Printing apparatus, control method thereof, and storage medium

Abstract

The present application provides a printing apparatus, a control method thereof, and a storage medium. The printing apparatus includes a supply member configured to supply a print medium; a first roller configured to convey the print medium; a print member configured to print onto the print medium; and a control member capable of controlling the supply member and the first roller to generate an overlapping state in which a leading end portion of a subsequent print medium overlaps with a trailing end portion of a preceding print medium on an upstream side of the first roller in a conveyance direction of the print medium. The control member adjusts an overlapping amount in the overlapping state on the upstream side of the first roller in the conveyance direction of the print medium based on print data of the preceding print medium and print data of the subsequent print medium.

Description

Technical Field

[0001] The present invention relates to a printing apparatus capable of performing double-sided printing by automatically flipping the printing medium from the first side to the second side. Background Technology

[0002] In a printing device capable of double-sided printing by automatically flipping the printing medium from the first side to the second side, after the printing medium is conveyed to the printing area opposite the print head and printed while a portion of the printing medium overlaps with each other, it is necessary to remove the overlap to facilitate the discharge of the printing medium and prevent paper jams.

[0003] Japanese Patent Application Publication No. 6-56299 describes a printing apparatus in which, after the overlapping portion of the printing medium at the rear and front ends has passed through the image forming unit, the conveying speed of the preceding printing medium is increased to separate the printing medium from the subsequent printing medium, thereby removing the overlapping state.

[0004] However, in the device described in Japanese Patent Application Publication No. 6-56299, when increasing the transport speed of the preceding print media to separate it from the subsequent print media and thus remove the overlap, the preceding print media needs to be separated at a very high speed depending on the size of the transport path. In this case, high-speed driving of the transport unit and drive unit used for the separation operation poses a risk of increased noise and power consumption. Summary of the Invention

[0005] In view of the above problems, the present invention provides a printing device that can suppress the increase of noise and power consumption when the overlapping state of the printing media is removed.

[0006] According to a first aspect of the present invention, a printing apparatus is provided, comprising: a supply member for supplying a printing medium; a first roller for conveying the printing medium supplied by the supply member in a conveying direction; a printing member for printing onto the printing medium conveyed by the first roller; and a control member capable of controlling the supply member and the first roller to produce an overlapping state, wherein in the overlapping state, the front end of a subsequent printing medium overlaps with the rear end of a preceding printing medium on the upstream side of the first roller in the conveying direction of the printing medium, wherein the control member adjusts the amount of overlap in the overlapping state on the upstream side of the first roller in the conveying direction of the printing medium based on printing data of the preceding printing medium and printing data of the subsequent printing medium.

[0007] According to a second aspect of the present invention, a control method for a printing apparatus is provided, the printing apparatus comprising: a supply component for supplying a printing medium; a first roller for conveying the printing medium supplied by the supply component in a conveying direction; and a printing component for printing onto the printing medium conveyed by the first roller, the control method comprising: a control step capable of controlling the supply component and the first roller to produce an overlapping state, wherein in the overlapping state, the front end of a subsequent printing medium overlaps with the rear end of a preceding printing medium on the upstream side of the first roller in the conveying direction of the printing medium, wherein, in the control step, the amount of overlap in the overlapping state is adjusted on the upstream side of the first roller in the conveying direction of the printing medium based on printing data of the preceding printing medium and printing data of the subsequent printing medium.

[0008] According to a third aspect of the present invention, a non-transitory computer-readable storage medium is provided, which stores a program that causes a computer to perform the control method of the printing device described above.

[0009] Further features of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view showing the main components of a printing device according to a first embodiment of the present invention.

[0011] Figure 2 This is a cross-sectional view showing the main components of a printing device according to a first embodiment of the present invention.

[0012] Figure 3 This is a block diagram illustrating a printing apparatus according to a first embodiment.

[0013] Figure 4 This is a table showing the printing order according to the first embodiment.

[0014] Figure 5 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0015] Figure 6 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0016] Figure 7 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0017] Figure 8 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0018] Figure 9 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0019] Figure 10 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0020] Figure 11 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0021] Figure 12 This is a diagram illustrating the various states in the overlapping continuous feed operation according to the first embodiment.

[0022] Figure 13A and Figure 13B This is a flowchart illustrating the overlapping continuous feed operation in the printing process according to the first embodiment.

[0023] Figure 14A and Figure 14B This is a flowchart illustrating the overlapping continuous feed operation in the printing process according to the first embodiment.

[0024] Figure 15 This is a flowchart illustrating the overlapping continuous feed operation in the printing process according to the first embodiment.

[0025] Figure 16 This is a flowchart illustrating the separation operation according to the first embodiment.

[0026] Figure 17 This is a conceptual diagram illustrating the separation operation according to the first embodiment.

[0027] Figure 18 This diagram illustrates the operations used to overlap subsequent sheets with preceding sheets.

[0028] Figure 19 This diagram illustrates the operations used to overlap subsequent sheets with preceding sheets.

[0029] Figure 20 This is a flowchart illustrating the overlap determination according to the first embodiment.

[0030] Figure 21 This is a flowchart illustrating the overlap adjustment operation according to the first embodiment.

[0031] Figure 22 This is a flowchart illustrating the operations used to calculate the leading edge position of subsequent slices.

[0032] Figure 23 This is a flowchart illustrating the overlap adjustment operation according to the second embodiment.

[0033] Figure 24This is a flowchart illustrating the overlap adjustment operation according to the third embodiment.

[0034] Figure 25 This is a timing diagram illustrating the separation operation.

[0035] Figure 26 This is a diagram illustrating the overlap adjustment operation. Detailed Implementation

[0036] In the following, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention. Several features are described in the embodiments, but it is not a limitation requiring all such features, and multiple such features can be suitably combined. Furthermore, in the drawings, the same reference numerals are given to the same or similar configurations, and redundant descriptions thereof are omitted.

[0037] First Embodiment

[0038] Figure 1 and Figure 2 This is a cross-sectional view showing the main components of a printing apparatus 200 according to a first embodiment of the present invention. (The text will be used...) Figure 1 STA to STC and Figure 2 The overall configuration of the printing device 200 according to this embodiment is described in the accompanying drawings, which are shown in the STD to STF diagrams.

[0039] Overall configuration

[0040] exist Figure 1 In the STA, P indicates the printing media. Multiple sheets of printing media P are loaded in the paper loading unit 11. 2 indicates the pickup roller that contacts the topmost printing media P loaded in the paper loading unit 11 to pick it up. 3 indicates the feed roller for feeding the printing media P picked up by the pickup roller 2 downstream in the conveying direction along the first conveying path 100. The pickup roller 2 is a unidirectional roller, and the conveying of the feed roller 3 can continue even after the pickup roller 2 has been stopped, even after the printing media P has been conveyed beyond the position of the feed roller 3. 4 indicates the feed driven roller that applies force to the feed roller 3 and feeds the printing media P by clamping the printing media P together with the feed roller 3.

[0041] 5 indicates a first transfer roller for conveying the printing medium P fed by the feed roller 3 and the feed driven roller 4 to a position opposite the print head 7. 6 indicates a clamping roller that applies force to the first transfer roller 5 and conveys the printing medium P by clamping it together with the first transfer roller 5.

[0042] Between the feed roller gap formed by the feed roller 3 and the feed driven roller 4 and the transfer roller gap formed by the first transfer roller 5 and the clamping roller 6, the printing medium P is guided by a guide within the first transfer path 100. A printing medium sensor 16 indicates the front and rear ends of the printing medium P. The printing medium sensor 16 is positioned downstream of the feed roller 3 in the printing medium transport direction.

[0043] 7 indicates the printhead used for printing on the printing medium P conveyed by the first conveying roller 5 and the clamping roller 6. In this embodiment, the printhead will be described as an inkjet printhead that prints on the printing medium P by jetting ink. 8 indicates the platform that supports the second side (back side) of the printing medium P at a position opposite to the printhead 7. 1 indicates the carriage on which the printhead 7 is mounted and which moves in a direction intersecting the printing medium conveying direction.

[0044] 10 indicates the second conveyor roller that conveys the print medium P printed by the print head 7 in the direction of the third conveyor roller. 12 indicates the ratchet spur that rotates during contact with the print surface of the print medium printed by the print head 7. Here, the ratchet 12 is forced toward the second conveyor roller 10.

[0045] 20 indicates the third conveyor roller, which is capable of... Figure 1 The print media P printed by printhead 7 is conveyed in the direction of arrow E or F in the STA. For example... Figure 1 As shown in STB, during transport in the direction of arrow E, the discharge roller 22 rotates together with the third transport roller 20, which allows the printing medium P to be transported along the guide within the fourth transport path (discharge path) 104 and discharged to the paper discharge unit 25. Figure 1 As shown in the STC diagram, during transport in the direction of arrow F, the printing medium P is transported towards the reversing roller 9 along the guide within the third transport path 102. Figure 1 As shown in STB and STC, baffle 24 branches in the direction of arrow E or F. Note that 21 indicates a third transfer driven roller that applies force to the third transfer roller 20 and transfers the printing medium P by clamping it together with the third transfer roller 20. 23 indicates an discharge driven roller that applies force toward the discharge roller 22 and transfers the printing medium P by clamping it together with the discharge roller 22.

[0046] The reverse roller 9 is capable of being driven by the double-sided conveyor motor 216 (see...) Figure 3 Positive drive comes from Figure 2 The roller rotates (forward) in the direction of arrow A in the STD and is able to convey the print media P printed by printhead 7 in the direction of arrow C. Then, a portion of the print media P can be exposed to the outside of the device. Additionally, as... Figure 2 As shown in the STE, in Figure 2 After the printing medium P is conveyed in the direction of arrow C in the STE, the double-sided conveyor motor 216 is driven in the reverse direction, and the printing medium P reaches the vicinity of the reversing roller 9 at the upstream end in the conveying direction. As a result, the reversing roller 9... Figure 2 The STF rotates (reverses) in the direction of arrow B, and the printing medium P is flipped and conveyed along the guide in the direction of arrow D in the figure along the second conveying path (reverse path) 101.

[0047] At this time, when the reverse roller 9 rotates in the opposite direction, the intermediate roller 15 also... Figure 2 The STF rotates in the direction of arrow B (reverse direction), which will convey the print media P in the second conveying path 101 toward the feed roller 3. Note that the intermediate roller 15 is a unidirectional roller and can be... Figure 2 Driven and idling in the direction of arrow B in the STF. 13 indicates the reverse driven roller that applies force toward the reverse roller 9 and conveys the printing medium P by clamping the printing medium P together with the reverse roller 9. 14 indicates the intermediate driven roller that applies force toward the intermediate roller 15 and conveys the printing medium P by clamping the printing medium P together with the intermediate roller 15.

