording sheet 1 is provided in the conveyance section.

The transport guide 15 includes a portion (mainly a lower portion in the drawing) forming a normal path for guiding the recording sheet 1 transported from the feeding nip portion to the transport nip portion. Further, the transport guide 15 includes a portion (mainly an upper portion in the drawing) forming a reversal path for guiding the recording sheet 1 transported from the transport nip portion to the feeding nip portion.

Next, the control unit of the recording device 100 will be described. FIG. 6 is a block diagram of a control unit of the recording device 100.

The recording device 100 includes an MPU 201. The MPU 201 can control the operation of each component of the recording device 100, and also processes data. As will be described later, the MPU 201 can execute conveyance control of the recording sheet 1 so that the trailing edge of the preceding sheet and the leading edge of the succeeding sheet overlap. The ROM 202 stores programs and data executed by the MPU 201. The RAM 203 is a RAM that temporarily stores the process data executed by the MPU 201 and the print data received from the host computer 214. It is also possible to use another storage device instead of the ROM 202 and the RAM 203.

The recording head driver 207 drives the recording head 7. The carriage motor driver 208 drives the carriage motor 204, which is the drive source of the drive mechanism that moves the carriage 10. The carry motor 205 is a drive source of a drive mechanism for the carry roller 5 and the discharge roller 9. The carry motor 205 is driven by the carry motor driver 209.

The feeding motor 206 is a driving source of a driving mechanism for the pickup roller 2, the feeding roller 3, and the reversing roller 21. The feeding motor 206 is driven by the feeding motor driver 210. A drive force connection/disconnection mechanism (not shown) is provided between the feeding motor 206 and the drive shaft 19 of the pickup roller 2.

The drive force connecting/disconnecting mechanism is a mechanism that cuts off the transmission of the drive force to the drive shaft 19 in a predetermined case. As a result, it is possible to prevent the pickup roller 2 from rotating while rotating the feeding roller 3 and the reversing roller 21. The driving force connection/disconnection mechanism may be, for example, in a non-transmission state when the transport roller 5 is reversely rotated by a certain amount, and then returned to the transmission state when the transport roller 5 is normally rotated by a certain amount. Alternatively, for example, an electromagnetic actuator such as a solenoid may be provided, and the non-transmission state and the transmission state may be switched by the action of the electromagnetic actuator. The switching between the non-transmission state and the transmission state may be performed, for example, by displacing a part of the gear that constitutes the driving force transmission mechanism, and any switching control can be performed by the MPU 201. It may be one. In the initial state, the drive shaft 19 is in the transmission state.

The MPU 201 controls the recording operation (ink ejection and movement of the recording head 7) by the recording head 7 via the recording head driver 207 and the carriage motor driver 208. Further, the MPU 201 executes conveyance control of the recording sheet 1 via the conveyance motor driver 209 and the feeding motor driver 210. The position of the recording head 7 and the rotation amount of the transport roller 5 can be detected by a sensor (not shown).

The host computer 214 is provided with a printer driver 2141 for collecting print information such as print images and print image quality and communicating with the printing apparatus when a user gives an instruction to execute the print operation. The MPU 201 exchanges recorded images with the host computer 214 via the I/F unit 213.

<Operation example>
With reference to FIGS. 1 to 5, conveyance control of a preceding sheet and a succeeding sheet when performing double-sided recording on the recording sheet 1 will be described in time series.

When the print data on the front side is transmitted from the host computer 214 via the I/F unit 213, it is processed by the MPU 201 and then expanded in the RAM 203. The MPU 201 starts the recording operation based on the expanded data.

Description will be made with reference to the state ST1 of FIG. First, the feed motor driver 210 drives the feed motor 206. As a result, the pickup roller 2 is rotated. When the pickup roller 2 rotates, the uppermost recording sheet (preceding sheet 1-A) stacked on the feeding tray 11 is picked up. The preceding sheet 1-A picked up by the pickup roller 2 is conveyed by the feeding roller 3 rotating in the same direction as the pickup roller 2. The feeding roller 3 is also driven by the feeding motor 206.

The leading edge of the preceding sheet 1-A is detected by the sheet detection sensor 16 provided on the downstream side of the feeding roller 3.

Description will be made with reference to the state ST2 of FIG. By continuing to rotate the feeding roller 3, the leading end of the preceding sheet 1-A pushes up the flapper 20 and advances to the downstream side, and the sheet pressing lever 17 is rotated clockwise around the rotation shaft 17b against the biasing force of the spring. Rotate to. When the feeding roller 3 is further rotated, the leading edge of the preceding sheet 1-A comes into contact with the conveyance nip portion formed by the conveyance roller 5 and the pinch roller 6. At this time, the transport roller 5 is in a stopped state. By rotating the feeding roller 3 by a predetermined amount even after the leading edge of the preceding sheet 1-A hits the transport nip portion, the leading sheet 1-A is aligned with the leading edge abutting the transport nip portion and skew is corrected. To be done. The skew correction operation is also called a registration operation.

Description will be made with reference to the state ST3 of FIG. When the skew feed correcting operation of the preceding sheet 1-A is completed, the driving of the feeding motor 206 is stopped. Further, the transmission state of the driving force to the drive shaft 19 is switched to the non-transmission state, and the pickup roller 2 is switched to the non-rotated state. Then, the carry motor 205 is driven to start the rotation of the carry roller 5. When the conveyance roller 5 is rotated in a state where the preceding sheet 1-A is sandwiched by both the conveyance nip portion and the feeding nip portion, the feeding roller 3 rotates together with the conveyance roller 5 and the feeding roller 3 between them. The seat is in tension.

The preceding sheet 1-A is indexed to a position facing the recording head 7, and then a recording operation is performed by ejecting ink from the recording head 7 based on the recording data. In the cueing operation, the front end of the recording sheet is once positioned at the position of the transport roller 5 by abutting against the transport nip portion, and then the rotation amount of the transport roller 5 is controlled with the position of the transport roller 5 as a reference. Done by. Subsequent control recognition of the position of the preceding sheet 1-A can be performed based on the rotation amount of the transport roller 5 based on the position of the transport roller 5.

