Image recording device

Abstract

To inhibit time until image recording onto one of sheet-like media ends from becoming long to suppress deterioration in image recording accuracy due to that an upstream end of the sheet-like medium is pushed out when passing through a pair of transportation rollers.SOLUTION: A printer includes a control unit that can execute: a divided transportation step of transporting a sheet a plurality of times by a transportation amount X2 which is smaller than a distance L2 from before a paper sensor detects the trailing end of the sheet until when detecting the trailing end; a correction step of correcting a transportation amount after the paper sensor detects the trailing end of the sheet to a transportation amount X3 which is smaller than the transportation amount; and an image recording step of recording an image on the sheet after transportation by the transportation amount X3 is performed.SELECTED DRAWING: Figure 5

Description

[[Technical Field]]

[0001] The present invention relates to an image recording apparatus that records an image on a sheet-shaped medium. [[Background Art]]

[0002] Patent Document 1 describes a printer including a pair of conveyance rollers that convey a sheet (a sheet-shaped medium) in the conveyance direction by rotating while nipping the sheet from the thickness direction, and a recording section that records an image on the sheet conveyed by the pair of conveyance rollers. In this printer, an image is recorded on the sheet by alternately executing a conveyance process of conveying a predetermined amount of the sheet by the pair of conveyance rollers and an image recording process of recording an image on the sheet by the recording section. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2022-85051 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] One roller of the pair of conveyance rollers is biased toward the other roller of the pair of conveyance rollers. Therefore, when the trailing end, which is the upstream end of the sheet in the conveyance direction, passes between the pair of conveyance rollers, the pair of conveyance rollers approach each other so as to come into contact. After a predetermined amount of the sheet has been conveyed by the pair of conveyance rollers, when the trailing end of the sheet passes between the pair of conveyance rollers, the force of the pair of conveyance rollers tending to approach each other pushes the sheet out in the conveyance direction. As a result, when the trailing end of the sheet passes the pair of conveyance rollers, the conveyance amount of the sheet becomes the predetermined amount plus the push-out amount. Even though the actual conveyance amount deviates from the predetermined amount, if the image recording process is performed in accordance with conveyance of the predetermined amount, a problem may arise in that the accuracy of image recording on the sheet decreases.

[0005] To solve the above problem, the inventor considered transporting the paper with a corrected transport amount, which is a predetermined amount minus the extrusion amount, when the trailing edge of the paper passes through a pair of transport rollers. In this case, since it is necessary to accurately predict the timing when the trailing edge of the paper passes through the pair of transport rollers, the inventor also considered installing a sensor to detect the trailing edge of the paper upstream of the pair of transport rollers in the transport direction. When the transport amount when transporting the paper is less than the distance between the detection position by the sensor and the gripping position by the pair of transport rollers, the trailing edge of the paper that has passed the detection position during transport at that transport amount will be upstream of the gripping position of the pair of transport rollers in the transport direction. Therefore, the position of the trailing edge of the paper can be determined at a position relatively close to the pair of transport rollers, and it becomes possible to accurately predict how many more transports are needed for the trailing edge of the paper to pass through the pair of transport rollers. As a result, the paper can be transported with the corrected transport amount at the appropriate timing.

[0006] However, if the transport process is repeated with a transport volume less than the above distance, the amount transported in each transport process will be small. This may increase the time it takes to complete image recording on the paper. On the other hand, if the transport process is repeated with a transport volume exceeding the above distance, the amount transported in each transport process will be large. This makes it possible to suppress the increase in the time it takes to complete image recording on the paper. However, when transporting at this transport volume, the trailing edge of the paper that has passed the detection position may pass the pair of transport rollers all at once. In this case, there is a risk that the paper may be pushed out by the pair of transport rollers without being able to take the appropriate timing to transport the paper with the corrected transport volume.

[0007] Therefore, the object of the present invention is to provide an image recording device that can suppress the time required to complete image recording on a sheet-like medium and suppress the decrease in image recording accuracy caused by the upstream end of the sheet-like medium being pushed out as it passes through a pair of transport rollers. [Means for solving the problem]

[0008] The image recording device of the present invention includes a pair of transport rollers that rotate while gripping a sheet-like medium, a transport unit that transports the sheet-like medium in the transport direction, a recording unit that is located downstream of the pair of transport rollers in the transport direction and records an image on the sheet-like medium, a first sensor that is located upstream of the pair of transport rollers in the transport direction and detects the sheet-like medium, and a control unit. The control unit is capable of performing the following: a first transport process in which the sheet-like medium is transported by the transport unit with a first transport amount greater than the distance from the detection position by the first sensor to the gripping position of the sheet-like medium by the pair of transport rollers; a first image recording process in which an image is recorded on the sheet-like medium transported by the first transport process by the recording unit; a divided transport process performed after the first image recording process, in which the sheet-like medium is transported in multiple stages with a second transport amount smaller than the distance from before the first sensor detects the upstream end of the sheet-like medium in the transport direction until the upstream end is detected; a correction process in which the transport amount in transport after the first sensor detects the upstream end is corrected to a third transport amount smaller than the said transport amount; and a second image recording process in which an image is recorded on the sheet-like medium by the recording unit after transport by the third transport amount has been performed. [Effects of the Invention]

[0009] According to the image recording apparatus of the present invention, it is possible to perform a first transport process and a divided transport process after the first image recording process. By performing the divided transport process at an appropriate timing, it is possible to suppress the time required for transporting the sheet-like medium. In other words, it is possible to suppress the time required until image recording on one sheet-like medium is completed. When any of the transport passes in the divided transport process is completed, the upstream end of the sheet-like medium is located between the detection position by the first sensor and the gripping position of the sheet-like medium by the pair of transport rollers. In other words, the upstream end of the sheet-like medium, which is upstream of the detection position, will no longer pass through the gripping position in a single transport pass. Therefore, it becomes possible to transport the sheet-like medium with a third transport volume from a state where the rear end of the sheet-like medium is between the detection position and the gripping position. That is, by transporting with a transport volume greater than the distance between the detection position and the gripping position, it becomes possible to correct the transport volume during the period corresponding to the time when the rear end of the sheet-like medium passes through the detection position and the gripping position in one go and the transport is completed. Consequently, the effect of extrusion on image recording by the second image recording process after the divided transport process can be suppressed, and the decrease in image recording accuracy can be suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic side view showing the internal structure of a printer according to one embodiment of the present invention. [Figure 2] Figure 1 is a schematic side view showing the inkjet head, a portion of the transport section, and two paper sensors. [Figure 3] This is a block diagram showing the electrical configuration of a printer. [Figure 4] Figure 1 shows a flowchart illustrating an example of the processing steps involved when printing with the printer shown. [Figure 5] This flowchart shows an example of the processing procedure when performing a transport operation. [Figure 6] (a) is a diagram showing the situation when the splitting and transporting process is performed when the trailing edge of the paper is between the two paper sensors, and (b) is a diagram showing the situation of splitting and transporting after the trailing edge of the paper has passed the nip position of the transport roller pair. [Modes for carrying out the invention]

