JP2021066033A - Inkjet recording apparatus and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress ejection failure of a recording head by flushing a predetermined area even during a recording operation. SOLUTION: A transport means capable of transporting a recording medium in a first direction and a second direction opposite to the first direction, and a discharge port for ejecting ink are provided in an area corresponding to the width of the recording medium to perform a recording operation. With respect to the recording head to be performed and the outside of the area on the recording medium on which the image is recorded by the recording head between the start of the recording operation for recording a predetermined image and the end of the recording operation. It is provided with a preliminary ejection means for pre-discharging ink from the recording head. [Selection diagram] Fig. 6

Description

The present invention relates to an inkjet recording device that ejects ink and records an image, and a control method thereof.

Patent Document 1 discloses an inkjet recording apparatus equipped with a so-called line head in which a discharge port is arranged in a region corresponding to the width of a recording medium. When recording the first image and the second image in this order, after recording the first image, preliminary ejection (flushing) is performed between the first image and the second image to eject ink that does not contribute to recording. As a result, it is possible to suppress discharge defects such as clogging of the discharge port.

Japanese Unexamined Patent Publication No. 2012-166450

However, during recording of one image, recording is performed for various reasons such as delay in transferring image data, running out of ink, and the cover of the recording device that should have been closed during recording was opened during recording. May be interrupted. Therefore, as in Patent Document 1, there is a case where the discharge defect of the discharge port cannot be sufficiently suppressed when the interruption time is long or the like only by the so-called pre-recording preliminary discharge before recording one image.

The present invention has been made in view of the above problems, and provides an inkjet recording apparatus capable of suppressing ejection defects of a recording head by performing preliminary ejection to a predetermined region even during a recording operation. The purpose.

In order to solve the above problems, the inkjet recording apparatus according to the present invention has a transport means capable of transporting a recording medium in a first direction and a second direction opposite to the first direction, and a discharge port for ejecting ink. A recording head provided in an area corresponding to the width of the medium and performing a recording operation, and a recording head on the recording medium between the start of the recording operation for recording a predetermined image and the end of the recording operation. The recording head is provided with a preliminary ejection means for pre-discharging the ink from the recording head to the outside of the area where the image is recorded.

According to the present invention, it is possible to provide an inkjet recording apparatus capable of suppressing ejection defects of a recording head by performing preliminary ejection to a predetermined region even during a recording operation.

It is a schematic cross-sectional view of the inkjet recording apparatus which concerns on 1st Embodiment. It is a figure explaining the recording head of the inkjet recording apparatus which concerns on 1st Embodiment. It is a block diagram explaining the control system of the inkjet recording apparatus which concerns on 1st Embodiment. It is explanatory drawing of the multipath recording system using the recording head which concerns on 1st Embodiment. It is explanatory drawing of the multipath recording system using the recording head which concerns on 1st Embodiment. It is a top surface schematic view which shows the periphery of the recording head during the recording operation which concerns on 1st Embodiment. It is a table which shows the time interval which performs flushing according to the temperature and humidity which concerns on 1st Embodiment, and the number of discharges per nozzle. It is a top surface schematic view which shows the periphery of the recording head during the recording operation which concerns on 3rd Embodiment. It is a top surface schematic view which shows the periphery of the recording head during the recording operation which concerns on 5th Embodiment. It is a top surface schematic view which shows the periphery of the recording head during the recording operation which concerns on 6th Embodiment. It is a top surface schematic view which shows the periphery of the recording head during the recording operation which concerns on 7th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments do not limit the present invention, and not all combinations of features described in the present embodiment are essential to the means for solving the present invention. In addition, the relative arrangement, shape, and the like of the components described in the embodiments are merely examples, and the scope of the present invention is not limited to them.

In the present specification, "ink" is used as a general term for liquids such as recording liquids. Further, in the present specification, the term "record" includes not only a record for a two-dimensional object but also a record for a three-dimensional object. In the present specification, the "recording medium" is a medium that discharges a liquid, and is used as a general term for recording media such as paper, cloth, plastic film, metal plate, glass, ceramics, wood, and leather. Further, the recording medium is not limited to sheet-shaped continuous paper, but also includes cut paper. Further, the term "nozzle" is used as a general term for the ejection port, the liquid passage communicating with the ejection port, and the element for generating energy used for ink ejection, unless otherwise specified.

[First Embodiment]
FIG. 1 is a cross-sectional view schematically showing a main part of the inkjet recording device (hereinafter, recording device) 1 of the present embodiment. The recording device 1 records an image on the recording medium 4 using the recording head 2 while transporting the sheet-shaped recording medium 4 in the transport direction indicated by the arrow X. A platen 12 that supports the back surface of the recording medium 4 is arranged at a position facing the recording head 2.