Description will be made with reference to the state ST4 of FIG. The recording apparatus according to the present embodiment is a serial type recording apparatus in which the recording head 7 is mounted on the carriage 10. An image is recorded on one side of the preceding sheet 1-A by a recording operation that repeats the conveying operation and the image forming operation. The transport operation is an operation of intermittently transporting the recording sheet 1 by a predetermined amount by the transport roller 5. The image forming operation is an operation of ejecting ink from the recording head 7 while moving the carriage 10 carrying the recording head 7 while the transport roller 5 is stopped. Done. As a result, an image is recorded on the first surface (upper surface in the figure) of the preceding sheet 1-A.

This will be described with reference to the state ST5 of FIG. After the recording operation on the first surface of the preceding sheet 1-A is completed, the reverse rotation of the transport roller 5 and the discharge roller 9 is started. The trailing end of the preceding sheet 1-A rotates the sheet pressing lever 17 in the counterclockwise direction around the rotation shaft 17b, and advances on the flapper 20. When the transport roller 5 continues to rotate in the reverse direction, the trailing edge of the preceding sheet 1-A is transported to the reverse feeding nip portion formed by the reverse roller 21 and the reverse driven roller 22.

The driving of the feeding motor 206 is started together with the reverse rotation of the transport roller 5 and the discharge roller 9. As a result, the feeding roller 3 is rotated, the reversing roller 21 is rotated in the same direction as the reverse direction of the conveying roller 5, and the recording sheet is conveyed. Even if the driving of the feeding motor 206 is started, the pickup roller 2 is not rotated in the state ST3 of FIG. 1, and therefore the pickup roller 2 is not rotated.

Description will be made with reference to the state ST6 of FIG. Further, by continuing to rotate the reversing roller 21 and the feeding roller 3, the preceding sheet 1-A is conveyed to the feeding nip portion. When the preceding sheet 1-A reaches the feeding nip portion, the driving of the carry motor 205 is stopped, and the carry roller 5 and the discharge roller 9 are stopped.

At this time, the leading sheet 1-A has the leading end and the trailing end of the sheet interchanged as compared with the state of the state ST2 of FIG. 1 picked up from the feeding tray 11. That is, at the position facing the recording head 7, the front surface and the back surface of the preceding sheet 1-A are reversed, and the first surface faces downward, the second surface faces upward, and the second surface faces the recording head 7. To do. In order to distinguish the leading sheet 1-A from the leading sheet 1-A before and after reversing so that the leading end and the trailing end of the leading sheet 1-A will not be confused about the direction, It may be referred to as the reverse preceding sheet 1-A.

This will be described with reference to the state ST7 of FIG. Further, by continuing to rotate the feeding roller 3, the leading end of the reversing preceding sheet 1-A rotates the sheet pressing lever 17 in the clockwise direction around the rotating shaft 17b to proceed to the downstream side, and the registration of the reversing preceding sheet 1-A is performed. The action is taken. The subsequent control recognition of the position of the reverse preceding sheet 1-A can be performed based on the rotation amount of the transport roller 5 with the position of the transport roller 5 as a reference.

This will be described with reference to the state ST8 of FIG. When the print data of the second surface is transmitted from the host computer 214, the reversed preceding sheet 1-A is indexed to a position facing the print head 7. Then, the recording operation is performed on the second surface of the reversal preceding sheet 1-A by ejecting ink from the recording head 7 based on the recording data. In addition to the cueing of the reverse preceding sheet 1-A, the transmission state of the driving force to the drive shaft 19 is switched from the non-transmission state to the transmission state, and the pickup roller 2 is rotated.

This will be described with reference to the state ST9 in FIG. When the trailing edge of the reverse preceding sheet 1-A passes a predetermined position, the feeding motor 206 is driven and the pickup roller 2 and the feeding roller 3 start intermittent driving. As a result, the recording sheet 1 (subsequent sheet 1-B) is newly conveyed from the feeding tray 11. The trailing edge position of the reverse preceding sheet 1-A is determined by the rotation amount of the transport roller 5 after the registration operation based on the position of the transport roller 5.

The intermittent drive of the pickup roller 2 and the feeding roller 3 also rotates the pickup roller 2 and the feeding roller 3 when the conveying roller 5 is rotated, and the pickup roller 2 and the feeding roller 3 when the conveying roller 5 is stopped. Stop. The rotation speed of the feed roller 3 is lower than the rotation speed of the transport roller 5. Therefore, the reverse preceding sheet 1-A is stretched between the transport roller 5 and the feeding roller 3. Further, the feeding roller 3 is rotated by the reversal preceding sheet 1-A conveyed by the conveying roller 5.

This will be described with reference to the state ST10 in FIG. An image forming operation is performed by the recording head 7 on the second surface of the reverse preceding sheet 1-A based on the recording data. When the trailing edge of the preceding sheet 1-A is removed from the feeding nip portion by the intermittent conveyance of the conveying roller 5, the intermittent driving of the pickup roller 2 and the feeding roller 3 is stopped, and the pickup roller 2 and the feeding roller 3 are continuously connected. The sheet is rotated to advance the feeding of the succeeding sheet 1-B. The leading edge of the succeeding sheet 1-B is detected by the sheet detection sensor 16 provided on the downstream side of the feeding roller 3.

This will be described with reference to the state ST11 of FIG. The rear end of the inverted preceding sheet 1-A is pushed downward by the sheet pressing lever 17 as shown in the state ST10 of FIG. The succeeding sheet 1-B is moved at a high speed with respect to the speed at which the reverse preceding sheet 1-A is moved to the downstream side by the recording operation. This makes it possible to form a state in which the leading edge of the succeeding sheet 1-B overlaps the trailing edge of the reverse preceding sheet 1-A.