[0048] Control unit and drive allocation

[0049] Figure 3This is a block diagram illustrating a printing apparatus according to this embodiment. 201 indicates an MPU for controlling the operation and data processing of various units, etc. As will be described later, the MPU 201 functions as a transport control unit capable of controlling the transport of the printing media such that the rear end of a preceding printing media and the front end of a subsequent printing media overlap, and an overlap adjustment control unit 300 for adjusting the amount of overlap. As will be described later, the overlap adjustment control unit 300 includes an initial overlap calculation unit 301 for calculating an initial overlap based on printing data of the preceding printing media, a transport time calculation unit 302 for calculating a transport time based on printing data of the subsequent printing media, and a transport stop time calculation unit 303 for calculating a transport stop time based on printing data of the subsequent printing media. The overlap adjustment control unit 300 also includes at least one of a transport speed calculation unit 304 for calculating the transport speed of the preceding printing media, a transport distance calculation unit 305 for calculating the transport distance of the preceding printing media, and a transport time calculation unit 306 for calculating the transport time of the preceding printing media. The overlap adjustment control unit 300 also includes an overlap determination unit 307 for determining whether to adjust the overlap based on the transport speed, transport distance, and transport time of the preceding printing media. 202 indicates a ROM for storing programs and data executed by the MPU 201. 203 indicates RAM for temporarily storing data processed by the MPU 201 and data received from the host computer 214. Note that the aforementioned units 300 to 307 are implemented by the MPU 201 executing the program stored in ROM 202.

[0050] Printhead 7 is controlled by printhead driver 220. Carriage 1 is driven by carriage motor 204. First transfer roller 5 and second transfer roller 10 are driven by transfer motor 205. Pick-up roller 2 is driven by first feed motor 206. Feed roller 3 is driven by second feed motor 207. Third transfer roller 20 and discharge roller 22 are driven by discharge motor 215. Reversing roller 9 and intermediate roller 15 are driven by double-sided transfer motor 216. Baffle 24 is driven by baffle solenoid 217. The above motors are controlled by motor driver 218 (which represents multiple motors). Baffle solenoid 217 is controlled by solenoid driver 219.

[0051] The host computer 214 is equipped with a printer driver 2141, which is used to compile printing information such as the printed image and the printed image quality when the user instructs to perform a printing operation, and communicate the printing information to the printing device 200. The MPU 201 exchanges printed images with the host computer 214 via the I / F unit 213.

[0052] The process of overlapping continuous feed operation in double-sided printing

[0053] Reference Figure 4 and Figure 5 ST1 to Figure 12 ST22 in the example describes the operation of overlapping continuous feed during duplex printing mode in chronological order, using the example of printing four pages of print data on two print media P in a single job. When the print data for duplex printing mode is sent from the host computer 214 via I / F unit 213, the print data is processed by MPU 201 and then expanded in RAM 203. The printing operation is then started based on the data expanded by MPU 201.

[0054] This embodiment will describe the process by means of, for example Figure 4 The printing order is shown below. Note that the printing order is set to print face-down, with the front side facing down. However, the printing order is not intended to be limited to the above order.

[0055] Reference Figure 5 ST1 in the figure describes the process. First, the first feed motor 206 is driven at a low speed. As a result, the pickup roller 2 rotates at 7.6 inches per second. As the pickup roller 2 rotates, the topmost print media P loaded in the paper loading unit 11 is picked up. The first print media P picked up by the pickup roller 2 ("Print Media 1P" in the figure) is conveyed by the feed roller 3, which rotates in the same direction as the pickup roller 2. The feed roller 3 is driven by the second feed motor 207 at the same speed as the pickup roller 2.

[0056] After rotating a predetermined amount to allow the printing medium P to be conveyed beyond the position of the feed roller 3, the pickup roller 2 stops to prevent the pickup roller 2 from picking up the next printing medium P. The pickup roller 2 is a unidirectional roller, so the conveying of the feed roller 3 can continue even after the pickup roller 2 stops. This embodiment describes a configuration including the pickup roller 2 and the feed roller 3. However, this configuration could also include only the feed roller 3 for feeding the printing medium loaded in the paper loading unit 11.

[0057] When the print media sensor 16, located downstream of the feed roller 3 in the conveying direction, senses the leading edge of the first print media 1P, the second feed motor 207 switches to high-speed drive. In other words, the feed roller 3 rotates at 20 inches per second.

[0058] Now refer to Figure 5ST2 in the diagram describes this process. As the feed roller 3 continues to rotate, the leading edge of the first print media 1P on its downstream side in the conveying direction contacts the conveyor roller gap formed by the first conveyor roller 5 and the clamping roller 6. At this point, the first conveyor roller 5 stops. Even after the leading edge of the first print media 1P contacts the conveyor roller gap on its downstream side in the conveying direction, the feed roller 3 rotates a predetermined amount, and as a result, the leading edge of the first print media 1P is aligned while in contact with the conveyor roller gap, thus correcting skew. These skew correction operations are also referred to as "registration operations".

[0059] Now refer to Figure 5 ST3 in the document describes the process. Once the skew correction operation of the first print media 1P is completed, the first transport roller 5 begins to rotate as a result of being driven by the transport motor 205. The first transport roller 5 transports the print media P at 15 inches per second. After aligning the first print media 1P with the position opposite to the print head 7, the print head 7 ejects ink based on the print data to begin printing the second page of print data on the second side of the first print media 1P. Note that the alignment operation is performed by first positioning the tip of the first print media 1P at the position of the first transport roller 5 by contacting the tip of the first print media 1P with the gap of the transport roller, and then using the position of the first transport roller 5 as a reference to control the amount of rotation of the first transport roller 5.

[0060] The printing device in this embodiment is a serial printing device in which the printhead 7 is mounted on the carriage 1. Repeated transport and image forming operations are performed. In the transport operation, the first transport roller 5 intermittently transports the printing medium P in a predetermined amount each time. In the image forming operation, with the first transport roller 5 stopped, ink is ejected from the printhead 7 while the carriage 1 on which the printhead 7 is mounted is moved. As a result, a printing operation is performed on the first printing medium 1P.

[0061] Once the first print media 1P is aligned, the second feed motor 207 is switched to low-speed drive. In other words, the feed roller 3 rotates at 7.6 inches per second. The feed roller 3 is also intermittently driven by the second feed motor 207 as the first conveyor roller 5 intermittently conveys the first print media 1P in a predetermined amount each time. In other words, the feed roller 3 rotates when the first conveyor roller 5 rotates, and stops when the first conveyor roller 5 stops. The rotational speed of the feed roller 3 is lower than that of the first conveyor roller 5. Therefore, the print media P becomes taut between the first conveyor roller 5 and the feed roller 3. Additionally, the feed roller 3 is rotated by the first print media 1P conveyed by the first conveyor roller 5.

[0062] Due to factors such as sensor responsiveness, the print media sensor 16 requires at least a predetermined interval between print media to sense the ends of print media P. In other words, a predetermined time interval is needed between when the print media sensor 16 senses the upstream end of the first print media 1P in the transport direction and when the print media sensor 16 senses the downstream front end of the second print media P (hereinafter referred to as "2P") in the transport direction. Accordingly, the upstream end of the first print media 1P in the transport direction and the downstream front end of the second print media 2P in the transport direction need to be separated by a predetermined distance. Therefore, after determining that the upstream end of the first print media 1P in the transport direction has passed the sensor 16, a pickup operation for the second print media 2P is performed. Additionally, the rotation of the pickup roller 2 is controlled such that the interval between the upstream end of the first print media 1P in the transport direction and the downstream front end of the second print media 2P in the transport direction is at least a predetermined distance. The front and rear positions of each print media can be obtained based on the rotation amount of various rollers, or can be calculated by individual sensors.

[0063] Note that when the first conveyor roller 5 intermittently conveys the first printing medium 1P in a predetermined amount each time, the discharge motor 215 and the double-sided conveyor motor 216 intermittently drive the third conveyor roller 20 and the reverse roller 9 in the same direction and speed as the first conveyor roller 5.

[0064] Now refer to Figure 6 ST4 in the document provides a description. The second print media 2P picked up by the pickup roller 2 is conveyed by the feed roller 3. At this time, the print head 7 is performing an image forming operation on the first print media 1P based on the print data. When the print media sensor 16 senses the leading edge of the second print media 2P, the second feed motor 207 switches to high-speed drive. In other words, the feed roller 3 rotates at 20 inches per second.

[0065] Now refer to Figure 6ST5 in the document describes this process. The second print media 2P moves at a higher speed than the first print media 1P moves downstream as a result of the printing operation of printhead 7. As a result, the downstream leading edge of the second print media 2P in the transport direction overlaps with the upstream leading edge of the first print media 1P in the transport direction. The printing operation is performed based on the printing data of the first print media 1P, and therefore the first print media 1P is intermittently transported by the first transport roller 5. On the other hand, after the print media sensor 16 senses the downstream leading edge of the second print media 2P in the transport direction, the feed roller 3 rotates continuously at 20 inches per second, making it possible to catch up with the first print media 1P. The second print media 2P is then transported via the feed roller 3 until the downstream leading edge of the second print media 2P in the transport direction stops at a predetermined position upstream of the transport roller gap. The position of the downstream front end of the second printing medium 2P in the conveying direction is calculated based on the amount of rotation of the feed roller 3 after the printing medium sensor 16 senses the downstream front end of the second printing medium 2P in the conveying direction, and the position of the downstream front end of the second printing medium 2P in the conveying direction is controlled based on the result of the calculation. At this time, the print head 7 is performing an image forming operation on the first printing medium 1P based on the printing data.

[0066] Now refer to Figure 6 ST6 in the document describes the process. When the first conveyor roller 5 is stopped to perform an image forming operation (ink jetting operation) on the final line of the first print media 1P, a skew correction operation for the second print media 2P is performed by driving the feed roller 3 so that the leading edge of the second print media 2P contacts the gap of the conveyor roller.

[0067] Note that the processing after printing onto the first print medium 1P is reversed; therefore, the baffle solenoid 217 pre-pivots the baffle 24 toward the path leading to the reversing roller 9 via the third conveying path 102. Thus, the first print medium 1P is conveyed toward the reversing roller 9 while being guided by the third conveying path 102. In subsequent operations, after the upstream end of the print medium P in the conveying direction passes the baffle 24, the baffle 24 is pivoted according to the processing following printing of the next print medium P passing through the baffle 24. The determination regarding whether the upstream end of the print medium P in the conveying direction has passed the baffle 24 can be based on the amount of rotation of various rollers, or it can be done by a separately configured sensor.

[0068] Now refer to Figure 7ST7 in the document provides a description. When the image forming operation of the final line of the first print medium 1P is completed, the second print medium 2P can be aligned by rotating the first transfer roller 5 by a predetermined amount and keeping the second print medium 2P overlapping the first print medium 1P.

[0069] Once the second print media 2P is aligned, the second feed motor 207 switches to low-speed drive. In other words, the feed roller 3 rotates at 7.6 inches per second. The feed roller 3 is also intermittently driven by the second feed motor 207 as the first conveyor roller 5 intermittently conveys the second print media 2P in predetermined amounts each time. Printing operations for printing the fourth page of print data onto the second side of the second print media 2P begin by ejecting ink from the print head 7 onto the second print media 2P based on the print data. The first print media 1P is also intermittently conveyed while the second print media 2P is intermittently conveyed for the printing operation.