[0011] A printer 100 according to a preferred embodiment of the present invention will be described below with reference to the drawings. In the following description, the vertical and horizontal directions are defined based on the state in which the printer 100 is installed for use (the state in Figure 1), and the left-right direction (the direction perpendicular to the plane of the paper in Figure 1) is defined when viewing the printer 100 from the front.

[0012] As shown in Figure 1, the printer 100 (the "image recording device" of the present invention) includes a housing 100a, a feeding cassette 1, a transport unit 3, a cutting unit 4, an inkjet head 5, a moving mechanism 6, a control unit 8, an output tray 9, paper sensors 51, 52, and the like.

[0013] The feed cassette 1 is located below the inkjet head 5 within the housing 100a. The feed cassette 1 is designed to selectively accommodate either roll paper Rp or cut paper Kp so that it can selectively transport either roll paper Rp or cut paper Kp. As shown in Figure 1, the feed cassette 1 has a tray 11, a roll storage section 20 capable of accommodating roll paper R, and a cut paper storage section 13 capable of accommodating multiple layers of cut paper Kp.

[0014] As shown in Figure 1, the roll body R is formed by winding a long roll of paper (the "sheet-like medium" of the present invention) Rp around the outer circumference of a cylindrical core member Rc. The cut paper (the "sheet-like medium" of the present invention) Kp is a sheet of paper that is shorter than the long roll of paper Rp that constitutes the roll body R in the direction of transport of the cut paper Kp and the roll of paper Rp, and is, for example, A4 size or B5 size paper. In the following description, when the roll of paper Rp and the cut paper Kp unwound from the roll body R are not distinguished, they may be referred to as "paper P".

[0015] As shown in Figure 1, the tray 11 has a box shape with an opening at the top. The tray 11 can be inserted into and removed from the housing 100a along the front-to-back direction.

[0016] The roll body accommodating portion 20 is arranged on the front side of the bottom wall 11a of the tray 11 as shown in FIG. 1, and rotatably supports the roll body R while supporting the outer peripheral surface of the lower portion of the roll body R. The roll body R is accommodated in the roll body accommodating portion 20 in a state where the rotation axis thereof (the central axis of the core member Rc) extends along the left-right direction (the width direction of the roll paper Rp).

[0017] The roll body accommodating portion 20 has a recess 21 for accommodating the roll body R as shown in FIG. 1. Two rollers 22 and 23 are provided at the bottom of the recess 21. Each of the two rollers 22 and 23 is rotatable about a rotation axis extending in the left-right direction. When the roll body R is accommodated in the recess 21, the outer peripheral surface of the lower portion thereof is supported by the two rollers 22 and 23.

[0018] As shown in FIG. 1, the roll body accommodating portion 20 has a hole 25 that communicates with the recess 21 and extends in the up-down direction, and a groove 26 that communicates with the hole 25 and extends in the front-rear direction. Both the hole 25 and the groove 26 open to the bottom surface of the roll body accommodating portion 20. The roll paper Rp unwound from the roll body R passes through the hole 25 and the groove 26, and is conveyed toward the inkjet head 5.

[0019] As shown in FIG. 1, the cut sheet accommodating portion 13 is constituted by the bottom wall 11a at a portion rearward of the roll body accommodating portion 20 (that is, on the downstream side along the conveyance direction), and accommodates the cut sheet Kp while supporting the cut sheet Kp from below. The cut sheet accommodating portion 13 accommodates the cut sheet Kp in a posture where the longitudinal direction of the cut sheet Kp coincides with the left-right direction and the width direction thereof coincides with the front-rear direction.

[0020] The conveyance unit 3 includes a feeding portion 41, three conveyance roller pairs 42 to 44, and a conveyance motor 45M (see FIG. 3). The feeding portion 41 feeds out either one of the roll body R accommodated in the feeding cassette 1 and the cut sheet Kp, which is the sheet P, rearward from the feeding cassette 1.

[0021] The feeding unit 41 is positioned above the feeding cassette 1 and includes a feeding roller 41a, an arm 41b, and a feeding motor 41M (see Figure 3). The feeding roller 41a is pivotally supported at the tip of the arm 41b. The arm 41b is rotatably supported on a support shaft 41c. The arm 41b is biased by a spring or the like in a direction that causes the feeding roller 41a to contact the bottom wall 11a of the tray 11. The arm 41b is also configured to be retractable upward when attaching or detaching the feeding cassette 1. The feeding roller 41a rotates when a driving force is transmitted from the feeding motor 41M. When the feeding motor 41M is driven by the control unit 8, the feeding roller 41a rotates, and the paper P contained in the tray 11 is fed backward.

[0022] These three transport roller pairs 42-44 transport the paper P fed by the feeding unit 41 within the housing 100a along a transport direction perpendicular to the left-right direction. The three transport roller pairs 42-44 are arranged in this order from the upstream side in the transport direction. Transport roller pair 42 transports the paper P sent out from the feeding cassette 1 by the feeding unit 41 to transport roller pair 43. Transport roller pair 43 receives the paper P transported by transport roller pair 42 and sends it to the inkjet head 5 side. Transport roller pair 44 receives the paper P transported by transport roller pair 43 and discharges it.

