WO2021070856A1

WO2021070856A1 - Inkjet recording device

Info

Publication number: WO2021070856A1
Application number: PCT/JP2020/037975
Authority: WO
Inventors: 丸田　正晃
Original assignee: 京セラドキュメントソリューションズ株式会社
Priority date: 2019-10-11
Filing date: 2020-10-07
Publication date: 2021-04-15
Also published as: JPWO2021070856A1

Abstract

This inkjet recording device (100) comprises a control unit (110) that causes recording heads (17a-17c) to execute flushing to discharge ink at a timing differing from the timing for contributing to image formation on a recording medium (P). A conveying belt (8) has, in the conveying direction of the recording medium (P), a plurality of opening groups (82) in which openings (80) for passing the ink discharged from nozzles (18) of the recording heads (17a-17c) during the flushing are aligned in a belt width direction perpendicular to the conveying direction of the recording medium (P). The control unit (110) determines, in accordance with the size of the recording medium (P), the pattern of the plurality of opening groups (82) used during the flushing in one cycle of the conveying belt (8), and causes the recording heads (17a-17c) to execute the flushing at the timing at which the opening groups (82) positioned in the pattern face the recording heads (17a-17c) due to the travel of the conveying belt (8).

Description

Inkjet recording device

The present invention relates to an inkjet recording device that discharges ink onto a recording medium and records an image.

Conventionally, in an inkjet recording device such as an inkjet printer, flushing (empty ejection) in which ink is periodically ejected from the nozzle is performed in order to reduce or prevent clogging of the nozzle due to drying of the ink. For example, in the inkjet recording apparatus described in Patent Documents 1 and 2, an opening is provided in the transport belt, and a recording medium is placed on the transport belt so as not to cover the opening for transport, and the opening is opened by running the transport belt. When the position facing the recording head is reached, ink is ejected from the nozzle of the recording head to perform flushing. An ink absorber such as a sponge is arranged on the side opposite to the recording head (inner peripheral surface side) with respect to the transport belt. The ink ejected from the recording head during flushing and passing through the opening is absorbed by the ink absorber.

Further, for example, in the inkjet recording apparatus of Patent Document 3, a plurality of openings are provided in the transport belt in the transport direction of the recording medium, and when the size of the recording medium is large, the transport speed of the recording medium is slowed down to perform flushing. I try to do it. By slowing down the transport speed of the recording medium, the number of rows in the transport direction of the openings located between the recording medium and the recording medium in the transport belt increases, so that the amount of ink ejected during flushing is increased. Discharge defects can be reduced. Further, in Patent Document 4, the position of the opening is recognized based on the detection result of the mark provided on the transport belt, and the ink ejection in flushing is controlled to take into account deformation such as elongation of the transport belt. The ink is allowed to pass through the opening more accurately.

Japanese Unexamined Patent Publication No. 2006-21399 Japanese Unexamined Patent Publication No. 2008-179167 Japanese Unexamined Patent Publication No. 2011-189717 Japanese Unexamined Patent Publication No. 2011-79293

However, in the configurations of Patent Documents 1 and 2, the number of flushing in the same recording head is once in one cycle of the transport belt regardless of the size of the recording medium used, and the frequency of flushing is low. Therefore, regardless of the size of the recording medium, insufficient flushing is likely to occur, which is insufficient in reducing the clogging of the nozzle due to flushing. Further, in a configuration as in Patent Document 3 in which the transport speed of the recording medium is slowed down to eliminate the insufficient flushing, the number of recording media transported in one cycle of the transport belt is reduced due to the decrease in the transport speed, so that the recording medium is recorded. The number of prints, that is, the productivity is reduced. On the other hand, in Patent Document 4, the productivity of the recording medium is not examined at all.

The inkjet recording apparatus according to one aspect of the present invention includes a recording head having a plurality of nozzles for ejecting ink, and an endless transport belt for transporting a recording medium at a position facing the recording head. The recording head is provided with a control unit that causes the recording head to perform flushing to eject the ink at a timing different from the timing that contributes to image formation on the recording medium. The transport belt is a group of openings in which openings for passing the ink discharged from each nozzle of the recording head at the time of flushing are arranged in the belt width direction perpendicular to the transport direction of the recording medium. A plurality of recording media are provided in the transport direction. The control unit determines a pattern of a plurality of the openings used at the time of flushing in one cycle of the transport belt according to the size of the recording medium, and positions the pattern in the pattern by running the transport belt. At the timing when the opening group faces the recording head, the recording head is made to perform the flushing.

According to the above configuration, it is possible to reduce nozzle clogging due to insufficient flushing while avoiding a decrease in the productivity of the recording medium regardless of the size of the recording medium used.

It is explanatory drawing which shows the schematic structure of the printer as the inkjet recording apparatus which concerns on one Embodiment of this invention. It is a top view of the recording part provided in the said printer. It is explanatory drawing which shows typically the structure around the paper transport path from the paper feed cassette of the printer to the 2nd transport unit through the 1st transport unit. It is a block diagram which shows the hardware composition of the main part of the said printer. It is explanatory drawing which shows typically the region where the suction force is different in the said 1st transport unit. It is explanatory drawing which shows one structural example of the 1st transfer unit schematically. It is explanatory drawing which shows typically the other structural example of the said 1st transfer unit. It is a top view which shows one structural example of the 1st transfer belt which the 1st transfer unit has. It is explanatory drawing which shows typically an example of the pattern of the opening group for flushing when the 1st transport belt of FIG. 8 is used, and the paper which is arranged on the 1st transport belt according to the said pattern. is there. It is explanatory drawing which shows the other example of the said pattern and the paper which is arranged on the said 1st transport belt according to the said pattern schematically. It is explanatory drawing which shows still another example of the said pattern, and the paper which is arranged on the said 1st transport belt according to the said pattern. It is explanatory drawing which shows still another example of the said pattern, and the paper which is arranged on the said 1st transport belt according to the said pattern. It is a top view which shows the other structural example of the 1st conveyor belt. It is explanatory drawing which shows typically the example of the said pattern when the 1st transport belt of FIG. 13 is used, and the paper which is arranged on the said 1st transport belt according to the said pattern. It is explanatory drawing which shows the other example of the said pattern and the paper which is arranged on the said 1st transport belt according to the said pattern schematically. It is explanatory drawing which shows still another example of the said pattern, and the paper which is arranged on the said 1st transport belt according to the said pattern. It is explanatory drawing which shows still another example of the said pattern, and the paper which is arranged on the said 1st transport belt according to the said pattern.

The present invention provides an inkjet recording apparatus capable of avoiding a decrease in productivity of a recording medium, avoiding insufficient flushing, and reducing nozzle clogging regardless of the size of the recording medium used.

[1. Inkjet recording device configuration]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a printer 100 as an inkjet recording device according to an embodiment of the present invention. The printer 100 includes a paper feed cassette 2 which is a paper storage unit. The paper feed cassette 2 is arranged below the inside of the printer main body 1. Paper P, which is an example of a recording medium, is housed inside the paper feed cassette 2.

