Storage device, control method, storage medium and program

Abstract

To reduce an overlapping amount of a preceding recording medium and a subsequent recording medium, while slowing down the conveyance speed of the preceding recording medium.SOLUTION: A recording device includes: recording means for recording an image in a recording medium; first conveyance means for conveying the recording medium in a conveyance direction; second conveyance means for conveying the recording medium recorded by the recording means, on the downstream side in the conveyance direction of the first conveyance means; and control means capable of performing reduction control which reduces an overlapping amount of a preceding recording medium and a subsequent recording medium, from a state where the following subsequent recording medium overlaps with a rear end of the preceding medium which precedes it. The reduction control includes control which, in a state where the subsequent recording medium can be conveyed by the first conveyance means in the conveyance direction, stops the conveyance of the subsequent recording medium by the first conveyance means, and conveys the preceding recording medium by the second conveyance means.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The present invention relates to a recording device. [Background technology]

[0002] There is known a recording device that conveys a preceding recording medium and a succeeding recording medium while maintaining an overlapping state in which the leading edges of the recording medium are overlapped, and records on the succeeding recording medium. After the overlapping portion passes the recording head, it may be desirable to eliminate the overlapping state or reduce the amount of overlap from the viewpoint of ease of ejection of the recording medium and prevention of clogging. Patent Document 1 discloses a recording device that eliminates the overlapping state by increasing the conveyance speed of the preceding recording medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-56299 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method of eliminating the overlapping state by increasing the transport speed of the preceding recording medium may require extremely high-speed transport depending on the dimensions of the recording medium transport path, which is disadvantageous in terms of noise and power consumption.

[0005] The present invention provides a technique for reducing the amount of overlap between the preceding and succeeding recording media by lowering the conveyance speed of the preceding recording media. [Means for solving the problem]

[0006] According to the present invention, a recording means for recording an image on a recording medium; a first conveying means for conveying the recording medium in a conveying direction; a second conveying means, downstream of the first conveying means in the conveying direction, for conveying a recording medium recorded by the recording means; a control unit capable of reducing the amount of overlap between the preceding recording medium and the succeeding recording medium from an overlapping state in which the succeeding recording medium overlaps the rear end of the preceding recording medium; A recording device comprising: the reduction control includes control to stop the conveyance of the subsequent recording medium by the first conveyance means and to convey the preceding recording medium by the second conveyance means when the subsequent recording medium can be conveyed by the first conveyance means in the conveyance direction. A recording device is provided. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technique for reducing the amount of overlap between the preceding and succeeding recording media by lowering the conveying speed of the preceding recording media. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a recording apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of a control unit of the recording apparatus of FIG. 1. [Figure 3] 10A and 10B are diagrams showing examples of recording conditions. [Figure 4] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 5] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 6] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 7] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 8] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 9] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 10]2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 11] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 12] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 13] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 14] 2A and 2B are diagrams illustrating the operation of the recording device of FIG. 1. [Figure 15] 3 is a flowchart showing an example of processing by the control unit in FIG. 2; [Figure 16] 3 is a flowchart showing an example of processing by the control unit in FIG. 2; [Figure 17] 3 is a flowchart showing an example of processing by the control unit in FIG. 2; [Figure 18] (A) to (C) are explanatory diagrams of the reduction control. [Figure 19] (A) to (C) are explanatory diagrams of the reduction control. [Figure 20] 3 is a flowchart showing an example of processing by the control unit in FIG. 2; [Figure 21] 10A and 10B are explanatory diagrams illustrating the operation of a recording apparatus showing another example of reduction control. [Figure 22] 10A and 10B are explanatory diagrams illustrating the operation of a recording apparatus showing another example of reduction control. [Figure 23] 10A and 10B are explanatory diagrams illustrating the operation of a recording apparatus showing another example of reduction control. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] First Embodiment <Outline of the recording device> FIG. 1 is a schematic diagram of a recording apparatus 1 according to this embodiment. In this embodiment, the present invention is described as being applied to a serial-type inkjet recording apparatus, but the present invention can also be applied to other types of recording apparatus. In the figure, arrows X and Y indicate horizontal directions that are orthogonal to each other, and arrow Z indicates the up-down direction. Furthermore, the downstream side and upstream side are based on the direction in which the recording medium is transported.

[0011] "Recording" not only includes the formation of meaningful information such as characters and figures, but also includes the formation of images, patterns, designs, etc. on a recording medium, whether meaningful or insignificant, or the processing of the medium, regardless of whether it is manifested in a way that can be perceived visually by humans. In addition, although sheet-like paper is assumed as the "recording medium" in this embodiment, it may also be cloth, plastic film, etc.

[0012] The recording device 1 performs recording on sheets SH, which are recording media, loaded on a feed tray (stacking section) 2, and discharges the sheets onto a discharge tray 17. A main transport path RT1 that guides the transport of the sheets SH is formed from the feed tray 2 to the discharge tray 17, and the sheets SH on the feed tray 2 are introduced into the main transport path RT1 one by one by a pickup roller 3. The pickup roller 3 is rotated by the driving force of a feed motor 22. Of the main transport path RT1 that is schematically illustrated in each figure, there is only one path between the feed unit 4 and the transport unit 5, but upper and lower paths along upper and lower transport guides are also shown.

[0013] The recording apparatus 1 also has a sub-transport path RT2 that branches off from the main transport path RT1 at a branch point BP. The sub-transport path RT2 is a path that turns the sheet SH upside down and returns the sheet SH to the main transport path RT1, and is used when double-sided recording is to be performed on the sheet SH. Note that the recording apparatus 1 may be configured without the double-sided recording function for the sheet SH, in which case the sub-transport path RT2 and related components are not necessary.

[0014] The recording apparatus 1 includes a feeding unit 4 and a plurality of transport units 5 to 10. The feeding unit 4 and the transport units 5 to 8 are arranged along a main transport path RT1. In the transport direction of the sheet SH on the main transport path RT1, these are arranged in the following order from upstream to downstream: feeding unit 4, transport unit 5, transport unit 6, transport unit 7, and transport unit 8. Transport units 9 and 10 are arranged along a sub-transport path RT2, and in the transport direction of the sheet SH on the sub-transport path RT2, they are arranged in the following order from upstream to downstream: transport unit 9, transport unit 10.

[0015] In the following description, unless otherwise specified, the upstream side and downstream side refer to the upstream side and downstream side in the conveying direction of the sheet SH on the main conveying path RT1. Also, the leading edge and trailing edge of the sheet SH refer to the downstream edge and upstream edge of the sheet SH.

[0016] The feeding unit 4 feeds the sheet SH introduced into the main transport path RT1 by the pickup roller 3 or the sheet SH returned from the sub-transport path RT2 to the main transport path RT1 to the transport unit 5. The feeding unit 4 includes a feeding roller 4a and a driven roller 4b that is pressed against the feeding roller 4a by a spring or the like (not shown). The feeding roller 4a is a rotating body that rotates by the driving force of the feeding motor 23, and the driven roller 4b is a rotating body that rotates following the rotation of the feeding roller 4a.

[0017] The sheet SH is sandwiched in the nip between the drive roller 4a and the driven roller 4b, and is transported by the rotation of the drive roller 4a and the driven roller 4b. Note that the pickup roller 3 is a one-way roller, and once the sheet SH has been transported to a position beyond the nip of the feeding unit 4, the feeding unit 4 can continue to transport the sheet SH even if the driving of the pickup roller 3 is stopped.

[0018] Although the present embodiment includes the pickup roller 3 and the feeding roller 4a, the configuration may include only the feeding roller 4a that feeds the sheets SH stacked on the feeding tray 2.

[0019] The sensor 31 is a sensor that detects the passage of the leading and trailing ends of the sheet SH, and is, for example, an optical sensor. The detection position of the sensor 31 is set at a position downstream of the nip portion of the feeding unit 4.

[0020] The transport unit 5 is disposed upstream of the recording head 12 and transports the sheet SH fed by the feeding unit 2 to the recording head 12. The transport unit 5 transports the sheet SH downstream between the recording head 12 and a platen 15 facing the recording head 12. The transport unit 5 includes a transport roller 5a and a driven roller (pinch roller) 5b that is pressed against the transport roller 5a by a spring or the like (not shown). The transport roller 5a is a rotating body that rotates by the driving force of the transport motor 24, and the driven roller 5b is a rotating body that rotates following the rotation of the transport roller 5a. The sheet SH is sandwiched in the nip portion between the transport roller 5a and the driven roller 5b, and is transported by the rotation of the transport roller 5a and the driven roller 5b.

[0021] The transport unit 6 is disposed downstream of the recording head 12 and transports the sheet SH transported by the transport unit 5 downstream. The transport unit 6 includes a transport roller 6a and a spur 6b that is pressed against the transport roller 6a by a spring or the like (not shown). The transport roller 6a is a rotating body that rotates by the driving force of a transport motor 24, and the spur 6b is a rotating body that rotates following the rotation of the transport roller 6a. In this embodiment, the transport unit 5 and the transport unit 6 share a driving source (motor 24).