This will be described with reference to the state ST12 of FIG. The succeeding sheet 1-B is fed by the feeding roller 3 until the leading edge of the succeeding sheet 1-B stops at a predetermined position upstream of the conveying nip. The position of the leading edge of the succeeding sheet 1-B is calculated from the rotation amount of the feeding roller 3 after the leading edge of the succeeding sheet 1-B is detected by the sheet detection sensor 16, and is controlled based on the calculation result.

This will be described with reference to the state ST13 of FIG. The feeding roller 3 is driven when the conveyance roller 5 is stopped to perform the image forming operation of the reverse preceding sheet 1-A (here, it is stopped for the image forming operation of the last row). As a result, the leading edge of the succeeding sheet 1-B is brought into contact with the transport nip portion, and the skew correction operation of the succeeding sheet 1-B is performed. When the skew correction operation of the succeeding sheet 1-B is completed, the driving of the feeding motor 206 is stopped. Further, the transmission state of the driving force to the drive shaft 19 is switched to the non-transmission state, and the pickup roller 2 is switched to the non-rotated state.

This will be described with reference to the state ST14 of FIG. When the image forming operation on the second surface of the reverse preceding sheet 1-A is completed, the conveying roller 5 is rotated by a predetermined amount. As a result, the front end of the succeeding sheet 1-B is overlapped on the rear end of the reverse preceding sheet 1-A conveyed through the reverse path, and the overlapping portion is sandwiched by the conveying roller 5 and the pinch roller 6. The continuous transfer is carried out.

Then, the succeeding sheet 1-B is cued, and the succeeding sheet 1-B starts the printing operation based on the printing data. When the succeeding sheet 1-B is intermittently conveyed for the recording operation, the reverse preceding sheet 1-A is also intermittently conveyed, and the reverse preceding sheet 1-A is eventually discharged onto the discharge tray 23 by the discharge roller 9.

Thereafter, double-sided recording of the recording sheet 1 and continuous feeding are performed in the same procedure. In this way, the recording speed can be improved in the case of continuously performing double-sided recording on a plurality of sheets 1.

Note that single-sided recording and overlapped continuous feeding in that case are not particularly described, but overlapped continuous feeding can also be performed for single-sided recording by substantially the same procedure as part of the procedure for double-sided recording.

<Processing example>
An example of processing executed by the MPU 201 in order to realize the operations illustrated in FIGS. 1 to 5 will be described. 7 to 9 are flowcharts showing an example of processing executed by the MPU 201, which is an example of control of the recording apparatus 100.

When an instruction to print on both sides of the print sheet is transmitted from the host computer 214 in step S101 of FIG. 7, the MPU 201 starts the control of this flowchart.

In step S102, the feeding operation of the preceding sheet 1-A is started. Specifically, the MPU 201 drives the feeding motor 206 at a low speed via the feeding motor driver 210. When driven at a low speed, the pickup roller 2 and the feeding roller 3 rotate at 7.6 inch/sec. The pickup roller 2 picks up the preceding sheet 1-A from the feeding tray 11, and the feeding roller 3 feeds the preceding sheet 1-A toward the recording head 7.

In step S103, the sheet detection sensor 16 detects the leading edge of the preceding sheet 1-A. When the sheet detection sensor 16 detects the leading edge of the preceding sheet 1-A, the MPU 201 switches the feeding motor 206 to high-speed driving through the feeding motor driver in step S104. In high speed driving, the pickup roller 2 and the feeding roller 3 rotate at 20 inches/sec.

By controlling the rotation amount of the feeding motor 206 after the leading edge of the preceding sheet 1-A is detected by the sheet detection sensor 16, the skew feeding correcting operation of the preceding sheet 1-A is performed in step S105. When the skew feed correcting operation of the preceding sheet 1-A is completed, the driving of the feeding motor 206 is stopped. Further, the transmission state of the driving force to the drive shaft 19 is switched to the non-transmission state.

When the print data for the first side is transmitted from the host computer 214, the preceding sheet 1-A is cueed based on the print data for the first side in step S106. The MPU 201 controls the rotation amount of the carry motor 205 via the carry motor driver 209. The transport roller 5 rotates at 15 inches/sec. Then, the preceding sheet 1-A is conveyed to the recording start position based on the position of the conveying roller 5 based on the recording data.

In step S107, the recording head 7 ejects ink to start the recording operation on the first surface of the preceding sheet 1-A. Specifically, the carriage 10 controls the rotation amount of the carry motor 205 to intermittently carry the preceding sheet 1-A by the carry roller 5, and controls the rotation amount of the carriage motor 204 via the carriage motor driver to move the carriage 10. To move. Further, based on the print data developed in the RAM 203, the image forming operation of ejecting ink from the print head 7 (ink ejecting operation) is repeated through the print head driver, thereby performing the print operation on the preceding sheet 1-A. ..

In step S108, the completion of the recording operation for the first surface of the preceding sheet 1-A is waited, and when completed, the reverse feeding operation of the preceding sheet 1-A is started in step S109. The carry motor 205 and the feed motor 206 are driven at a low speed, and the carry roller 5 and the reversing roller 21 rotate at 7.6 inch/sec. Further, the transport motor 205 rotates the transport roller 5 to feed the preceding sheet 1-A in reverse, contrary to the intermittent transport during the recording operation.

When the preceding sheet 1-A reaches the feeding roller 3 via the reversing roller 21, the driving of the carry motor 205 is stopped. The front and back of the preceding sheet 1-A are reversed. By continuing the rotation of the feeding roller 3, the leading edge of the reversed preceding sheet 1-A is detected by the sheet detection sensor 16. Then, the skew correction of the preceding sheet 1-A is performed in step S110 by controlling the rotation amount of the feeding motor 206.

When the print data of the second surface is transmitted from the host computer 214 in step S111, the carry motor 205 is driven while controlling the rotation amount. The transport roller 5 rotates at 15.0 inches/sec to perform the cueing of the reverse preceding sheet 1-A. Further, the transmission state of the driving force to the drive shaft 19 is switched from the non-transmission state to the transmission state. In step S112, the recording operation for the second surface of the preceding sheet 1-A is started.