The paper feed device 3 is arranged on the downstream side of the paper feed cassette 2 in the paper transport direction, that is, above the right side of the paper feed cassette 2 in FIG. By the paper feeding device 3, the paper P is separated and sent out one by one toward the upper right side of the paper feed cassette 2 in FIG.

The printer 100 is provided with a first paper transport path 4a inside. The first paper transport path 4a is located on the upper right side of the paper feed cassette 2 in the paper feed direction. The paper P sent out from the paper feed cassette 2 is vertically upwardly conveyed along the side surface of the printer main body 1 by the first paper conveying path 4a.

A resist roller pair 13 is provided at the downstream end of the first paper transport path 4a in the paper transport direction. Further, the first transport unit 5 and the recording unit 9 are arranged in the immediate vicinity of the resist roller pair 13 on the downstream side in the paper transport direction. The paper P sent out from the paper feed cassette 2 reaches the resist roller pair 13 through the first paper transport path 4a. The resist roller pair 13 corrects the oblique feed of the paper P, measures the timing with the ink ejection operation executed by the recording unit 9, and feeds the paper P toward the first transport unit 5.

The paper P fed to the first transport unit 5 is transported by the first transport belt 8 (see FIG. 2) to a position facing the recording unit 9 (particularly, the recording heads 17a to 17c described later). An image is recorded on the paper P by ejecting ink from the recording unit 9 onto the paper P. At this time, the ink ejection in the recording unit 9 is controlled by the control unit 110 inside the printer 100. The control unit 110 is composed of, for example, a CPU (Central Processing Unit).

In the paper transport direction, the second transport unit 12 is arranged on the downstream side (left side in FIG. 1) of the first transport unit 5. The paper P on which the image is recorded by the recording unit 9 is sent to the second transport unit 12. The ink ejected onto the surface of the paper P is dried while passing through the second transport unit 12.

In the paper transport direction, a decaler portion 14 is provided on the downstream side of the second transport unit 12 and near the left side surface of the printer main body 1. The paper P whose ink has been dried by the second transport unit 12 is sent to the decaler unit 14, and the curl generated on the paper P is corrected.

In the paper transport direction, a second paper transport path 4b is provided on the downstream side (upper side of FIG. 1) of the decaler portion 14. When double-sided recording is not performed, the paper P that has passed through the decaler portion 14 passes through the second paper transport path 4b and is discharged to the paper ejection tray 15 provided outside the left side surface of the printer 100.

An inversion transport path 16 for double-sided recording is provided above the recording unit 9 and the second transport unit 12 in the upper part of the printer main body 1. When double-sided recording is performed, the paper P that has passed through the second transport unit 12 and the decaler section 14 after the recording on one side (first side) of the paper P is completed is reversed through the second paper transport path 4b. It is sent to the transport path 16.

The paper P sent to the reverse transport path 16 is subsequently switched in the transport direction for recording on the other side (second side) of the paper P. Then, the paper P passes through the upper part of the printer main body 1 and is fed toward the right side, and is fed to the first transport unit 5 again with the second side facing upward via the resist roller pair 13. In the first transfer unit 5, the paper P is conveyed to a position facing the recording unit 9, and an image is recorded on the second surface by ejecting ink from the recording unit 9. The paper P after double-sided recording is discharged to the paper discharge tray 15 via the second transport unit 12, the decaler section 14, and the second paper transport path 4b in this order.

Further, a maintenance unit 19 and a cap unit 20 are arranged below the second transport unit 12. The maintenance unit 19 moves horizontally below the recording unit 9 when executing purging, wipes the ink extruded from the ink ejection port of the recording head, and collects the wiped ink. Note that purging refers to an operation of forcibly pushing out ink from the ink ejection port of the recording head in order to eject thickened ink, foreign matter, and air bubbles in the ink ejection port. When capping the ink ejection surface of the recording head, the cap unit 20 moves horizontally below the recording unit 9, further moves upward, and is mounted on the lower surface of the recording head.

FIG. 2 is a plan view of the recording unit 9. The recording unit 9 includes a head housing 10 and line heads 11Y, 11M, 11C, and 11K. The line heads 11Y to 11K have a predetermined interval (for example, 1 mm) with respect to the transport surface of the endless first transport belt 8 stretched on a plurality of rollers including the drive roller 6a, the driven roller 6b, and the other rollers 7. ) Is formed in the head housing 10.

The line heads 11Y to 11K each have a plurality of (three in this case) recording heads 17a to 17c. The recording heads 17a to 17c are arranged in a staggered manner along the paper width direction (arrow BB'direction) orthogonal to the paper transport direction (arrow A direction). The recording heads 17a to 17c have a plurality of ink ejection ports 18 (nozzles). The ink ejection ports 18 are arranged side by side at equal intervals in the width direction of the recording head, that is, in the paper width direction (arrow BB'direction). From the line heads 11Y to 11K, inks of each color of yellow (Y), magenta (M), cyan (C), and black (K) are first conveyed through the ink ejection ports 18 of the recording heads 17a to 17c. Each is ejected toward the paper P conveyed by the belt 8.

FIG. 3 schematically shows the configuration around the transport path of the paper P from the paper feed cassette 2 to the second transport unit 12 via the first transport unit 5. Further, FIG. 4 is a block diagram showing a hardware configuration of a main part of the printer 100. In addition to the above configuration, the printer 100 further includes a resist sensor 21, a first paper sensor 22, a second paper sensor 23, and

belt sensors

24 and 25.

The resist sensor 21 detects the paper P that is conveyed from the paper cassette 2 by the paper feeding device 3 and sent to the resist roller pair 13. The control unit 110 can control the rotation start timing of the resist roller pair 13 based on the detection result of the resist sensor 21. For example, the control unit 110 can control the supply timing of the paper P to the first transport belt 8 after the skew (skew) correction by the resist roller pair 13 based on the detection result of the resist sensor 21.

The first paper sensor 22 is a line sensor that detects the position of the paper P sent from the resist roller pair 13 to the first transport belt 8 in the width direction. Based on the detection result of the first paper sensor 22, the control unit 110 inks from the ink ejection port 18 corresponding to the width of the paper P among the ink ejection ports 18 of the recording heads 17a to 17c of the line heads 11Y to 11K. Can be ejected to record an image on paper P.

The second paper sensor 23 is a sensor that detects the position of the paper P transported by the first transport belt 8 in the transport direction. The second paper sensor 23 is located on the upstream side of the recording unit 9 and on the downstream side of the first paper sensor 22 in the paper transport direction. Based on the detection result of the second paper sensor 23, the control unit 110 determines the ink ejection timing for the paper P that reaches the position facing the line heads 11Y to 11K (recording heads 17a to 17c) by the first transport belt 8. Can be controlled.