[0022] The transport unit 7 is disposed downstream of the recording head 12 and the transport unit 6, and transports the sheet SH transported by the transport unit 6 downstream. The transport unit 7 includes a transport roller 7a and a driven roller 7b that is pressed against the transport roller 7a by a spring or the like (not shown). The transport roller 7a is a rotating body that rotates by the driving force of the transport motor 25, and the driven roller 7b is a rotating body that rotates following the rotation of the transport roller 7a. The sheet SH is sandwiched in the nip portion between the transport roller 7a and the driven roller 7b, and is transported by the rotation of the transport roller 7a and the driven roller 7b.

[0023] The transport unit 8 is disposed downstream of the recording head 12 and the transport units 6 and 7, and is a discharge unit that discharges the sheet SH transported by the transport unit 7 onto a discharge tray 17. The transport unit 8 includes a transport roller 8a and a driven roller 8b that is pressed against the transport roller 8a by a spring or the like (not shown). The transport roller 8a is a rotating body that rotates by the driving force of a transport motor 25, and the driven roller 8b is a rotating body that rotates following the rotation of the transport roller 8a. The sheet SH is sandwiched in a nip portion between the transport roller 8a and the driven roller 8b, and is transported by the rotation of the transport roller 8a and the driven roller 8b. In this embodiment, the transport unit 7 and the transport unit 8 share a drive source (motor 25).

[0024] A flapper 16 is disposed at the branch point BP. The flapper 16 switches the destination path of the sheet SH between the main transport path RT1 and the sub-transport path RT2. When in the position shown in FIG. 1, the flapper 16 maintains the destination path of the sheet SH as the main transport path RT1, and the sheet SH is discharged onto a discharge tray 17 via a transport unit 8. The flapper 16 is provided rotatably, and is rotated by an actuator 27 such as an electromagnetic solenoid to switch paths.

[0025] The transport unit 9 is a reversing unit that transports the sheet SH that has entered the sub-transport path RT2 from the branch point BP. The sub-transport path RT2 has a reversing path RT21 that extends upward from the branch point BP via the branch point BP', and a return path RT22 that extends from the branch point BP' to the feeding unit 4. The transport unit 9 is disposed on the reversing path RT21.

[0026] The transport unit 9 includes a transport roller 9a and a driven roller 9b that is pressed against the transport roller 9a by a spring or the like (not shown). The transport roller 9a is a rotating body that rotates by the driving force of a transport motor 26, and the driven roller 9b is a rotating body that rotates following the rotation of the transport roller 9a.

[0027] The sheet SH that enters the sub-conveyance path RT2 from the branch point BP moves along the reversal path RT21. The conveyance roller 9a rotates in both directions, the R1 direction and the R2 direction opposite. As the conveyance roller 9a rotates in the R1 direction, the sheet SH is conveyed in the direction of arrow F. When the rear end of the sheet SH passes the branch point BP', the rotation direction of the conveyance roller 9a is switched to the R2 direction. The sheet SH is conveyed in the reverse direction. The sheet SH is turned over and introduced into the return path RT22 from the branch point BP'.

[0028] The transport unit 10 is an intermediate unit disposed on the return path RT22. The transport unit 10 includes a transport roller 10a and a driven roller 10b that is pressed against the transport roller 10a by a spring or the like (not shown). The transport roller 10a is a rotating body that rotates by the driving force of a transport motor 26, and the driven roller 10b is a rotating body that rotates following the rotation of the transport roller 10a. The sheet SH is sandwiched in a nip portion between the transport roller 10a and the driven roller 10b, and is transported by the rotation of the transport roller 10a and the driven roller 10b. In this embodiment, the transport unit 9 and the transport unit 10 share a drive source (motor 26). Note that the transport roller 10a is a one-way roller, and once the sheet SH has been transported beyond the nip portion of the feeding unit 4, the feeding unit 4 can continue transporting the sheet even if the driving of the transport roller 10a is stopped.

[0029] The recording head 12 is disposed midway along the main transport path RT1. In this embodiment, the recording head 12 is disposed downstream of the transport unit 5 and upstream of the transport unit 6. The recording head 12 performs recording on the sheet SH. The sheet SH is transported in the X direction near the recording head 12. In this embodiment, the recording head 12 is an inkjet recording head that ejects ink to perform recording on the recording medium. The recording head 12 is supported by a carriage 11.

[0030] The carriage 11 is reciprocated in a direction crossing the sheet SH (a direction intersecting the conveying direction of the sheet SH near the recording head 12) by a drive unit 14. In this embodiment, the carriage 11 reciprocates in the Y direction guided by a guide shaft 13 extending in the Y direction.

[0031] The drive unit 14 is a mechanism that uses the carriage motor 21 as a drive source, and is, for example, a belt transmission mechanism that includes a drive pulley and a driven pulley that are spaced apart in the Y direction, and an endless belt that is wound around these pulleys. The carriage 11 is connected to the endless belt. When the carriage motor 21 rotates the drive pulley, the endless belt runs and the carriage 11 moves. The recording head 6 may be replaceably attached to the carriage 7.

[0032] As described above, the recording apparatus 1 of this embodiment is a serial type recording apparatus in which the recording head 12 is mounted on the carriage 11. Recording control for the sheet SH is performed by alternately repeating an intermittent conveying operation (intermittent conveying operation) in which the conveying unit 5 and / or 6 conveys the recording medium a predetermined amount and a recording operation while conveyance by the conveying unit 5 and / or 6 is stopped. The recording operation is an operation in which ink is ejected from the recording head 12 while the carriage 11 carrying the recording head 12 is moved.

[0033] <Control unit> 2 is a block diagram of the control unit 40 of the recording device 1. The MPU 41 is a processor that controls the various operations of the recording device 1 and the processing of data. The MPU 41 executes programs stored in the storage device 42 to control the entire recording device 1. The storage device 42 is composed of, for example, a ROM and a RAM. In addition to the programs executed by the MPU 41, the storage device 42 also stores various data required for processing, such as data received from the host computer 100.

[0034] The MPU 41 controls the recording head 12 via a driver 44a. The MPU 41 controls the carriage motor 21 via a driver 44b. The MPU 41 also controls the feed motors 22 and 23, the transport motors 24 to 26, and the actuator 27 via drivers 44c to 44i.

[0035] In addition to the sensor 31, the sensor group 30 includes a sensor (not shown) that detects the position of the carriage 11 in the Y direction, and sensors (not shown) that detect the rotation amounts of the feed motors 22 and 23 and the transport motors 24 to 26. By detecting the rotation amount of each motor, the rotation amount of the corresponding feed roller or transport roller can be identified, and the transport amount of the sheet SH can be calculated.

[0036] The host computer 100 is, for example, a personal computer or a mobile terminal (such as a smartphone or tablet terminal) used by a user. A printer driver 100a that performs communication between the host computer 100 and the recording device 1 is installed in the host computer 100. The recording device 1 includes an I / F (interface) unit 43, and communication between the host computer 100 and the MPU 41 is performed via the interface unit 43.

[0037] For example, when a user inputs a command to execute printing control to the host computer 100, the printer driver 100a compiles the data of the image to be printed and the printing conditions (various information such as the quality of the printed image) to generate a printing job and sends it to the printing device 1.

[0038] <Control example> An example of control executed by the MPU 41 will be described below. When a recording job is sent from the host computer 15 via the I / F unit 43, it is processed by the MPU 41 and then written to the storage device 42. The MPU 41 starts control based on the written data.

[0039] <Recording conditions> 3(A) and 3(B) show examples of recording conditions related to the transport operation of sheets SH, among the recording conditions included in a recording job. The recording apparatus 1 of this embodiment is capable of single-sided and double-sided recording. FIG. 3(A) shows an example of recording conditions when double-sided recording is performed on two sheets SH, and FIG. 3(B) shows an example of recording conditions when single-sided recording is performed on three sheets SH. Note that the recording order is assumed to be a face-down method in which the most recently recorded side is discharged onto the discharge tray 17 facing downward, but a face-up method is also possible.

[0040] "Printing sequence N" indicates the number and order of printing control for each side of the sheet SH, and N is its variable. In the example of Figure 3(A), printing control is executed for four sides (four times), and in the example of Figure 3(B), printing control is executed for three sides (three times).

[0041] "Page number K" indicates which page of the final recording corresponds to recording order N, and K is its variable. "Sheet M" indicates the target sheet SH of recording order N, and M is its variable. In this embodiment, the sheets are numbered in the order they are fed from feed tray 2. Sheet SH1 indicates the first sheet SH fed from feed tray 2 in that recording job, sheet SH2 indicates the second sheet SH fed from feed tray 2, and sheet SH3 indicates the third sheet SH fed from feed tray 2.

[0042] The variable M may be expressed as M(N) as a function of the recording order N. In the example of Fig. 3(A), M(1) means sheet SH1, M(2) means sheet SH2, and M(3) means sheet SH1. In the example of Fig. 3(B), M(3) means sheet SH3.

[0043] "Recording surface F" indicates which of the front and back surfaces of sheet SH (in other words, the first and second surfaces) is the surface to be recorded, and may be expressed as F(N) as a function of the recording order N. In the example of Figure 3(A), F(1) means that the back surface of sheet SH1 is the surface to be recorded, and F(3) means that the front surface of sheet SH1 is the surface to be recorded.