The recording device 1 includes a recording medium holder 8 that holds a recording medium 4 such as continuous paper wound in a roll shape, a recording medium shaft 11 that supports the recording medium 4, and a transfer roller (conveyance) that conveys the recording medium 4 in the transfer direction. Means) 7 is provided. Further, the recording device 1 includes a recording unit 3 that records an image on the recording medium 4 using the recording head 2.

The recording unit 3 includes a head holder 5 that holds the recording head 2, and the head holder 5 of the present embodiment has four color inks of C (cyan), M (magenta), Y (yellow), and K (black). The four recording heads 2 capable of ejecting the ink are integrally held. The ink of each color is supplied to the corresponding recording head 2 from the ink tank that can be attached to and detached from the recording device 1 via a supply path such as a tube. The head holder 5 is further provided with a temperature / humidity sensor (not shown) capable of measuring the ambient temperature and humidity.

The head holder 5 is provided with a first moving mechanism capable of changing the distance between each recording head 2 and the surface of the recording medium 4 in the Z direction. In this embodiment, the Z direction is the direction of gravity. The first moving mechanism moves the head holder 5 up and down along the head holder operating shaft 13. Further, the head holder 5 is provided with a second moving mechanism for moving the head holder 5 in the Y direction intersecting the transport direction of the recording medium 4. In this embodiment, the Y direction is orthogonal to the X direction, which is the transport direction.

The recording medium shaft 11 is interlocked with the transfer drive unit 10 via a gear, and a back tension is always applied between the transfer roller 7 and the transfer drive unit 10 by the torque limiter of the transfer drive unit 10. When the recording medium 4 is cut paper, a feeding roller for feeding the cut paper is provided upstream of the transport roller 7.

The recording device 1 can convey the recording medium 4 in the X1 direction (first direction) and in the X2 direction (second direction) opposite to the X1 direction by the conveying roller 7. Here, the X1 direction is the direction in which the recording medium 4 is conveyed from the recording medium holder 8 to the recording head 2, and the X2 direction is the direction in which the recording medium 4 is conveyed from the recording head 2 toward the recording medium holder 8. is there. The transport direction in the present embodiment includes both the X1 direction and the X2 direction.

Further, the recording device 1 is provided with a cutter unit for cutting the recording medium 4 and a paper ejection basket for receiving the cut recording medium 4 downstream of the recording unit 3 in the X1 direction (both are not available). Illustrated). The recording medium 4 for which recording has been completed is cut by the cutter unit and loaded in the paper ejection basket.

The detailed configuration of the recording head 2 will be described with reference to FIG. FIG. 2A is a view of the recording head 2 viewed from the upstream in the X1 direction, and FIG. 2B is a bottom view of the recording head 2 viewed from below in the direction of gravity.

As the inkjet method for ejecting ink from the nozzle (ejection port) of the recording head 2, various methods using ejection energy generating elements such as an electric heat conversion element (heater), a piezo element, an electrostatic element, or a MEMS element are used. Can be adopted. The recording head 2 is a so-called full-line type line head in which a nozzle row 42 is formed in a region corresponding to the width of the recording medium 4. The arrangement direction of the nozzle rows 42 of the recording head 2 is the Y direction which intersects (in this example, orthogonal) with the transport direction (X direction). That is, the arrangement direction of the nozzle rows 42 is orthogonal to the transport direction of the recording medium 4.

As shown in FIG. 2B, a nozzle chip 41 is provided on the base substrate 40 of the recording head 2. The nozzle tip 41 has a nozzle surface on which a nozzle row 42 for ejecting ink is formed, and a nozzle substrate in which an ejection energy generating element corresponding to each nozzle is embedded. In the case of this example, the nozzle rows 42 corresponding to the four colors of ink are arranged.

The recording device 1 is further provided with a cleaning unit 6 for cleaning the nozzle surface of the recording head 2 (see FIGS. 1 and 2A). The cleaning unit 6 has a wiper blade 43 that comes into contact with the nozzle surface and moves relative to the nozzle surface to wipe off ink, and a wiper holder 44 that holds the wiper blade 43.

In the present embodiment, the wiper holder 44 is moved in the Y direction by the drive belt 46 while being guided by the shaft 45. As a result, the ink and dust adhering to the nozzle surface of the recording head 2 are wiped off by the wiper blade 43. As described above, the cleaning unit 6 is configured to move along the nozzle surface of the recording head 2 in the Y direction orthogonal to the transport direction by the drive motor.

2 (c) and 2 (d) show a modification of the recording head 2. In the recording head 2 shown in FIG. 2B, one nozzle chip 41 is arranged on one base substrate 40, but as shown in FIG. 2C, one nozzle chip 41 is placed on one base substrate 40. A form in which a plurality of nozzle tips 41 are arranged may be used. Further, as shown in FIG. 2D, a plurality of base substrates 40 may be connected by a support member 48.