[0023] As shown in Figure 1, the transport roller pair 43 is positioned upstream of the inkjet head 5 in the transport direction. The transport roller pair 44 is positioned downstream of the inkjet head 5 in the transport direction. The paper P transported by these two transport roller pairs 43 and 44 is fed from rear to front.

[0024] Each transport roller pair 42-44, as shown in Figure 1, consists of drive rollers 42a-44a and driven rollers 42b-44b that move in conjunction with the drive rollers 42a-44a. The drive rollers 42a-44a of each transport roller pair 42-44 receive driving force from the transport motor 45M via a transmission mechanism (not shown). The driven rollers 42b-44b of each transport roller pair 42-44 are biased toward the drive rollers 42a-44a by biasing members 42c-44c such as springs. As a result, each transport roller pair 42-44 can grip the paper P at the nip position (the "gripping position" in this invention) between the drive rollers 42a-44a and the driven rollers 42b-44b. Then, when the transport motor 45M is driven by the control unit 8, the drive rollers 42a to 44a and driven rollers 42b to 44b of each transport roller pair 42 to 44 rotate with the paper P nipped, and the paper P is transported in the transport direction.

[0025] Furthermore, the transport motor 45M is equipped with a rotary encoder 14 (see Figure 3). The rotary encoder 14 outputs signals to the control unit 8 indicating the amount of movement and angle of rotation of the shaft of the transport motor 45M.

[0026] As shown in Figure 1, the cutting section 4 is located between the rear end of the tray 11 and the transport roller pair 42. The cutting section 4 includes a fixed blade 4a that is elongated in the left-right direction and a disc-shaped rotating blade 4b that is movable in the left-right direction while in contact with the fixed blade 4a. The rotating blade 4b reciprocates along the left-right direction by the drive of a cutting motor 4M (see Figure 3) controlled by the control unit 8. As the rotating blade 4b moves in either the left or right direction, it receives a rotational moment from the roll paper Rp and the fixed blade 4a and rotates in response. The roll paper Rp, which has been unwound from the roll body R and transported, is cut in the width direction (left-right direction) by the cutting section 4. As a result, a rear end is formed on the roll paper Rp that is sent to the discharge tray 9.

[0027] The inkjet head (the "recording unit" of the present invention) 5 includes a plurality of nozzles formed on its lower surface and a driver IC 5d (see Figure 3). When the driver IC 5d is driven by the control unit 8, ink is ejected from the nozzles and an image is recorded on the paper P transported by the transport roller pair 43.

[0028] As shown in Figure 1, the moving mechanism 6 includes a carriage 6a, two guide rails 6b and 6c, and a carriage motor 6M (see Figure 3). The inkjet head 5 is mounted on the carriage 6a. The two guide rails 6b and 6c are spaced apart from each other in the front-rear direction and each extends in the left-right direction. The carriage 6a is positioned to straddle the two guide rails 6b and 6c. The carriage 6a is connected to the carriage motor 6M via a belt (not shown) or the like. When the carriage motor 6M is driven by the control unit 8, the carriage 6a moves along the guide rails 6b and 6c in the scanning direction (left-right direction, perpendicular to the transport direction).

[0029] The output tray 9 forms the front side wall of the upper part of the housing 100a and can be opened and closed relative to the housing 100a. The paper P on which the image has been formed by the inkjet head 5 is transported forward by the transport unit 3 and received in the open output tray 9. As a result, the paper P is ejected from the printer 100 (inside the housing 100a).

[0030] As shown in Figure 1, the paper sensor 51 (the "second sensor" of the present invention) is positioned between the cutting unit 4 and the transport roller pair 42. The paper sensor 51 detects the paper P that has been transported between the cutting unit 4 and the transport roller pair 42. More specifically, the paper sensor 51 outputs a signal indicating the front end of the paper P and a signal indicating the rear end of the paper P to the control unit 8.

[0031] As shown in Figure 1, the paper sensor 52 (the "first sensor" of the present invention) is located downstream of the paper sensor 51 in the transport direction and is positioned between the transport roller pair 42 and the transport roller pair 43. The paper sensor 52 also detects the paper P that has been transported between the transport roller pair 42 and the transport roller pair 43. More specifically, the paper sensor 52 outputs a signal indicating the front end of the paper P and a signal indicating the rear end of the paper P to the control unit 8.

[0032] Furthermore, the two paper sensors 51 and 52 are arranged such that the distance L1 is greater than the distance L2, as shown in Figure 2. Distance L1 is the separation distance from the upstream detection position where paper sensor 51 detects paper P to the downstream detection position where paper sensor 52 detects paper P along the transport direction. Distance L2 is the separation distance from the downstream detection position to the nip position where paper P is gripped by the transport roller pair 43 along the transport direction. Distance L1 is greater than the distance corresponding to the transport amount X1 (the "first transport amount" of the present invention) described later. Distance L2 is greater than the distance corresponding to the transport amount X2 (the "second transport amount" of the present invention) described later.

[0033] Next, with reference to Figure 3, the control unit 8, which is responsible for the overall control of the printer 100, will be described. The control unit 8 includes a CPU (Central Processing Unit) 81, ROM (Read Only Memory) 82 and RAM (Random Access Memory) 83, an ASIC (Application Specific Integrated Circuit) 84, and flash memory 85, all of which are connected to each other by a bus. These components work together to control the operation of the driver IC 5d, feed motor 41M, transport motor 45M, carriage motor 6M, cutting motor 4M, etc. For example, based on a recording command transmitted from an external device (e.g., a PC or smartphone), the control unit 8 controls the driver IC 5d, feed motor 41M, transport motor 45M, carriage motor 6M, cutting motor 4M, etc., to alternately execute transport processing and image recording processing, thereby recording an image on the paper P. The recording command includes header data indicating the size of the image to be used for image recording, and image data indicating the content of the image to be recorded.