[0044] "Feed source Q" indicates whether the sheet SH is fed from the feed tray 2 or the sub-transport path RT2, and may be expressed as Q(N) as a function of the recording order N. In this embodiment, in the case of double-sided recording, after recording on the back side, the sheet SH is reversed by the reversing path RT21 of the sub-transport path RT2, and is returned to the feeding unit 4 via the return path RT22. In the case of double-sided recording, the feed source is either the feed tray 2 or the sub-transport path RT2. In the case of single-sided recording, the feed source is always the feed tray 2.

[0045] "Process G after printing" indicates whether the processing of the sheet SH after printing is to be discharged to the discharge tray 17 or inverted on the sub-transport path RT2, and may be expressed as G(N) as a function of the printing order N. In the case of single-sided printing, process G is always discharge. In the case of double-sided printing, process G after printing on the first side is inversion, and process G after printing on the next side is discharge.

[0046] <Example of operation> An example of the operation of the recording apparatus 1 will be described with reference to Figures 4(A) to 14(B). Here, an example of the operation will be described in which double-sided recording is performed on two sheets SH according to the recording conditions of Figure 3(A).

[0047] See FIG. 4(A). Since the recording conditions in FIG. 3(A) are double-sided recording, the flapper 16 is moved in advance to guide the sheet SH to the sub-transport path RT2. The feed motor 22 is driven at a low speed. This causes the pickup roller 3 to rotate at, for example, 7.6 inches / sec (the conveying speed of the sheet SH; hereinafter, the same expression has the same meaning). When the pickup roller 3 rotates, it picks up the topmost sheet SH stacked on the feed tray 2. This is designated as sheet SH1.

[0048] Sheet SH1 picked up by pickup roller 3 is transported along main transport path RT1 by feed roller 4a, which rotates in the same direction as pickup roller 3. Feed roller 4a is driven by feed motor 23 at the same speed as pickup roller 3. When pickup roller 3 transports sheet SH1 to a position beyond feed roller 4a, it stops so as not to pick up the next sheet SH. As described above, pickup roller 3 is a one-way roller, and feeding by feed roller 4a can continue even when pickup roller 3 is stopped.

[0049] When the leading edge of the sheet SH1 is detected by a sensor 31 provided downstream of the feed roller 4a in the conveying direction, the feed motor 23 is switched to high-speed driving. The feed roller 4a rotates at, for example, 20 inches / sec.

[0050] See Figure 4(B). As the feeding of sheet SH1 by the feeding roller 4a continues, the leading edge of sheet SH1 hits the nip formed by the conveying roller 5a and the pinch roller 5a. At this time, the conveying roller 5a is stationary. By continuing to rotate the feeding roller 4a a predetermined amount even after the leading edge of sheet SH1 hits the nip, the entire width of the leading edge of sheet SH1 hits the nip, and skew correction of sheet SH1 can be performed (skew correction operation).

[0051] When the skew correction operation for sheet SH1 is completed, the transport motor 24 is driven, causing the transport roller 5a to start rotating. The transport roller 5a transports sheet SH1 at, for example, 15 inches / sec. When sheet SH1 is cue-positioned to a position opposite the recording head 12, recording control can begin. As shown in the condition N=1 in FIG. 3(A), the recording operation for the second page of recording data begins on the back surface (top surface) of sheet SH1.

[0052] The leading edge of sheet SH1 is temporarily positioned at the position of the conveying roller 5a when it abuts against the nip portion of the conveying unit 5. Using this position as a reference, the positions of the leading and trailing edges of sheet SH1 can be calculated from the amount of rotation of the conveying roller 5a thereafter, and even during cueing, sheet SH1 is conveyed to a position facing the recording head 12 by this position control.

[0053] As described above, the recording apparatus 1 of this embodiment is a serial-type recording apparatus in which the recording head 12 is mounted on the carriage 11. Recording is performed on the sheet SH1 by repeating a conveying operation in which the conveying roller 5a intermittently conveys the recording medium by a predetermined amount, and a recording operation in which ink is ejected from the recording head 12 while the carriage 11 is moving. When the sheet SH1 is cue-aligned, the feed motor 23 is switched to low-speed driving. That is, the feed roller 4a rotates at, for example, 7.6 inches / sec. While the conveying roller 5a intermittently conveys the sheet SH1 by a predetermined amount, the feed motor 23 also intermittently drives the feed roller 4a. That is, when the conveying roller 5a rotates, the feed roller 4a also rotates, and when the conveying roller 5a is stopped, the feed roller 4a is also stopped. The rotational speed of the feed roller 4a is slower than that of the conveying roller 5a. As a result, the sheet SH is in a taut state between the conveying roller 5a and the feed roller 4a. The feeding roller 4a is rotated along with the sheet SH1 conveyed by the conveying roller 5a.

[0054] As recording on sheet SH1 progresses, the leading edge of sheet SH1 reaches transport unit 6. Transport rollers 6a and 5a are controlled synchronously because they share the same drive source, transport motor 24. Figure 5(B) shows the stage when the leading edge of sheet SH1 has passed transport rollers 6a.

[0055] Next, feeding of sheet SH2 begins following sheet SH1. Here, sensor 31 needs a predetermined interval between successive sheets SH in order to detect the edge of sheet SH due to factors such as sensor responsiveness. Therefore, the pickup operation of sheet SH2 begins after the trailing edge of sheet SH1 is detected by sensor 16 and it is determined that sheet SH1 has passed sensor 16. Furthermore, the rotation of pickup roller 3 during feeding of sheet SH2 is controlled so that the distance between the trailing edge of sheet SH1 and the leading edge of sheet SH2 is equal to or greater than a predetermined distance. In this embodiment, the positions of the leading and trailing edges of sheet SH are determined by calculation from the amount of rotation of various rollers, but they may also be calculated using separate sensors.

[0056] See FIG. 5(B). The trailing edge of sheet SH1 passes the feed roller 4a and hangs down slightly. Sheet SH2 is picked up by the pickup roller 3 and transported by the feed roller 4a. At this time, recording control is being executed on sheet SH1 in parallel. When the sensor 31 detects the leading edge of sheet SH2, the feed motor 23 is switched to high-speed driving. That is, the feed roller 4a rotates at, for example, 20 inches / sec.

[0057] When the sheet SH1 is intermittently conveyed by a predetermined amount by the conveying rollers 5a and 6a, the conveying rollers 7a and 9a are intermittently driven by the conveying motors 25 and 26 in the same rotation direction and at the same speed as the conveying roller 5a.

[0058] In this embodiment, control for forming an overlapping state can be performed. See FIG. 6A. By feeding sheet SH2 at a high speed relative to the conveying speed of sheet SH1, an overlapping state is formed in which the leading edge of sheet SH2 overlaps the trailing edge of sheet SH1 within the movement of the conveying roller 5a. Since sheet SH1 is controlled based on the recording data, sheet SH1 is intermittently conveyed by the conveying roller 5a. On the other hand, after the trailing edge of sheet SH2 is detected by sensor 31, sheet SH2 can catch up with sheet SH1 by continuously rotating the feed roller 4a at 20 inches / sec. Thereafter, sheet SH2 is conveyed until its leading edge reaches a predetermined position just before the nip of the conveying unit 5. The leading edge position of sheet SH2 is calculated from the amount of rotation of the feed roller 4a after the leading edge of sheet SH2 is detected by sensor 31, and is controlled based on this calculation result. Sheet SH1 enters the sub-conveyor path RT2 under the guidance of the flapper 16.

[0059] Next, a skew correction operation for sheet SH2 is performed. When the conveyance roller 5a is stopped to perform the recording operation for sheet SH1, the feed roller 4a is driven to abut the leading edge of sheet SH2 against the nip portion. In this embodiment, in order to minimize the effect on the recording quality of sheet SH1, the skew correction operation for sheet SH2 is performed when the conveyance roller 5a is stopped to perform the recording operation for the last line of sheet SH1.

[0060] See Figure 6(B). When the recording operation of the last line on sheet SH1 is completed, the conveying roller 5a is rotated a predetermined amount, so that sheet SH2 can be aligned while maintaining the state in which sheet SH2 is overlapped on sheet SH1. The overlapping portion of sheets SH1 and SH2 is sandwiched in the nip portion of the conveying unit 5 and conveyed.

[0061] When sheet SH2 is fed to the cue, the feed motor 23 is switched to low-speed driving. That is, the feed roller 4a rotates at, for example, 7.6 inches / sec. While the conveying roller 5a is intermittently conveying sheet SH2 by a predetermined amount, the feed motor 23 also drives the feed roller 4a intermittently. As shown in the condition N=2 in FIG. 3(A), the recording operation of the recording data for the fourth page is started on the back surface (top surface) of sheet SH2. When sheet SH2 is intermittently conveyed for the recording operation, sheet SH1 is also intermittently conveyed.

[0062] In this embodiment, it is possible to control the amount of overlap to be reduced. When the overlapping portions of sheets SH1 and SH2 pass through the branch point BP, a paper jam may occur. For example, if sheets SH1 and SH2 are transported to different paths at the branch point BP, sheet SH2 may interfere with sheet SH1, causing a paper jam, depending on the vertical relationship between sheets SH1 and SH2. For example, this may occur when sheet SH1 passes through the branch point BP along the main transport path RT1, while the following sheet SH2, which is overlapped above sheet SH1, is transported to the sub-transport path RT2.