[0070] Separation operation (in the case of moving towards the second transport path 101)

[0071] Now refer to Figure 7 Descriptions are given in ST8-1 and ST8-2. After determining that the upstream end of the first print media 1P has passed the second conveyor roller 10 in the conveying direction based on the rotation amount of the first conveyor roller 5 after the start of the alignment operation and the length of the paper, the separation operation continues by continuously rotating the third conveyor roller 20 independently of the first and second conveyor rollers 5 and 10 using the discharge motor 215. Note that the double-sided conveyor motor 216 rotates in the forward direction, and the reverse roller 9 also rotates at the same speed as the third conveyor roller 20. Figure 2 The first printing medium 1P is rotated in the direction of arrow A. At this time, the first printing medium 1P is conveyed by the third conveyor roller 20. Before the upstream end of the second printing medium 2P passes the third conveyor roller 20 in the conveying direction, the speed of the third conveyor roller 20 is controlled such that the distance between the downstream end of the second printing medium 2P in the conveying direction and the upstream end of the first printing medium 1P in the conveying direction is at least a predetermined distance. The method for calculating the speed of the third conveyor roller 20 at this time will be described in detail later with reference to the control flow. Setting the aforementioned predetermined distance to be greater than 0 makes it possible to separate the first printing medium 1P and the second printing medium 2P, thereby removing the overlap between the upstream end of the first printing medium 1P in the conveying direction and the downstream front end of the second printing medium 2P in the conveying direction.

[0072] This reduces the likelihood of paper jams when switching the conveyor path using baffle 24.

[0073] Note that when de-overlapping, the speed of the third conveyor roller 20 can be faster than the speed of the first conveyor roller 5, but it is not necessary for the speed of the third conveyor roller 20 to be faster than the speed of the first conveyor roller 5. When the first conveyor roller 5 intermittently conveys the second printing medium 2P for printing operations, a certain amount of time, such as the scanning time of the carriage 1, is required for intermittent conveying. In this case, compared to the case where the second printing medium 2P is not intermittently conveyed for printing operations, the time until the second printing medium 2P conveyed by the first conveyor roller 5 passes the third conveyor roller 20 at its downstream end in the conveying direction is longer. Therefore, the speed of the third conveyor roller 20 can be reduced. In other words, compared to the case where no separation operation is performed during printing operations, performing a separation operation during printing operations allows for a reduction in the conveying speed used for separation and suppresses increases in noise and power consumption.

[0074] Then, as described later, the first print media 1P is reversed by the reversing roller 9 and enters the second transport path 101, with the upstream end of the first print media 1P entering the second transport path 101 in the transport direction. Then, the downstream front end of the second print media 2P in the transport direction can reach the reversing roller 9 through the branch for branching into the second transport path 101.

[0075] Now refer to Figure 7 ST9 is described in the text. When the reverse roller 9 is in Figure 2 When rotating in the direction of arrow A in STD, in Figure 2 The first printing medium 1P is conveyed in the direction of arrow C in STD. As a result, the first printing medium 1P is continuously conveyed until its upstream end in the conveying direction reaches the predetermined position of the reverse roller 9 on the upstream side of the conveying direction.

[0076] Note that after the upstream end of the printing medium P passes through the baffle 24 in the conveying direction, the baffle 24 is pivoted according to the post-printing processing of the next printing medium P that passes through the baffle 24. The post-printing processing of the second printing medium 2P is reversed, so the second printing medium 2P is conveyed towards the reversing roller 9 while being guided by the third conveying path 102. The determination of whether the upstream end of the printing medium P in the conveying direction has passed through the baffle 24 can be based on the rotation amount of various rollers, or it can be done by a separately provided sensor.

[0077] Now refer to Figure 8 ST10 in the document describes this. When the first printing medium 1P reaches the predetermined position on the upstream side of the reverse roller 9 in the conveying direction, the double-sided conveyor motor 216 switches to high-speed reverse drive. As a result, the reverse roller 9 and the intermediate roller 15... Figure 2The STF rotates at 18 inches per second in the direction of arrow B. Then, the reverse roller 9 and the intermediate roller 15 convey the first printing medium 1P along the guide within the second conveying path (reverse path) 101 until its downstream leading edge in the conveying direction reaches a predetermined position before the first conveying path 100. The aforementioned predetermined position at this time is also calculated based on the amount of rotation of the conveying rollers since the start of the alignment operation and the length of the sheet.

[0078] Now refer to Figure 8 ST11 in the document describes the process. When the second print media 2P is being transported and the print media sensor 16 senses the upstream end of the second print media 2P in the transport direction, the duplex conveyor motor 216 is driven in reverse at low speed, and the second feed motor 207 is driven at low speed. As a result, the intermediate roller 15 and the feed roller 3 rotate at 7.6 inches per second. The intermediate roller 15 and the feed roller 3 then transport the first print media 1P from the second transport path 101 to the first transport path 100 in the direction of the first conveyor roller 5. At this time, the printhead 7 is performing an image forming operation on the second print media 2P based on print data. When the print media sensor 16 senses the downstream leading edge of the first print media 1P in the transport direction, the duplex conveyor motor 216 switches to high-speed drive while maintaining reverse direction, and the second feed motor 207 switches to high-speed drive. In other words, the intermediate roller 15 and the feed roller 3 rotate at 20 inches per second.

[0079] Compared to the downstream movement speed of the second print medium 2P as a result of the printing operation of printhead 7, the first print medium 1P moves at a higher speed, enabling the front end of the first print medium 1P to overlap with the rear end of the second print medium 2P. The printing operation is performed based on the printing data of the second print medium 2P, and thus the second print medium 2P is intermittently conveyed by the first transport roller 5. On the other hand, after the print medium sensor 16 senses the front end of the first print medium 1P, the feed roller 3 rotates continuously at 20 inches per second, enabling it to catch up with the second print medium 2P. Then, the first print medium 1P is conveyed via the feed roller 3 until its downstream front end in the transport direction stops at a predetermined position upstream of the transport roller gap. The position of the downstream front end of the first print medium 1P in the transport direction is calculated based on the amount of rotation of the feed roller 3 after the print medium sensor 16 senses the downstream front end of the first print medium 1P in the transport direction, and the position of the downstream front end of the first print medium 1P in the transport direction is controlled based on this calculation. At this time, printhead 7 is performing an image forming operation on the second print medium 2P based on the print data.

[0080] Now refer to Figure 8ST12 in the document describes this process. When the first transport roller 5 is stopped to perform an image forming operation (ink jetting operation) on the final line of the second print media 2P, the feed roller 3 is driven so that the leading edge of the first print media 1P on the downstream side in the transport direction contacts the gap of the transport roller. In this way, a skew correction operation is performed on the first print media 1P.

[0081] Now refer to Figure 9 ST13 in the document provides a description. When the image forming operation of the final line of the second print medium 2P is completed, the first print medium 1P can be aligned by rotating the first transfer roller 5 by a predetermined amount and keeping the first print medium 1P overlapping the second print medium 2P.

[0082] Once the first print media 1P is aligned, the second feed motor 207 switches to low-speed drive. In other words, the feed roller 3 rotates at 7.6 inches per second. The feed roller 3 is also intermittently driven by the second feed motor 207 as the first conveyor roller 5 intermittently conveys the first print media 1P in predetermined amounts each time. The printing operation for printing the first page of print data onto the first side of the first print media 1P begins by ejecting ink from the print head 7 onto the first print media 1P based on the print data. While the first print media 1P is intermittently conveyed for the printing operation, the second print media 2P is also intermittently conveyed.

[0083] Separation operation (in the case of moving towards the second transport path 101)

[0084] Now refer to Figure 9 The descriptions in ST14-1 and ST14-2 are as follows. After determining that the second printing medium 2P has passed the second conveyor roller 10 at its upstream end in the conveying direction based on the rotation amount of the first conveyor roller 5 after the start of the alignment operation and the length of the paper, a separation operation is performed by continuously rotating the third conveyor roller 20 independently of the first and second conveyor rollers 5 and 10 using the discharge motor 215. Note that the double-sided conveyor motor 216 rotates in the forward direction, and the reverse roller 9 also rotates at the same speed as the third conveyor roller 20. Figure 2The first printing medium 1P rotates in the direction of arrow A. At this time, the second printing medium 2P is conveyed by the third conveyor roller 20. Before the upstream end of the first printing medium 1P passes the third conveyor roller 20 in the conveying direction, the speed of the third conveyor roller 20 is controlled such that the interval between the downstream end of the first printing medium 1P in the conveying direction and the upstream end of the second printing medium 2P in the conveying direction is at least a predetermined distance. The method for calculating the speed of the third conveyor roller 20 at this time will be described in detail later with reference to the control flow. Setting the aforementioned predetermined distance to be greater than 0 makes it possible to separate the second printing medium 2P and the first printing medium 1P, thereby removing the overlap between the upstream end of the second printing medium 2P in the conveying direction and the downstream front end of the first printing medium 1P in the conveying direction.

[0085] This reduces the likelihood of paper jams when switching the conveyor path using baffle 24.

[0086] Note that when de-overlapping, the speed of the third conveyor roller 20 can be faster than the speed of the first conveyor roller 5, but it is not necessary for the speed of the third conveyor roller 20 to be faster than that of the first conveyor roller 5. When the first conveyor roller 5 intermittently conveys the first print medium 1P for printing operations, a certain amount of time, such as the scanning time of the carriage 1, is required for intermittent conveying. In this case, compared to the case where the first print medium 1P is not intermittently conveyed for printing operations, the time until the first print medium 1P conveyed by the first conveyor roller 5 passes the third conveyor roller 20 at its downstream end in the conveying direction is longer. Therefore, the speed of the third conveyor roller 20 can be reduced. In other words, compared to the case where no separation operation is performed during printing operations, performing a separation operation during printing operations allows for a reduction in the conveying speed used for separation and suppresses increases in noise and power consumption.

[0087] Now refer to Figure 9 ST15 in the document provides a description. When the reverse roller 9 is in Figure 2 When rotating in the direction of arrow A in STD, in Figure 2 The second printing medium 2P is conveyed in the direction of arrow C in STD. As a result, the second printing medium 2P is continuously conveyed until its upstream end in the conveying direction reaches the predetermined position of the reverse roller 9 on the upstream side of the conveying direction.

[0088] Note that after the upstream end of the printing medium P passes through the baffle 24 in the conveying direction, the baffle 24 is pivoted according to the post-printing processing of the next printing medium P passing through the baffle 24. The post-printing processing of the first printing medium 1P is discharge, so the first printing medium 1P is conveyed towards the discharge roller 22 while being guided by the fourth conveying path 104. The determination of whether the upstream end of the printing medium P in the conveying direction has passed through the baffle 24 can be based on the amount of rotation of various rollers, or it can be done by a separately provided sensor.

[0089] Now refer to Figure 10 ST16 in the document describes this. When the second printing medium 2P reaches the predetermined position on the upstream side of the reversing roller 9 in the conveying direction, the double-sided conveyor motor 216 switches to high-speed reverse drive. As a result, the reversing roller 9 and the intermediate roller 15... Figure 2 The STF rotates at 18 inches per second in the direction of arrow B. Then, the reverse roller 9 and the intermediate roller 15 convey the second printing medium 2P along the guide within the second conveying path (reverse path) 101 until its downstream leading edge in the conveying direction reaches a predetermined position before the first conveying path 100. The aforementioned predetermined position at this time is also calculated based on the amount of rotation of the conveying rollers since the start of the alignment operation and the length of the sheet.