FIG. 3 is a block diagram illustrating a control system of the recording device 1. The CPU 501 reads a program that controls the system control of the recording device 1 from the ROM 502 and executes it, and controls the entire system according to the program. The RAM 512 is used as a work area for developing a program. That is, the RAM 512 temporarily stores data and input data required for processing executed by the CPU 501. The CPU 501 also controls the operations of the cleaning unit 6, the transport roller 7, and the like.

Further, the CPU 501 controls the recording operation by the recording head 2 through the drive circuit 507, the binarization circuit 508, and the image processing unit 509. The image processing unit 509 performs predetermined image processing on the input color image data to be recorded.

The image processing unit 509 executes data conversion for mapping the color gamut reproduced by the input image data of each RGB color component into the color gamut reproduced by the recording device 1, for example. Further, the image processing unit 509 performs processing for obtaining color separation data (CMYK component density data) corresponding to the combination of inks that reproduce the colors indicated by each data based on the converted data, and is decomposed into each color. Gradation conversion is performed for each of the color separation data.

The binarization circuit 508 performs halftone processing or the like on the multi-value density image data converted by the image processing unit 509, and then converts it into binary data (bitmap data). The drive circuit 507 ejects ink from the nozzle of the recording head 2 according to the binary data obtained by the binarization circuit 508 and the like.

The defective nozzle complementing unit 510 executes a process of generating complementary data for a nozzle (defective nozzle) in which the ink droplet ejection state is in a defective state. The defective nozzle detection unit 511 detects a defective nozzle among a plurality of nozzles formed on the recording head 2. At that time, the CPU 501 drives the recording head 2 via the drive circuit 507 based on the pattern data read from the ROM 502, and controls the transport roller 7 and the like related to the recording operation, so that the recording medium 4 is defective. Record the pattern for nozzle detection. The defective nozzle is detected by reading the recorded pattern by the defective nozzle detection unit 511.

4 and 5 are explanatory views of a multipath recording method using the recording head 2 which is a line head. First, in the single-pass recording method using a line head, an image is recorded by ejecting ink while conveying the recording medium 4 in the X1 direction. That is, the recording is completed only by one transfer in the X1 direction with respect to the unit area and the accompanying discharge operation. Therefore, in the single-pass recording method, the ejection operation of ejecting ink while conveying the recording medium 4 in the X2 direction is not performed.

On the other hand, in the multipath recording method, an image is recorded by ejecting ink while transporting the recording medium not only in the X1 direction but also in the X2 direction. Therefore, as compared with the single-pass recording method, the multi-pass recording method in which recording is completed by a plurality of times of transportation and the discharge operation accompanying it takes more time.

However, by adopting the multipath recording method, the so-called bleeding phenomenon, in which the inks of each color are mixed with each other and bleed before being absorbed by the recording medium 4, is unlikely to occur. Therefore, especially when the amount of ink applied per unit area is large, the recording image quality can be improved by adopting the multipath recording method.

In FIGS. 4 and 5, as a multipath recording method using a line head, the recording medium is alternately conveyed in the X1 direction and the X2 direction eight times, and the discharge operation is performed accordingly, so that the length in the transfer direction is L. An example of an 8-pass recording method for completing an image of the unit area of is shown. Here, the "pass" indicates a transport operation in one direction. That is, in the 8-pass recording method, the recording medium 4 is reciprocated four times in order to complete the image in the unit area. In the multi-pass recording method, the number of passes is not limited to 8 and may be 2 or more.

4 and 5 show the recording operation from 1 pass to 18 passes when the 8-pass recording method is adopted. FIG. 4 is a diagram that virtually shows the positional relationship between the recording heads 2 and the recording medium 4 as if they were moving relative to each other. Actually, as shown in FIG. 5, the recording head 2 is fixed, and the recording medium 4 moves in the X direction.

In FIG. 4, the unit area shown in white indicates the unit area where recording has not started. Further, the unit area indicated by a dot indicates a unit area in the middle of recording, and the unit area painted in gray indicates a unit area in which recording is completed. On the other hand, in FIG. 5, the numbers shown in each unit area indicate how many times the transfer and discharge operations have been performed for each unit area in each pass.

From the 1st pass to the 6th pass, the recording medium 4 for recording the tip of the image is reciprocally transported (conveyed in the X1 direction and the X2 direction). In the transfer for tip recording from 1 pass to 6 passes, the transfer amount increases as the number of transfers increases. For example, when the unit transport amount of the recording medium 4 is L, the transport amount of 1 pass and 2 pass is L, the transport amount of 3 pass and 4 pass is 2 L, and the transport amount of 5 pass and 6 pass is 3 L. Become.

After 7 passes, the amount of ink conveyed by the recording medium 4 accompanied by the ink ejection operation by the recording head 2 becomes 4 L. That is, the transfer amount of 7 passes and 8 passes is 4 L. At the end of the eight passes, the image of the area A1 which is one unit area is completed.