[0063] Therefore, reduction control is performed to reduce the amount of overlap before the overlapping portion reaches the branch point BP (in other words, before the sheet SH2 reaches the branch point BP). In this embodiment, the amount of overlap is set to 0. However, even if the amount of overlap is not 0, there is a certain effect if it can be reduced.

[0064] See FIG. 7A. Whether the trailing edge of sheet SH1 has passed through the conveying roller 6a is determined based on the amount of rotation of the conveying roller 5a from the start of the indexing operation of sheet SH1 and the length of sheet SH1. As shown in FIG. 7A, when the trailing edge of sheet SH1 passes through the conveying roller 6a, the preceding sheet SH1 can be conveyed by the conveying roller 7a, and the following sheet SH2 can be conveyed by the conveying rollers 5a and 6a. At this timing, the conveying rollers 5a and 6a do not affect the conveyance of sheet SH1, and the conveying roller 7a does not affect the conveyance of sheet SH2. At this timing, the reduction control is started.

[0065] In the reduction control, the conveying roller 7a is continuously rotated by the conveying motor 25, independently of the conveying rollers 5a and 6a. The conveying roller 9a is also rotated by the conveying motor 26 in the R1 direction (see FIG. 1) at the same speed as the conveying roller 7a.

[0066] Due to the relative speed difference between sheets SH1 and SH2, the trailing edge of sheet SH1 can be separated from sheet SH2, as shown in Fig. 7B. At this time, the speed of the conveying roller 7a is controlled so that the reduction control can be completed before the trailing edge of the preceding sheet SH1 passes through the conveying roller 7a. An example of speed control will be described later.

[0067] This reduction control prevents the overlapping portion of sheets SH1 and SH2 from passing through branch point BP, thereby preventing paper jams. Because the reduction control is executed during recording control of sheet SH2, it includes at least a control section in which the conveyance of the succeeding sheet SH2 by conveyance rollers 5a and 6a is stopped and the preceding sheet SH1 is conveyed by conveyance roller 7a.

[0068] That is, the transport of sheet SH2 is stopped during the printing operation. By continuously transporting sheet SH1 during this printing operation, the relative speed difference between sheets SH1 and SH2 can be maximized, efficiently reducing the amount of overlap. Therefore, the speed of the transport roller 7a does not necessarily need to be faster than that of the transport roller 5a to reduce the amount of overlap. The amount of overlap between sheets SH1 and SH2 can be reduced by transporting sheet SH1 at a slower speed. In other words, by performing reduction control during the printing operation, the transport speed can be reduced and noise and power consumption can be reduced compared to when reduction control is not performed during the printing operation. However, if reduction control is not completed during the printing operation of sheet SH2, reduction control can also be performed during the conveying operation of sheet SH2. In this case, having the speed of the transport roller 7a faster than that of the transport roller 5a is effective in reducing the amount of overlap. Of course, reduction control may also be performed when reduction control is completed during the printing operation of sheet SH2.

[0069] See FIG. 8(A). The conveying roller 9a continuously conveys the sheet SH1 to a position where its trailing edge passes through the branch point BP'. When the trailing edge of the sheet SH1 passes through the branch point BP', the conveying motor 26 is reversed in the R2 direction (see FIG. 1) and switched to high-speed driving. When viewed in the conveying direction, the leading edge and trailing edge of the sheet SH1 are swapped. The conveying roller 9a and the conveying roller 10a are rotated at, for example, 18 inches / sec. The sheet SH1 enters the return path RT22 and is conveyed to the feed roller 4a as shown in FIG. 8(B).

[0070] As the conveyance of sheet SH1 progresses and the leading edge of sheet SH1 is detected by sensor 31, conveyance motor 26 and feed motor 23 are driven at a low speed. As a result, conveyance roller 10a and feed roller 4a are rotated at, for example, 7.6 inches / sec. Then, sheet SH1 is conveyed from return path RT22 to main conveyance path RT1 by conveyance roller 10a and feed roller 4a.

[0071] Next, control for forming an overlapping state is performed. See FIG. 9A. Unlike the case of FIG. 6A, sheet SH2 is the leading sheet and sheet SH1 is the trailing sheet. Sheet SH2 is controlled to be printed based on the print data. When the sensor 31 detects the trailing edge of sheet SH2, the conveying motor 26 and the feed motor 23 are switched to high-speed driving. That is, the conveying roller 10a and the feed roller 4a rotate at, for example, 20 inches / sec. By moving sheet SH1 at high speed, an overlapping state is formed in which the leading edge of sheet SH1 overlaps the trailing edge of sheet SH2. Since the print control for sheet SH2 is performed based on the print data, sheet SH2 is intermittently conveyed by the conveying roller 5a. Meanwhile, after the trailing edge of sheet SH1 is detected by the sensor 31, sheet SH1 can catch up with sheet SH2 by continuously rotating the feed roller 4a at 20 inches / sec. Thereafter, sheet SH1 is conveyed until its leading edge reaches a predetermined position just before the nip portion of the conveying unit 5. The position of the leading edge of sheet SH1 is calculated from the amount of rotation of feed roller 4a after the leading edge of sheet SH1 is detected by sensor 31, and is controlled based on this calculation result. Sheet SH2 is guided by flapper 16 and enters sub-conveyance path RT2.

[0072] Next, a skew correction operation for sheet SH1 is performed. When the conveyance roller 5a is stopped to perform the recording operation for sheet SH2, the feed roller 4a is driven to abut the leading edge of sheet SH1 against the nip portion. In this embodiment, in order to minimize the effect on the recording quality of sheet SH2, the skew correction operation for sheet SH1 is performed when the conveyance roller 5a is stopped to perform the recording operation for the last line of sheet SH2.

[0073] See Figure 9(B). When the recording operation of the last line on sheet SH2 is completed, the conveying roller 5a is rotated a predetermined amount, so that sheet SH1 can be aligned while maintaining the state in which sheet SH1 is overlapped on sheet SH2. The overlapping portion of sheets SH1 and SH2 is sandwiched in the nip portion of the conveying unit 5 and conveyed.

[0074] When sheet SH1 is cue-fed, the feed motor 23 is switched to low-speed driving. That is, the feed roller 4a rotates at, for example, 7.6 inches / sec. While the conveying roller 5a is intermittently conveying sheet SH2 by a predetermined amount, the feed roller 4a is also intermittently driven by the feed motor 23. Ink is ejected from the recording head 12 onto the front surface (upper surface) of sheet SH1 based on the recording data, thereby starting the recording operation of the first page of recording data. When sheet SH1 is intermittently conveyed for the recording operation, sheet SH2 is also intermittently conveyed.

[0075] Next, the overlap amount is reduced. Sheet SH2 is introduced into the sub-transport path RT2, while sheet SH1 continues to be transported on the main transport path RT1 and is then discharged. Therefore, the reduction control is performed again.

[0076] See FIG. 10(A). Whether the trailing edge of sheet SH2 has passed through the conveying roller 6a is determined based on the amount of rotation of the conveying roller 5a from the start of the indexing operation of sheet SH2 and the length of sheet SH2. As shown in FIG. 10(A), when the trailing edge of sheet SH1 passes through the conveying roller 6a, the preceding sheet SH2 can be conveyed by the conveying roller 7a, and the following sheet SH1 can be conveyed by the conveying rollers 5a and 6a. At this timing, the conveying rollers 5a and 6a do not affect the conveyance of sheet SH2, and the conveying roller 7a does not affect the conveyance of sheet SH1. At this timing, the reduction control is started.

[0077] In the reduction control, the conveying roller 7a is continuously rotated by the conveying motor 25, independently of the conveying rollers 5a and 6a. The conveying roller 9a is also rotated by the conveying motor 26 in the R1 direction (see FIG. 1) at the same speed as the conveying roller 7a.

[0078] Due to the relative speed difference between sheets SH2 and SH1, the trailing edge of sheet SH2 can be separated from sheet SH1, as shown in Fig. 10(B). At this time, the speed of the conveying roller 7a is controlled so that the reduction control can be completed before the trailing edge of the preceding sheet SH2 passes through the conveying roller 7a. An example of speed control will be described later.

[0079] The reduction control is executed during the recording control of the sheet SH1, and therefore includes at least a control section in which the conveyance rollers 5a and 6a stop conveying the succeeding sheet SH1 and the conveyance rollers 7a convey the preceding sheet SH2.

[0080] That is, the transport of sheet SH1 is stopped during the recording operation. By continuously transporting sheet SH2 during this recording operation, the relative speed difference between sheets SH2 and SH1 can be maximized, and the amount of overlap can be efficiently reduced. The amount of overlap between sheets SH2 and SH1 can be reduced by slowing the transport speed of sheet SH2. If the reduction control is not completed during the recording operation of sheet SH2, it is also performed during the transport operation of sheet SH2. In this case, the speed of transport roller 7a is faster than that of transport roller 5a, which is effective in reducing the amount of overlap.