In step S113 of FIG. 8, it is determined whether or not there is print data for the next page. Information on whether or not there is recorded data on the next page is transmitted from the host computer 214. If there is no print data for the next page, the process proceeds to step S114. In step S114, the completion of the recording operation on the second surface of the preceding sheet 1-A is waited, and when the recording operation is completed, the preceding sheet 1-A is discharged in step S115, and the process is finished in step S116.

If there is print data for the next page in step S113, it is determined in step S117 whether the trailing edge of the reverse preceding sheet 1-A has passed a predetermined position. The trailing edge position of the reversed preceding sheet 1-A can be calculated by adding the size of the recording sheet 1 from the leading edge position. The tip position is defined by the distance from the transport nip portion, and is calculated by the rotation amount of the transport motor 5 after the skew correction operation.

When the trailing edge of the reversed preceding sheet 1-A has passed the predetermined position, the feeding operation of the succeeding sheet 1-B is started in step S118. The predetermined position may be a position where a predetermined space is formed between the reverse preceding sheet 1-A and the succeeding sheet 1-B, and is set by the distance between the feeding roller 3 and the feeding tray 11 or the like. It Regardless of whether or not the continuous feeding is performed, when the trailing edge of the reverse preceding sheet 1-A passes through the predetermined position, the feeding operation of the succeeding sheet 1-B is started to further improve the succeeding sheet 1-B. It will be possible to deliver it quickly.

In step S118, the pickup roller 2 picks up the succeeding sheet 1-B, and the feeding roller 3 feeds the succeeding sheet 1-B toward the recording head 7. The feeding motor 206 is driven at a low speed, and the pickup roller 2 and the feeding roller 3 rotate at 7.6 inch/sec.

In step S119, the sheet detection sensor 16 detects the leading edge of the succeeding sheet 1-B. When the sheet detection sensor 16 detects the leading edge of the succeeding sheet 1-B, the feeding motor 206 is switched to high speed driving in step S120. That is, the pickup roller 2 and the feeding roller 3 rotate at 20 inches/sec. The leading edge position of the succeeding sheet is controlled by using the rotation amount of the feeding motor 206 after the leading edge of the succeeding sheet 1-B is detected by the sheet detection sensor 16.

In step S121, it is determined whether the first condition is satisfied. When the first condition is satisfied, the process proceeds to S122, and when not satisfied, the process proceeds to S134 in FIG. At the stage of this determination, the succeeding sheet 1-B is at a position apart from the reverse preceding sheet 1-A. At step S121, thereafter, as shown in the state ST11 of FIG. 4, is the succeeding sheet 1-B conveyed to a position where the trailing edge of the reversing preceding sheet 1-A and the leading edge of the succeeding sheet 1-B overlap each other? Determine whether or not. Details of the determination will be described later.

In step S122, the succeeding sheet 1-B is conveyed until the leading edge of the succeeding sheet 1-B reaches a position before the conveying nip portion by a predetermined amount. When it reaches, the driving of the feeding motor 206 is stopped and the feeding of the succeeding sheet 1-B is stopped.

In step S123, it is determined whether the second condition is satisfied. If the second condition is satisfied, the process proceeds to step S124, and if not, the process proceeds to S127. At the stage of this determination, as described with reference to the state ST12 of FIG. 4, the succeeding sheet 1-B is before the conveyance nip portion, and the leading end of the succeeding sheet 1-B is the preceding sheet 1-A. It is in a position that overlaps with the rear end of the. In step S123, thereafter, as shown in the states ST12 and ST13 of FIG. 5, it is determined whether or not the skew feed correcting operation and the continuous feeding of the succeeding sheet 1-B can be executed. In the present embodiment, regardless of whether or not the continuous feeding is performed, by conveying the leading end of the succeeding sheet 1-B to the position where the leading end of the succeeding sheet 1-A overlaps with the rear end of the preceding sheet 1-A, the continuous feeding is performed. Even if the process is not performed, the recording of the succeeding sheet 1-B is started early. Details of the determination in step S123 will be described later.

In step S124, the recording operation is performed until the image formation of the last line on the second surface of the reverse preceding sheet 1-A is started. In step S125, the skew feed correcting operation of the succeeding sheet 1-B is performed as shown in the state ST12 of FIG. Further, the transmission state of the driving force to the drive shaft 19 is switched from the transmission state to the non-transmission state. In step S126, the recording operation is performed until the image formation of the last line on the second surface of the reverse preceding sheet 1-A is completed. Then, it progresses to S130.

The process of steps S127 to S129 is a process in the case where the continuous feeding is not performed. In step S127, the recording operation is performed until the recording operation on the second surface of the reversed preceding sheet 1-A is completed. In step S128, the conveyance motor 205 is driven to eject the reversed preceding sheet 1-A. After discharging the preceding sheet 1-A, the driving of the carry motor 205 is stopped. In S129, the feeding motor 206 is driven with the conveyance roller 5 stopped, and the skew feeding correcting operation of the succeeding sheet 1-B is performed. Further, the transmission state of the driving force to the drive shaft 19 is switched from the transmission state to the non-transmission state.

When the print data of the front surface of the next page is transmitted from the host computer 214, the succeeding sheet 1-B is cued based on the print data in step S130, and the first surface of the succeeding sheet 1-B is checked in step S131. To start the recording operation.

In step S132, the completion of the recording operation for the first surface of the succeeding sheet 1-B is waited for. In step S133, the succeeding sheet 1-B is set as the preceding sheet 1-A, and the process returns to step S109. The succeeding sheet 1-B is controllably replaced by the reverse preceding sheet 1-A, and thereafter, the above control is repeated. As a result, double-sided recording on the plurality of recording sheets 1 is continuously performed.

In the processing from step S134 to step S143 in FIG. 9, it is determined in step S121 that the succeeding sheet 1-B must be conveyed to a position where the trailing end portion of the reverse preceding sheet 1-A and the leading end portion of the succeeding sheet 1-B overlap. This is the process when it is determined. In this case, the recording speed is improved by conveying the succeeding sheet 1-B while maintaining the distance between the sheets within a certain range.