Here, in FIGS. 4 and 5, the black arrow indicates that the transfer is accompanied by a discharge operation with respect to the corresponding unit region, and is also referred to as a record transfer. On the other hand, the white arrow indicates the transport without the discharge operation for the corresponding unit region, and is also referred to as the empty transport C.

The transport amount of 9 passes is 5 L, but the transport amount of 5 L includes an empty transport C of the transport amount L with respect to the region A1 and a record transport of the transport amount of 4 L. Then, in 10 passes, only the recording transfer of the transfer amount of 4 L is performed. After that, the image of the regions A1, A2, A3 ... Of the recording medium 4 is completed by alternately repeating the transfer of the transfer amount of 5 L in the X1 direction and the transfer of the transfer amount of 4 L in the X2 direction. To.

In the present embodiment, as shown in FIG. 5, a region on the recording medium 4 downstream of the recorded image (region A1) in the X1 direction for ejecting ink that does not contribute to the recording operation. A flushing region (downstream region) FD1 is provided.

FIG. 6 is a schematic top view of the periphery of the recording head 2 during the recording operation as viewed from above. When performing the recording operation, in order to eject ink droplets in a good state, the recording head 2 performs flushing (preliminary ejection) to eject ink that does not contribute to the recording operation. By flushing, thickened ink or the like can be discharged in the vicinity of the nozzle of the recording head 2. In the present embodiment, when the recording head 2 flushes, the recording medium 4 is conveyed by the transfer roller 7 to a position where the downstream flushing area FD1 and the recording head 2 face each other.

The alternate long and short dash line C1 shown in FIG. 6 is a position that is the upper end of the completed image. The alternate long and short dash line C1 is not shown on the actual recording medium and is shown for explanation.

The recording head 2 flushes before the start of the recording operation and during the recording operation. Flushing during the recording operation is performed at predetermined time intervals determined by the properties of the ink used and the temperature / humidity acquired by the temperature / humidity sensor. In the present embodiment, flushing is performed when the elapsed time since the previous flushing exceeds the threshold value, but the trigger for starting time measurement may be set to another recovery operation or the like.

The number of ink droplets to be ejected by one flushing is determined by the properties of the ink and the temperature / humidity acquired by the temperature / humidity sensor. FIG. 7 is a table showing the time interval for performing flushing according to the temperature and humidity and the number of discharges per nozzle.

The flow of recording operation and flushing by the recording head 2 will be described with reference to FIG. When the recording device 1 receives the recording command, it first acquires the temperature and humidity by the temperature / humidity sensor. When the acquired temperature was 23 ° C. and the humidity was 50%, the flushing time interval was 20 seconds, the number of flushing was 10 per nozzle for C and M, and Y, based on the table in FIG. K is set to 8 shots per nozzle.

Before starting the recording operation, the recording medium 4 is first conveyed in the X1 direction toward the position where the recording head 2 and the downstream flushing area FD1 face each other, and is set from the recording head 2 to the downstream flushing area FD1. Flushing of the above conditions is performed. After that, the recording medium 4 is conveyed in the X1 direction as it is, and the recording operation for the area A1 is started. Further, along with the execution of flushing for the downstream flushing region FD1, time measurement by a timer (measuring means) is started.

After that, it is assumed that the recording operation of the 2nd to 5th passes is completed, and when the recording operation of the 6th pass is completed, the timer measurement time of 20 seconds, which is the threshold value, has elapsed. In the sixth pass, the recording transfer for the amount of transfer in the X2 direction is performed for 3 L, and then the recording medium 4 is further conveyed in the X2 direction in order to continuously perform flushing. At the position where the downstream flushing region FD1 and the recording head 2 face each other, the recording head 2 flushes, resets the timer, and starts measuring the elapsed time again.

After that, it is assumed that the recording operation of the 7th to 9th passes is completed and the measurement time of the timer has passed 20 seconds again during the recording operation of the 10th pass. Even in the 10th pass, recording and conveying for a transport amount of 4 L in the X2 direction is performed, but after the recording operation in the 10th pass is completed, the recording medium 4 is continuously conveyed in the X2 direction and flushed downstream from the recording head 2. Flushing is performed toward the region FD1.

After flushing, the timer is reset again to start measuring the elapsed time, and the recording transfer of the 11th pass is started. In this way, flushing according to the elapsed time is performed on the predetermined area of the recording medium 4 until the recording operation of one image is completed.

When the recording operation of one image is completed, the recording medium 4 is conveyed to the position where the alternate long and short dash line C1 shown in FIG. 6 and the cutter unit face each other, and the cutter unit cuts the recording medium 4 at the position of the alternate long and short dash line C1. The alternate long and short dash line C1 is the front end of the image in the X1 direction, and the rear end of the image in the X1 direction is also cut by the cutter unit in the same manner to complete one image.

As described above, it is possible to reliably suppress the ejection failure of the recording head by flushing the area outside the area where the image is recorded while the recording operation is being performed on the recording medium.