[0081] See FIG. 11(A). Sheet SH2 is continuously conveyed by conveying roller 9a until its trailing edge passes branch point BP'. When the trailing edge of sheet SH2 passes flapper 16, the flapper 16 is rotated to match the post-recording processing of sheet SH1, which is to pass through the flapper 16 next. Since the post-recording processing of sheet SH1 is discharge, the flapper 16 moves to a position where the conveying path of sheet SH1 is maintained as the main conveying path RT1. Whether or not the trailing edge of sheet SH2 has passed through the flapper 16 may be determined from the amount of rotation of various rollers, or may be determined by providing a separate sensor.

[0082] When the trailing edge of sheet SH2 passes branch point BP', the conveying motor 26 is reversed in the R2 direction (see FIG. 1) and switched to high-speed driving. As viewed in the conveying direction, the leading edge and trailing edge of sheet SH2 are swapped. Conveying rollers 9a and 10a are rotated at, for example, 18 inches / sec. Sheet SH2 enters return path RT22 and is conveyed to feed roller 4a as shown in FIG. 11(B).

[0083] As the conveyance of sheet SH2 progresses and the leading edge of sheet SH2 is detected by sensor 31, conveyance motor 26 and feed motor 23 are driven at a low speed. As a result, conveyance roller 10a and feed roller 4a are rotated at, for example, 7.6 inches / sec. Then, sheet SH2 is conveyed from return path RT22 to main conveyance path RT1 by conveyance roller 10a and feed roller 4a.

[0084] Next, control for forming an overlapping state is performed. See FIG. 12A. Sheet SH1 is again the leading sheet, and sheet SH2 is the trailing sheet. Sheet SH1 is controlled for recording based on the recording data. When the sensor 31 detects the trailing edge of sheet SH1, the conveying motor 26 and the feed motor 23 are switched to high-speed driving. That is, the conveying roller 10a and the feed roller 4a rotate at, for example, 20 inches / sec. By moving sheet SH2 at high speed, an overlapping state is formed in which the leading edge of sheet SH2 overlaps the trailing edge of sheet SH1. Since recording control for sheet SH1 is performed based on the recording data, sheet SH1 is intermittently conveyed by the conveying roller 5a. Meanwhile, after the trailing edge of sheet SH2 is detected by the sensor 31, sheet SH2 can catch up with sheet SH2 by continuously rotating the feed roller 4a at 20 inches / sec. Thereafter, sheet SH2 is conveyed until its leading edge reaches a predetermined position just before the nip portion of the conveying unit 5. The position of the leading edge of sheet SH2 is calculated from the amount of rotation of feed roller 4a after the leading edge of sheet SH2 is detected by sensor 31, and is controlled based on this calculation result. The leading edge of sheet SH1 has passed branch point BP and is heading toward conveyance roller 8a.

[0085] Next, a skew correction operation for sheet SH2 is performed. When the conveyance roller 5a is stopped to perform the recording operation for sheet SH1, the feed roller 4a is driven to abut the leading edge of sheet SH2 against the nip portion. In this embodiment, in order to minimize the effect on the recording quality of sheet SH1, the skew correction operation for sheet SH2 is performed when the conveyance roller 5a is stopped to perform the recording operation for the last line of sheet SH1.

[0086] See Figure 12(B). When the recording operation of the last line on sheet SH1 is completed, the conveying roller 5a is rotated a predetermined amount, so that sheet SH2 can be aligned while maintaining the state in which sheet SH2 is overlapped on sheet SH1. The overlapping portion of sheets SH1 and SH2 is sandwiched in the nip portion of the conveying unit 5 and conveyed.

[0087] When sheet SH2 is cue-fed, the feed motor 23 is switched to low-speed driving. That is, the feed roller 4a rotates at, for example, 7.6 inches / sec. While the conveying roller 5a is intermittently conveying sheet SH2 by a predetermined amount, the feed roller 4a is also intermittently driven by the feed motor 23. Ink is ejected from the recording head 12 onto the front (upper) surface of sheet SH2 based on the recording data, thereby starting the recording operation of the third page of recording data. When sheet SH2 is intermittently conveyed for the recording operation, sheet SH1 is also intermittently conveyed.

[0088] Next, control is performed to reduce the amount of overlap. If sheets SH1 and SH2 are discharged with a large overlap, the stacking order of sheets SH1 and SH2 on the discharge tray 25 may be reversed. Therefore, control is performed to reduce the amount of overlap. In this embodiment, the amount of overlap is set to 0. However, even if the amount of overlap is not 0, there is a certain effect if it can be reduced.

[0089] See FIG. 13(A). Whether the trailing edge of sheet SH1 has passed through the conveying roller 6a is determined based on the amount of rotation of the conveying roller 5a from the start of the indexing operation of sheet SH1 and the length of sheet SH1. As shown in FIG. 13(A), when the trailing edge of sheet SH1 passes through the conveying roller 6a, the preceding sheet SH1 can be conveyed by the conveying roller 7a, and the following sheet SH2 can be conveyed by the conveying rollers 5a and 6a. At this timing, the conveying rollers 5a and 6a do not affect the conveyance of sheet SH1, and the conveying roller 7a does not affect the conveyance of sheet SH2. At this timing, the reduction control is started.

[0090] In the reduction control, the conveying roller 7a is continuously rotated by the conveying motor 25 independently of the conveying rollers 5a and 6a. The conveying roller 8a, which shares the conveying motor 25, also continuously rotates.

[0091] Due to the relative speed difference between sheets SH1 and SH2, the trailing edge of sheet SH1 can be separated from sheet SH2, as shown in Fig. 13(B). At this time, the speed of the conveying roller 7a is controlled so that the reduction control can be completed before the trailing edge of the preceding sheet SH1 passes through the conveying roller 7a. An example of speed control will be described later.

[0092] This reduction control prevents the sheets SH1 and SH2 from being discharged in an overlapping state, which would result in the stacking order being reversed on the discharge tray 17. The reduction control is executed during the recording control of the sheet SH2, and therefore includes at least a control section in which the conveyance of the succeeding sheet SH2 by the conveyance rollers 5a and 6a is stopped, and the preceding sheet SH1 is conveyed by the conveyance roller 7a.

[0093] That is, the transport of sheet SH2 is stopped during the printing operation. By continuously transporting sheet SH1 during this printing operation, the relative speed difference between sheets SH1 and SH2 can be maximized, and the amount of overlap can be efficiently reduced. Therefore, the speed of the transport roller 7a does not necessarily need to be faster than that of the transport roller 5a to reduce the amount of overlap. The amount of overlap between sheets SH1 and SH2 can be reduced by transporting sheet SH1 at a slower speed. In other words, by performing reduction control during the printing operation, the transport speed can be reduced and deterioration in noise, power consumption, etc. can be suppressed compared to when reduction control is not performed during the printing operation. However, if reduction control is not completed during the printing operation of sheet SH2, it is also performed during the transport operation of sheet SH2. In this case, the speed of the transport roller 7a is faster than that of the transport roller 5a, which is effective in reducing the amount of overlap.

[0094] See Figure 14(A). Sheet SH1 has completed printing on both sides, so it is discharged to the discharge tray 17. When printing on the last line of sheet SH2 is completed, double-sided printing on sheet SH2, the last sheet of the current job, is also completed. By rotating conveying rollers 8a, 7a, 6a, and 5a in the same direction, sheet SH2 is discharged to the discharge tray 17 as shown in Figure 14(B).

[0095] This completes the double-sided recording operation based on the recording conditions in Fig. 3(A). In the case of single-sided recording based on the recording conditions in Fig. 3(B), the operation is performed in the same manner except for the operation of introducing the sheet SH into the sub-transport path RT2, and the control of forming an overlap state and the control of reducing the amount of overlap are performed sequentially between successive sheets.

[0096] <Control processing example> An example of the processing performed by the MPU 41 to realize the operation of the recording device 1 described above will be described with reference to Fig. 15. In step S1, the recording order N is initialized by setting it to 1. In step S2, the maximum recording order Nmax is obtained from the recording conditions. Nmax is the maximum value of the recording order N, and is 4 in the example of Fig. 3(A) and 3 in the example of Fig. 3(B).

[0097] In step S3, the position of the flapper 16 is controlled so as to correspond to the process G(N) corresponding to the recording order N=1. In the example of Fig. 3(A), the process G(1) after recording is inversion, so the flapper 16 moves to the position shown in Fig. 4(B), and in the example of Fig. 3(B), the process G(1) after recording is discharge, so the flapper 16 moves to the position shown in Fig. 1.

[0098] In step S4, feeding of the M(N)th sheet SH from the paper feed source Q(N) begins. If the paper feed source Q(N) is the feed tray 2, the feed motor 22 is first driven at a low speed. This causes the pickup roller 3 to rotate at, for example, 7.6 inches / sec. As the pickup roller 3 rotates, it picks up the topmost sheet SH stacked on the feed tray 2. The sheet SH picked up by the pickup roller 3 is transported by the feed roller 4a, which rotates in the same direction as the pickup roller 3. The feed roller 4a is driven by the feed motor 23 at the same speed as the pickup roller 3. After the pickup roller 3 rotates a predetermined amount to transport the sheet SH beyond the feed roller 4a, the pickup roller 3 stops so as not to pick up the next transport medium. The pickup roller 3 is a one-way roller, so that even if the pickup roller 3 is stopped, the feed roller 4a can continue transporting the sheet SH.