[0090] Now refer to Figure 10 ST17 in the document describes the process. When the first print media 1P is being transported and the print media sensor 16 senses the upstream end of the first print media 1P in the transport direction, the duplex conveyor motor 216 is driven in reverse at a low speed, and the second feed motor 207 is driven at a low speed. As a result, the intermediate roller 15 and the feed roller 3 rotate at 7.6 inches per second. Then, the second print media 2P is transported from the second transport path 101 to the first transport path 100 in the direction of the first transport roller 5 by the intermediate roller 15 and the feed roller 3. At this time, the print head 7 is performing an image forming operation on the first print media 1P based on print data. When the print media sensor 16 senses the downstream leading edge of the second print media 2P in the transport direction, the duplex conveyor motor 216 switches to high-speed drive while maintaining reverse direction, and the second feed motor 207 switches to high-speed drive. In other words, the intermediate roller 15 and the feed roller 3 rotate at 20 inches per second.

[0091] Compared to the downstream movement speed of the first print medium 1P as a result of the printing operation of printhead 7, the second print medium 2P moves at a higher speed, enabling the leading edge of the second print medium 2P to overlap with the trailing edge of the first print medium 1P. The printing operation is performed based on the printing data of the first print medium 1P, and thus the first print medium 1P is intermittently conveyed by the first conveyor roller 5. On the other hand, after the print medium sensor 16 senses the leading edge of the second print medium 2P, the feed roller 3 rotates continuously at 20 inches per second, enabling it to catch up with the first print medium 1P. The feed roller 3 then conveys the second print medium 2P until its downstream leading edge in the conveying direction stops at a predetermined position upstream of the conveyor roller gap. The position of the downstream leading edge of the second print medium 2P in the conveying direction is calculated based on the amount of rotation of the feed roller 3 after the print medium sensor 16 senses the downstream leading edge of the second print medium 2P in the conveying direction, and the position of the downstream leading edge of the second print medium 2P in the conveying direction is controlled based on the result of this calculation. At this time, printhead 7 is performing an image forming operation on the first print medium 1P based on the print data.

[0092] Now refer to Figure 10 ST18 in the document describes this process. When the first transport roller 5 is stopped to perform an image forming operation (ink jetting operation) on the final line of the first print media 1P, the feed roller 3 is driven so that the downstream leading edge of the second print media 2P contacts the gap of the transport roller in the transport direction. In this way, a skew correction operation is performed on the second print media 2P.

[0093] Now refer to Figure 11 ST19 in the document provides a description. When the image forming operation of the final line of the first print medium 1P is completed, the second print medium 2P can be aligned by rotating the first transfer roller 5 by a predetermined amount and keeping the second print medium 2P overlapping the first print medium 1P.

[0094] Once the second print media 2P is aligned, the second feed motor 207 switches to low-speed drive. In other words, the feed roller 3 rotates at 7.6 inches per second. The feed roller 3 is also intermittently driven by the second feed motor 207 as the second print media 2P is intermittently fed by the first conveyor roller 5 in predetermined amounts each time. Printing operations for printing a third page of print data onto the first side of the second print media 2P begin by ejecting ink from the print head 7 onto the second print media 2P based on the print data. The first print media 1P is also intermittently fed while the second print media 2P is intermittently fed for the printing operation.

[0095] Separation operation (in the case of moving towards the fourth transport path 104)

[0096] Now refer to Figure 11 ST20-1 and ST20-2 are described below. After determining that the upstream end of the first print media 1P in the transport direction has passed the second print media 10 based on the rotation amount of the first conveyor roller 5 after the start of the alignment operation and the length of the paper, a separation operation is performed by continuously rotating the third conveyor roller 20 and the discharge roller 22 independently of the first and second conveyor rollers 5 and 10 using the discharge motor 215. At this time, the first print media 1P is conveyed by the third conveyor roller 20. Then, before the upstream end of the second print media 2P passes the third conveyor roller 20 in the transport direction, the speed of the third conveyor roller 20 is controlled such that the distance between the downstream end of the second print media 2P in the transport direction and the upstream end of the first print media 1P in the transport direction is at least a predetermined distance. The method for calculating the speed of the third conveyor roller 20 at this time will be described in detail later with reference to the control flow. Setting the aforementioned predetermined distance to be greater than 0 makes it possible to separate the first print media 1P and the second print media 2P, thereby removing the overlap between the upstream end of the first print media 1P in the transport direction and the downstream end of the second print media 2P in the transport direction.

[0097] In this way, the order of the flakes can be prevented from being rearranged during discharge and the discharge process can be prevented from being obstructed.

[0098] Note that when de-overlapping, the speed of the third conveyor roller 20 can be faster than the speed of the first conveyor roller 5, but it is not necessary for the speed of the third conveyor roller 20 to be faster than the speed of the first conveyor roller 5. When the first conveyor roller 5 intermittently conveys the second printing medium 2P for printing operations, a certain amount of time, such as the scanning time of the carriage 1, is required for intermittent conveying. In this case, compared to the case where the second printing medium 2P is not intermittently conveyed for printing operations, the time until the second printing medium 2P conveyed by the first conveyor roller 5 passes the third conveyor roller 20 at its downstream end in the conveying direction is longer. Therefore, the speed of the third conveyor roller 20 can be reduced. In other words, compared to the case where no separation operation is performed during printing operations, performing a separation operation during printing operations allows for a reduction in the conveying speed used for separation and suppresses increases in noise and power consumption.

[0099] Now refer to Figure 12 ST21 in the document provides a description. Printing on the first and second sides of the first print media 1P has been completed, so the first print media 1P is discharged into the discharge tray 25 by rotating the discharge roller 22 and the third transfer roller 20.

[0100] Note that after the upstream end of the printing medium P passes through the baffle 24 in the conveying direction, the baffle 24 is pivoted according to the post-printing processing of the next printing medium P passing through the baffle 24. The post-printing processing of the second printing medium 2P is discharged, so the second printing medium 2P is conveyed towards the discharge roller 22 while being guided by the fourth conveying path 104. The determination related to whether the upstream end of the printing medium P in the conveying direction has passed through the baffle 24 can be based on the rotation amount of various rollers, or it can be done by a separately provided sensor.

[0101] Now refer to Figure 12 ST22 in the document describes the process. When the image formation operation for the final line of the second print media 2P is completed, printing on the first and second sides of the second print media 2P, which is the final print media in a job, ends. Here, the discharge roller 22, the third transfer roller 20, the second transfer roller 10, and the first transfer roller 5 are rotated in the same direction to discharge the second print media 2P into the discharge tray 25, thereby ending the double-sided printing.

[0102] Control process

[0103] Figures 13A to 15 This is a flowchart illustrating the overlapping continuous feed operation in the printing process according to this embodiment. (Refer to...) Figure 4 The table shown assumes that in the printing order N, each variable is a function of N, such that when the M(N)th printing medium P is fed from the feed source Q(N), the K(N)th page of print data is printed on the F(N)th face of the printing medium, and post-printing processing G(N) is performed, with a maximum printing order of Nmax. Note that the printing order is merely an example and is not limited to the order described above. When print data in duplex printing mode is sent from the host computer 214 via the I / F unit 213, the duplex printing operation S30 begins.

[0104] exist Figure 13A In step S301, the printing order N is set to 1 for initialization. In step S302, the maximum printing order Nmax is obtained from the printing data.

[0105] In step S303, the baffle solenoid 217 pre-pivots the baffle 24 to prepare for the post-printing processing G(N).

[0106] In step S304, the M(N)th print media P is fed from the feed source Q(N) at a rate of 7.6 inches / second.

[0107] When the feed source Q(N) is the paper loading unit 11, the first feed motor 206 is driven at a low speed. As a result, the pickup roller 2 rotates at 7.6 inches per second. As the pickup roller 2 rotates, it picks up the topmost print media loaded in the paper loading unit 11. The first print media 1P picked up by the pickup roller 2 is conveyed by the feed roller 3, which rotates in the same direction as the pickup roller 2. The feed roller 3 is driven by the second feed motor 207 at the same speed as the pickup roller 2. After rotating a predetermined amount so that the print media P can be conveyed beyond the position of the feed roller 3, the pickup roller 2 stops to not pick up the next print media P. The pickup roller 2 is a unidirectional roller, so even after the pickup roller 2 stops, the conveying of the feed roller 3 can continue.

[0108] When the feed source Q(N) is in the second transport path 101, the double-sided transport motor 216 is driven in reverse at low speed, and the second feed motor 207 is also driven at low speed. As a result, the intermediate roller 15 and the feed roller 3 rotate at 7.6 inches / second. Then, the intermediate roller 15 and the feed roller 3 transport the printing medium P from the second transport path 101 to the first transport path 100 in the direction of the first transport roller 5.

[0109] In step S305, it is determined whether the downstream end of the M(N)th printing medium in the conveying direction has passed sensor 16. If it is determined that the end has not passed (step S305: No), the process of step S305 is repeated. However, if it is determined that the end has passed (step S305: Yes), step S306 is executed.

[0110] In step S306, the feed speed of the M(N)th print media is switched to 20 inches / second. At this time, as a result of switching the second feed motor 207 to high-speed drive, the feed roller 3 rotates at 20 inches / second. If there is an M(N-1)th print media, this operation is performed to catch up with that print media.

[0111] In step S307, it is determined whether N is 1. If N is 1 (step S307: Yes), then there is no printing medium P to be overlapped, so the process moves to step S308. However, if N is not 1 (step S307: No), there is a possibility that an overlap feed will be performed, so the overlap preparation operation in step S40 is executed.

[0112] when Figure 14A and Figure 14BWhen the overlap preparation operation in step S40 begins, step S401 is executed, in which the M(N)th print media P stops at a predetermined position before the first conveyor roller 5. The position of the downstream front end of the M(N)th print media P in the conveying direction is calculated based on the amount of rotation of the feed roller 3 after the print media sensor 16 senses the downstream front end of the M(N)th print media P in the conveying direction, and the position of the downstream front end of the M(N)th print media P in the conveying direction is controlled based on the result of the calculation.

[0113] In step S402, it is determined whether the predetermined overlap implementation conditions are met. The overlap implementation conditions will be described in more detail later. If it is determined that the overlap implementation conditions are met (step S402: Yes), then step S408 is executed. In step S408, it is determined whether the overlap amount set in step S402 is the initial overlap amount. The determination of the initial overlap amount will be described later.

[0114] If the overlap is determined to be the initial overlap (step S408: Yes), then proceed to step S403. In step S403, it is determined whether image formation for the final line of the M(N-1)th print medium has started. If image formation has not started (step S403: No), then the process of step S403 is repeated. If image formation has started (step S403: Yes), then the process ends, and then proceeds to the next step. Figure 13A Step S308. In step S408, if it is determined that the overlap amount is not the initial overlap amount (step S408: No), then step S409 is executed. In step S409, it is determined whether the image formation of the final line of the M(N-1)th print medium has been completed. If it is determined that the image formation has not been completed (step S409: No), then the processing of step S409 is repeated. If it is determined that the image formation has been completed (step S409: Yes), then step S410 is executed, and the M(N-1)th print medium P is conveyed at 10 inches / second using the first conveyor roller 5.