[Second Embodiment]
In the second embodiment, for example, due to a delay in transferring image data, the image data of the fifth pass is not prepared even at the timing after the recording operation of the fourth pass is completed, and the recording operation of the fifth pass is performed. Will be described when cannot be started. In that case, the recording operation is interrupted due to waiting for the transfer of image data without starting the recording operation of the fifth pass.

If the measurement time elapses 20 seconds while the recording operation is interrupted, the transport roller 7 conveys the recording medium 4 to a position where the recording head 2 and the downstream flushing region FD1 face each other, and the recording medium 4 is conveyed from the recording head 2. Flushing is performed on the downstream flushing region FD1. After that, the timer is reset and the measurement of the elapsed time is started again.

When the transfer of the image data progresses and the image data of the 5th pass is prepared, the recording medium 4 is conveyed to the recording start position of the 5th pass, and the recording operation of the 5th pass is started.

As described above, even when the recording operation is interrupted due to the transfer delay of the image data or the like, the ejection failure of the recording head 2 can be suppressed by performing the flushing at a predetermined time interval.

[Third Embodiment]
FIG. 8 is a schematic top view of the periphery of the recording head 2 during the recording operation in the third embodiment as viewed from above. The rectangle surrounded by the dotted line P indicates the size of the image for one page recorded by the recording head 2. The alternate long and short dash line C2 is the lower position of the completed image. The alternate long and short dash line C2 is not shown on the actual recording medium and is shown for explanation.

Further, in the recording medium 4, an upstream flushing region (upstream region) FU1 is provided upstream from the alternate long and short dash line C2 in the X1 direction. As a result, in the third embodiment, which of the downstream flushing region FD1 and the upstream flushing region FU1 is flushed is selected according to the path.

As shown in FIG. 5, the recording medium 4 is conveyed in the X1 direction in the first pass, and the recording medium 4 is conveyed in the X2 direction in the next second pass. Since this is repeated in the third and subsequent passes, the recording medium 4 is conveyed in the X1 direction in the odd-numbered passes, and the recording medium 4 is conveyed in the X2 direction in the even-numbered passes.

Further, the recording head 2 flushes before the start of the recording operation and during the recording operation, as in the first embodiment. Further, the flushing condition is also determined by the temperature / humidity acquired by the temperature / humidity sensor as in the first embodiment.

When the recording device 1 receives the recording command, the recording operation of the first pass is started after flushing the downstream flushing area FD1 as in the first embodiment. When the timer measurement time elapses 20 seconds during the subsequent recording operation, flushing is performed in the upstream flushing area FU1 after the odd-numbered path recording operation and before the start of the even-numbered path recording operation. Since the recording medium 4 is conveyed in the X1 direction in the odd-numbered pass, flushing can be performed without changing the conveying direction of the recording medium 4 by selecting the upstream flushing area FU1.

After the flushing in the upstream flushing region D1 is completed, the recording medium 4 can be conveyed to the recording start position in the next even-numbered pass by reversing the conveying direction in the X2 direction.

On the other hand, after the even-numbered path recording operation and before the odd-numbered path recording operation starts, flushing is performed in the downstream flushing area FD1. Since the recording medium 4 is conveyed in the X2 direction in the even-numbered pass, flushing can be performed without changing the conveying direction of the recording medium 4 by selecting the downstream flushing area FD1.

After the flushing in the downstream flushing region FD1 is completed, the recording medium 4 can be conveyed to the recording start position in the next odd-numbered pass by reversing the conveying direction in the X1 direction.

In this way, in the flushing performed during the recording operation, the flushing area is selected based on whether it is after the recording operation of the even-numbered path or after the recording operation of the odd-numbered path. As a result, the number of times of reversal of the transport direction for flushing can be reduced, and the throughput can be improved while suppressing the ejection failure during the recording operation.

[Fourth Embodiment]
In the fourth embodiment, the downstream flushing region FD1 and the upstream flushing region FU1 are provided as in the third embodiment. In the fourth embodiment, when the timer measurement time elapses 20 seconds, the flushing area is selected based on the distance between the recording head 2 and the area facing the recording head 2.

For example, when the timer measurement time elapses 20 seconds after the end of the recording operation of the 10th pass, flushing is executed by selecting a flushing area having a short distance from the recording end position of the 10th pass.

As a result, the amount of the recording medium 4 transported for flushing can be reduced, and the throughput can be improved while suppressing ejection defects during the recording operation. The third embodiment and the fourth embodiment may be combined in consideration of the transport direction at the end of the recording operation.

[Fifth Embodiment]
In the fifth embodiment, as in the third and fourth embodiments, the downstream flushing region FD1 and the upstream flushing region FU1 are provided. Then, in the fifth embodiment, it is controlled to select the flushing region having the shorter transport time for flushing. This will be described with reference to FIG.