In step S134, it is determined whether or not the leading edge of the succeeding sheet 1-B has reached a position before the conveyance roller 5 by a predetermined amount (the same position as the determination position in step S122). If it has arrived, the process proceeds to S137, and if it has not arrived, the process proceeds to S135. In step S135, the feeding state of the succeeding sheet 1-B is confirmed. If the sheet is being fed (conveying), the process proceeds to step S136, and if the feeding is stopped (conveying stopped), the process proceeds to step S138.

In step S136, the distance between the trailing edge of the reversed preceding sheet 1-A and the leading edge of the succeeding sheet 1-B is calculated, and it is determined whether the distance is less than the first threshold value. If the interval is less than the first threshold value, the process proceeds to step S137, and if it is more than the threshold value, the feeding is continued. In step S137, the feeding of the succeeding sheet 1-B is stopped.

In step S138, the distance between the trailing edge of the reversed preceding sheet 1-A and the leading edge of the succeeding sheet 1-B is calculated, and it is determined whether the distance is equal to or larger than the second threshold value. If the interval is greater than or equal to the threshold, the feeding of the succeeding sheet 1-B is restarted in step S139, and if it is less than the threshold, the stopped state is continued.

By such control, a fixed interval is secured between the reversed preceding sheet 1-A and the succeeding sheet 1-B. Since the reverse preceding sheet 1-A and the succeeding sheet 1-B are conveyed apart from each other while maintaining the relationship of not being separated from each other, the succeeding sheet 1-B is jammed or the succeeding sheet 1-B is fed. It is possible to prevent the delivery from being greatly delayed. The first threshold value and the second threshold value may be the same value or different values, as long as the relationship of the first threshold value≦the second threshold value is satisfied.

In step S140, it is determined whether or not the recording operation on the second surface of the reversed preceding sheet 1-A is completed. If not completed, the process returns to step S134, and if completed, the process proceeds to step S141.

In step S142, the conveyance motor 205 is driven to eject the reversed preceding sheet 1-A. After discharging the preceding sheet 1-A, the driving of the carry motor 205 is stopped. In S143, the feeding motor 206 is driven with the transport roller 5 stopped, and the skew feeding correcting operation of the succeeding sheet 1-B is performed. Further, the transmission state of the driving force to the drive shaft 19 is switched from the transmission state to the non-transmission state. Then, it progresses to S130.

<Determination of first condition>
Details of the determination in step S121 will be described. An image has already been recorded on the first surface of the reverse preceding sheet 1-A, and there is a possibility that the trailing edge portion is deformed due to the influence of the image. For example, in the case of the inkjet recording apparatus as in the present embodiment, wrinkles or curls may occur on the recording sheet depending on the amount of ink used for recording an image and the properties of the sheet. If there are wrinkles or curls in the trailing edge of the reverse preceding sheet 1-A, the leading edge of the succeeding sheet 1-B may not be properly overlapped and the succeeding sheet 1-B may be jammed. In step S121, it is possible to prevent the sheet from being jammed by determining the possibility of this failure and switching the conveyance control thereafter.

FIG. 10 is a flowchart showing a processing example of step S121. The process starts in step S201. In step S202, it is determined whether or not an image is recorded in the first area of the first surface (recorded surface) of the preceding sheet 1-A.

As described above, this determination process estimates the deformation of the sheet due to the recording of the image on the first surface. Therefore, the print data on the first side is referred to. However, in terms of processing speed, it is more advantageous to refer to less recorded data. Therefore, in the present embodiment, the reference range is limited to the first area of the first surface, which is likely to affect the superimposition with the succeeding sheet 1-B. In the present embodiment, the area is on the rear end side of the reversal preceding sheet 1-A. FIG. 12A is a plan view of the preceding sheet 1-A showing an example thereof.

FIG. 12A shows the first surface which is the recorded surface. The image to be recorded is not shown. The first region R1 to be referred to is set on the rear end side in the transport direction after being inverted. In the case of this embodiment, the first region R1 is a strip-shaped region extending in the left-right direction. By setting the first region R1 to be a strip-shaped region, it is possible to relatively evenly refer to the range that easily affects the superimposition with the succeeding sheet 1-B.

In the example of FIG. 12A, it is assumed that the recording is performed with edges, and thus the first region R1 is a region excluding the rear end and the left and right ends in the transport direction. However, in the case of borderless recording, the first region R1 may be a region including the rear end or the left and right ends in the transport direction. In addition, the range of the first region R1 may be changed depending on whether the recording condition is edged or edgeless.

The first region R1 may be a region including at least a range overlapping with the leading end of the succeeding sheet 1-B. This makes it possible to set a reference range to a range that easily affects the superimposition with the succeeding sheet 1-B. The range in which the trailing edge of the reverse preceding sheet 1-A and the leading edge of the succeeding sheet 1-B overlap may vary depending on the print data and the like. The first region R1 may be a variable range set each time in accordance with the overlapping range. On the contrary, the first region R1 may be an invariable range (fixed range) set on the assumption of a range in which superimposition is likely to be affected.

The deformation of the recording sheet is also affected by the type of recording sheet. For example, thin paper may be more easily deformed than thick paper. The first region R1 may be a variable range that is changed according to the type of recording sheet. For example, in the case of a recording sheet that is relatively less deformed such as thick paper, the first region R1 may be set narrower than that of thin paper. The type of recording sheet may be specified based on the information transmitted from the host computer 214.

Returning to FIG. 10, if it is determined in step S202 that the image is recorded in the first area R1, the process proceeds to step S205, and if it is determined that the image is not recorded, the process proceeds to step S203. In step S203, it is determined that the first condition is satisfied (the overlapping state is formed), and the process ends. In the case of this determination result, the process proceeds to step S122 in FIG.

In step S205, it is determined whether or not there is a pixel whose recording density is equal to or higher than the first threshold in the first region R1. If there is such a pixel, the process proceeds to step S207, and if not, the process proceeds to step S206. In step S206, it is determined that the first condition is satisfied (the overlapping state is formed), and the process ends. In the case of this determination result, the process proceeds to step S122 in FIG. In step S207, it is determined that the first condition is not satisfied in step S207, and the process ends. In the case of this determination result, the process proceeds to step S134 in FIG.