[0115] In step S411, it is determined whether printing media have been conveyed up to the point where the overlap between the rear end of the M(N-1)th printing media and the front end of the M(N)th printing media reaches the overlap amount set in step S402. If it is determined that the printing media has not been conveyed to the predetermined overlap amount (step S411: No), the process of step S411 is repeated. If it is determined that the printing media has been conveyed to the predetermined overlap amount (step S411: Yes), step S412 is executed, and the first conveying roller 5 is stopped. The process ends, and then the following steps are executed. Figure 13A Step S308 in the process.

[0116] On the other hand, in step S402, if it is determined that the overlap condition is not met (step S402: No), then step S404 is executed. By executing steps S404 to S407 in sequence (described later), operations can be performed to de-overlap upstream of the first conveyor roller 5 in the conveying direction, or operations can be performed when the M(N)th print medium P has not yet fully caught up with the M(N-1)th print medium P.

[0117] In step S404, it is determined whether the image formation of the final row of the M(N-1)th print media has been completed. If it is determined that the image formation has not been completed (step S404: No), the process of step S404 is repeated. If it is determined that the image formation has been completed (step S404: Yes), step S405 is executed, and the M(N-1)th print media P is conveyed at 18 inches / second using the first conveyor roller 5.

[0118] In step S406, after the rear end of the M(N-1)th print media P has passed the first conveyor roller 5, it is determined whether the print media P has been conveyed in a predetermined amount. If it is determined that the print media P has not been conveyed in a predetermined amount (step S406: No), then the process of step S406 is repeated. If it is determined that the print media P has been conveyed in a predetermined amount (step S406: Yes), then step S407 is executed, and the first conveyor roller 5 is stopped. The process ends, and then execution... Figure 13A Step S308 in the process.

[0119] By sequentially executing steps S404 to S407, if an overlapping state exists but does not meet the conditions for achieving overlap, the overlapping state can be released upstream of the first conveying roller 5 in the conveying direction. Additionally, when the M(N)th printing medium P has not yet fully caught up with the M(N-1)th printing medium P, preparations for correcting the skewness of the M(N)th printing medium P can be made independently.

[0120] In step S308, the skewness of the M(N)th print medium P is corrected. When the first conveyor roller 5 is stopped, the skewness correction operation of the M(N)th print medium P is performed by driving the feed roller 3 so that the downstream front end of the M(N)th print medium P contacts the conveyor roller gap in the conveying direction. At this time, if it is determined in step S307 that N is 1 (step S307: Yes), the skewness of the M(N)th print medium P is corrected independently. If it is determined in step S402 that the overlap realization condition is met (step S402: Yes), the skewness is corrected when the M(N)th print medium P overlaps with the M(N-1)th print medium P. On the other hand, if it is determined in step S402 that the overlap realization condition is not met (step S402: No), the skewness of the M(N)th print medium P is corrected independently.

[0121] In step S309, the M(N)th print medium P is aligned. The M(N)th print medium P can be aligned by rotating the first conveyor roller 5 by a predetermined amount. At this time, if the skewness was corrected in step S308 when the M(N)th print medium P overlapped with the M(N-1)th print medium P, alignment is performed while maintaining this overlap.

[0122] In step S310, the feed speed of the M(N)th printing medium is switched to 7.6 inches / second. As a result of switching the second feed motor 207 to low-speed drive, the feed roller 3 rotates at 7.6 inches / second.

[0123] In step S311, the printing operation begins on the F(N)th face of the M(N)th print medium P for the K(N)th page of data. While the M(N)th print medium P is intermittently conveyed by the first conveyor roller 5 in predetermined amounts each time, the feed roller 3 is also intermittently driven by the second feed motor 207. When the M(N)th print medium P is intermittently conveyed for the printing operation, the M(N-1)th print medium P is also intermittently conveyed.

[0124] In step S312, it is determined whether N is 1. If N is 1 (step S312: Yes), then step S313 is executed. On the other hand, if N is not 1 (step S312: No), then step S316 is executed.

[0125] In step S316, it is determined whether overlapping feed has been performed. If it is determined that overlapping feed has been performed (step S316: Yes), then the separation operation of step S50 is executed. The separation operation will be described in more detail later. After executing step S50, the following steps are performed: Figure 15 The reverse / discharge operation in step S60. If it is determined that overlapping feed has not yet been performed (step S316: No), then the separation operation in step S50 is not performed. Figure 15 The reverse / discharge operation of S60 in the middle.

[0126] When it begins Figure 15 During the reverse / ejection operation in step S60, step S601 is executed. In step S601, it is determined whether the printed process G(N-1) is reversed. If it is determined that the process is reversed (step S601: yes), then step S602 is executed, and the M(N-1)th print medium P is conveyed toward the reverse roller 9 while the reverse roller 9 is rotated.

[0127] In step S603, it is determined whether the upstream end of the M(N-1)th printing medium P in the conveying direction has passed the baffle 24. This determination can be based on the rotation amount of various rollers or by a separately configured sensor. If it is determined that the end has not yet passed the baffle 24 (step S603: No), the process of step S603 is repeated. If it is determined that the end has passed the baffle 24 (step S603: Yes), step S604 is executed.

[0128] In step S604, the baffle 24 is pivoted to accommodate the post-printing process G(N). In step S601, it is determined that the post-printing process G(N) is reversed, and therefore the baffle 24 is pivoted to allow it to be conveyed toward the reverse roller 9.

[0129] In step S605, the M(N-1)th printing medium P is continuously conveyed until its upstream end in the conveying direction reaches the predetermined position of the reverse roller 9 on the upstream side of the conveying direction, and then stops. In step S606, the M(N-1)th printing medium P is conveyed towards the second conveying path 101. The duplex conveyor motor 216 is switched to high-speed drive in the reverse direction, which causes... Figure 2 The reverse roller 9 and intermediate roller 15 are rotated at 18 inches / second in the direction of arrow B in the STF. Then, in step S607, the M(N-1)th print media P is stopped when the leading edge of the print media P on the downstream side in the conveying direction reaches a predetermined position before the first conveying path 100. This predetermined position is also calculated based on the amount of rotation of the conveying rollers since the start of the alignment operation and the length of the sheet. When step S607 ends, the following steps are performed: Figure 13B Step S313 in the process.

[0130] On the other hand, if in Figure 15 If it is determined in step S601 that the post-printing processing G(N-1) is not reversed (step S601: No), then step S608 is executed, and the M(N-1)th printing medium P is discharged to the discharge tray 25 by rotating the discharge roller 22 and the third conveyor roller 20.

[0131] In step S609, it is determined whether the upstream end of the M(N-1)th printing medium P in the conveying direction has passed the baffle 24 during the discharge period. The determination regarding whether the end has passed the baffle 24 can be based on the rotation amount of various rollers, or it can be performed by a separately configured sensor. If it is determined that the end has not yet passed the baffle 24 (step S609: No), the process of step S609 is repeated. If it is determined that the end has passed the baffle 24 (step S609: Yes), step S610 is executed.

[0132] In step S610, the baffle 24 is pivoted to accommodate the printed process G(N). In step S601, it is determined that the printed process G(N) is not reversed, and therefore discharge is performed. Therefore, the baffle 24 is pivoted to allow conveying toward the discharge roller 22. When step S610 ends, the following steps are executed: Figure 13B Step S313 in the process.

[0133] exist Figure 13B In step S313, the printing order N is incremented to N+1.

[0134] In step S314, it is determined whether the printing order N is less than or equal to the maximum printing order Nmax. If it is determined that the printing order N is less than or equal to the maximum printing order Nmax (step S314: Yes), then step S315 is executed. In step S315, it is determined whether the upstream end of the M(N-1)th printing medium P in the conveying direction has passed the sensor 16. If it is determined that the end has passed the sensor 16 (step S315: Yes), then the process returns to step S304, where paper feeding is performed, and then control is carried out through a similar process.

[0135] On the other hand, in step S314, if it is determined that the printing order N is not less than or equal to the maximum printing order Nmax (step S314: No), then it is determined that the final printing has ended, and step S317 is executed. In step S317, the M(N-1)th print media P is discharged. By rotating the discharge roller 22, the third conveyor roller 20, the second conveyor roller 10, and the first conveyor roller 5 in the same direction, the M(N-1)th print media P can be discharged into the discharge tray 25. Once the discharge is completed, the process ends.

[0136] Separation operation

[0137] Figure 16 This is a control flow diagram illustrating the separation operation. Figure 17 This is a conceptual diagram illustrating the relationships between variables, which will be described later. The following will describe methods for separating variables as referenced... Figures 5 to 12 The operation of the preceding and subsequent printing media in the described overlapping state.

[0138] Figure 17 This is a conceptual diagram illustrating the relationship between variables (described later) in the operation of separating a first print media 1P from a subsequent second print media 2P. The separation operation uses two rollers. In this embodiment, the second transfer roller 10 is located upstream in the transfer direction, and the third transfer roller 20 is located downstream.

[0139] Figure 17 ST1 in Figure 13AStep S308 is the state where skew correction is being performed on the subsequent printing media P. (See reference...) Figure 6 As described in ST6, when the first conveyor roller 5 is stopped to perform an image forming operation (ink jetting operation) on the final line of the first print medium 1P, a skew correction operation is performed on the second print medium 2P so that the leading edge of the second print medium 2P contacts the gap of the conveyor roller. At this time, the first print medium 1P and the second print medium 2P overlap by an overlap amount W. Figure 17 In the diagram, Ky indicates the planned printing area on the printing medium P, and Kd indicates the printing area. Additionally, Dn indicates the nozzle area distance, which is the distance from the upstream to the downstream region of the ejector nozzles 71 located in the printhead 7 (i.e., the maximum print width during printing). Therefore, if the print width of each scan operation of the carriage 1 is represented by Ds, then Ds ≦ Dn. Furthermore, the print width does not need to be constant, but can instead vary depending on the scan operation.

[0140] exist Figure 17 In ST2, as shown in the reference Figure 7 As described in ST7, when the image formation operation of the final line of the first print medium 1P is completed, the second print medium 2P can be aligned by rotating the first transfer roller 5 by a predetermined amount and holding the second print medium 2P on top of the first print medium 1P in an overlap state of W. In this embodiment, alignment is performed such that the farthest downstream portion of the planned printing area Ky of the second print medium 2P is aligned with the farthest downstream jet nozzle of the print head 7.

[0141] Now refer to Figure 17 ST3 in the document provides a description. The separation operation begins after the first printed medium 1P passes the upstream side roller used in the separation operation at its upstream end in the conveying direction. This embodiment will be described as follows: Figure 17 The separation operation, as shown in ST3, begins immediately after the upstream end of the first print media 1P in the transport direction passes the upstream side roller used in the separation operation. Note that the timing of the start is not limited to immediately after passing, but can be any timing after passing. The separation operation is controlled to end before the upstream end of the first print media P in the transport direction passes a given point T. In this embodiment, point T coincides with the third transport roller 20. In other words, the operation is controlled to end before the upstream end of the first print media P in the transport direction passes the third transport roller 20.

[0142] The area from the upstream side roller used in the separation operation to point T is used as the separation region, and its distance is denoted by L. The sheet spacing between the upstream end of the preceding print media P in the conveying direction and the downstream end of the subsequent print media P in the conveying direction after the separation operation is denoted by Dp. At this time, the distance (LW-Dp) is used as the scan judgment distance, which is referenced in the calculation of the number of scans S when printing onto the subsequent print media P.