The

belt sensors

24 and 25 detect the positions of a plurality of opening groups 82 (see FIG. 8) provided on the first conveyor belt 8. That is, the

belt sensors

24 and 25 are detection sensors that detect the passage of at least one of the opening group 82 due to the traveling of the first transport belt 8. The belt sensor 24 is located on the downstream side of the recording unit 9 in the paper transport direction (traveling direction of the first transport belt 8). The belt sensor 25 is located between the driven roller 6b that stretches the first transport belt 8 and the other rollers 7. The driven roller 6b is located on the upstream side of the first transport belt 8 in the traveling direction with respect to the recording unit 9. The belt sensor 24 has the same function as the second paper sensor 23. The control unit 110 can control the resist roller pair 13 so as to supply the paper P to the first conveyor belt 8 at a predetermined timing based on the detection result of the

belt sensor

24 or 25.

Further, the position of the paper is detected by a plurality of sensors (second paper sensor 23, belt sensor 24), and the position of the opening group 82 of the first transport belt 8 is detected by a plurality of sensors (belt sensors 24 and 25). As a result, it is possible to correct the error of the detected position and detect an abnormality.

The above-mentioned first paper sensor 22, second paper sensor 23,

belt sensor

24 and 25 may be composed of a transmissive or reflective optical sensor and a CIS sensor (Contact Image Sensor, close contact image sensor). Further, a mark corresponding to the position of the opening group 82 is formed at the end of the first transport belt 8 in the width direction, and the

belt sensors

24 and 25 detect the mark to form the opening group 82. The position may be detected.

In addition, the printer 100 may be provided with a meandering detection sensor that detects the meandering of the first conveying belt 8, and may be configured to correct the meandering of the first conveying belt 8 based on the detection result.

Further, the printer 100 further includes an operation panel 27, a storage unit 28, and a communication unit 29. The operation panel 27 is an operation unit for receiving various setting inputs by the user. For example, the user can operate the operation panel 27 to input information on the size of the paper P to be set in the paper feed cassette 2, that is, the size of the paper P to be conveyed by the first transfer belt 8. The storage unit 28 is a memory that stores the operation program of the control unit 110 and various information, and is configured to include a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile memory, and the like. There is. The information set by the operation panel 27 (for example, the size information of the paper P) is stored in the storage unit 28. The communication unit 29 is a communication interface for transmitting and receiving information to and from an external device (for example, a personal computer (PC)). For example, when the user operates a PC and sends a print command to the printer 100 together with the image data, the above image data and the print command are input to the printer 100 via the communication unit 29. In the printer 100, the control unit 110 controls the recording heads 17a to 17c based on the image data to eject ink, so that the image can be recorded on the paper P.

Further, as shown in FIG. 3, the printer 100 has

ink receiving portions

31Y, 31M, 31C, and 31K on the inner peripheral surface side of the first transport belt 8. When flushing is executed by the recording heads 17a to 17c, the ink receiving portions 31Y to 31K are discharged from the recording heads 17a to 17c and are discharged from the opening 80 of the opening group 82 described later of the first transport belt 8 (FIG. 8). Ink that has passed through (see) is received and collected. Therefore, the ink receiving portions 31Y to 31K are provided at positions facing the recording heads 17a to 17c of the line heads 11Y to 11K via the first transport belt 8. The ink collected by the ink receiving units 31Y to 31K is sent to, for example, a waste ink tank and discarded, but the ink may be reused without being discarded.

Here, flushing is to eject ink at a timing different from the timing that contributes to image formation (image recording) on the paper P for the purpose of reducing or preventing clogging of the ink ejection port 18 due to ink drying. Say. The execution of flushing in the recording heads 17a to 17c is controlled by the control unit 110.

The above-mentioned second transport unit 12 includes a second transport belt 12a and a dryer 12b. The second transport belt 12a is stretched by two driving rollers 12c and a driven roller 12d. The paper P conveyed by the first transfer unit 5 and whose image is recorded by ink ejection by the recording unit 9 is conveyed by the second transfer belt 12a, dried by the dryer 12b during transfer, and transferred to the decaler unit 14 described above. Be transported.

[2. Details of the first transport unit]
(2-1. Example of configuration of the first transport unit)
In the present embodiment, a negative pressure suction method is adopted as a method for transporting the paper P in the first transport unit 5. The negative pressure suction method is a method in which the paper P is attracted to the first transport belt 8 by negative pressure suction and transported.

Here, as described above, the ink receiving portions 31Y to 31K are provided at positions facing the recording heads 17a to 17c of the line heads 11Y to 11K via the first transport belt 8. When the suction force in the area where the ink receiving portions 31Y to 31K are provided is strong during negative pressure suction, the ink discharged from the recording heads 17a to 17c during flushing momentum the opening 80 of the first transport belt 8. Mist that passes well and collides with the liquid surface of the ink already contained in the ink receiving portions 31Y to 31K and scatters the ink may be generated. When mist is generated, the scattered ink adheres to the inner peripheral surface of the first transport belt 8 and stains the inner peripheral surface. As a result, the surface of the roller on which the first transport belt 8 is stretched may become dirty, causing uneven transport (for example, meandering or slipping) of the first transport belt 8.

Therefore, in the present embodiment, as shown in FIG. 5, the suction force of the region where the ink receiving portions 31Y to 31K are provided, that is, the region facing the line heads 11Y to 11K via the first transport belt 8 is applied. By making the area weaker than the areas on the upstream side and the downstream side in the paper transport direction, the above-mentioned inconvenience caused by mist is reduced. Specifically, regions having different suction forces are generated by the following configurations.

FIG. 6 is an explanatory diagram schematically showing a configuration example of the first transport unit 5. The first suction chambers 51a to 51e and the second suction chambers 52a to 52d are provided on the inner peripheral surface side of the first transport belt 8 of the first transport unit 5. The first suction chambers 51a to 51e and the second suction chambers 52a to 52d are formed in a long shape in the belt width direction of the first transport belt 8. The first suction chambers 51a to 51e and the second suction chambers 52a to 52d are open on the side facing the first transfer belt 8.

The first suction chambers 51a to 51e are provided in this order from the downstream side to the upstream side in the paper transport direction (A direction). The second suction chamber 52a is provided between the first suction chamber 51a and the first suction chamber 51b at positions facing each other via the line head 11Y and the first transport belt 8. The second suction chamber 52b is provided between the first suction chamber 51b and the first suction chamber 51c at a position facing each other via the line head 11M and the first transfer belt 8. The second suction chamber 52c is provided between the first suction chamber 51c and the first suction chamber 51d at a position facing each other via the line head 11C and the first transfer belt 8. The second suction chamber 52d is provided between the first suction chamber 51d and the first suction chamber 51e at a position facing each other via the line head 11K and the first transfer belt 8. The ink receiving portions 31Y to 31K described above are arranged in the second suction chambers 52a to 52d, respectively.