A pixel having a high recording density has a large number of ink droplets and is therefore likely to be deformed. Therefore, in the present embodiment, when there is a pixel whose print density is equal to or higher than the first threshold value, the succeeding sheet 1-B is not conveyed to a position overlapping the reverse preceding sheet 1-A, and the continuous feeding is not performed.

In the present embodiment, the recording density is determined for each pixel, but the recording density (for example, the average recording density) for a plurality of adjacent pixels may be determined.

The possibility of deformation with respect to recording density depends on the type of recording sheet. For example, thin paper may be more easily deformed at a lower recording density than thick paper. Therefore, the first threshold may be set based on the type of recording sheet.

Further, the possibility of deformation with respect to the recording density also differs depending on the position. For example, in the peripheral portion of the recording sheet, the degree of deformation with respect to the recording density may be stronger than that in the central portion. Therefore, the first threshold may be set based on the position in the first region R1.

Note that, in the present embodiment, the first condition is only the condition relating to the print data, but other conditions that can predict the deformation of the preceding sheet 1-A may be included. For example, conditions such as temperature and humidity may be included.

<Determination of second condition>
Details of the determination in step S123 will be described. In the present embodiment, the succeeding sheet 1-B is conveyed to the position where it overlaps with the reversed preceding sheet 1-A as much as possible, and it is determined in step S123 whether or not the continuous feeding is performed. This contributes to the improvement of recording speed. Further, at the time of starting the feeding of the succeeding sheet 1-B, it is not necessary to determine whether or not the continuous feeding is performed. For example, even if the margin amount of the succeeding sheet 1-B is unknown at the time when the feeding of the succeeding sheet 1-B is started, the continuous feeding can be executed when the margin amount is subsequently known. It is advantageous in terms.

FIG. 11 is a flowchart showing a processing example of step S123. The process starts in step S301. In step S302, it is determined whether the leading edge of the succeeding sheet 1-B has reached a predetermined position (the position described with reference to the state ST12 of FIG. 4) upstream of the transport nip portion. If it is determined that it has been reached, the process proceeds to step S305. If it is determined that the sheet has not arrived, it is unclear whether the leading edge of the succeeding sheet 1-B abuts the conveying nip portion when the sheet is conveyed by a predetermined amount. Therefore, it is determined that the second condition is not satisfied, the skew correction operation for only the succeeding sheet is determined (step S303), and the process ends. In the case of this determination result, the process proceeds to step S127 in FIG.

In step S305, it is determined whether or not the trailing edge of the reversed preceding sheet 1-A has passed through the transport nip portion. If it is determined that it has not passed, the process proceeds to step S307. When it is determined that the sheets have passed, the reversed preceding sheet 1-A and the succeeding sheet 1-B do not overlap. Therefore, it is determined that the second condition is not satisfied, the skew correction operation for only the succeeding sheet is determined (step S306), and the process ends. In the case of this determination result, the process proceeds to step S127 in FIG.

In step S307, it is determined whether or not the overlapping amount of the trailing edge of the reversed preceding sheet 1-A and the leading edge of the succeeding sheet 1-B is smaller than the threshold value. The position of the trailing edge of the reverse preceding sheet 1-A changes with the recording operation on the preceding sheet 1-A. That is, the amount of overlap decreases with the recording operation of the reversal preceding sheet 1-A. If it is determined that the overlapping amount is smaller than the threshold value, the overlapped continuous feeding may become unstable. Therefore, the overlapped state is canceled and the overlapped continuous feeding is not performed. Therefore, it is determined that the second condition is not satisfied, the skew feeding correcting operation is performed only for the succeeding sheet (step S308), and the process is ended. In the case of this determination result, the process proceeds to step S127 in FIG. If it is determined that the overlapping amount is equal to or more than the threshold value, the process proceeds to step S309.

In step S309, it is determined whether or not the succeeding sheet 1-B reaches the presser spur 12 when the succeeding sheet 1-B is cueed. If it is determined that the arrival is reached, the process proceeds to step S311. If it is determined that the sheet does not arrive, the overlapped feeding may affect the image formation of the succeeding sheet 1-B. Therefore, the overlapped state is canceled and the overlapped feeding is not performed. Therefore, it is determined that the second condition is not satisfied, the skew feeding correcting operation is performed only for the succeeding sheet (step S310), and the process is ended. In the case of this determination result, the process proceeds to step S127 in FIG.

In step S311, it is determined whether or not there is a gap between the last line of the second surface of the reversed preceding sheet 1-A and the preceding line of the last line. If there is a gap, the process proceeds to S313. When it is determined that there is no gap, the overlapped state is canceled and the overlapped feeding is not performed. The skew correction operation of the succeeding sheet 1-B may not affect the image forming operation of the reverse preceding sheet 1-A. If there is no gap, the influence may be conspicuous. Therefore, the overlapping state is canceled and the skew feeding correcting operation of only the succeeding sheet 1-B is performed. Therefore, it is determined that the second condition is not satisfied, the skew correction operation for only the succeeding sheet is determined (step S312), and the process ends. In the case of this determination result, the process proceeds to step S127 in FIG.

The determinations in steps S313 to S317 are determinations regarding double-sided recording. An image is already recorded on the first surface of the reverse preceding sheet 1-A, and the recorded image may affect the conveyance of the succeeding sheet 1-B when superposed and continuously fed. For example, the friction between the conveying roller 5 and the reverse preceding sheet 1-A may not be constant due to the recorded image, and the succeeding sheet 1-B may skew. In steps S313 to S317, it is possible to prevent the conveyance failure of the succeeding sheet 1-B by determining the possibility of this failure and switching whether or not the continuous feeding is performed.