[0143] Reference Figure 16 A control flow diagram describing the separation operation. Figure 16 In step S501, MPU 201 obtains the overlap amount W. In step S502, MPU 201 calculates the number of scans S of the downstream end of the subsequent printing medium P across the scan judgment distance (LW-Dp) in the transport direction based on the print data printed onto the subsequent printing medium P.

[0144] In step S503, MPU 201 calculates the separable time Tmax. This is calculated based on the overlap W, the number of scans S, the time Ts required for one scan, the distance L between the separated regions, the sheet interval Dp after the separation operation, and the transport speed V1 of the subsequent printing media P. Specifically, the calculation is performed using the following formula.

[0145] Tmax = (L - W - Dp) / V1 + STs

[0146] In this embodiment, the conveying speed V1 of the subsequent printing medium P is the conveying speed of the second conveyor roller 10. Note that the time Ts required for one scan is the time during which the carriage 1 performs... Figure 25 The timing diagram shows the length of time required for the scan operation. Ts can include standby time before and after the operation, acceleration / deceleration time, etc. If the time required for carriage 1 to perform the scan operation varies for each drive instance, the average value can be used for Ts. Note that Figure 25 In this context, "Vc" represents the drive speed of carriage 1.

[0147] In step S504, MPU 201 calculates the velocity V2 of the preceding printed media P used for the separation operation. This is calculated based on the separable time Tmax and the distance L of the separation area using the following formula.

[0148] V2 = L / Tmax

[0149] In step S505, MPU 201 determines whether the upstream end of the preceding printing medium P in the conveying direction has passed the upstream roller in the conveying direction used in the separation operation. In this embodiment, it determines whether the end has passed the second conveying roller 10. If it is determined that the end has not passed (step S505: No), the process of step S505 is repeated. On the other hand, if it is determined that the end has passed (step S505: Yes), the process moves to step S506.

[0150] In step S506, the downstream roller used in the separation in the conveying direction is rotated at a speed of at least V2. In this embodiment, the third conveying roller 20 is rotated. As a result of these operations, such as Figure 17 As shown in ST4, the preceding printing medium P separates from the subsequent printing medium P, and the overlap W is reduced to W'. At this time, by rotating at a speed of at least V2, as... Figure 17 As shown in ST5, a sheet spacing of at least sheet spacing Dp can be provided before the downstream end of the subsequent printing medium P passes through the third conveyor roller 20 in the conveying direction, which makes it possible to remove the overlapping state.

[0151] In step S507, MPU 201 determines whether the interval between the upstream end of the preceding printing medium P in the conveying direction and the downstream end of the subsequent printing medium P in the conveying direction is at least the sheet interval Dp after the separation operation. If it is determined that the interval is less than a predetermined amount (step S507: No), the process of step S507 is repeated. On the other hand, if it is determined that the interval is at least the sheet interval Dp (step S507: Yes), it is determined that the separation operation is completed, and the process ends.

[0152] Regarding the sheet spacing Dp, in this embodiment, Dp ≥ 0, and setting Dp ≥ 0 enables the elimination of overlapping states. Therefore, the possibility of paper jams when switching transport paths using baffle 24, and the possibility of sheet ejection degradation, can be reduced. It is desirable that the value of the sheet spacing Dp be set to be greater than the amount of printing media transported during the pivoting of baffle 24. Considering the speed at which the sheets fall during ejection, this value is desirable to be high enough not to cause alignment degradation of the sheets during ejection.

[0153] However, Dp can also be set to less than 0. In this case, the overlap will not be completely eliminated, but the amount of overlap will be reduced. Furthermore, the values ​​at which the baffle can pivot and the values ​​at which the order of preceding and subsequent sheets does not switch during paper discharge can be experimentally determined and set. Therefore, the possibility of paper jams when switching the transport path using baffle 24 and the possibility of sheet discharge degradation can be reduced.

[0154] Note that the separable time T'max when no separation operation is performed during the scanning operation of carriage 1 is:

[0155] T'max = (L - W - Dp) / V1.

[0156] Therefore, the velocity V'2 of the preceding printing medium P during the separation operation is:

[0157] V'2 = L / T'max.

[0158] At this point, Tmax > T'max holds true, and therefore, V2 < V'2 also holds true. In other words, performing a separation operation during the printing operation allows for a reduction in the transfer speed used for separation and suppresses increases in noise and power consumption, compared to not performing a separation operation during the printing operation.

[0159] When the time ST required for S scan operations is long, V2 can be reduced. A separate standby time unrelated to the scan operations can also be set. In this case, the transmission speed can be further reduced, and the increase in noise and power consumption can be suppressed.

[0160] When the overlapping state is removed, the speed of the downstream roller in the conveying direction used in the separation operation can be faster than the speed of the upstream roller in the conveying direction of the separation area, but it is not necessary to make the speed faster, and it can be similar or slower, depending on the result of V2 calculation.

[0161] Additionally, it is not necessary to continuously drive the downstream rollers used in the separation operation in the conveying direction at a constant speed of at least V2, and control can be made, for example, such that the average speed, including stopping and acceleration / deceleration, is at least V2.

[0162] Furthermore, in step S507, if it is determined that the interval between the upstream end of the preceding printing medium P in the conveying direction and the downstream end of the subsequent printing medium P in the conveying direction is at least the sheet interval Dp after the separation operation (step S507: Yes), then it is determined that the separation operation is completed and the process ends. However, other termination conditions can also be set. For example, the process can end when the upstream end of the preceding printing medium P in the conveying direction reaches the third conveyor roller 20. If the separation operation is being performed at a higher speed than V2 at this time, the sheet interval can be further increased.

[0163] Overlapping operations

[0164] Figure 18 and Figure 19 This diagram illustrates the operation for overlapping a preceding print medium and a subsequent print medium according to this embodiment. The method for generating... Figures 5 to 12The operation described herein, in which the front end of the subsequent printing medium overlaps with the rear end of the preceding printing medium.

[0165] Figure 18 and Figure 19 This is an enlarged view of the area between the feed roller gap formed by the feed roller 3 and the feed driven roller 4, and the transfer roller gap formed by the first transfer roller 5 and the clamping roller 6. The explanatory diagram in this embodiment will show the configuration including a print media holding rod for suppressing the lifting of the rear end of the print media P.

[0166] The process of conveying the printing media by the first conveyor roller 5 and the feed roller 3 will be described sequentially as three states. (Refer to...) Figure 18 ST1 and ST2 describe the operations performed on subsequent print media to follow the first state of the preceding print media. (Refer to...) Figure 19 ST3 and ST4 describe the second state used to overlap subsequent printing media with preceding printing media. (Refer to...) Figure 19 ST5 in the text describes the third state, which determines whether to perform skew correction on subsequent printing media while maintaining the overlap state.

[0167] exist Figure 18 In ST1, the feed roller 3 is controlled to convey the subsequent printing medium P, and the printing medium sensor 16 senses the leading edge of the subsequent printing medium P. The interval from the printing medium sensor 16 to a position P1 where the subsequent printing medium P overlaps with the preceding printing medium P is defined as a first interval A1. Within the first interval A1, operation is performed on the leading edge of the subsequent printing medium P to follow the trailing edge of the preceding printing medium P. P1 is determined according to the configuration of the mechanism.

[0168] In the first state, there is a situation where the following operation is stopped in the first segment A1. For example... Figure 18 As shown in ST2, when the leading edge of the subsequent printing medium P exceeds the trailing edge of the preceding printing medium P before P1, no operation is performed to make the subsequent printing medium overlap with the preceding printing medium.

[0169] exist Figure 19 In ST3, the interval from P1 to the position P2 where the printing media holding rod 17 is located is defined as the second interval A2. An operation to overlap the subsequent printing media P with the preceding printing media P is performed in the second interval A2.

[0170] In the second state, within the second interval A2, there is a situation where the operation used to cause subsequent printing media to overlap with previous printing media is stopped. For example... Figure 19As shown in ST4, if the leading edge of the subsequent printing medium P cannot catch up with the trailing edge of the preceding printing medium P in the second interval A2, then the operation to make the subsequent printing medium overlap with the preceding printing medium cannot be performed.

[0171] exist Figure 19 In ST5, the interval from P2 to P3 is defined as the third interval A3. P3, for example, is the interval in the subsequent printing media. Figure 14A The position of the leading edge at the stop in step S401. The printing media is conveyed while the subsequent printing media P overlaps with the preceding printing media P until the leading edge of the subsequent printing media P reaches P3. In the third interval A3, it is determined whether the subsequent printing media P should contact the gap of the conveyor rollers used for alignment while maintaining the overlapping state. In other words, it is determined whether alignment should be performed after the skew correction operation while maintaining the overlapping state, or after the skew correction operation should be performed after the overlapping state has been removed.

[0172] Overlap judgment

[0173] Figure 20 This is a flowchart illustrating the skew correction operation of subsequent printing media according to this embodiment. A detailed description will follow here. Figure 14A The judgment related to whether the overlapping realization condition is met is described in S402.

[0174] The operation described is used to determine the following: (i) while maintaining the overlap between the preceding print medium P and the subsequent print medium P at the initial overlap, a skew correction operation is performed by bringing the leading edge of the subsequent print medium P into contact with the conveyor roller gap; (ii) a skew correction operation is performed by bringing the leading edge of the subsequent print medium into contact with the conveyor roller gap by an overlap less than the initial overlap; or (iii) after the overlap between the preceding print medium P and the subsequent print medium P is released, a skew correction operation is performed by bringing the leading edge of the subsequent print medium P into contact with the conveyor roller gap.

[0175] In step S101, processing begins. In step S102, it is determined whether the leading edge of the subsequent printing medium P has reached the determination position. Figure 19 (P3 in ST5). If the leading edge has not yet reached the judgment position (step S102: No), it is unclear whether the leading edge of the subsequent printing medium P will contact the conveyor roller gap by being conveyed in a predetermined amount. Therefore, it is determined that only the skew correction operation will be performed on the subsequent printing medium (step S103), after which the judgment operation ends (step S104). In other words, after the rear end of the preceding printing medium P passes through the conveyor roller gap, only the subsequent printing medium P is conveyed and the subsequent printing medium P is brought into contact with the conveyor roller gap for skew correction operation, and then only the subsequent printing medium P is aligned.

[0176] On the other hand, if the leading edge of the subsequent printing medium P has reached the judgment position P3 (step S102: Yes), it is determined whether the trailing edge of the preceding printing medium P has passed through the conveyor roller gap (step S105). If it is determined that the trailing edge has passed through the conveyor roller gap (step S105: Yes), the preceding and subsequent printing media do not overlap, and therefore it is determined that only the subsequent printing medium will undergo skew correction operation (step S106). In other words, skew correction operation is performed by only making the subsequent printing medium P contact the conveyor roller gap, and then only the subsequent printing medium P is aligned.