The insides of the first suction chambers 51a to 51e and the second suction chambers 52a to 52d are sucked by the suction member 53. The suction member 53 sucks the paper P onto the first transport belt 8 by negative pressure suction. Such a suction member 53 is composed of, for example, a fan or a compressor. In the present embodiment, the insides of the first suction chamber 51a and the second suction chamber 52a are sucked by the common suction member 53. Further, the inside of the first suction chamber 51b and the second suction chamber 52b is sucked by the common suction member 53. Similarly, the insides of the first suction chamber 51c and the second suction chamber 52c are sucked by the common suction member 53, and the insides of the first suction chamber 51d and the second suction chamber 52d are sucked by the common suction member 53. To. The first suction chamber 51e is independently sucked by the suction member 53.

Filters 54 are arranged in the first suction chambers 51a to 51e, respectively, and filters 55 are arranged in the second suction chambers 52a to 52d, respectively. Therefore, when each suction member 53 is driven, the inside of the first suction chambers 51a to 51e is sucked through the filter 54, and the inside of the second suction chambers 52a to 52d is sucked through the filter 55. As a result, the insides of the first suction chambers 51a to 51e and the second suction chambers 52a to 52d become negative pressure, and the suction holes 8a (see FIG. 8) or the opening group 82 provided in the first transfer belt 8 to be described later are formed. Air is sucked through the sheet P, and the paper P is transported while being attracted to the first transport belt 8.

Here, the filter 54 has a coarser mesh than the filter 55. Therefore, the resistance of the air passing through the filter 54 is lower than the resistance of the air passing through the filter 55. Therefore, when each suction member 53 is driven with the same driving force, the inside of the first suction chambers 51a to 51e is sucked with a relatively strong suction force, and the inside of the second suction chambers 52a to 52d is relatively weak suction. It is sucked by force. Therefore, the speed at which the ink ejected from the recording heads 17a to 17c during flushing passes through the opening 80 of the first transport belt 8 is suppressed, and the ink with the liquid level of the ink accumulated in the ink receiving portions 31Y to 31K is suppressed. It is possible to reduce ink scattering (mist) due to collision. Thereby, the above-mentioned inconvenience caused by the mist can be reduced.

(2-2. Another configuration example of the first transport unit)
FIG. 7 is an explanatory diagram schematically showing another configuration example of the first transport unit 5. In the first transfer unit 5 of FIG. 7, the same filter 54 is arranged in the first suction chambers 51a to 51e and the second suction chambers 52a to 52d shown in FIG. Each of 52a to 52d is configured to be sucked by a separate suction member 53. In such a configuration, the suction force of the second suction chambers 52a to 52d is switched between strong suction and weak suction by switching the driving force of each suction member 53 that sucks the inside of the second suction chambers 52a to 52d. .. The drive of each suction member 53 is controlled by, for example, the control unit 110.

For example, when ink is ejected to the paper P conveyed by the first transfer belt 8 (at the time of image recording), all the suction members 53 that suck the first suction chambers 51a to 51e and the second suction chambers 52a to 52d are sucked. It is driven by the first driving force. On the other hand, at the time of flushing, each suction member 53 that sucks the first suction chambers 51a to 51e is driven by the first driving force, and each suction member 53 that sucks the second suction chambers 52a to 52d is driven by the first driving force. It is driven by a second driving force lower than that. As a result, during image recording, the first suction chambers 51a to 51e and the second suction chambers 52a to 52d are sucked with strong suction to convey the paper P, while at the time of flushing, only the second suction chambers 52a to 52d are weakly sucked. The mist can be reduced. Thereby, the above-mentioned inconvenience caused by the mist can be reduced.

In addition, instead of using the

filter

54 or 55, the diameter (flow path cross-sectional area) of the pipe serving as the flow path of the air sucked from the first suction chambers 51a to 51e and the second suction chambers 52a to 52d is made different. , The suction force may be different between the first suction chambers 51a to 51e and the second suction chambers 52a to 52d.

[3. Details of the first transport belt]
(3-1. Example of configuration of the first transport belt)
Next, the details of the first transport belt 8 of the first transport unit 5 will be described. FIG. 8 is a plan view showing a configuration example of the first transport belt 8. In the present embodiment, as described above, the paper P is conveyed by the negative pressure suction method. Therefore, as shown in the figure, the first transport belt 8 is provided with innumerable suction holes 8a through which the suction air generated by the negative pressure suction of the suction member 53 passes.

The first transport belt 8 is also provided with an opening group 82. The opening group 82 is a set of openings 80 through which ink discharged from each nozzle (ink ejection port 18) of the recording heads 17a to 17c is passed during flushing. The opening area of the opening 80 is larger than the opening area of the suction hole 8a. The first transport belt 8 has a plurality of opening groups 82 in the transport direction (A direction) of the paper P in one cycle, and the present embodiment has six. When the opening groups 82 are distinguished from each other, the six opening groups 82 are referred to as opening groups 82A to 82F from the downstream side in the A direction. The suction hole 8a is located between the opening group 82 and the opening group 82 that are adjacent to each other in the A direction. That is, in the first transport belt 8, the suction hole 8a is not formed in the region overlapping the opening group 82.

The opening group 82 is irregularly located in the A direction in one cycle of the first transport belt 8. That is, in the A direction, the distance between the adjacent opening group 82 and the opening group 82 is not constant but changes (there are at least two types of the above distances). At this time, the maximum distance between the two opening groups 82 adjacent to each other in the A direction (for example, the distance between the opening group 82A and the opening group 82B in FIG. 8) is the minimum printable size (for example, A4 size (horizontal placement)). ) Is longer than the length of the paper P in the A direction when it is placed on the first transport belt 8.

The opening group 82 has an opening row 81. The opening row 81 is configured by arranging a plurality of openings 80 in the belt width direction (paper width direction, BB'direction) orthogonal to the A direction. One opening group 82 has a plurality of opening rows 81 in the A direction, and in the present embodiment, has two rows of opening rows 81. When the two rows of opening rows 81 are distinguished from each other, one is referred to as the opening row 81a and the other is referred to as the opening row 81b.

In one opening group 82, the opening 80 of any opening row 81 (eg, opening row 81a) is in the BB'direction with the opening 80 of the other opening row 81 (eg, opening row 81b). It is positioned so as to be offset and overlap with a part of the opening 80 of another opening row 81 (for example, the opening row 81b) when viewed in the A direction. Further, in each opening row 81, the plurality of openings 80 are located at equal intervals in the BB'direction.

By arranging the plurality of opening rows 81 in the A direction to form one opening group 82 as described above, the width of the opening group 82 in the BB'direction is the BB' direction of the recording heads 17a to 17c. It is larger than the width of. Therefore, the opening group 82 covers the entire ink ejection region of the recording heads 17a to 17c in the BB'direction, and the ink ejected from all the ink ejection ports 18 of the recording heads 17a to 17c during flushing is opened. It passes through any opening 80 of the group 82.

(3-2. About the pattern of the opening group used for flushing)
In the present embodiment, the control unit 110 drives the recording heads 17a to 17c based on the image data transmitted from the outside (for example, a PC) while conveying the paper P using the first conveying belt 8. The image is recorded on the paper P. At that time, clogging of the ink ejection port 18 is reduced or prevented by causing the recording heads 17a to 17c to perform flushing (flushing between papers) between the conveyed paper P and the paper P. ..