In step S313, it is determined whether or not an image is recorded in the second area of the first surface (recorded surface) of the preceding sheet 1-A. As described above, this determination process estimates a conveyance defect of the succeeding sheet 1-B due to the recording of the image on the first surface. Therefore, the print data on the first side is referred to. However, in terms of processing speed, it is more advantageous to refer to less recorded data. Therefore, in the present embodiment, the reference range is limited to the second area of the first surface that is likely to affect the conveyance of the succeeding sheet 1-B. In the present embodiment, the area is on the rear end side of the reversal preceding sheet 1-A. FIG. 12B is a plan view of the preceding sheet 1-A showing an example thereof.

FIG. 12B shows the first surface which is the recorded surface. The image to be recorded is not shown. The second region R2 that is the reference target is set on the rear end side in the transport direction after being inverted. In the case of this embodiment, the second region R2 is a region which is partially different from the first region R1 shown in FIG. The first region R1 is for estimating the deformation of the preceding sheet 1-A, and the second region R2 is for estimating the conveyance failure of the succeeding sheet 1-B. .. Of course, the first region R1 and the second region R2 may end up in the same range. In addition, the first region R1 and the second region R2 may be regions that do not have overlapping ranges and are entirely different from each other.

The second region R2 has a strip-shaped portion R21 that extends to the left and right, and a pair of strip-shaped portions R22L and R22R that extends from both ends of the strip-shaped portion R21 toward the tip side. In order to estimate the influence of skewing on the succeeding seat 1-B, a relatively wide range is set in the front-rear direction at the left and right ends of the first surface, while a relatively narrow range is formed in the front-rear direction at the center part. It is set.

Similar to the example of FIG. 12A, in the example of FIG. 12B, since recording with a border is assumed, the second region R2 is a region excluding the rear end and the left and right ends in the transport direction. ing. However, in the case of borderless recording, the second region R2 may be a region including the rear end and the left and right ends in the transport direction. In addition, the range of the second region R2 may be changed depending on whether the recording condition is edged or edgeless.

The second region R2 may be a region within a range overlapping the leading end of the succeeding sheet 1-B. As a result, it is possible to set a range in which the conveyance of the subsequent sheet 1-B is likely to be affected as a reference target. The range in which the trailing edge of the reverse preceding sheet 1-A and the leading edge of the succeeding sheet 1-B overlap may vary depending on the print data and the like. The second region R2 may be a variable range set each time in accordance with the overlapping range. On the contrary, the second region R2 may be an invariable range (fixed range) set assuming a range in which the conveyance of the succeeding sheet 1-B is likely to be affected.

The influence of the recorded image of the preceding sheet 1-A on the conveyance of the succeeding sheet 1-B also depends on the type of the recording sheet. For example, the difference in friction coefficient between the place where an image is recorded and the place where no image is recorded may become large depending on the smoothness of the surface of the recording sheet. The second region R2 may be a variable range that is changed according to the type of recording sheet. For example, in the case of a recording sheet having a small difference in friction coefficient between a place where an image is recorded and a place where no image is recorded, even if the second region R2 is set narrower than a recording sheet having a large difference. Good. The type of recording sheet may be specified based on the information transmitted from the host computer 214.

Returning to FIG. 11, if it is determined in step S313 that the image is recorded in the second area R2, the process proceeds to step S315, and if it is determined that the image is not recorded, the process proceeds to step S314. In step S314, it is determined that the second condition is satisfied (the overlapping state is maintained and the skew feeding is corrected), and the process ends. In the case of this determination result, the process proceeds to step S124 in FIG.

In step S315, it is determined whether or not there is a pixel whose recording density is equal to or higher than the second threshold value in the second region R2. If there is such a pixel, the process proceeds to step S316, and if not, the process proceeds to step S317. In step S316, it is determined that the second condition is not satisfied, the skew correction operation for only the succeeding sheet is determined, and the process ends. In the case of this determination result, the process proceeds to step S127 in FIG.

In pixels with high recording density, the surface roughness of the recording sheet is likely to be affected by the properties of the ink, and the surface roughness of the recording sheet may become uneven as a whole. This may cause skew of the succeeding sheet 1-B. Therefore, in the present embodiment, when there is a pixel whose recording density is equal to or higher than the second threshold value, the continuous feeding is not executed.

In the present embodiment, the recording density is determined for each pixel, but the recording density (for example, the average recording density) for a plurality of adjacent pixels may be determined.

The effect of surface roughness due to recording density differs depending on the type of recording sheet. For example, the effect is different between a sheet having good ink absorption and a sheet having poor ink absorption. Therefore, the second threshold may be set based on the type of recording sheet.

Further, the influence on the conveyance of the succeeding sheet 1-B also differs depending on the position. For example, in the peripheral portion of the recording sheet, the deviation of the surface roughness due to the recording density may be more likely to affect the skew of the succeeding sheet 1-B than in the central portion. Therefore, the second threshold may be set based on the position in the second region R2.

In step S317, it is determined whether the recording density difference between the left and right regions of the second region R2 is equal to or larger than the third threshold value. Referring back to FIG. The second region R2 can be virtually divided into a region R2L and a region R2R at the left and right center lines CL. These regions R2L and R2R are both L-shaped and have the same shape and area. If the area R2L and the area R2R have large differences in the friction coefficient, the subsequent sheet 1-B is more likely to skew during the continuous feeding.

In step S317, the recording densities of the region R2L and the region R2R are compared. The comparison method may be, for example, a method of determining whether or not the difference between the maximum recording densities of the region R2L and the region R2R is equal to or larger than the third threshold value. Alternatively, it may be determined whether or not the difference between the average recording densities of the region R2L and the region R2R is equal to or larger than the third threshold value. Alternatively, these may be combined.

Returning to FIG. 11, if it is determined in step S317 that the recording density difference between the left and right regions of the second region R2 is greater than or equal to the third threshold value, the process proceeds to step S318 and it is determined that the recording density difference is less than the third threshold value. In this case, the process proceeds to step S319.