[0177] On the other hand, if it is determined that the rear end of the preceding printing medium P has not yet passed the gap between the conveyor rollers (step S105: No), it is determined whether the overlap between the rear end of the preceding printing medium P and the front end of the subsequent printing medium P is lower than a threshold (step S107). The position of the rear end of the preceding printing medium P is updated as the printing operation on the preceding printing medium P proceeds. The position of the front end of the subsequent printing medium P is the position determined above. In other words, the overlap decreases as the printing operation on the preceding printing medium P proceeds. If it is determined that the overlap is lower than the threshold (step S107: Yes), a determination is made to release the overlap state and only the subsequent printing medium is subjected to a skew correction operation (step S108). In other words, after the image formation operation of the preceding printing medium P is completed, the subsequent printing medium P is not conveyed together with the preceding printing medium P. Specifically, the preceding printing medium P is conveyed by the first conveyor roller 5 driven by the conveyor motor 205. However, the feed roller 3 is not driven. As a result, the overlap state is released. In addition, a skew correction operation is performed by only contacting the subsequent printing medium P with the gap of the conveyor rollers, and then only the subsequent printing medium P is aligned.

[0178] If it is determined that the overlap is at least a threshold (step S107: No), then when aligning the subsequent printing medium P, it is determined whether the subsequent printing medium P will reach the ratchet (not shown) (step S109). The ratchet (not shown) is a ratchet that rotates by contacting the printed surface of the printed sheet already printed by the print head 7, and is positioned upstream of the ratchet 12 in the transport direction. The ratchet (not shown) is a ratchet used to prevent the printed sheet from lifting, and is also called a holding ratchet. If it is determined that the subsequent printing medium P will not reach the ratchet (not shown) (step S109: No), a determination is made to release the overlap state and only the skew correction operation is performed on the subsequent printing medium (step S110). In other words, after the image formation operation of the preceding printing medium P is completed, the subsequent printing medium P is not transported together with the preceding printing medium P. Specifically, the first transport roller 5, driven by the transport motor 205, transports the preceding printing medium P. However, the feed roller 3 is not driven. As a result, the overlap state is released. In addition, a skew correction operation is performed by only contacting the subsequent printing medium P with the gap of the conveyor rollers, and then only the subsequent printing medium P is aligned.

[0179] If it is determined that the subsequent printing medium P will reach the ratchet (not shown) (step S109: Yes), then it is determined whether there is a gap between the last line of the preceding printing medium and the line preceding that last line (step S111). If it is determined that there is no gap (step S111: No), then a determination is made to remove the overlap and only the subsequent printing medium is subjected to skew correction operation (step S112). If it is determined that there is a gap (step S111: Yes), then... Figure 21 The overlap adjustment operation in step S70.

[0180] Overlap adjustment operation

[0181] Figure 21 This is a control flowchart illustrating the overlap adjustment operation.

[0182] In step S701 of the overlap adjustment operation in step S70, MPU 201 calculates the initial overlap amount W0 based on the print data to be printed onto the preceding print medium P, and sets the initial overlap amount W0 for the overlap amount W in step S702 (initial overlap amount calculation unit 301). In step S703, MPU 201 calculates the number of scans S of the subsequent print medium P during the period when the downstream end of the subsequent print medium P crosses the scan judgment distance (LW-Dp) in the transport direction based on the print data to be printed onto the subsequent print medium P.

[0183] In step S704, MPU 201 calculates the separable time Tmax. The separable time Tmax is calculated using the following formula based on the overlap W, the number of scans S, the time Ts required for one scan, the distance L of the separation area, the sheet interval Dp after the separation operation, and the transfer speed V1 of the subsequent printing medium P.

[0184] Tmax = (L - W - Dp) / V1 + STs

[0185] In this formula, the first term on the right (LW-Dp) / V1 is the transport time of the subsequent printing medium P, and the second term on the right STs is the transport stop time of the subsequent printing medium P. The separable time Tmax is the sum of the transport time and the transport stop time.

[0186] In this embodiment, the conveying speed V1 of the subsequent printing medium P is the conveying speed of the second conveying roller 10. Note that the time Ts required for one scan is the time during which the carriage 1 performs... Figure 25 The timing diagram shows the length of time required for the scanning operation. The required time Ts may include standby time before and after the operation, and acceleration / deceleration time, etc. The transport time calculation unit 302 calculates the time for the subsequent second printing medium 2P to be transported based on the distance L of the separation area, the overlap W, the sheet interval Dp after the separation operation, and the transport speed V1. The transport stop time calculation unit 303 calculates the time for the first transport roller 5 to stop transporting the subsequent second printing medium 2P based on the number of scans S and the time Ts required for one scan.

[0187] In step S705, MPU 201 calculates the speed V2 of the preceding printing medium P used for the separation operation (transfer speed calculation unit 304). This is calculated based on the separable time Tmax and the distance L of the separation area using the following formula.

[0188] V2 = L / Tmax

[0189] In step S706, MPU 201 determines whether the speed V2 of the preceding printing medium P is less than or equal to a threshold. This is the conveying speed of the third conveyor roller 20 in this embodiment. If it is determined that the speed V2 is less than or equal to the threshold (step S706: Yes), the process moves to step S707 (overlap amount determination unit 307). In step S707, MPU 201 sets the overlap amount W in RAM 203, and the process moves to step S708.

[0190] In step S708, a skew correction operation is performed on the subsequent printing medium P while maintaining the overlapping state, and then the MPU 201 determines the alignment operation. In other words, after the image formation operation of the preceding printing medium P is completed, the subsequent printing medium P is brought into contact with the gap of the transport rollers while maintaining its overlap with the preceding printing medium P. Specifically, the first transport roller 5 and the feed roller 3 are rotated by simultaneously driving the second feed motor 207 with the transport motor 205. After the skew correction operation, alignment is performed while the subsequent printing medium P remains overlapping with the preceding printing medium P.

[0191] In step S706, if it is determined that the speed V2 is greater than the threshold (step S706: no), the process moves to step S709.

[0192] In step S709, MPU 201 subtracts a predetermined amount from the set overlap amount W and sets the overlap amount W again in RAM 203. After this, the process moves to step S710. For example, the amount can be reduced in 1 mm increments or in 2 mm increments. In step S710, MPU 201 determines whether the overlap amount W between the rear end of the preceding print media P and the front end of the subsequent print media P is less than or equal to a threshold. If it is determined that the overlap amount W is less than or equal to the threshold (step S710: Yes), then MPU 201 determines to release the overlap state and performs a skew correction operation only on the subsequent print media (step S711). In other words, after the image formation operation of the preceding print media P is completed, the subsequent print media P is not conveyed together with the preceding print media P. Specifically, the preceding print media P is conveyed by the first conveyor roller 5 driven by the conveyor motor 205. However, the feed roller 3 is not driven. As a result, the overlap state is released. In addition, a skew correction operation is performed by only contacting the subsequent printing medium P with the gap of the conveyor rollers, and then only the subsequent printing medium P is aligned.

[0193] In step S710, if it is determined that the overlap amount W is greater than the threshold (step S710: no), the process returns to step S703. In step S703, MPU 201 calculates the number of scans S in the scan judgment distance based on the print data to be printed on the subsequent print medium P with the reduced overlap amount W.

[0194] Reference Figure 26 This describes the operation used to adjust the amount of overlap between the first print media 1P and the second print media 2P.

[0195] Figure 26 ST1 in Figure 14AIn step S409, the image forming operation for the final row of the first print medium 1P is completed. At this time, the upstream end of the first print medium 1P in the conveying direction is located upstream of the first conveying roller 5 at a distance W0. In other words, if the skew correction operation of the second print medium 2P is performed in this state, the first print medium 1P and the second print medium 2P will overlap by an initial overlap amount W0. Figure 26 In the diagram, Ky indicates the planned printing area on the printing medium P, and Kd indicates the printing area. Additionally, Dn indicates the nozzle area distance, which is the distance from the upstream to the downstream region of the ejector nozzles 71 located in the printhead 7 (i.e., the maximum print width during printing). Therefore, if the print width of each scan operation of the carriage 1 is represented by Ds, then Ds ≦ Dn. Furthermore, the print width does not need to be constant, but can instead vary depending on the scan operation.

[0196] like Figure 26 As shown in ST2, when the image formation operation of the final line of the first print media 1P is completed, the MPU transfers only the first print media 1P by rotating the first transfer roller 5 by a predetermined amount. Figure 14A (Step S410 in the process). At this time, MPU 201 rotates the first conveyor roller 5 to convey the first printing medium 1P until its upstream end in the conveying direction reaches the upstream position at a distance W0. Figure 21 The position of the overlap amount W set in step S707 is reached ( Figure 14A Step S411 in the process. Once the printing media has been conveyed to the position of overlap W, MPU 201 stops the first conveyor roller 5 ( Figure 14A Step S412 in the process.

[0197] Figure 26 ST3 in Figure 13A In step S308, the skew correction of the second printing medium 2P is being performed. (See reference...) Figure 6 As described in ST6, when the first transport roller 5 is stopped during the image formation operation of the final line of the first print media 1P, a skew correction operation is performed on the second print media 2P so that the leading edge of the second print media 2P contacts the gap of the transport roller. At this time, the first print media 1P and the second print media 2P overlap by an overlap amount W.

[0198] Figure 26 ST4 indicates in Figure 13AIn step S309, the second printing medium 2P is being aligned. The first conveyor roller 5 is rotated by a predetermined amount via the MPU 201, and the second printing medium 2P is held in a state where it overlaps with the first printing medium 1P by an overlap amount W, thus aligning the second printing medium 2P. In this embodiment, alignment is performed such that the downstream portion of the planned printing area Ky of the second printing medium 2P aligns with the downstream jet nozzle of the printhead 7.

[0199] This is done to adjust the overlap between the first print media 1P and the second print media 2P.

[0200] Note that this only applies to skew correction for subsequent printing media. Figure 20 Steps S103 and S106) and skew correction after de-overlapping ( Figure 20 Steps S108, S110, and S112 in the process and Figure 21 Step S711) and Figures 13A to 15 The series of processes in steps S404 to S407 and S308 correspond to this. Similarly, skew correction is performed while maintaining the overlap state. Figure 21 Step S708 in the middle) and Figures 13A to 15 The series of processes in steps S403, S408 to S412 and S308 correspond to each other.

[0201] Configuration used to calculate the front-end position after alignment

[0202] Figure 22 This is a flowchart illustrating the operation for calculating the leading edge position after alignment with the subsequent printing media according to this embodiment.

[0203] At step S201, processing begins. In step S202, the printable area of ​​the print media is read. The topmost printable position (i.e., the top margin) is identified, and thus the top margin of the printable area is set as the leading edge position (step S203). Here, the leading edge position is defined as the distance from the gap of the conveyor rollers.

[0204] Then, the initial print data is read (step S204). This identifies the position from the front of the print media to which the initial print data corresponds (detecting non-printing areas), and therefore determines whether the distance from the front of the print media to the initial print data is greater than the set front position (step S205). If the distance from the front of the print media to the initial print data is greater than the set front position (step S205: Yes), the front position is updated to the distance from the front of the print media to the initial print data (step S206). However, if the distance from the front of the print media to the initial print data is not greater than the set front position (step S205: No), the process moves to step S207.