[0099] When the sheet feed source Q(N) is the sub-transport path RT2, the transport motor 26 is driven at a low speed, and the feed motor 23 is also driven at a low speed. As a result, the transport roller 10a and the feed roller 4a are rotated at, for example, 7.6 inches / sec. Then, the sheet SH is transported by the transport roller 10a and the feed roller 4a from the return path RT22 through the main transport path RT1 toward the transport roller 5a.

[0100] In step S5, it is determined whether the leading edge of the M(N)th sheet SH has been detected by the sensor 16 (whether the leading edge has passed the sensor 16). If it is determined that the leading edge has passed, step S6 is executed. In step S6, the feeding speed of the M(N)th sheet SH is switched to a high speed (for example, 20 inches / sec). By switching the feeding motor 23 to high speed driving, the feeding roller 4a rotates at 20 inches / sec. If a preceding M(N-1)th sheet SH exists, an operation is started to allow the succeeding sheet SH to catch up with the preceding sheet SH.

[0101] In step S7, it is determined whether N=1. If it is determined that N=1, there is no preceding sheet SH to be overlapped, so the process proceeds to step S9. On the other hand, if it is determined that N=1, there is a possibility that the preceding sheet SH and the succeeding sheet SH will be conveyed overlapping each other, so the process executes the overlapping state formation control in step S8.

[0102] 16 is a flowchart of the overlapping state formation control. In step S21, the conveyance of the sheet SH is stopped so that the leading edge of the M(N)th sheet SH is positioned at a predetermined position in front of the conveyance roller 5a. If the trailing edge of the preceding sheet SH is positioned upstream of the conveyance roller 5a, an overlapping state is formed in which the leading edge of the succeeding sheet SH overlaps the trailing edge of the preceding sheet SH. The leading edge position of the M(N)th sheet SH is calculated from the amount of rotation of the feed roller 4a after the leading edge of the M(N)th sheet SH is detected by the sensor 31, and control is performed based on this calculation result.

[0103] In step S22, it is determined whether a predetermined overlapping condition is met. The overlapping condition is a determination of whether the trailing edge of the preceding sheet SH and the leading edge of the succeeding sheet SH can be conveyed with overlapping. For example, if the preceding sheet SH has already passed through the conveying roller 5a, the result is "No." Also, for example, if the overlap amount is smaller than a predetermined amount, the result is "No." Also, for example, if the overlap amount is equal to or greater than the conveying distance between the conveying roller 6a and the conveying roller 7a, it will be difficult to separate the sheets in the reduction control described below, so the result is "No." Also, for example, if the reduction control described below is executed by setting a target distance as the separation distance between the sheets, the result is also "No" if the overlap amount exceeds the target separation distance.

[0104] If it is determined that the overlapping conditions are met, step S23 is executed. In step S23, it is determined whether the printing operation for the last line of the M(N-1)th preceding sheet SH has started. If it is determined that the printing operation has not started (step S23: NO), the process waits for the start of the printing operation. If it is determined that the printing operation has started (step S23: YES), the process of step S9 in FIG. 15 (skew correction) is executed.

[0105] If it is determined in step S22 that the overlapping conditions are not met, a process to eliminate the overlapping state is performed in step S24. For example, this process waits for the conveyance of the M(N)th succeeding sheet SH until the M(N-1)th preceding sheet SH passes the conveyance roller 5a. After that, the process of step S9 in FIG. 15 (skew correction) is performed.

[0106] Returning to FIG. 15, in step S9, skew correction of the M(N)th sheet SH is performed. While the conveying roller 5a is stopped, the feed roller 4a is driven to abut the leading edge of the M(N)th sheet SH against the nip portion of the conveying unit 5, thereby performing skew correction of the M(N)th sheet SH. Note that if it is determined in step S7 that N=1, or if it is determined in step S22 that the stacking conditions are not met, the M(N)th sheet SH is subjected to skew correction without overlapping with the preceding sheet SH. On the other hand, if it is determined in step S22 that the stacking conditions are met, the M(N)th sheet SH is subjected to skew correction while overlapping with the M(N-1)th preceding sheet SH.

[0107] In step S10, the M(N)th sheet SH is aligned. The M(N)th sheet SH can be aligned by rotating the conveying roller 5a a predetermined amount. At this time, if the M(N)th sheet SH has been corrected for skew while overlapping the M(N-1)th sheet SH in step S9, the sheet SH is aligned while maintaining the overlapping state.

[0108] In step S11, the feeding speed of the M(N)th sheet SH is switched to a low speed (for example, 7.6 inches / sec). By switching the feeding motor 23 to low speed driving, the feeding roller 4a rotates at 7.6 inches / sec.

[0109] In step S12, the operation of recording data for page K(N) is started on the recording surface F(N) of the M(N)th sheet SH. While the sheet SH is being intermittently conveyed by the conveying roller 5a at a predetermined distance, the feed roller 4a is also intermittently driven by the feed motor 23. When the M(N)th sheet SH is intermittently conveyed for the recording operation, the M(N-1)th sheet SH is also intermittently conveyed.

[0110] In step S13, it is determined whether N=1. If it is determined that N=1, step S16 is executed, and if it is determined that N=1 is not, step S14 is executed. In step S14, it is determined whether an overlapping state is formed between the M(N)th sheet SH and the M(N-1)th sheet SH. If it is determined that an overlapping state is formed, reduction control in step S15 is executed. Details of the reduction control will be described later.

[0111] In S16, inversion / discharge control is executed. FIG. 20 is a flowchart showing an example of this process. In step S41, it is determined whether the post-recording process G(N-1) is inversion. If it is determined that inversion is required, step S42 is executed, and the conveying roller 7a is rotated to convey the M(N-1)th sheet SH to the sub-conveying path RT2. At this time, the position of the flapper 16 has been moved in advance by another process to a position where the sheet SH is guided to the sub-conveying path RT2.

[0112] In step S43, it is determined whether the trailing edge of the M(N-1)th sheet SH has passed the flapper 16. The determination of whether the sheet has passed the flapper 16 may be made from the amount of rotation of various rollers, or may be made by providing a separate sensor. If it is determined that the trailing edge has passed the flapper 16, step S44 is executed. In step S44, the flapper 16 is moved so as to correspond to the post-recording process G(N) of the subsequent sheet SH.

[0113] In step S45, it is determined whether the trailing edge of the M(N-1)th sheet SH has passed through the branch point BP'. If it is determined that it has passed through, step S46 is executed. In step S46, the M(N-1)th sheet SH is conveyed toward the return path RT22. By switching the conveying motor 26 to high-speed driving in the reverse direction (direction R2 in FIG. 1), the conveying rollers 9a and 10a are rotated at, for example, 18 inches / sec. By switching the conveying direction of the M(N-1)th sheet SH, the leading edge and trailing edge are swapped. Thereafter, in step S47, the M(N-1)th sheet SH is stopped when the leading edge of the sheet SH reaches a predetermined position just before the main conveying path RT1. The position at this time is also calculated from the amount of rotation of each roller since the start of the cueing operation and the length of the sheet. Then, step S17 in FIG. 15 is executed.

[0114] If it is determined in step S41 that the post-recording process G(N-1) is not inversion, step S48 is executed, and the M(N-1)th sheet SH is discharged to the discharge tray 17 by the rotation of the conveying rollers 8a and 7a. In step S49, it is determined whether the trailing edge of the M(N-1)th sheet SH has passed through the flapper 16. If it is determined that the trailing edge has passed through the flapper 16, step S50 is executed. In step S50, the flapper 16 is moved so as to correspond to the post-recording process G(N) of the subsequent sheet SH.

[0115] Returning to FIG. 15, in step S17, the recording order is incremented by one. In step S18, it is determined whether the recording order N after the increment is equal to or less than the maximum recording order Nmax. If it is determined that it is equal to or less than the maximum recording order Nmax, step S19 is executed. In step S19, it is determined whether the trailing edge of the M(N-1)th sheet SH has passed the sensor 16. If it is determined that the trailing edge has passed the sensor 16, the process returns to step S4, where the feeding operation is started, and control is executed in the same manner thereafter.

[0116] If it is determined in step S18 that the recording order N is not equal to or less than the maximum recording order Nmax, it is determined that recording has ended and step S20 is executed. In step S20, the M(N-1)th sheet SH is discharged. By rotating the conveying rollers 8a, 7a, 6a, and 5a in the same direction, the sheet SH can be discharged onto the discharge tray 17. This completes the process.

[0117] <Decrease control> Fig. 17 is a flowchart showing a processing example of the decrease control in S 15. Fig. 18(A) to Fig. 19(C) are explanatory diagrams of the decrease control.

[0118] See Figure 18(A). Reduction control uses at least two transport units. Here, transport unit 6 and transport unit 7 are used. In the transport direction of sheet SH, transport unit 6 is located upstream of transport unit 7. Here, we will explain the case where the overlap amount between the preceding sheet SH1 and the following sheet SH2 is reduced.