FIG. 9 is a schematic cross-sectional view of the periphery of the recording head 2 during the recording operation as viewed from the side. As shown in FIG. 9, it is assumed that the transport direction of the recording medium 4 on the Nth pass is the X1 direction, and the transport direction on the N + 1th pass is the X2 direction. Then, a case where the measurement time of the timer elapses during the recording operation of the Nth pass and it is determined to perform flushing after the recording operation of the Nth pass is completed will be described.

In this case, the recording end position (position shown in FIG. 9) of the Nth pass is closer to the upstream flushing area FU1 than to the downstream flushing area FD1. Here, when the recording medium 4 is conveyed so that the upstream flushing region FU1 faces the recording head 2 as shown by the broken line (a), it is necessary to reverse the conveying direction. Since the reversal of the transport direction includes the steps of decelerating, stopping, and accelerating the transport speed, a predetermined time is required. Therefore, it takes, for example, 1.2 seconds for the upstream flushing region FU1 to be conveyed to a position facing the recording head 2.

Although the downstream flushing region FD1 is far from the recording end position of the Nth pass, it is not necessary to reverse the transport direction as shown by the broken line (b). Therefore, although the transport amount is long, since the transport direction is not reversed, the flushing region FD1 on the downstream side can be transported to the position facing the recording head 2 in, for example, 0.7 seconds.

Therefore, it is calculated which flushing region is selected to shorten the transport time according to the relative positional relationship between the recording medium 4 and the recording head 2 at the timing of performing flushing, and the flushing region is determined based on the calculation result. select. As a result, the transport time for flushing can be further shortened.

Since the transfer of the recording medium 4 for flushing does not involve the ejection of ink by the recording head 2, the transfer speed may be faster than the recording transfer accompanied by the recording operation. As a result, the transport time of the recording medium 4 for flushing can be further shortened.

[Sixth Embodiment]
In the sixth embodiment, the recording medium 4 is not cut each time one (one page) image is recorded, and the recording medium 4 is cut in another step after recording a plurality of (page) images. To explain. Generally, the recording medium 4 has a limit on the amount of ink that can be received per unit area, and when the ink lands in excess of the acceptable amount, the unacceptable ink stains the inside of the recording device 1 and the user's hands. There is a risk. Further, when the recording medium 4 is placed at an angle with respect to the horizontal direction, unacceptable ink may flow on the recording medium 4 and stain the recorded image.

Therefore, an upper limit value of the amount of ink flushed by the recording head 2 is set for the downstream flushing region FD1. In the present embodiment, the upper limit is 68.4 ng per area of a square having a side length of 1/600 inch.

Also in the sixth embodiment, as in the third to fifth embodiments, the downstream flushing region FD1 and the upstream flushing region FU1 are provided. Then, for example, when the amount of ink landed on the downstream flushing area FD1 exceeds the upper limit value, the area for subsequent flushing is changed. The amount of ink landed by flushing is calculated from the amount of ink droplets ejected by one flushing and the number of times of flushing.

FIG. 10 is a schematic top view of the periphery of the recording head 2 during the recording operation in the sixth embodiment as viewed from above. The rectangle surrounded by the dotted line (image P1) indicates the size of the image to be recorded by the recording head 2. Further, in the present embodiment, since the recording medium 4 is cut in a separate step after recording a plurality of images, the image P0 whose recording is completed before the image P1 has not been cut yet.

Therefore, when the amount of ink landed on the downstream flushing area FD1 during the recording operation of the image P1 exceeds the upper limit value, the downstream flushing area FD2 flushed during the recording operation of the image P0 is flushed. Change to.

If the amount of ink landed on the upstream flushing area FU1 exceeds the upper limit value during the recording operation of the image P1, a new upstream flushing area FU2 is provided further upstream in the X1 direction with respect to the area. Change to flush.

In this way, the amount of ink that has landed is measured for each flushing area, and when the upper limit is exceeded, the flushing location is changed to another flushing area. As a result, it is possible to prevent the inside of the recording device 1 from being contaminated.

[7th Embodiment]
In the seventh embodiment, unlike the first to sixth embodiments, the case where the present invention is adopted in the single-pass recording method using the line head will be described. Since it is a single-pass recording system, ink is ejected from the recording head 2 while conveying the recording medium 4 in the X1 direction to complete the image. In the case of the single-pass recording method, flushing is usually performed on the recording medium 4 before the start of the recording operation and outside the area where the image is recorded.

FIG. 11 is a schematic top view of the periphery of the recording head 2 during the recording operation in the seventh embodiment as viewed from above. The flushing area F is an area that has been flushed before starting the recording operation of the image Print 1 for which recording has already been completed. Then, flushing is not performed before the start of the recording operation of the image Print 2, and flushing is performed on the downstream flushing region FD1 before the start of the recording operation of the image Print 3. The dotted line P in FIG. 11 is an image P to be recorded from now on, and is a part of the image Print 3.