Here, in the present embodiment, the control unit 110 uses a pattern (combination) in the A direction of a plurality of opening groups 82 used for flushing in one cycle of the first transport belt 8 to be the size of the paper P to be used. Decide accordingly. The size of the paper P to be used can be recognized by the control unit 110 based on the information stored in the storage unit 28 (the size information of the paper P input by the operation panel 27).

9 to 12 show an example of the above pattern for each sheet P. For example, when the paper P to be used is A4 size (horizontal placement) or letter size (horizontal placement), the control unit 110 selects the pattern of the opening group 82 shown in FIG. That is, the control unit 110 selects the opening

groups

82A, 82C, and 82F as the opening group 82 used for flushing from the six opening groups 82 shown in FIG. When the paper P to be used is A4 size (vertical installation) or letter size (vertical installation), the control unit 110 has the opening group 82 used for flushing out of the six opening groups 82 as shown in FIG. As the

opening groups

82A and 82D are selected. When the paper P to be used is A3 size, B4 size or legal size (all vertically installed), the control unit 110 has an opening group used for flushing out of the six opening groups 82 as shown in FIG. As 82, opening

groups

82A, 82B, 82E are selected. When the paper P to be used has a size of 13 inches × 19.2 inches, as shown in FIG. 12, the control unit 110 selects an opening as the opening group 82 used for flushing from the six opening groups 82.

Groups

82A and 82D are selected. In each drawing, the opening 80 of the opening group 82 belonging to the above pattern is shown in black for convenience.

Then, the control unit 110 causes the recording heads 17a to 17c to perform flushing at the timing when the opening group 82 located in the determined pattern faces the recording heads 17a to 17c by the traveling of the first transport belt 8. Here, the traveling speed of the first transport belt 8 (paper transport speed), the distance between the opening groups 82A to 82E, and the positions of the recording heads 17a to 17c with respect to the first transport belt 8 are all known. Therefore, when the

belt sensor

24 or 25 detects that the reference opening group 82 (for example, the opening group 82A) has passed by the traveling of the first transport belt 8, the opening group 82A is several seconds after the detection time. It can be seen whether or not ~ 82E passes through the position facing the recording heads 17a to 17c. Therefore, the control unit 110 flushes the recording heads 17a to 17c at the timing when the opening group 82 located in the pattern determined above faces the recording heads 17a to 17c based on the detection result of the

belt sensor

24 or 25. Can be executed.

At this time, the control unit 110 passes the ink through the same opening group 82 in each cycle of the first conveyor belt 8 for each class determined according to the size of the paper P based on the detection result by the

belt sensor

24 or 25. The flushing in the recording heads 17a to 17c is controlled so as to do so.

For example, when the paper P to be used is A4 size (horizontal placement) or letter size (horizontal placement) (first class), the control unit 110 has the same opening shown in FIG. 9 in each cycle of the first transport belt 8. Flushing in the recording heads 17a to 17c is controlled so that the ink passes through the

groups

82A, 82C, and 82F. When the paper P to be used is A4 size (vertical installation) or letter size (vertical installation) (second class), the control unit 110 has the same opening group shown in FIG. 10 in each cycle of the first transport belt 8. Flushing in the recording heads 17a to 17c is controlled so that the ink passes through the 82A and 82D. When the paper P to be used is A3 size, B4 size or legal size (all vertically placed) (third class), the control unit 110 has the same opening shown in FIG. 11 in each cycle of the first transport belt 8. Flushing in the recording heads 17a to 17c is controlled so that the ink passes through the

groups

82A, 82B, and 82E. When the paper P to be used has a size of 13 inches × 19.2 inches (fourth class), the control unit 110 uses the

same opening groups

82A and 82D shown in FIG. 12 in each cycle of the first transport belt 8. Flushing in the recording heads 17a to 17c is controlled so that the ink can pass through.

Further, the control unit 110 controls the supply of the paper P to the first transport belt 8 so as to deviate in the A direction from the opening group 82 located in the determined pattern. That is, the control unit 110 supplies the paper P on the first transport belt 8 by the resist roller pair 13 as the recording medium supply unit between the plurality of opening groups 82 arranged in the A direction in the above pattern.

For example, when the paper P to be used is A4 size (horizontal placement) or letter size (horizontal placement), the control unit 110 has an opening group 82A and an opening on the first transport belt 8 as shown in FIG. Two sheets of paper P are arranged between the group 82C and two sheets of paper P are arranged between the opening group 82C and the opening group 82F, and between the opening group 82F and the opening group 82A. The resist roller pair 13 is controlled to supply the paper P to the first transport belt 8 at a predetermined supply timing so that one sheet P is arranged. At this time, the control unit 110 is located on the first transport belt 8 at a position separated by a predetermined distance or more in the A direction (including both the upstream side and the downstream side) from the opening

groups

82A, 82C, and 82F located in the above pattern. The resist roller pair 13 is controlled to supply the paper P to the first transport belt 8 so that the paper P is arranged on the first transport belt 8. The predetermined distance is set to 10 mm as an example here.

Here, the supply timing of the paper P by the resist roller pair 13 can be determined by the control unit 110 based on the detection result of the

belt sensor

24 or 25. For example, when the

belt sensor

24 or 25 detects that the reference opening group 82 (for example, the opening group 82A) has passed due to the traveling of the first transport belt 8, the control unit 110 resists after a few seconds from the detection time. If the paper P is supplied to the first transport belt 8 by the roller pair 13, it can be determined whether the paper P can be arranged at each position shown in FIG. Therefore, the control unit determines the supply timing of the paper P based on the detection result of the

belt sensor

24 or 25, and controls the resist roller pair 13 so that the paper P is supplied at the determined supply timing. As a result, the paper P can be arranged at each position shown in FIG. 9 on the first transport belt 8 at approximately equal intervals. In the example of FIG. 9, five sheets of paper P can be conveyed in one cycle of the first conveying belt 8, and 150 ipm (images per minute) is realized as the number of prints (productivity) per minute of the paper P. be able to.

Further, as shown in FIG. 9, when the A4 size (horizontally placed) paper P is supplied to the first transport belt 8, there is a gap between the opening group 82F and the opening group 82A of the first transport belt 8. Only one sheet of paper P is supplied. In this case, the control unit 110 is based on the detection result of the

belt sensor

24 or 25 so that the center Po in the A direction of the paper P is located at the intermediate position 8 m between the opening group 82F and the opening group 82A. The resist roller pair 13 is controlled to supply the paper P from the resist roller pair 13 to the first transport belt 8.

On the other hand, when the paper P to be used is A4 size (vertical installation) or letter size (vertical installation), the control unit 110 has an opening group 82A and an opening on the first transport belt 8 as shown in FIG. A predetermined number of sheets P are controlled by controlling the resist roller pair 13 so that the two sheets P are arranged between the group 82D and the two sheets P are arranged between the opening group 82D and the opening group 82A. Paper P is supplied to the first transport belt 8 at the supply timing. In the example of FIG. 10, four sheets of paper P can be conveyed in one cycle of the first conveying belt 8, and a productivity of 120 ipm can be realized.