[0034] The transport process involves transporting a predetermined amount of paper P to the transport roller pair 42-44. The control unit 8 controls the transport motor 45M to cause the transport roller pair 42-44 to perform the transport process. The image recording process involves moving the carriage 6a along the left-right direction while controlling the driver IC 5d to eject ink droplets from the nozzles. The control unit 8 then temporarily stops the transport of paper P between the current transport process and the next transport process, and performs the image recording process while the transport of paper P is stopped. In other words, in the image recording process, the control unit 8 performs one pass of ejecting ink droplets from the nozzles while moving the carriage 6a to the right or left. This performs one pass of image recording on paper P. By repeatedly performing the transport process and the image recording process alternately, the control unit 8 can record images on the entire image-recordable area of ​​paper P. In other words, the control unit 8 records images on paper P in multiple passes.

[0035] Furthermore, the control unit 8 receives signals from paper sensors 51 and 52. This enables the detection of the front and rear end positions of the paper P. The control unit 8 also receives signals from the rotary encoder 14. This makes it possible to derive the amount of paper P transported by each transport roller pair 42 to 44. The control unit 8 also stores the cumulative transport amount Z1 since the rear end of the paper P was detected by paper sensor 51 in the flash memory 85. The control unit 8 also stores the cumulative transport amount Z2 since the rear end of the paper P was detected by paper sensor 52 in the flash memory 85. The control unit 8 also stores the cumulative transport amount Z3 in the split transport process described later in the flash memory 85. The flash memory 85 also stores the transport counts M1 and M2, described later.

[0036] Furthermore, the control unit 8 may perform various processing tasks solely with the CPU 81, solely with the ASIC 84, or collaboratively with the CPU 81 and ASIC 84. Also, the control unit 8 may be performed by a single CPU 81 alone, or by multiple CPUs 81 sharing the processing tasks. Similarly, the control unit 8 may be performed by a single ASIC 84 alone, or by multiple ASICs 84 sharing the processing tasks.

[0037] <Printing control> Next, we will explain the control of printer 100 during printing. When printer 100 receives a record command to execute printing, the control unit 8 processes the data according to the flow shown in Figure 4.

[0038] To explain the flow in Figure 4 in more detail, the control unit 8 first determines whether or not it has received a record command (S1). If it has not received a record command (S1: NO), it repeats S1. If it has received a record command (S1: YES), the control unit 8 determines whether or not the current print is roll paper printing based on the record command (S2). Whether or not it is roll paper printing or cut paper printing is determined by deriving the length of the paper P used (length of the paper P along the transport direction) based on the size of the image in the header data included in the record command. If the header data contains data on the length of the paper P used, the determination may be made based on that data. It is also assumed that the printer 100 has the roll paper Rp (roll body R) or cut paper Kp to be used during printing already stored in it by the user.

[0039] If it is determined that roll paper printing is required (S2: YES), the control unit 8 starts feeding the roll paper Rp (S3). That is, the control unit 8 drives the feed motor 41M and the transport motor 45M to transport the roll paper Rp, which has been unwound from the roll body R, from the tray 11 toward the inkjet head 5. Then, when the leading edge of the roll paper Rp reaches the transport roller pair 43, the control unit 8 performs the leading edge of the roll paper Rp. During leading edge, the control unit 8 stops the roll paper Rp at the image recording start position. The image recording start position is the position where the leading edge (downstream end) of the image recording area of ​​the roll paper Rp in the transport direction faces the nozzle located furthest downstream in the transport direction among the multiple nozzles.

[0040] In S3, the control unit 8 drives the carriage motor 6M to move the carriage 6a (inkjet head 5) to the starting position. The starting position is the starting position of the carriage 6a's movement when the image recording process (S4) is executed, and is determined based on the recording command. In S3, the operation from feeding the roll paper Rp to leading it out and the movement of the carriage 6a are executed in parallel.

[0041] Next, in S4, the control unit 8 performs image recording processing. That is, the control unit 8 performs one pass in which ink droplets are ejected from the nozzle while moving the carriage 6a from the starting position. In this embodiment, the image recording processing performed before the divided transport processing described later corresponds to the "first image recording processing" of the present invention, and the image recording processing performed after the divided transport processing corresponds to the "second image recording processing" of the present invention.

[0042] Next, in S5, the control unit 8 determines whether or not the roll paper Rp has been cut. The determination of whether or not the roll paper Rp has been cut is made by checking whether or not a cut flag is stored in the flash memory 85. When the roll paper Rp is cut, the control unit 8 stores the cut flag in the flash memory 85. The cut flag is erased from the flash memory 85 when the current print job is finished. If the roll paper Rp has been cut (S5: YES), the process proceeds to S8.

[0043] On the other hand, if the paper has not been cut (S5:NO), the control unit 8 determines, based on the recording command, whether the position that will be the rear end of the roll paper Rp has reached the cutting unit 4 (S6). If the position that will be the rear end of the roll paper Rp has not reached the cutting unit 4 (S6:NO), the process proceeds to S8.

[0044] When the trailing end of the roll of paper Rp reaches the cutting section 4 (S6:YES), the control unit 8 drives the cutting motor 4M and performs a cutting process to cut the roll of paper Rp (S7). At this time, as described above, the cutting flag is stored in the flash memory 85.

[0045] Next, in S8, the control unit 8 determines whether or not image recording on the roll paper Rp based on the recording command has been completed. If image recording on the roll paper Rp has not been completed (S8: NO), the process proceeds to S9, and the transport process is executed according to the flow in Figure 5.

[0046] <Control of transport process> To explain the flow in Figure 5 in more detail, the control unit 8 determines whether the cumulative transport amount Z1 is greater than or equal to a threshold (S201). In this embodiment, the threshold is the value of the transport amount X1. In this embodiment, the distance corresponding to the transport amount X1 is greater than distance L2 and less than distance L1. Note that the threshold can be set as appropriate and is not particularly limited. The transport process is carried out in the same manner in S13, which will be described later. Therefore, in the transport process, roll paper Rp and cut paper Kp are referred to as paper P without distinction.

[0047] If the paper sensor 51 has not detected the trailing edge of the paper P, or if the paper sensor 51 has not performed transport of a transport amount X1 or more since detecting the trailing edge of the paper P, the cumulative transport amount Z1 will be less than the threshold. In this case (S201: NO), the control unit 8 sets the current transport amount to transport amount X1 (S202). The transport amount X1 is the amount of paper P to be transported for the next image recording process, and is derived by the control unit 8 based on information such as the size and resolution of the image included in the recording command.