In step S318, it is determined that the second condition is not satisfied, the overlapping state is canceled, the skew feeding correcting operation of only the succeeding sheet is determined, and the processing is ended. In the case of this determination result, the process proceeds to step S127 in FIG. In step S319, it is determined that the second condition is satisfied (the overlapping state is maintained and the skew feeding is corrected), and the process ends. In the case of this determination result, the process proceeds to step S124 in FIG.

With the above, the processing ends. In the present embodiment, a plurality of conditions are listed as the second condition, but it is not necessary to set all of these conditions as the second condition. Conversely, conditions other than the above conditions may be added to the second condition.

<Other Embodiments>
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. It can also be realized by the processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

3 feeding roller, 5 conveying roller, 6 pinch roller, 7 recording head, 21 reversing roller, 100 recording device, 201 MPU

Claims (14)

Feeding means for feeding the sheet,
Conveying means for conveying the sheet fed by the feeding means,
Recording means capable of performing a recording operation on the first surface and the second surface of the sheet conveyed by the conveying means based on recording data;
Reversing means for performing a reversing operation for reversing the front and back of the sheet on which the first surface is recorded,
It is possible to perform a stacking operation of stacking the leading sheet, which is reversed by the reversing means after the first surface is recorded by the recording means, and the leading end of the succeeding sheet fed next to the preceding sheet by the feeding means. A recording device including a conveyance control unit,
The conveyance control unit performs the overlapping operation when the recording density on the first surface of the preceding sheet is less than the first threshold value, and does not execute the overlapping operation when the recording density is equal to or higher than the first threshold value. Recording device characterized by. If the recording density in the first area on the trailing edge side after reversal of the first surface of the preceding sheet is less than the first threshold value, the conveyance control unit executes the overlapping operation to perform recording in the first area. The recording apparatus according to claim 1, wherein the overlapping operation is not executed when the density is equal to or higher than the first threshold value. The recording apparatus according to claim 2, wherein the area of the first region is changed according to the type of sheet. The recording apparatus according to any one of claims 1 to 3, wherein the transport control unit performs the stacking operation between the feeding unit and the transport unit. The transport control unit transports the succeeding sheet while providing a predetermined interval between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet after the reversal when the stacking operation is not executed. The recording apparatus according to any one of 1 to 4. 2. The reversing unit includes a reversing path for reversing the front and back of a sheet having the first surface recorded by the recording unit, and a reversing roller arranged in the reversing path. The recording apparatus according to any one of 5 above. When the recording density on the first surface of the preceding sheet is less than a first threshold value, the conveyance control unit executes the overlapping operation, and then the recording start position at which the recording unit starts recording on the succeeding sheet. 7. The recording apparatus according to claim 1, wherein the succeeding sheet is conveyed in an overlapping state in which the preceding sheet and the succeeding sheet overlap each other. After the stacking operation is performed, the conveyance control unit performs the stacking operation when the print density in the second area of the first surface of the preceding sheet on the trailing end side after reversal is less than the second threshold value. When the succeeding sheet is conveyed to the recording starting position, and the recording density in the second area is equal to or more than the second threshold value, a space is provided between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet after reversal The recording apparatus according to claim 7, which conveys a succeeding sheet. The second region includes a right region on the right side and a left region on the left side of the center line in the width direction of the sheet,
When the difference between the recording density of the right area and the recording density of the left area is less than a third threshold value in the second area, the conveyance control means sets the succeeding sheet to the recording start position of the succeeding sheet in the overlapping state. When the recording density in the second area is equal to or higher than the third threshold value, the succeeding sheet is conveyed with a space provided between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet after reversal. The recording device according to claim 8. A carriage that moves in a direction intersecting the sheet conveying direction by the conveying means,
The recording means has a recording head mounted on the carriage for ejecting ink,
An image is formed on the sheet by repeating a transport operation of transporting the sheet by a predetermined amount by the transport unit and an ejection operation of ejecting ink from the recording head while moving the carriage when the transport unit is stopped. The recording apparatus according to any one of claims 1 to 9, wherein the recording apparatus records. The feeding unit includes a pickup roller that picks up a sheet from a stacking portion on which the sheet is stacked, and a feeding roller that is arranged downstream of the pickup roller in the sheet conveying direction,
The recording apparatus according to claim 6, wherein the pickup roller, the feeding roller, and the reversing roller are driven by a common drive source. The recording apparatus according to claim 11, further comprising a transmission mechanism that can switch between a transmission state in which the drive is transmitted to the pickup roller and a non-transmission state in which the drive is not transmitted. A method for controlling a recording device, comprising:
The recording device is
Feeding means for feeding the sheet,
Conveying means for conveying the sheet fed by the feeding means,
Recording means capable of performing a recording operation on the first surface and the second surface of the sheet conveyed by the conveying means based on recording data;
And a reversing unit that performs a reversing operation for reversing the front and back of the sheet on which the first surface is recorded,
The control method is
Conveyance for performing a stacking operation of stacking the leading sheet, which is reversed by the reversing unit after the first surface is recorded by the recording unit, and the leading end of the succeeding sheet fed next to the preceding sheet by the feeding unit. Equipped with control process,
In the conveyance control step, if the recording density on the first surface of the preceding sheet is less than a first threshold value, the overlapping operation is executed, and if the recording density is equal to or more than the first threshold value, the overlapping operation is not executed. Control method characterized by. A program for controlling the recording device,
The recording device is
Feeding means for feeding the sheet,
Conveying means for conveying the sheet fed by the feeding means,
Recording means capable of performing a recording operation on the first surface and the second surface of the sheet conveyed by the conveying means based on recording data;
And a reversing unit that performs a reversing operation for reversing the front and back of the sheet on which the first surface is recorded,
The program is
Conveyance for performing a stacking operation of stacking the leading sheet, which is reversed by the reversing unit after the first surface is recorded by the recording unit, and the leading end of the succeeding sheet fed next to the preceding sheet by the feeding unit. Causing the recording device to perform a control step,
In the conveyance control step, if the recording density on the first surface of the preceding sheet is less than a first threshold value, the overlapping operation is executed, and if the recording density is equal to or more than the first threshold value, the overlapping operation is not executed. A program characterized by.

Images