As shown in FIG. 11, it is assumed that the recording device 1 detects an abnormality during the recording operation of the image Print 3. For example, there is a case where it is detected that the cover covering the recording head 2 is opened by the user so that the user does not touch the recording head 2 during the recording operation.

The recording device 1 interrupts the recording operation according to the type of detected abnormality. If the cover is opened as in this example, the recording operation is interrupted. Then, when the elapsed time from interrupting the recording operation exceeds 5 seconds, the recording device 1 conveys the recording medium 4 and flushes the downstream flushing area FD1 or the upstream flushing area FU1. .. The upstream flushing region FU1 is outside the image P to be recorded, and is provided upstream of the image P in the X1 direction in the present embodiment.

Further, in the present embodiment, the flushing is performed by selecting the one having the shorter transport distance from the position where the recording operation is interrupted (the area facing the recording head 2) from the downstream flushing area FD1 and the upstream flushing area FU1. Do. The flushing in this embodiment is performed once every 7 seconds. When the recording device 1 no longer detects an abnormality (for example, when it detects that the cover is closed), the recording medium 4 is conveyed to the position where the recording operation is interrupted and the recording operation is restarted.

In this way, even if the recording operation is interrupted by the abnormality detection of the recording device 1, the ejection state of the nozzle of the recording head 2 can be kept good by appropriately flushing during the interruption. This makes it possible to complete the image without discarding the image recorded halfway due to the interruption of the recording operation.

In the present embodiment, when the recording operation is interrupted, a configuration in which flushing is performed for one image from the start to the end of the recording operation has been described, but the area where the image on the recording medium 4 is recorded is recorded. It can also be used in a configuration in which flushing is performed by superimposing on an image. When flushing over an image, flush with a small amount of ink so as not to stain the image.

Generally, when the recording operation is interrupted, the nozzle of the recording head 2 is left in contact with air, so that the ink in the nozzle is thickened and ejection failure occurs. Therefore, flushing when the recording operation is interrupted cannot maintain the ejection state with an amount of ink that does not stain the image. On the other hand, by flushing the outside of the area where the image is recorded on the recording medium 4 at an appropriate timing as in the present embodiment, the ejection failure of the nozzle is suppressed and the image is contaminated. Can also be suppressed.

Further, the flushing is not limited to the recording medium 4, and may be performed on the platen 12 that supports the recording medium 4. When flushing the platen 12, the recording medium 4 is conveyed in the X2 direction so that it does not exist in the region facing the recording head 2. In addition, it is preferable to arrange an absorber or the like on the platen 12 so that the ink can be received by the platen 12. As a result, even when a sufficient flushing area cannot be secured on the recording medium 4, ejection defects due to clogging of the nozzles of the recording head 2 can be suppressed.

1 Inkjet recording device 2 Recording head 4 Recording medium 7 Conveying roller (conveying means)

Claims (19)