[0119] 18A shows the state in which skew correction is being performed on the succeeding sheet SH2. When the conveying roller 5a is stopped to perform the recording operation of the last line of sheet SH1, the leading edge of sheet SH2 is abutted against the nip portion of the conveying unit 5 to perform skew correction of sheet SH2. At this time, the rear end of sheet SH1 and the leading edge of sheet SH2 overlap by an overlap amount W in the conveying direction. As a prerequisite for reduction control, the overlap amount W is smaller than the distance between the conveying roller 6a and the conveying roller 7a.

[0120] In Figure 18(A), Dn is the distance of the nozzle region of the print head 12, which is the distance from the most upstream to the most downstream of the ejection nozzles of the print head 12, i.e., the maximum print width in the transport direction. Therefore, if the print width for one print operation is Ds, then Ds≦Dn. The print width Ds may be different for each print operation. IM1 is the image already printed on sheet SH1.

[0121] When the printing operation of the last line of sheet SH1 is completed, the conveying roller 5a is rotated a predetermined amount, so that sheet SH2 can be aligned with sheet SH1, with the overlap amount W maintained. Figure 18(B) shows the aligned state, with the downstream-most edge of the intended printing area of ​​sheet SH2 coinciding with the position of the downstream-most ejection nozzle of the printing head 12. The speed of intermittent conveyance of sheets SH1 and SH2 is indicated as V1.

[0122] See Figure 18(C). The reduction control starts after the trailing edge of the preceding sheet SH1 passes the upstream conveying roller 6a used for the reduction control. The start timing is not limited to immediately after the passage, but may be any time after the passage. IM2 is an image already recorded on sheet SH2.

[0123] The reduction control is controlled so as to end before the trailing edge of the preceding sheet SH1 passes an arbitrary position T. In the illustrated example, the position T is set in front of the conveying roller 7a. However, it may also coincide with the conveying roller 7a. In other words, the reduction control is performed so as to end before the trailing edge of the preceding sheet SH1 passes the conveying roller 7a. Furthermore, according to the setting of the position T, the reduction control is performed so as to end before the leading edge of the succeeding sheet SH2 reaches the conveying roller 7a.

[0124] The area from the conveying roller 6a to position T is the separation area, and its distance is L. Furthermore, the distance between the rear end of the preceding sheet SH1 and the leading end of the succeeding sheet SH2 after reduction control is Dp. At this time, the distance (LW-Dp) is the scan determination distance, and is referenced in calculating the number of scans S when recording on the succeeding sheet SH2. The number of scans can also be said to be the number of times the carriage 11 moves.

[0125] Please refer to the flowchart in Figure 17. In step S31, the conveying speed V2 of the preceding sheet SH1 is calculated. Here, the overlap amount W is acquired by the MPU 41. Also, from the recording data to be recorded on the subsequent sheet SH2, the number of scans S while the leading edge of the subsequent sheet SH2 moves through the scan determination distance (LW-Dp) is calculated. Also, the separation possible time Tmax is calculated.

[0126] From the overlap amount W, number of scans S, time required for one scan Ts, distance L of the separation area, paper spacing Dp after reduction control, and conveying speed V1 of the following sheet SH2, Tmax can be calculated as Tmax = (LW - Dp) / V1 + S · Ts.

[0127] In this embodiment, the conveying speed V1 of the succeeding sheet SH2 is the conveying speed of the conveying roller 6a. The time Ts required for one scan is the time t2-t3 or the time t4-t5 in FIG. 19(C). The time t4-t5 includes the waiting time before and after printing. If the required time Ts differs for each printing operation, the average value of each time may be used.

[0128] The speed V2 of the sheet SH1 is calculated from the separation possible time Tmax and the separation area distance L, and is given by V2=L / Tmax.

[0129] In step S32, it is determined whether the trailing edge of the preceding sheet SH1 has passed through the conveying rollers 6a. In this embodiment, it is determined whether the trailing edge has passed through the conveying rollers 6a. If it is determined that the trailing edge has passed through, the process proceeds to step S33.

[0130] In step S33, the conveying roller 7a, which is used for separation and is located downstream in the conveying direction, is rotated at a speed equal to or greater than V2. FIG. 18C shows the state in which the conveying roller 7a has started to rotate at a speed equal to or greater than V2. This operation separates the leading sheet SH1 from the trailing sheet SH2, as shown in FIG. 19A, and the overlap amount W decreases to W'. In FIG. 18C, the conveying rollers 5a and 6a are stationary, but in FIG. 19A, they are rotating at a speed V1.

[0131] As shown in FIG. 19B, it becomes possible to provide a sheet interval of equal to or greater than the interval Dp before the trailing edge of the sheet SH1 passes through the position T, and the overlapping state can be resolved.

[0132] In step S34, it is determined whether the distance between the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 is equal to or greater than Dp. If it is determined that the distance is equal to or greater than Dp, the decrease control is terminated.

[0133] FIG. 19C illustrates the changes in the printing operation and conveying speed of the succeeding sheet SH2 and the conveying speed of the preceding sheet SH1 after the start of the reduction control. The reduction control starts at time t1, and the preceding sheet SH1 is conveyed at speed V2 (>V1) due to the continuous rotation of the conveying roller 7a. The succeeding sheet SH2 is conveyed intermittently, and conveyance stops while the printing operation is being performed. In the time period from time t2 to t3 and the time period from time t4 to t5, the relative speed difference between the preceding sheet SH1 and the succeeding sheet SH2 is maximized, facilitating a reduction in the amount of overlap. By lowering the conveying speed of the preceding sheet SH1, the amount of overlap between the preceding sheet SH1 and the succeeding sheet SH2 can be reduced. Furthermore, the reduction control does not have any adverse effect, such as delaying the printing control of the succeeding sheet SH2.

[0134] In this embodiment, the distance Dp is set to Dp≧0, which can eliminate the overlapping state. However, it is also possible to set Dp<0. In this case, the overlapping state is not completely eliminated, but the amount of overlap can be reduced. Dp may be set by previously obtaining through experiments an amount of overlap that does not cause a paper jam at the branch point BP or an amount of overlap that does not change the stacking order of multiple sheets SH on the discharge tray 17.

[0135] In addition, when the reduction control is not performed during the recording operation, the separation possible time Tmax' is T'max=(LW-Dp) / V1. Therefore, in this case, the speed V2' of the preceding sheet SH1 during the decrease control is V2'=L / Tmax' This results in Tmax > Tmax’. Therefore, V2 < V2’. That is, by performing the reduction control during the recording operation in which the conveyance of the subsequent sheet SH2 has stopped, it is possible to reduce the conveyance speed and suppress deterioration such as noise and power consumption compared to the case where the reduction control is not performed during the recording operation.

[0136] When the time S·Ts required for the S scan operations is large, V2 can be made smaller. Also, a standby time unrelated to the scan operation may be provided separately. In this case, the conveyance speed can be further reduced and deterioration such as noise and power consumption can be suppressed. Note that V2 in the reduction control may be faster than V1, but since there is a conveyance stop period for the subsequent sheet SH2, it is not always necessary to be fast depending on the calculation result of V2 and it may be the same or slower. The conveyance roller 7a that continuously conveys the preceding sheet SH1 does not necessarily need to be continuously driven at a constant speed of V2 or more. For example, it may be controlled so that the average speed including stops and acceleration / deceleration is V2 or more.

[0137] In the determination of the end of the deceleration control (step S34), another end condition may be provided. For example, it may be ended when the rear end of the preceding sheet SH1 reaches the conveyance roller 7a. At this time, if the reduction control is performed at a speed higher than V2, the sheet interval can be further widened.

[0138] <Second Embodiment> In the first embodiment, the conveyance rollers 6a and 7a were used during the reduction control, but the selection of the rollers used for the reduction control is not limited to this. For example, although limited to the conveyance of the sheet SH in the main conveyance path RT1, the rollers used for the reduction control may be the conveyance roller 6a and the conveyance roller 8a.

[0139] Since the conveyance roller 7a and the conveyance roller 8a are driven by the same conveyance motor 25, it is necessary for the reduction control to be completed by the time the leading end of the subsequent sheet SH reaches the conveyance roller 7a. The position T in Fig. 18(A) is set, for example, at a position advanced Dp downstream in the conveyance direction from the conveyance roller 7a. The distance L of the separation area is the distance from the conveyance roller 6a to the position T advanced Dp downstream in the conveyance direction from the conveyance roller 7a.

[0140] Figure 21(A) shows an example of the timing to start the reduction control in this embodiment. The trailing edge of the preceding sheet SH1 passes through the conveying roller 6a. The conveying motor 25 rotates the conveying rollers 8a and 7a at a speed V2. Figure 21(B) shows the point in time when the reduction control ends, when the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 are separated from each other across the conveying roller 7a.

[0141] Even when control is performed in this manner, the overlapping state between the preceding sheet SH1 and the following sheet SH2 can be eliminated.

[0142] Third Embodiment The rollers used for reduction control may be the conveying roller 5a and the conveying roller 8a. In this case, however, the conveying roller 8a is driven independently of the conveying roller 7a by a separate dedicated motor that is not shared with the conveying roller 7a. The conveying rollers 6a and 7a are one-way rollers that can rotate freely in the conveying direction. Position T in Figure 18(A) coincides with the conveying roller 8a. The distance L of the separation region is the distance from the conveying roller 5a to the conveying roller 8a.