When the paper P to be used is A3 size, B4 size or legal size (all vertically installed), the control unit 110 has the opening group 82A and the opening group on the first transport belt 8 as shown in FIG. One sheet of paper P is arranged between the opening group 82B, one sheet of paper P is arranged between the opening group 82B and the opening group 82E, and one sheet is arranged between the opening group 82E and the opening group 82A. The resist roller pair 13 is controlled so that the sheets P are arranged, and the sheets P are supplied to the first transport belt 8 at a predetermined supply timing. In the example of FIG. 11, three sheets of paper P can be conveyed in one cycle of the first conveying belt 8, and a productivity of 90 ipm can be realized. The control unit 110 detects the result of the

belt sensor

24 or 25 so that the center of one sheet of paper P in the A direction is located at an intermediate position between two adjacent opening groups 82 included in the determined pattern. It is desirable to control the resist roller pair 13 based on the above to supply the paper P to the first transport belt 8.

When the paper P to be used has a size of 13 inches × 19.2 inches, the control unit 110 is placed between the opening group 82A and the opening group 82D on the first transport belt 8 as shown in FIG. The resist roller pair 13 is controlled so that one sheet of paper P is arranged and one sheet of paper P is arranged between the opening group 82D and the opening group 82A, and the paper P is arranged at a predetermined supply timing. It is supplied to the first transport belt 8. In the example of FIG. 12, two sheets of paper P can be conveyed in one cycle of the first conveying belt 8, and a productivity of 60 ipm can be realized.

As described above, the control unit 110 determines the pattern (combination) in the A direction of the plurality of opening groups 82 used at the time of flushing according to the size of the paper P to be used. As a result, no matter what size of paper P is used, as much paper P as possible can be arranged on the first transport belt 8 so as not to overlap the opening group 82 arranged in the above pattern. Therefore, it is possible to avoid a decrease in productivity (decrease in the number of printed sheets) regardless of the size of the paper P used.

Further, during one cycle of the first transport belt 8, flushing can be performed a plurality of times using a plurality of opening groups 82 located in the above pattern. Therefore, regardless of the size of the paper P, insufficient flushing and resulting clogging of the nozzle (ink ejection port 18) can be reduced. In particular, the control unit 110 causes the recording head 17 to perform flushing at the timing when the opening group 82 located in the above pattern faces the recording heads 17a to 17c due to the traveling of the first transport belt 8. As a result, it is possible to reliably perform flushing a plurality of times during one cycle of the first transport belt 8 and eliminate the lack of flushing.

Further, in order to solve the lack of flushing, it is not necessary to reduce the transport speed of the paper P as in the conventional case, which also contributes to the improvement of productivity. Further, since it is not necessary to change the transport speed of the paper P, complicated transport control of the paper P (complex drive control of the first transport belt 8) becomes unnecessary.

Further, in the present embodiment, the storage unit 28 stores the information on the size of the paper P input in advance by the operation panel 27, that is, the information on the size of the paper P transported by the first transport belt 8. Then, the control unit 110 recognizes the size of the paper P to be used based on the information stored in the storage unit 28, and determines the pattern of the opening group 82 according to the recognized size. For example, the printer 100 has a sensor that detects the size of the paper P to be used, and the control unit 110 can determine the pattern of the opening group 82 according to the size detected by the sensor. In this case, , A dedicated sensor for detecting the size of the paper P is required. In the present embodiment, in order for the control unit 110 to recognize the size of the paper P and determine the pattern based on the information stored in the storage unit 28, a dedicated sensor for detecting the size of the paper P is separately provided. The effect of the present embodiment can be obtained by determining the above pattern.

Further, the control unit 110 supplies the paper P from the resist roller pair 13 between the plurality of opening groups 82 arranged in the above pattern on the first transport belt 8. As a result, even if the ink ejected from the recording heads 17a to 17c adheres to the opening 80 of the opening group 82 during flushing and the opening 80 becomes dirty, the paper P stays in the dirty opening 80. Do not overlap and be transported. Thereby, it is possible to reduce the situation where the paper P is soiled due to the ink stain of the opening 80.

Further, on the first transport belt 8, the paper P is located at a distance of a predetermined distance or more in the A direction from the opening group 82. As a result, for example, the ink ejected from the recording heads 17a to 17c during flushing deviates in the A direction for some reason (for example, due to the influence of negative pressure suction of the paper P) from the path toward the opening group 82. Even if the ink collides with the periphery of the opening 80 of the opening group 82 and is scattered around (even if a splash is generated), the scattered ink is difficult to reach the paper P. Therefore, it is possible to reduce the situation where the paper P is soiled due to the splash of ink during flushing. The predetermined distance is appropriately set according to the viscosity of the ink, the suction force of the paper P (the driving force of the suction member 53 described above), the traveling speed of the first transport belt 8 (the transport speed of the paper P), and the like. However, it is not limited to the above 10 mm.

Further, in the present embodiment, the control unit 110 is located on the first conveyor belt 8 at the position (from the opening group 82 to the A direction) between the plurality of opening groups 82 based on the detection result of the

belt sensor

24 or 25. The timing of supplying the paper P to a position separated by a predetermined distance or more is determined, and the paper P is supplied from the resist roller pair 13 to the first transport belt 8 at the determined timing. As a result, the paper P can be reliably supplied to the above-mentioned position between the opening group 82 and the opening group 82 of the first transport belt 8 by the resist roller pair 13, and the above-mentioned effect can be surely obtained.

Further, in the present embodiment, as described above, the control unit 110 performs in each cycle of the first transport belt 8 for each class determined according to the size of the paper P based on the detection result of the

belt sensor

24 or 25. Flushing in the recording heads 17a to 17c is controlled so that the ink passes through the same opening group 82. In this case, in each cycle of the first transport belt 8, the other opening group 82 is not contaminated with the ink at the time of flushing. Therefore, for any class of paper P, there is no concern that the paper P will be soiled even if it is transported so as to overlap with the other opening group 82 in each cycle of the first transport belt 8, and such paper P can be transported. .. That is, for any class of paper P, the opening group 82 through which the ink during flushing passes is avoided in each cycle, and the paper P can be conveyed without being soiled.

Further, in the present embodiment, as shown in FIG. 9, control is performed when one sheet of paper P is supplied from the resist roller pair 13 between the opening group 82F and the opening group 82A adjacent to each other in the A direction. The portion 110 is based on the detection result of the

belt sensor

24 or 25 so that the center Po in the A direction of the paper P is located at the intermediate position 8 m between the two

adjacent opening groups

82F and 82A of the first transport belt 8. The resist roller pair 13 is controlled to supply the paper P from the resist roller pair 13 to the first transport belt 8.