A transport means capable of transporting the recording medium in the first direction and the second direction opposite to the first direction,
A recording head in which an ejection port for ejecting ink is provided in an area corresponding to the width of the recording medium and performs a recording operation.
Between the start of the recording operation for recording a predetermined image and the end of the recording operation, the recording is performed on the recording medium outside the area where the image is recorded by the recording head. An inkjet recording apparatus including a preliminary ejection means for pre-discharging ink from a head. A transport means capable of transporting the recording medium in the first direction and the second direction opposite to the first direction,
A recording head that is provided downstream of the transport means in the first direction and has an ink ejection port provided in a region corresponding to the width of the recording medium to perform a recording operation.
A first recording transfer in which the recording medium is conveyed to the transfer means in the first direction while ejecting ink to the recording head, and a second recording transfer to the transfer means while ejecting ink to the recording head. A control means for completing an image of a unit region having a predetermined length in the first direction by alternately performing a second recording transfer in the direction at least once.
An image on the recording medium and by the recording head between the start of the recording operation for recording a predetermined image composed of the images of at least one unit region and the end of the recording operation. An inkjet recording apparatus comprising: a preliminary ejection means for pre-discharging ink from the recording head to the outside of a region where an image is recorded. The inkjet recording apparatus according to claim 1 or 2, wherein the preliminary ejection means ejects preliminary ejection to an upstream region upstream of the predetermined image in the first direction. The inkjet recording apparatus according to claim 3, wherein the preliminary ejection means ejects preliminary ejection to a downstream region downstream of the predetermined image in the first direction. Further equipped with a measuring means to measure the elapsed time from the previous preliminary discharge,
When the elapsed time exceeds the threshold value, the preliminary discharge means is a region of the upstream region and the downstream region of the recording medium facing the recording head when the elapsed time exceeds the threshold value. The inkjet recording apparatus according to claim 4, wherein the pre-discharge is performed to a side closer to the image. Further equipped with a measuring means to measure the elapsed time from the previous preliminary discharge,
When the elapsed time exceeds the threshold value, the preliminary discharge means is a region of the upstream region and the downstream region of the recording medium facing the recording head when the elapsed time exceeds the threshold value. The inkjet recording apparatus according to claim 4, wherein the pre-discharge is performed on the side having the shorter transport time. Further equipped with a measuring means to measure the elapsed time from the previous preliminary discharge,
The inkjet recording according to any one of claims 1 to 6, wherein the preliminary ejection means performs preliminary ejection when the recording operation is interrupted and the elapsed time exceeds a threshold value. apparatus. Further equipped with a measuring means to measure the elapsed time from the previous preliminary discharge,
When the elapsed time exceeds the threshold value during the first recording transport, the preliminary discharge means pre-discharges the elapsed time to the upstream region upstream of the predetermined image in the first direction, and the second recording transport. The inkjet recording apparatus according to claim 2, wherein when the elapsed time exceeds the threshold value, a preliminary discharge is performed in a downstream region downstream of the predetermined image in the first direction. With an acquisition means to acquire at least one of temperature and humidity,
The inkjet recording apparatus according to any one of claims 5 to 8, wherein the threshold value is determined based on a value acquired by the acquisition means. The inkjet recording apparatus according to claim 9, wherein the preliminary ejection means determines the number of shots of ink to be ejected in one preliminary ejection based on a value acquired by the acquisition means. The preparatory ejection means according to any one of claims 3 to 10, wherein when the amount of ink ejected to the upstream region exceeds the second threshold value, the preparatory ejection means thereafter performs the preliminary ejection to the downstream region. The inkjet recording apparatus according to item 1. When the amount of ink ejected to the upstream region exceeds the second threshold value, the preliminary ejection means causes the subsequent preliminary ejection to the second upstream region upstream of the upstream region in the first direction. 11. The inkjet recording apparatus according to claim 11. The preparatory ejection means according to any one of claims 3 to 10, wherein when the amount of ink ejected to the downstream region exceeds the third threshold value, the preparatory ejection means thereafter performs the preliminary ejection to the upstream region. The inkjet recording apparatus according to item 1. The inkjet recording apparatus according to any one of claims 1 to 13, wherein the predetermined image is an image for one page of the recording medium. A transport means capable of transporting the recording medium in the first direction and the second direction opposite to the first direction,
A recording head in which an ejection port for ejecting ink is provided in an area corresponding to the width of the recording medium and performs a recording operation.
During the period from the start of the recording operation for recording a predetermined image to the end of the recording operation, the ink is preliminarily ejected from the recording head to the outside of the area where the image is recorded by the recording head. An inkjet recording apparatus including a preliminary ejection means. A transport means capable of transporting the recording medium in the first direction and the second direction opposite to the first direction,
A recording head that is provided downstream of the transport means in the first direction and has an ink ejection port provided in a region corresponding to the width of the recording medium to perform a recording operation.
A first recording transfer in which the recording medium is conveyed to the transfer means in the first direction while ejecting ink to the recording head, and a second recording transfer to the transfer means while ejecting ink to the recording head. A control means for completing an image of a unit region having a predetermined length in the first direction by alternately performing a second recording transfer in the direction at least once.
The outside of the area where the image is recorded by the recording head between the start of the recording operation for recording a predetermined image composed of the images of at least one unit area and the end of the recording operation. An inkjet recording apparatus comprising: a preliminary ejection means for pre-discharging ink from the recording head. A platen arranged at a position facing the recording head and supporting the recording medium is provided.
The inkjet recording apparatus according to claim 15, wherein the pre-discharge means is pre-discharged to the platen. A transport means capable of transporting a recording medium in a second direction opposite to the first direction, and a recording head in which an ejection port for ejecting ink is provided in an area corresponding to the width of the recording medium to perform a recording operation. This is a control method for the inkjet recording device provided.
Between the start of the recording operation for recording a predetermined image and the end of the recording operation, the recording is performed on the recording medium outside the area where the image is recorded by the recording head. A control method comprising a pre-discharge step of pre-discharge ink from a head. The width of the recording medium is a transport means capable of transporting the recording medium in the first direction and the second direction opposite to the first direction, and a discharge port provided downstream of the transport means in the first direction and ejecting ink. It is a control method of an inkjet recording apparatus including a recording head provided in an area corresponding to the above and performing a recording operation.
A first recording transfer in which the recording medium is conveyed to the transfer means in the first direction while ejecting ink to the recording head, and a second recording transfer to the transfer means while ejecting ink to the recording head. A control step of completing an image of a unit region having a predetermined length in the first direction by alternately performing a second recording transfer in the direction at least once.
An image on the recording medium and by the recording head between the start of the recording operation for recording a predetermined image composed of the images of at least one unit region and the end of the recording operation. A control method comprising: a preliminary ejection step of pre-discharging ink from the recording head to the outside of a region where is recorded.

Images