[0143] FIG. 22(A) shows an example of the timing at which reduction control is started in this embodiment. The trailing edge of the preceding sheet SH1 has passed through the transport roller 5a, but is located upstream of the transport roller 6a. The transport roller 8a is rotated at a speed V2 by a dedicated motor. Because the transport rollers 6a and 7a are one-way rollers, the preceding sheet SH1 can be transported without receiving a large load from these rollers. FIG. 22(B) shows the point at which reduction control ends, when the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 are separated.

[0144] Even when control is performed in this manner, the overlapping state between the preceding sheet SH1 and the following sheet SH2 can be eliminated.

[0145] <Fourth embodiment> Although this is limited to the transport of sheet SH1 on sub-transport path RT2, the rollers used for the reduction control may be transport roller 5a and transport roller 9a. Transport roller 6a and transport roller 7a are one-way rollers that are capable of idling in the transport direction. Position T in Figure 18(A) is assumed to coincide with branch point BP. Distance L of the separation region is the distance from transport roller 5a to branch point BP.

[0146] FIG. 23(A) shows an example of the timing at which reduction control is started in this embodiment. The trailing edge of the preceding sheet SH1 has passed the conveying roller 5a, but is located upstream of the conveying roller 6a. The conveying roller 9a rotates at a speed V2. Because the conveying rollers 6a and 7a are one-way rollers, the preceding sheet SH1 can be conveyed without receiving a large load from these rollers. FIG. 23(B) shows the point at which reduction control ends, when the trailing edge of the preceding sheet SH1 and the leading edge of the succeeding sheet SH2 are separated.

[0147] Even when control is performed in this manner, the overlapping state between the preceding sheet SH1 and the following sheet SH2 can be eliminated.

[0148] Fifth Embodiment Before performing the skew correction described in step S9 of FIG. 15, an overlap adjustment operation may be performed to adjust the amount of overlap to reduce it. In this case, by reducing the amount of overlap, the speed V2 during reduction control can be set to a lower speed. In the overlap adjustment operation, for example, skew correction of the succeeding sheet SH is not performed when recording the last line of the preceding sheet SH, but skew correction is performed after the preceding sheet SH has been transported a certain distance after the last line has been recorded. This makes it possible to reduce the amount of overlap.

[0149] <Other embodiments> In the reduction control, the speed of the conveying rollers that convey the succeeding sheet SH may be controlled to be slower than normal.

[0150] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0151] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0152] 1 recording device, 4 feeding unit, 5-10 transport units, 12 recording head, 40 control unit

Claims

1. a recording means for recording an image on a recording medium; a first conveying means for conveying the recording medium in a conveying direction; a second conveying means, downstream of the first conveying means in the conveying direction, for conveying a recording medium recorded by the recording means; a control unit capable of reducing the amount of overlap between the preceding recording medium and the succeeding recording medium from an overlapping state in which the succeeding recording medium overlaps the rear end of the preceding recording medium; A recording device comprising: the reduction control includes control to stop the conveyance of the subsequent recording medium by the first conveyance means and to convey the preceding recording medium by the second conveyance means when the subsequent recording medium can be conveyed by the first conveyance means in the conveyance direction. A recording device characterized by:

2. 2. The recording device according to claim 1, a third conveying means for conveying the recording medium to the first conveying means, the third conveying means being located upstream of the recording means in the conveying direction; a feeding means for feeding a recording medium to the third conveying means; A recording device characterized by:

3. 2. The recording device according to claim 1, the reduction control includes control of continuously transporting the preceding recording medium by the second transport means when the subsequent recording medium is being intermittently transported by the first transport means; A recording device characterized by:

4. a feeding means for feeding a recording medium; a plurality of conveying means arranged along a conveying path of the recording medium, for conveying the recording medium fed by the feeding means; a recording means disposed midway along the transport path and configured to record on the recording medium; a control means for controlling the feeding means and the plurality of conveying means; A recording device comprising: The control means After recording on the preceding recording medium is performed while maintaining an overlapping state in which the leading end of the succeeding recording medium overlaps the preceding recording medium, a reduction control can be executed to reduce the amount of overlap between the preceding recording medium and the succeeding recording medium, The plurality of conveying means are a first conveying means; a second conveying means located downstream of the first conveying means in a conveying direction, The decrease control is The process is performed in a state where the second transport means can transport the preceding recording medium and the first transport means can transport the succeeding recording medium, and a control for stopping the conveyance of the subsequent recording medium by the first conveying means and conveying the preceding recording medium by the second conveying means; A recording device characterized by:

5. 5. The recording device according to claim 4, The decrease control is a control for conveying the succeeding recording medium by the first conveying means and conveying the preceding recording medium by the second conveying means faster than the succeeding recording medium; A recording device characterized by:

6. 6. The recording apparatus according to claim 4 or claim 5, The control means a forming control can be executed to form an overlapping state in which the leading end of the succeeding recording medium overlaps the preceding recording medium before the succeeding recording medium reaches the recording means; an overlapping amount between the preceding recording medium and the succeeding recording medium in the formation control is smaller than a transport distance between the first transport means and the second transport means; A recording device characterized by:

7. 7. The recording apparatus according to claim 4, In the reduction control, the overlap amount between the preceding recording medium and the succeeding recording medium is set to 0. A recording device characterized by:

8. 8. The recording apparatus according to claim 4, The transport path is The first route, a second path branching from the first path at a branch point, the recording means is disposed on the first path, upstream of the branch point in the transport direction, the reduction control is performed before the subsequent recording medium reaches the branch point. A recording device characterized by:

9. 5. The recording device according to claim 4, the first transport means is disposed downstream of the recording means in the transport direction, the control means executes the reduction control in a state where the preceding recording medium has passed the first transport means and the succeeding recording medium has not passed the first transport means. A recording device characterized by:

10. 5. The recording device according to claim 4, the first transport means is disposed upstream of the recording means in the transport direction, the control means executes the reduction control in a state where the preceding recording medium has passed the first transport means and the succeeding recording medium has not passed the first transport means. A recording device characterized by:

11. 5. The recording device according to claim 4, the control means ends the decrease control after starting the decrease control and before the rear end of the preceding recording medium reaches a predetermined position. A recording device characterized by:

12. 5. The recording device according to claim 4, the control unit ends the decrease control after starting the decrease control and before the rear end of the preceding recording medium reaches the second transport unit. A recording device characterized by:

13. 5. The recording device according to claim 4, The transport path is The first route, a second path branching from the first path at a branch point, the recording means is disposed on the first path, upstream of the branch point in the transport direction, the control means ends the decrease control after starting the decrease control and before the rear end of the preceding recording medium reaches the branch point. A recording device characterized by:

14. 5. The recording device according to claim 4, the control unit ends the decrease control after starting the decrease control and before the subsequent recording medium reaches the second transport unit. A recording device characterized by:

15. 5. The recording device according to claim 4, the first transport means is disposed upstream of the recording means in the transport direction, the second transport means is disposed downstream of the recording means in the transport direction. A recording device characterized by:

16. 5. The recording device according to claim 4, a carriage that carries the recording means and moves in a direction across the recording medium; the control means executes recording control to alternately perform a conveying operation of the recording medium and a recording operation of performing recording by the recording means while moving the carriage, the reduction control is performed during the recording control for the subsequent recording medium; the stopping of the conveyance of the subsequent recording medium in the reduction control is performed by stopping the conveyance of the subsequent recording medium during the recording operation. A recording device characterized by:

17. 5. The recording device according to claim 4, the second conveying means is a discharge means for conveying the preceding recording medium to a discharge tray; A recording device characterized by:

18. 5. The recording device according to claim 4, The transport path is The first route, a second path branching from the first path at a branch point, the recording means is disposed on the first path, upstream of the branch point in the transport direction, the second path is a path for conveying the preceding recording medium to the feeding means by turning it over, the second conveying means is disposed on the second path; A recording device characterized by:

19. 19. The recording device according to claim 8 or claim 18, A flapper for switching the path of the preceding recording medium is provided at the branch point. A recording device characterized by:

20. 5. The recording device according to claim 4, In the decrease control, a conveying speed of the second conveying means is set based on an overlapping amount between the preceding recording medium and the succeeding recording medium in the overlapping state; A recording device characterized by:

21. a recording means for recording an image on a recording medium; a first conveying means for conveying the recording medium in a conveying direction; a second conveying means, downstream of the first conveying means in the conveying direction, for conveying a recording medium recorded by the recording means; A control method for a recording device comprising: a reduction control step of reducing an overlapping amount between the preceding recording medium and the succeeding recording medium from an overlapping state in which the succeeding recording medium overlaps the rear end of the preceding recording medium, the reduction control step includes control of stopping the conveyance of the subsequent recording medium by the first conveying means and conveying the preceding recording medium by the second conveying means when the subsequent recording medium can be conveyed by the first conveying means in the conveying direction. A control method comprising:

22. A storage medium storing a program for causing a computer to execute the control method according to claim 21.

23. A program that causes a computer to execute the control method according to claim 21.

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