In this case, on the first transport belt 8, both the front end (the end on the downstream side in the A direction) and the rear end (the end on the upstream side in the A direction) of the paper P are located on the downstream side with respect to the paper P. It is equidistant from the opening group 82F and the opening group 82A located on the upstream side. As a result, the ink ejected from the recording heads 17a to 17c during flushing and traveling away from the path toward one opening group 82F or the other opening group 82A collides with the periphery of the opening 80 and scatters. However, it becomes difficult for the scattered ink to reach the front end and the rear end of the paper P. Therefore, it is possible to reliably reduce the situation where the paper P is soiled due to the splash of ink.

Further, in the present embodiment, as shown in FIGS. 9 to 12, the control unit 110 supplies the paper P from the resist roller pair 13 to the first transport belt 8 at regular intervals. In this case, since the supply of the paper P from the resist roller pair 13 to the first transport belt 8 may be controlled at a fixed timing, the supply control of the paper P (control of the resist roller pair 13) becomes easy.

Further, in the present embodiment, the first transport belt 8 further has a suction hole 8a in addition to the above-mentioned opening 80. Then, in the first transport belt 8, the size of the opening 80 (opening area) is larger than the size of the suction hole 8a (opening area). For example, if the suction hole 8a is large, the ink discharged from the recording heads 17a to 17c during flushing deviates from the direction toward the opening 80 toward the suction hole 8a and collides with the periphery of the opening 80, causing a splash. Is a concern. Since the suction hole 8a is relatively smaller than the opening 80, it is possible to further reduce the occurrence of the above-mentioned splash and further reduce the stain on the paper P due to the splash.

Further, the opening group 82 of the first transport belt 8 is irregularly located in the A direction in one cycle of the first transport belt. In this case, the effect of the present embodiment described above can be obtained by using the first transport belt 8 in which the minimum necessary opening groups 82 corresponding to the sizes of the plurality of sheets P are arranged in the A direction. Further, by suppressing the number of the opening group 82 to the necessary minimum, it is easy to secure the strength of the first transport belt 8.

Also, as shown in FIG. 9, A4 size (horizontal placement) and letter size (horizontal placement) belong to the same class (first class). And in this class, the opening group 82 used for flushing is a constant pattern of the

opening groups

82A, 82C, 82F. Further, as shown in FIG. 10, the A4 size (vertical installation) and the letter size (vertical installation) belong to the same class (second class). And in this class, the opening group 82 used for flushing is a constant pattern of the

opening groups

82A and 82D. Further, as shown in FIG. 11, A3 size, B4 size or legal size (all vertically placed) belong to the same class (third class). And in this class, the opening group 82 used for flushing is a constant pattern of the

opening groups

82A, 82B, 82E. Further, as shown in FIG. 12, the size of 13 inches × 19.2 inches constitutes one class (fourth class) by itself. And in this class, the opening group 82 used for flushing is a constant pattern of the

opening groups

82A and 82D.

As described above, the pattern of the opening group 82 used at the time of flushing is a constant pattern for each class determined according to the size of the paper P. In this case, at the time of flushing, the control unit 110 may perform ink ejection control in the recording heads 17a to 17c in a pattern corresponding to the pattern of the opening group 82 for each class, so that the ejection control is easy. Become.

Further, the patterns of the opening group 82 used at the time of flushing are different from each other in FIGS. 9 and 10, FIGS. 10 and 11, and FIGS. 11 and 12. On the other hand, the above pattern is the same in FIGS. 10 and 12. From this, it can be said that the above pattern is different between at least two classes determined according to the size of the paper P. By setting such a pattern, flushing can be performed for any size (class) of the paper P by using the opening group 82 of an appropriate pattern without reducing the productivity.

Further, in the first transport belt 8, the opening group 82 has a plurality of opening rows 81 in the A direction. The opening 80 of any of the opening rows 81 (for example, the opening row 81a) is positioned so as to be offset from the opening 80 of the other opening row 81 (for example, the opening row 81b) in the belt width direction. It is located so as to overlap a part of the opening 80 of the other opening row 81 when viewed in the A direction. In this case, ink is ejected from the nozzles (ink ejection ports 18) at any position in the width direction of the recording heads 17a to 17c, and an opening at any position in the belt width direction in the first transport belt 8. Flushing can be performed by passing through the portion 80. Therefore, clogging of the nozzles can be reduced or prevented for the nozzles at all positions in the width direction.

Further, in the first transport belt 8, the plurality of openings 80 of the opening row 81 are located at equal intervals in the belt width direction. In this configuration, by shifting the plurality of opening rows 81 in the belt width direction, it becomes easy to superimpose a part of the openings 80 of the adjacent opening rows 81 when viewed in the A direction. Therefore, it becomes easy to manufacture the first transport belt 8 having such a configuration.

Further, in the present embodiment, the first transport belt 8 possesses 6 opening groups 82 in the A direction in one cycle. In this case, for the four classes classified according to the size of the paper P, it is possible to generate a pattern in the A direction of the opening group 82 that does not reduce the productivity. The first transport belt 8 may have seven or more opening groups 82 in the A direction in one cycle. In this case, it is possible to generate a pattern in the A direction of the opening group 82 that does not reduce the productivity for five or more classes classified according to the size of the paper P.

(3-3. Other configuration example of the first transport belt)
FIG. 13 is a plan view showing another configuration example of the first transport belt 8. The first transport belt 8 may have a configuration in which the above-mentioned opening group 82 is located at equal intervals in the transport direction of the first transport belt 8, that is, in the A direction. At this time, the two opening groups 82 adjacent to each other in the A direction have an interval shorter than the length of the paper P in the A direction when the minimum printable size paper P is placed on the first transport belt 8. To position. Further, in the configuration of FIG. 13, the opening 80 constituting the opening group 82 also serves as the suction hole 8a in the configuration of FIG. The point that the opening group 82 has a plurality of opening rows 81 and the point that one opening row 81 has a plurality of openings 80 arranged at equal intervals in the BB'direction are shown in FIG. It is the same as the first transport belt 8 shown by the above.

Even when the first transport belt 8 shown in FIG. 13 is used, the control unit 110 may perform flushing according to the size of the paper P to be used, as in the case of using the first transport belt 8 shown in FIG. The pattern in the A direction of the plurality of opening groups 82 to be used is determined. For example, when the paper P to be used is A4 size (horizontal placement) or letter size (horizontal placement), the control unit 110 selects the pattern of the opening group 82 shown in FIG. When the paper P to be used is A4 size (vertical installation) or letter size (vertical installation), the control unit 110 selects the pattern of the opening group 82 shown in FIG. When the paper P to be used is A3 size, B4 size or legal size (all vertically installed), the control unit 110 selects the pattern of the opening group 82 shown in FIG. When the paper P to be used has a size of 13 inches × 19.2 inches, the control unit 110 selects the pattern of the opening group 82 shown in FIG. In addition, in FIGS. 14 to 17, for convenience, the opening group 82 located at the position corresponding to the opening group 82A to 82F in FIG. 8 is shown as the opening group 82A to 82F.

Then, the control unit 110 causes the recording heads 17a to 17c to perform flushing at the timing when the opening group 82 located in the determined pattern faces the recording heads 17a to 17c by the traveling of the first transport belt 8.