[0048] Next, the control unit 8 controls the transport motor 45M to transport the paper P along the transport direction by the set transport amount (S203). That is, if the paper P has come from S201 via S202 to S203, it will be transported for a transport amount of X1. Similarly, if the paper P has come from S201 via S226 (described later) to S203, it will be transported for a transport amount of X1. If the paper P has come from S201 via S210 (described later) to S203, it will be transported for a transport amount of X2. If the paper P has come from S201 via S219 (described later) to S203, it will be transported for a transport amount of X3. If the paper P has come from S201 via S223 (described later) to S203, it will be transported for a transport amount of X4. If the paper P has come from S201 via S229 (described later) to S203, it will be transported for a transport amount of X5. In this way, the S203 transports the paper P at the set transport volume.

[0049] Next, the control unit 8 determines whether the amount transported in S203 is either transport amount X1 or transport amount X5 (S204). If the amount transported in S203 is neither transport amount X1 nor transport amount X5 (S204: NO), the control unit 8 determines whether any of the flags G, J, or K is set (S205).

[0050] If any of flags G, J, or K is set (S205: YES), the control unit 8 resets the set flag J (S206). In S206, even if flags G or K are set, they are not reset and remain set. Thus, the transport process ends and the system returns to S4. Also, if the amount transported in S203 is either transport amount X1 or transport amount X5 (S204: YES), the transport process ends and the system returns to S4. Note that if the paper P is transported in S203 via S202 or S226, this corresponds to the first transport process of the present invention.

[0051] On the other hand, if none of the flags G, J, or K are set in S205 (S205: NO), the control unit 8 returns to S209, which will be described later. Since the flags G, J, and K indicate that the divided transport process in the current transport process has finished, if they are not set, the divided transport process has not finished, and the system returns to S209.

[0052] In this embodiment, after the rear end of the paper P is detected by the paper sensor 51, the paper is transported once at the transport amount X1 set in S202, then the process proceeds to S209, described later, and the split transport process begins. As shown in Figure 6(a), the distance L1 is greater than the distance corresponding to the transport amount X1. As a modification, the paper P may be transported two or more times at the transport amount X1 after the rear end of the paper P is detected by the paper sensor 51, before proceeding to S209, described later, and the split transport process may be executed. The number of times the paper P is transported at the transport amount X1 after the rear end of the paper P is detected by the paper sensor 51 can be determined by appropriately setting the above threshold according to the distance L1.

[0053] When the paper sensor 51 detects the trailing edge of the paper P and then performs one transport operation of transport amount X1, in S201 it is determined that the cumulative transport amount Z1 is greater than or equal to a threshold (S201: YES). In this case, the control unit 8 determines whether or not flag G is set in the flash memory 85 (S207). Flag G is a flag that indicates the completion of the following split transport process. Flag G also indicates that the trailing edge of the paper P has passed the nip position by the transport roller pair 43. When flag G is stored in the flash memory 85, the flag G is set, and when the flag is erased from the flash memory 85, the flag is reset.

[0054] If flag G is set (S207:YES), the process proceeds to S202. In other words, the transport after the division transport process described below is performed with a transport amount X1. On the other hand, if flag G is not set (S207:NO), the control unit 8 determines whether flag K is set or not (S208). Flag K is a flag that indicates the completion of the division transport process described below. Flag K also indicates that the trailing edge of the paper P has passed the downstream detection position. Flag K is set when it is stored in the flash memory 85, and reset when it is erased from the flash memory 85.

[0055] If flag K is not set (S208: NO), the divided transport process has not finished or has not started. In this case, the control unit 8 starts or continues the divided transport process. The divided transport process is a process in which transport is performed with one of the transport amounts X2, X3, or X4 described below. If all transport in the divided transport process is performed with transport amount X2, that is, if no correction of the transport amount is performed in S219 or S223 below, the total transport amount in the divided transport process is equal to the transport amount X1. On the other hand, if the transport in the divided transport process includes transport with either transport amount X3 or X4, the total transport amount in the divided transport process will be less than the transport amount X1.

[0056] Next, the control unit 8 determines whether the cumulative transport amount Z2 is less than the distance L2 (S209). In other words, it determines whether the distance corresponding to the cumulative transport amount Z2 is less than the distance L2. The cumulative transport amount Z2 is the amount of paper transported since the trailing edge of the paper P was detected by the paper sensor 52.

[0057] If the cumulative transport amount Z2 is less than the distance L2 (S209: YES), the control unit 8 sets the current transport amount to transport amount X2 (S210). Transport amount X2 is the value obtained by dividing transport amount X1 by a predetermined number of division transports, n (a natural number of 2 or more). In this embodiment, the number of division transports is "8", and transport amount X2 is derived as transport amount X1 / 8. Figure 6(a) shows the state in which X1 is divided into 8 equal parts in the section in which the division transport process is performed. Note that the number of division transports n can be set as appropriate, as long as it is 2 or more.

[0058] Next, the control unit 8 determines whether or not flag F2 is set (S211). When the trailing edge of the paper P is detected by the paper sensor 52, flag F2 is stored in the flash memory 85 by the control unit 8. When flag F2 is stored in the flash memory 85, it is set, and when flag F2 is erased from the flash memory 85, flag F2 is reset.

[0059] If flag F2 is not set (S211:NO), the control unit 8 performs the same processing as in S211 (S212). In S212, if flag F2 is not set (S212:NO), the control unit 8 adds 1 to the transport count M1 stored in the flash memory 85 and stores it in the flash memory 85 (S213). Initially, the transport count M1 is stored as 0 in the flash memory 85. In this embodiment, the transport count M1 also includes transport when the trailing end of the paper P is detected by the paper sensor 52 during split transport.