[0205] Next, an initial carriage movement command is generated (step S207). It is determined whether the amount of print media transported for the initial carriage movement is greater than the set leading edge position (step S208). If the amount of print media transported for the initial carriage movement is greater than the set leading edge position (step S208: Yes), the leading edge position is updated to the amount of print media transported for the initial carriage movement (step S209). If the amount of print media transported for the initial carriage movement is not greater than the set leading edge position (step S208: No), the leading edge position is not updated. As described above, the leading edge position of the subsequent print media P is finally determined (step S210), and then the process ends (step S211). The determination can be based on the finally determined leading edge position. Figure 20 Step S109) When aligning the subsequent printing medium P, will the subsequent printing medium P reach the ratchet (not shown)?

[0206] As described above, according to the foregoing embodiments, when performing an operation to separate the preceding printing medium from the subsequent printing medium to de-overlap, the transport speed of the preceding printing medium is reduced, which enables the suppression of increases in noise and power consumption.

[0207] Second Embodiment

[0208] The first embodiment describes a case where the overlap amount is adjusted by calculating the transport speed of the preceding printing media. However, this embodiment will refer to... Figure 23 This describes an example of determining whether to adjust the overlap amount by calculating the transport distance of the preceding printed media. Steps S801 to S804 are the same as those described in the first embodiment. Figure 21 Steps S701 to S704 are similar and will not be described.

[0209] In step S805, MPU 201 calculates the transport distance L2 of the preceding print media P used for the separation operation (transport distance calculation unit 305). This is calculated based on the separable time Tmax and the transport speed V2 of the preceding print media using the following formula.

[0210] L2 = V2 × Tmax

[0211] In step S806, MPU 201 determines whether the transport distance L2 of the preceding printing medium P is at least a threshold (overlap amount determination unit 307). If it is determined that the transport distance L2 is at least the threshold (step S806: Yes), the process moves to step S807. In step S807, MPU 201 sets the overlap amount W in RAM 203, and the process moves to step S808.

[0212] In step S808, a skew correction operation is performed on the subsequent printing medium P while maintaining the overlapping state, and then the MPU 201 determines the alignment operation. In other words, after the image formation operation of the preceding printing medium P is completed, the subsequent printing medium P is brought into contact with the gap of the transport rollers while maintaining overlap with the preceding printing medium P. Specifically, the first transport roller 5 and the feed roller 3 are rotated by driving the second feed motor 207 simultaneously with the transport motor 205. After the skew correction operation, alignment is performed while the subsequent printing medium P remains overlapping with the preceding printing medium P.

[0213] In step S806, if it is determined that the transmission distance L2 is lower than the threshold (step S806: No), the process moves to step S809.

[0214] In step S809, MPU 201 subtracts a predetermined amount from the set overlap amount W and sets the overlap amount W again in RAM 203. After this, the process moves to step S810. For example, the amount can be reduced in 1 mm increments or in 2 mm increments. In step S810, MPU 201 determines whether the overlap amount W between the rear end of the preceding print media P and the front end of the subsequent print media P is less than or equal to a threshold. If it is determined that the overlap amount W is less than or equal to the threshold (step S810: Yes), MPU 201 determines to release the overlap state and performs a skew correction operation only on the subsequent print media (step S811). In other words, after the image formation operation of the preceding print media P is completed, the subsequent print media P is not conveyed together with the preceding print media P. Specifically, the preceding print media P is conveyed by the first conveyor roller 5 driven by the conveyor motor 205. However, the feed roller 3 is not driven. As a result, the overlap state is released. In addition, a skew correction operation is performed by only contacting the subsequent printing medium P with the gap of the conveyor rollers, and then only the subsequent printing medium P is aligned.

[0215] In step S810, if it is determined that the overlap amount W is greater than the threshold (step S810: no), the process returns to step S803. In step S803, MPU 201 calculates the number of scans S in the scan judgment distance based on the print data to be printed on the subsequent print medium P with the reduced overlap amount W.

[0216] As described above, when performing operations to separate the preceding print media from the subsequent print media to de-overlap, it is possible to suppress the transmission speed of the preceding print media while also suppressing increases in noise and power consumption.

[0217] Third Embodiment

[0218] The first embodiment describes a case where the overlap amount is adjusted by calculating the transport speed of the preceding printing media. However, this embodiment will describe a case with reference to... Figure 24 This example demonstrates how to determine whether to adjust the overlap amount by calculating the delivery time of the preceding printing media. Steps S901 to S904 are the same as those described in the first embodiment. Figure 21 Steps S701 to S704 are similar and will not be described.

[0219] In step S905, MPU 201 calculates the transport time T2 of the preceding print media P used for the separation operation (transport time calculation unit 306). This is calculated based on the transport distance L2 of the preceding print media and the transport speed V2 of the preceding print media using the following formula.

[0220] T2 = L2 / V2

[0221] In step S906, MPU 201 determines whether the transfer time T2 of the preceding printing medium P is less than or equal to the separability time Tmax (overlap amount determination unit 307). If it is determined that the transfer time T2 is less than or equal to the separability time Tmax (step S906: Yes), the process moves to step S907. In step S907, MPU 201 sets the overlap amount W in RAM 203, and the process moves to step S908.

[0222] In step S908, a skew correction operation is performed on the subsequent printing medium P while maintaining the overlapping state, and then the MPU 201 determines the alignment operation. In other words, after the image formation operation of the preceding printing medium P is completed, the subsequent printing medium P is brought into contact with the gap of the transport rollers while maintaining overlap with the preceding printing medium P. Specifically, the first transport roller 5 and the feed roller 3 are rotated by simultaneously driving the second feed motor 207 with the transport motor 205. After the skew correction operation, alignment is performed while the subsequent printing medium P remains overlapping on the preceding printing medium P.

[0223] In step S906, if it is determined that the transmission time T2 is greater than the separable time Tmax (step S906: No), then the process moves to step S909.

[0224] In step S909, MPU 201 subtracts a predetermined amount from the set overlap amount W and sets the overlap amount W again in RAM 203. After this, the process moves to step S910. For example, the amount can be reduced in 1 mm increments or in 2 mm increments. In step S910, MPU 201 determines whether the overlap amount W between the rear end of the preceding print media P and the front end of the subsequent print media P is less than or equal to a threshold. If it is determined that the overlap amount W is less than or equal to the threshold (step S910: Yes), MPU 201 determines to release the overlap state and performs a skew correction operation only on the subsequent print media (step S911). In other words, after the image formation operation of the preceding print media P is completed, the subsequent print media P is not conveyed together with the preceding print media P. Specifically, the preceding print media P is conveyed by the first conveyor roller 5 driven by the conveyor motor 205. However, the feed roller 3 is not driven. As a result, the overlap state is released. In addition, a skew correction operation is performed by only contacting the subsequent printing medium P with the gap of the conveyor rollers, and then only the subsequent printing medium P is aligned.

[0225] In step S910, if it is determined that the overlap amount W is greater than the threshold (step S910: no), the process returns to step S903. In step S903, MPU 201 calculates the number of scans S in the scan judgment distance based on the print data to be printed on the subsequent print medium P with the reduced overlap amount W.

[0226] As described above, when performing operations to separate the preceding print media from the subsequent print media to de-overlap, it is possible to suppress the transmission speed of the preceding print media while also suppressing increases in noise and power consumption.

[0227] Other embodiments: Embodiments of the present invention can also be implemented by providing software (programs) that perform the functions of the above embodiments to a system or device via a network or various storage media, and the computer or central processing unit (CPU) or microprocessor unit (MPU) of the system or device reads and executes the program.

[0228] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A printing device, comprising: A supply component, configured to supply printing media; The first roller is configured to convey the printing medium supplied by the supply component in the conveying direction. A printing component configured to print onto a printing medium conveyed by the first roller; The second roller is arranged downstream of the printing unit and is configured to convey the printing medium conveyed by the first roller. as well as A control unit capable of controlling the supply unit and the first roller such that the first roller overlaps on the upstream side of the printing medium conveying direction, in which the leading edge of the subsequent printing medium overlaps with the trailing edge of the preceding printing medium. The control unit, based on the printing data of the preceding printing medium and the printing data of the subsequent printing medium, changes the overlap amount in the overlapping state on the upstream side of the first roller in the conveying direction of the printing medium, and after changing the overlap amount, the preceding printing medium and the subsequent printing medium are separated between the first roller and the second roller.

2. The printing device according to claim 1, further comprising: A third roller is arranged between the first roller and the second roller in the conveying direction. The preceding printing medium and the subsequent printing medium are separated between the second roller and the third roller.

3. The printing device according to claim 1, in, The control unit calculates the initial overlap amount based on the printing data of the preceding printing medium, and changes the overlap amount to be less than the initial overlap amount.

4. The printing device according to claim 2, in, The control unit calculates the conveying time for driving the first roller based on the printing data of the subsequent printing media in the predetermined interval, and changes the overlap amount according to the calculated conveying time.

5. The printing device according to claim 4, in, The control unit calculates the stop time for stopping the first roller based on the printing data of the subsequent printing media in the predetermined interval, and changes the overlap amount according to the calculated stop time.

6. The printing apparatus according to claim 5, in, The control unit calculates the transmission time and the transmission stop time based on the print data printed during the transmission of a predetermined distance from the position obtained when the leading edge of the subsequent printing medium has been conveyed from the first roller or the third roller by the amount of overlap.

7. The printing apparatus according to claim 6, in, The control unit determines the transmission speed of the pre-printing medium based on the transmission time and the transmission stop time.

8. The printing apparatus according to claim 7, in, If the control unit determines that the conveying speed of the preceding printing medium is greater than a threshold, the control unit will change the overlap amount to a smaller value.

9. The printing apparatus according to claim 5, in, The control unit determines the transmission distance of the pre-printed medium based on the transmission time and the transmission stop time.

10. The printing apparatus according to claim 9, in, If the control unit determines that the transmission distance of the preceding printing medium is less than a threshold, the control unit will change the overlap amount to be smaller.

11. The printing apparatus according to claim 5, in, The control unit determines the transmission time of the pre-printing medium based on the transmission distance and transmission speed of the pre-printing medium.

12. The printing apparatus according to claim 11, in, If it is determined that the transmission time of the preceding printing medium is greater than the sum of the transmission time and the transmission stop time, the control unit will change the overlap amount to be smaller.

13. The printing apparatus according to claim 1, in, The control unit reduces the overlap by transmitting the advance printing medium after the final row of the advance printing medium has been imaged.

14. A method for controlling a printing device, the printing device comprising: A supply component, configured to supply printing media; The first roller is configured to convey the printing medium supplied by the supply component in the conveying direction. A printing component configured to print onto a printing medium conveyed by the first roller; And a second roller, which is arranged downstream of the printing unit and configured to convey the printing media conveyed by the first roller, the control method comprising: A control step is used to control the supply component and the first roller such that the first roller overlaps on the upstream side of the printing medium conveying direction, in which the front end of the subsequent printing medium overlaps with the rear end of the preceding printing medium. In the control step, based on the printing data of the preceding printing medium and the printing data of the subsequent printing medium, the overlap amount in the overlapping state is changed on the upstream side of the first roller in the conveying direction of the printing medium, and after the overlap amount is changed, the preceding printing medium and the subsequent printing medium are separated between the first roller and the second roller.

15. A non-transitory computer-readable storage medium storing a program that, when executed by a computer, causes the computer to perform the control method for a printing apparatus according to claim 14.

16. A computer program product comprising a program that, when executed by a computer, causes the computer to perform the control method for a printing device according to claim 14.

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