Further, the control unit 110 is placed on the first transport belt 8 at the positions shown in FIGS. 14 to 17 (between the plurality of openings 82 arranged in the A direction in the above pattern) by the resist roller pair 13 on the paper P. To supply. At this time, the control unit 110 is located on the first transport belt 8 at a position separated from the opening group 82 located in the above pattern in the A direction (including both the upstream side and the downstream side) by a predetermined distance or more. The paper P is supplied to the first transport belt 8 by controlling the resist roller pair 13 so that the paper P is arranged.

As described above, even when the first transport belt 8 shown in FIG. 13 is used, the control unit 110 has the same control as when the first transport belt 8 shown in FIG. 8 is used (flushing control, paper P). By performing (supply control), it is possible to obtain the same effect as described above, such as reducing nozzle clogging due to insufficient flushing while avoiding a decrease in productivity regardless of the size of paper P used. Can be done.

In particular, a configuration in which the opening groups 82 are located at equal intervals in the A direction of the first transport belt 8 can be easily realized by making holes at regular intervals in the A direction with respect to the first transport belt 8. Therefore, the first transport belt 8 can be easily manufactured, and the manufacturing cost thereof can be reduced.

Further, in the configuration in which the opening 80 of the first transport belt 8 also functions as the suction hole 8a shown in FIG. 8, the opening area of the opening 80 = the opening area of the suction hole 8a, which is formed on the first transport belt 8. Only one type of hole is required. In this respect as well, the first transport belt 8 can be easily manufactured as compared with the configuration of FIG. 8 in which two types of holes having different sizes are formed.

In the configuration in which the paper P is conveyed by the first conveying belt 9 by the negative pressure suction method, the first is to obtain the effect of reducing the clogging of the nozzle due to insufficient flushing while avoiding the decrease in productivity. The transport belt 8 may have the configuration shown in FIG. 8 or the configuration shown in FIG. Therefore, to summarize the configurations of FIGS. 8 and 13, it can be said that the size of the opening 80 in the first transport belt 8 may be larger than the size of the suction hole 8a.

In the first transport belt 8 having the configuration of FIG. 13, since the flushing openings 80 are formed innumerably over the entire surface of the belt, the paper P is packed in the A direction in the first transport belt 8 and conveyed, and the paper is conveyed. Productivity can be significantly improved by performing flushing using the opening 80 at a position that does not overlap with P. However, when the paper P is conveyed in this way, the opening 80 that has become dirty due to the passage of ink during flushing and the paper P to be conveyed tend to overlap each other in each cycle of the first transfer belt 8, and the paper P becomes dirty. It will be easier.

Even in the configuration using the first transport belt 8 of FIG. 13, as described above, the pattern of the opening group 82 used for flushing is determined according to the size of the paper P, and the pattern is positioned in the determined pattern. By flushing using the opening group 82, flushing is performed using the same opening group 82 in each cycle, and the paper P is placed and conveyed at a position deviated from the opening group 82 used at the time of flushing. can do. As a result, it is possible to reduce stains on the paper P when the paper P is conveyed and printed over a plurality of cycles while ensuring productivity. In this respect, even when the first transport belt 8 having the configuration shown in FIG. 13 is used, the flushing control and the paper P supply control described in the present embodiment are effective.

When the paper P is transported by the first transport belt 8 shown in FIG. 13, the pattern of the opening group 82 used at the time of flushing is different from the pattern when the first transport belt 8 shown in FIG. 8 is used. It may be a pattern. For example, flushing may be performed on the opening group located between the paper P and the paper P conveyed at the positions shown in FIGS. 14 to 17.

In the above, the case where the paper P is attracted to the first transport belt 8 by negative pressure suction and transported has been described. However, the first transport belt 8 is charged and the paper P is electrostatically attracted to the first transport belt 8. It may be transported (electrostatic adsorption method). Even in this case, the same effect as that of the present embodiment can be obtained by performing the flushing control and the supply control of the paper P to the first transport belt 8 as in the present embodiment.

In the above, an example of using a color printer that records a color image using four colors of ink has been described as an inkjet recording device, but a case where a monochrome printer that records a monochrome image using black ink is used. However, it is possible to apply the controls described in this embodiment.

Although the example in which the recording medium supply unit is configured by the resist roller pair 13 alone has been described above, the recording medium supply unit may be configured by including the resist roller pair 13 and the paper feed device 3. Further, the recording medium supply unit may be configured by the paper feeding device 3 alone. For example, when the resist roller pair 13 does not perform skew correction, the recording medium supply unit can be configured by the paper feeding device 3 alone.

The present invention can be used in an inkjet recording device that discharges ink onto a recording medium and records an image.

Claims

A recording head with multiple nozzles that eject ink,
An inkjet recording apparatus including an endless transport belt that transports a recording medium to a position facing the recording head.
A control unit for causing the recording head to perform flushing to eject the ink at a timing different from the timing contributing to image formation on the recording medium is further provided.
The transport belt is a group of openings in which openings through which the ink discharged from each nozzle of the recording head is passed during flushing are arranged in a belt width direction perpendicular to the transport direction of the recording medium. It has multiple media in the transport direction,
The control unit determines a pattern of a plurality of the openings used at the time of flushing in one cycle of the transport belt according to the size of the recording medium, and positions the pattern in the pattern by running the transport belt. An inkjet recording apparatus characterized in that the recording head is made to perform the flushing at a timing when the opening group is opposed to the recording head.
A storage unit for storing information on the size of the recording medium conveyed by the transfer belt is further provided.
The first aspect of claim 1, wherein the control unit recognizes the size of the recording medium based on the information stored in the storage unit, and determines the pattern according to the recognized size. Inkjet recording device.
The inkjet recording apparatus according to claim 1, wherein the opening group is irregularly located in the transport direction in one cycle of the transport belt.
The inkjet recording apparatus according to claim 1, wherein the openings are located at equal intervals in the transport direction of the transport belt.
The inkjet recording apparatus according to claim 1, wherein the pattern is a constant pattern for each class determined according to the size of the recording medium.
The inkjet recording apparatus according to claim 1, wherein the pattern differs between at least two classes determined according to the size of the recording medium.
Further provided with a detection sensor for detecting the passage of at least one of the openings due to the traveling of the transport belt.
Based on the detection result of the detection sensor, the control unit allows the ink to pass through the same opening group located in the pattern in each cycle of the transport belt for each class determined according to the size of the recording medium. The inkjet recording apparatus according to claim 1, wherein the flushing in the recording head is controlled so as to be performed.
The opening group is configured to have a plurality of rows of openings in which the plurality of openings are lined up in the belt width direction orthogonal to the transport direction.
In the opening group, the openings of any of the opening rows are located offset from the openings of the other opening row in the belt width direction, and are of the other opening row when viewed in the transport direction. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is located so as to overlap a part of the opening.
The inkjet recording apparatus according to claim 8, wherein in the transport belt, the plurality of openings in the opening row are located at equal intervals in the belt width direction.