[0060] Next, the control unit 8 determines whether the transport count M1 is equal to the number of divided transport counts n (S214). If the transport count M1 is equal to the number of divided transport counts n, that is, even if divided transport is performed 8 times, the trailing edge of the paper P has not passed the downstream detection position. In this case (S214: YES), the control unit 8 resets the transport count M1 and the cumulative transport amount Z3 to 0. At this time, the flag J is stored in the flash memory 85 and set (S215). The flag J is a flag that indicates the end of the divided transport process. The flag J also indicates that the trailing edge of the paper P has not passed the downstream detection position. The flag J is set when it is stored in the flash memory 85, and reset when it is erased from the flash memory 85. In this way, the transport process (the "divided transport process" of the present invention) is completed via S203 to S206. Furthermore, if the number of transports M1 is not equal to the number of divided transports n (S214: NO), the process proceeds from S203 to S205 and then to S209, and the divided transport process continues.

[0061] The process is repeated from S201 through S205 (NO), with the transport amount X2 being divided and transported. In S211, if flag F2 is set (S211:YES), the control unit 8 determines whether the transport count M2 is equal to 0 (S216).

[0062] If the transport count M2 is equal to 0 (S216: YES), the control unit 8 derives the transport amounts Y1 and Y2 shown in Figure 6(a). Transport amount Y1 is the transport amount from the point when the trailing edge of the paper P passes the downstream detection position. Transport amount Y2 is the transport amount obtained by subtracting transport amount Y1 from the cumulative transport amount Z3 from the start of the split transport process until the transport when the trailing edge of the paper P passes the downstream detection position. On the other hand, if split transport has been performed at least once since flag F2 was set and the transport count M2 is not equal to 0 (S216: NO), the process proceeds to S218.

[0063] In S218, the control unit 8 determines whether the amount of transport X1 minus the amount of transport Y2 is less than the distance L2. If the trailing edge of the paper P does not pass the nip position of the transport roller pair 43 even after the current split transport process is completed, it is determined that the amount of transport X1 minus the amount of transport Y2 is less than the distance L2. In this case (S218: YES), the process proceeds to S212.

[0064] On the other hand, if it is predicted that the trailing edge of the paper P will pass the nip position of the transport roller pair 43 when the current split transport process is completed, it is determined that the transport amount X1 - transport amount Y2 is greater than or equal to the distance L2. In this case (S218: NO), proceed to S219.

[0065] Next, in S219, the control unit 8 sets the transport amount X3 (the "correction process" of the present invention). The transport amount X3 (the "third transport amount" of the present invention) is the value obtained by subtracting a predetermined correction amount α1 from the transport amount X2. In other words, the transport amount X3 is smaller than the transport amount X2. The correction amount α1 here is derived by {X2 / (X1-X2×M1)}×β. β corresponds to the amount of transport pushed out along the transport direction when the trailing edge of the paper P passes the nip position by the transport roller pair 43, and is a value that has been determined in advance by experiment. After this, the process proceeds to S212.

[0066] During the split transport process, the transport amount X2 is corrected to X3 by passing through S219. In the case of split transport as shown in Figure 6(a), the trailing edge of the paper P is detected by the paper sensor 52 when the split transport is performed twice (M1=2). After this, when the split transport is performed four more times (M2=4 below), the trailing edge of the paper P passes the nip position of the transport roller pair 43. The transport amount during split transport when the number of transports M2 is 1 to 4 is the transport amount X3, which is calculated by transport amount X2 - correction amount α1. Note that the split transport with this transport amount X3 is performed up to either the split transport that proceeds from S209 to S210, or the split transport in which the flag K is set by S222 below.

[0067] The process proceeds from S211 through S218 to S212. If flag F2 is set (S212: YES), the control unit 8 adds 1 to the transport count M2 stored in the flash memory 85 and stores it in the flash memory 85 (S220). The transport count M2 indicates the number of transports since the trailing edge of the paper P was detected by the paper sensor 52.

[0068] Next, the control unit 8 determines whether the total number of transports M1 + total number of transports M2 is equal to the number of divided transports n (S221). If the total number of transports M1 + total number of transports M2 is equal to the number of divided transports n (S221: YES), the control unit 8 stores and sets the flag K in the flash memory 85 (S222). In this way, the transport process (the "divided transport process" of the present invention) is completed via S203 to S206. If the total number of transports M1 + total number of transports M2 is not equal to the number of divided transports n (S221: NO), the process proceeds from S203 to S205 to S209, and the divided transport process continues.

[0069] For example, in the transport process (split transport process) by S9, when split transport is performed with a transport count M2 of 4, the cumulative transport amount Z2 becomes greater than or equal to the distance L2, as shown in Figure 6(b). In this way, the trailing edge of the paper P passes the downstream detection position, and in S209, if the cumulative transport amount Z2 is greater than or equal to the distance L2 (S209: NO), the control unit 8 sets the current transport amount to transport amount X4 (S223: "Correction process" of the present invention). The transport amount X4 ("third transport amount" of the present invention) is the value obtained by subtracting a predetermined correction amount α2 from the transport amount X6 calculated by X1-X2×(M1+M2). The correction amount α2 here is derived by {X6 / (X1-X2×M1)}×β.

[0070] Next, the control unit 8 stores and sets the flag G in the flash memory 85 (S224). Thus, the transport process is completed via S203 to S206.

[0071] In S222, when flag K is set, the trailing edge of the paper P has not yet passed the nip position by the transport roller pair 43, but it may pass the nip position due to the transport in the subsequent S203. Therefore, in S208, if flag K is set (S208: YES), the control unit 8 performs the same processing as in S209 (S225). If the cumulative transport amount Z2 is greater than or equal to the distance L2 (S225: NO), the control unit 8 sets the current transport amount to transport amount X1 (S226). Thus, the transport process is completed via S203 to S204 (YES).

[0072] On the other hand, if the cumulative transport amount Z2 is less than the distance L2 (S225: YES), the control unit 8 determines whether or not flag Q is set (S227). If flag Q is not set (S227: NO), the control unit 8 sets the current transport amount to transport amount X5 (S228). Transport amount X5 is the value obtained by subtracting the transport amount β that is pushed out from the transport amount X1.

[0073] Next, the control unit 8 stores and sets the flag Q in the flash memory 85 (S229). Thus, the transport process is completed via S203 to S204 (YES).

[0074] If flag Q is set in S227 (S227:NO), proceed to S226. This prevents repeated transport with transport amount X5. Then, the transport process ends via S203 to S204 (YES).

[0075] After the transport process in S9 is completed, the control unit 8 returns to S4 as shown in Figure 4 and executes the processes in S4 to S8 again. On the other hand, if image recording on the roll paper Rp is completed (S8: YES), the roll paper Rp on which the image is recorded is ejected and the flow ends. At this time, if the cut flag, flags G, K, Q, transport counts M1, M2, and cumulative transport amounts Z1 to Z3 are stored in the flash memory 85, the control unit 8 erases them from the flash memory 85.

[0076] Returning to S2, if it is determined that it is not roll paper printing (S2: NO), the control unit 8 starts feeding the cut paper Kp (S10). That is, the control unit 8 drives the feed motor 41M and the transport motor 45M to transport the cut paper Kp from the tray 11 toward the inkjet head 5. Then, when the leading edge of the cut paper Kp reaches the transport roller pair 43, the control unit 8 performs the cutting of the cut paper Kp, just as with roll paper Rp. At this time, the control unit 8 moves the carriage 6a to the starting position, just as in S3.

[0077] Next, in S11, the control unit 8 performs image recording processing. That is, the control unit 8 performs one pass in which ink droplets are ejected from the nozzle while moving the carriage 6a from the starting position.

[0078] Next, in S12, the control unit 8 determines whether or not image recording on the cut paper Kp based on the recording command has been completed. If image recording on the cut paper Kp has not been completed (S12: NO), the process proceeds to S13 and the transport process is executed.

[0079] Next, in S13, the control unit 8 performs the same processing as the transport process in S9 described above. After this, it returns to S11, and the control unit 8 performs the processes in S11 and S12 again. Meanwhile, when image recording on the cut paper Kp is completed (S12: YES), the cut paper Kp on which the image has been recorded is ejected, and the flow ends. At this time, if flags G, K, Q, transport counts M1, M2, and cumulative transport amounts Z1 to Z3 are stored in the flash memory 85, the control unit 8 erases them from the flash memory 85.

[0080] As described above, according to the printer 100 of this embodiment, transport processing (first transport processing) is performed in S9 or S13 with a transport amount X1, and after the image recording processing in S4 or S11, it is possible to perform divided transport processing in the transport processing in S9 or S13. By performing divided transport processing at an appropriate timing in this way, it is possible to suppress the time required to transport the paper P. In other words, it is not necessary to perform transport processing with a transport amount smaller than the transport amount X1 and smaller than the distance L2 from the beginning, and it is possible to suppress the time until image recording for one sheet of paper P is completed.

[0081] Furthermore, when any of the transports in the divided transport process is completed, the trailing end of the paper P (the upstream end in the transport direction) is located between the downstream detection position by the paper sensor 52 and the nip position by the transport roller pair 43. In other words, the trailing end of the paper P, which is upstream of the downstream detection position, will not pass through the nip position in a single transport. Therefore, it becomes possible to transport the paper P with a transport amount X3 or X5 (third transport amount) from the state where the trailing end of the paper P is between the downstream detection position and the nip position. In other words, by transporting with a transport amount X1 that is greater than the distance L2 between the downstream detection position and the nip position, it becomes possible to correct the transport amount during the period corresponding to the time when the trailing end of the paper P passes through the downstream detection position and the nip position in one go and the transport is completed. Consequently, the effect of extrusion on image recording after the divided transport process can be suppressed, and the decrease in image recording accuracy can be suppressed.

[0082] The transport volume X2 is the value obtained by dividing the transport volume X1 by the number of divided transports n. This makes it easier to derive the transport volume X2 in a single divided transport, simplifying control.

[0083] When proceeding from S218 to S219, the trailing edge of the paper P due to the split transport process passes the nip position of the transport roller pair 43. In this case, the transport amount is corrected to X3 in S219, so the effect of extrusion on image recording after the split transport process can be effectively suppressed.

[0084] The total transport volume in the split transport process (the total transport volume up to the point when a transport with flag K or G set occurs) is smaller than the transport volume X1 because it includes the split transport with the transport volume corrected. As a result, even if the transport volume increases due to the paper P being pushed out by the transport roller pair 43, the actual total transport volume in the split transport process does not significantly exceed the transport volume X1 and is even closer to the transport volume X1.

[0085] The correction of the transport volume in S219 and S223 is based on the transport volume X2, which is obtained by dividing the transport volume X1 by the number of divided transports n. In other words, the sum of the transport volumes X2 in the divided transport process before correction is equal to the transport volume X1. As a result, even if the transport volume increases due to extrusion, the actual total transport volume in the divided transport process does not significantly exceed the transport volume X1 and is even closer to the transport volume X1.

[0086] In S201, if the cumulative transport amount Z1 is greater than or equal to a threshold, that is, after the paper sensor 51 detects the rear end of the paper P, the split transport process can be executed. This makes it possible to determine the position of the rear end of the paper P between the transport process for transport amount X1 and the split transport process. Because the paper sensor 51 is positioned upstream of the paper sensor 52 in the transport direction, it is also possible to determine whether or not the paper P is being transported normally. Furthermore, in this embodiment, the split transport process can be executed after the rear end of the paper P has passed the upstream detection position and the transport process for transport amount X1 has been executed once. This makes it possible to start the split transport after the rear end of the paper P is closer to the paper sensor 52. Consequently, by not making the number of split transports too large, it is possible to suppress the time it takes to complete image recording for one sheet of paper P.

[0087] The control unit 8 sets flag K via S219, and if it determines NO in S225, it sets the transport amount to X1 in S226. Also, the control unit 8 sets flag G via S223, and sets the transport amount to X1 in S202. In other words, transport at transport amount X1 is performed after the total transport amount due to the divided transport process reaches a predetermined amount obtained by subtracting the transport amount β extruded from the transport amount X1. This makes it possible to return the transport amount to transport amount X1 relatively soon after the trailing edge of the paper P passes the nip position. Therefore, it is possible to further suppress the length of time until image recording for paper P is completed.

[0088] The control unit 8 executes the image recording process in S4 or S11 after the transport process in S9 or S13 is completed. In other words, the control unit 8 does not execute the image recording process in S4 or S11 during the segmented transport process. This suppresses a decrease in image recording accuracy.

[0089] The control unit 8, by proceeding from S209 to S223, corrects the total transport amount by the remaining transports from the divided transport process while transporting in a single transport. This makes it possible to further suppress the length of time required to complete image recording on one sheet of paper P.

[0090] In S209, the control unit 8 determines whether the cumulative transport amount Z2 has reached the distance L2. This makes it possible to accurately determine whether the trailing edge of the paper P has passed the transport roller pair 43.

[0091] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible as long as they are within the scope of the claims. For example, in the above embodiment, the transport roller pair 43 is configured such that the driven roller 43b is biased to the drive roller 43a by a biasing member 43c, but the biasing member 43c may not be provided if at least one surface of the drive roller 43a and the driven roller 43b is elastic and capable of gripping the paper P.

[0092] In the embodiment shown in Figure 6(a), the transport amount during divided transport when the transport count M2 is 1 to 4 is X3, and then the transport amount X4 is transported all at once. The sum of the correction amount for each divided transport when corrected to the transport amount X3 and the correction amount when corrected to the transport amount X4 is equal to the extruded transport amount β. In this way, when the total correction amount during divided transport is equal to the extruded transport amount β, the correction amounts during divided transport when the transport count M1 is 1 to 4 may be different from each other. Alternatively, divided transport may be performed with a transport amount obtained by subtracting the transport amount β from the transport amount in the first divided transport after the trailing edge of the paper P has passed the downstream detection position. Also, in S223, the transport amount correction may not be performed, and the transport amount X2 may be corrected only in S219.

[0093] In the above embodiment, the image recording process S4 or S11 is executed after the division transport process is completed, but the image recording process may be executed each time a division transport is performed.

[0094] In the above embodiment, the printer 100 is capable of selectively transporting roll paper Rp and cut paper Kp, but it may also be a printer capable of transporting only one of them. Furthermore, if the printer 100 is capable of transporting only cut paper Kp, the roll storage section 20 and the cutting section 4 may not be provided.

[0095] Furthermore, the paper sensor 51 does not need to be provided. Also, the paper sensor 51 may be placed anywhere as long as the distance between the upstream detection position and the downstream detection position is greater than the distance corresponding to the transport amount X1.

[0096] Furthermore, the present invention can be applied not only to inkjet printers, but also to electrophotographic printers equipped with a laser-type image forming unit that forms an electrostatic latent image by exposing a photoreceptor with a laser, and an LED-type image forming unit that forms an electrostatic latent image by exposing a photoreceptor with an LED. In addition, the sheet-like medium is not limited to paper, but may be cloth, plastic film, or other materials as long as it is in sheet form. [Explanation of Symbols]

[0097] 3. Conveying section 5. Inkjet head (recording unit) 8 Control Unit 43. Conveyor roller pair (a pair of conveyor rollers) 51 Paper sensor (second sensor) 52 Paper sensor (first sensor) 100 Printers (image recording devices)

Claims

1. A conveying unit that includes a pair of conveying rollers that rotate while gripping a sheet-like medium, and conveys the sheet-like medium in the conveying direction, A recording unit is positioned downstream of the pair of conveying rollers in the conveying direction and records an image on a sheet-like medium, A first sensor is positioned upstream of the pair of conveying rollers in the conveying direction and detects a sheet-like medium, It includes a control unit, The control unit, The conveying unit performs a first conveying process in which the sheet-like medium is conveyed by the conveying unit in a first conveying amount that is greater than the distance from the detection position by the first sensor to the position where the sheet-like medium is held by the pair of conveying rollers, A first image recording process in which an image is recorded on a sheet-like medium transported by the first transport process using the recording unit, A divided transport process performed after the first image recording process, wherein the sheet-like medium is transported in multiple portions with a second transport amount smaller than the distance, from before the first sensor detects the upstream end of the sheet-like medium in the transport direction until the upstream end is detected. A correction process that corrects the amount of transported in transport after the first sensor detects the upstream end to a third transport amount that is smaller than the said transport amount, An image recording device characterized in that, after conveyance by the third conveyance amount is performed, a second image recording process is performed in which the recording unit records an image on a sheet-like medium.

2. The image recording device according to claim 1, characterized in that the second transport amount is the value obtained by dividing the first transport amount by n (a natural number of 2 or more), which is the number of divided transports.

3. The control unit, In the aforementioned divided transport process, the multiple transports are continued until at least the upstream end of the sheet-like medium passes the clamping position. The image recording apparatus according to claim 1, characterized in that, in the correction process, the second transport amount in at least one of the transports in the divided transport process is corrected to the third transport amount.

4. The image recording device according to claim 3, characterized in that the total amount of transported material in the divided transport process is smaller than the first transport amount.

5. The image recording device according to claim 3, characterized in that the total amount of transported items in the divided transport process before correction by the correction process is equal to the first transported item.

6. The system further includes a second sensor positioned upstream of the first sensor in the transport direction for detecting a sheet-like medium. The separation distance along the transport direction between the detection position by the first sensor and the detection position by the second sensor is greater than the distance corresponding to the first transport amount. The control unit, The image recording device according to claim 1, characterized in that the second sensor detects the upstream end of the sheet-like medium and then performs the division and transport process.

7. The image recording apparatus according to claim 6, characterized in that the control unit performs the first transport process at least once after the second sensor detects the upstream end of the sheet-like medium, and then performs the divided transport process.

8. The control unit, The image recording device according to claim 3, characterized in that the first transport process is performed after the total transport amount by the divided transport process reaches a predetermined transport amount obtained by subtracting the amount by which the pair of transport rollers push out the sheet-like medium when the upstream end of the sheet-like medium passes the clamping position from the first transport amount.

9. The control unit, The image recording device according to claim 1, characterized in that the second image recording process is not performed during the division transport process.

10. The control unit, The image recording apparatus according to claim 3, characterized in that, in the divided transport process, the total amount of the sheet-like medium transported by the remaining transports among the multiple transports after the upstream end of the sheet-like medium has passed the clamping position is transported in a single transport.

11. The control unit, The image recording device according to claim 3, characterized in that the first sensor determines whether the cumulative amount of transported material since detecting the upstream end of the sheet-like medium has reached a transport amount corresponding to the distance.

Images