JP7415420B2 - inkjet recording device - Google Patents

Description

The present invention relates to an inkjet recording apparatus that records an image by ejecting ink onto a recording medium.

BACKGROUND ART Conventionally, in inkjet recording devices such as inkjet printers, flushing (dry ejection) in which ink is periodically ejected from the nozzles has been performed in order to reduce or prevent nozzle clogging due to ink drying. For example, in the inkjet recording devices described in Patent Documents 1 and 2, an opening is provided in the conveyor belt, and the recording medium is placed on the conveyor belt and conveyed so as not to cover the opening, and the opening is closed by the running of the conveyor belt. When the ink comes to a position facing the print head, ink is ejected from the nozzles of the print head to perform flushing.

Further, for example, in the inkjet recording apparatus of Patent Document 3, a plurality of openings are provided in the conveyance belt in the conveyance direction of the recording medium, and when the size of the recording medium is large, the conveyance speed of the recording medium is slowed down to perform flushing. I try to do it. By slowing down the conveyance speed of the recording medium, the number of rows of openings located between the recording media on the conveyance belt in the conveyance direction increases, which increases the amount of ink ejected during flushing. Ejection failure can be reduced. Furthermore, in Patent Document 4, the position of the opening is recognized based on the detection results of marks provided on the conveyor belt, and the ejection of ink during flushing is controlled, taking into account deformations such as elongation of the conveyor belt. This allows ink to pass through the openings with more precision.

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

By the way, there is a negative pressure suction method as a method for conveying a recording medium using a conveyor belt. The negative pressure suction method is a method in which the recording medium is attracted to a conveyor belt by negative pressure suction and conveyed. On the other hand, in a configuration in which flushing is performed by discharging ink from the nozzles of the recording head so as to pass through the opening of the conveyor belt, an ink receiving portion is provided to receive the ink that has passed through the opening. During negative pressure suction, if the suction force in the area where the ink receiving section is provided is strong, the ink ejected from the recording head during flushing will forcefully pass through the opening in the conveyor belt and may be already stored in the ink receiving section. mist that collides with the liquid surface of the ink and scatters ink droplets around it is likely to be generated. When mist is generated, scattered ink droplets adhere to the inner circumferential surface of the conveyor belt and stain the inner circumferential surface, thereby staining the surface of the roller that stretches the conveyor belt. The dirt on the roller surface causes uneven conveyance of the conveyor belt (for example, meandering or slipping) and causes misalignment of the recorded image with respect to the recording medium, so it is necessary to suppress it as much as possible.

Patent Documents 1 to 4 described above disclose a method of suppressing the generation of the above-mentioned mist and suppressing uneven conveyance of the conveyor belt caused by the mist in a configuration in which a recording medium is conveyed by a conveyor belt by negative pressure suction. has not been considered at all.

In view of the above problems, the present invention provides a structure in which a recording medium is conveyed by a conveyor belt by negative pressure suction, and ink ejected from a recording head during flushing collides with the liquid surface of ink already stored in an ink receiving part. To provide an inkjet recording device that can suppress the occurrence of mist, thereby suppressing the occurrence of uneven conveyance on the conveyor belt due to the inner circumferential surface of the conveyor belt becoming dirty due to the above-mentioned mist. With the goal.

In order to achieve the above object, an inkjet recording apparatus according to one aspect of the present invention includes a recording head having a plurality of nozzles that eject ink, and an endless conveyor that conveys a recording medium to a position facing the recording head. In addition to the belt, a negative pressure generating section that generates a negative pressure for suctioning the recording medium through the suction hole of the conveyor belt, and a negative pressure generator disposed opposite to the recording head via the conveyor belt. , when the recording head performs flushing in which the ink is discharged at a timing different from the timing at which the recording head contributes to image formation on the recording medium, the ink is discharged from the recording head and passes through the opening of the conveyor belt. The image forming apparatus further includes an ink receiving section that receives ink. The suction force generated by the negative pressure is greater in the non-opposing section on the upstream or downstream side in the conveyance direction of the recording medium with respect to the opposing section than in the opposing section where the recording head and the ink receiving section face each other. is strong.

According to the above configuration, in a configuration in which a recording medium is conveyed by a conveyor belt by negative pressure suction, the ink ejected from the recording head during flushing collides with the liquid surface of the ink already stored in the ink receiving part, resulting in mist. This can prevent the mist from staining the inner circumferential surface of the conveyor belt and causing uneven conveyance on the conveyor belt.

1 is an explanatory diagram showing a schematic configuration of a printer as an inkjet recording apparatus according to an embodiment of the present invention. FIG. 3 is a plan view of a recording section included in the printer. FIG. 2 is an explanatory diagram schematically showing a configuration around a paper conveyance path from a paper feed cassette to a second conveyance unit via a first conveyance unit of the printer. FIG. 2 is a block diagram showing the hardware configuration of the main parts of the printer. FIG. 7 is an explanatory diagram schematically showing another example of the configuration around the paper conveyance path. FIG. 3 is an explanatory diagram schematically showing regions with different suction forces in the first transport unit. FIG. 2 is an explanatory diagram schematically showing a configuration example of the first transport unit. FIG. 3 is an explanatory diagram showing an enlarged view of an ink receiving section included in the first transport unit. It is an explanatory view showing typically another example of composition of the above-mentioned 1st conveyance unit. FIG. 2 is a plan view showing an example of a configuration of a first conveyance belt included in the first conveyance unit. FIG. 11 is an explanatory diagram schematically showing an example of a pattern of a group of openings for flushing when the first conveyor belt of FIG. 10 is used, and sheets arranged on the first conveyor belt according to the pattern; be. FIG. 7 is an explanatory diagram schematically showing another example of the pattern and sheets arranged on the first conveyor belt according to the pattern. FIG. 7 is an explanatory diagram schematically showing still another example of the pattern and sheets arranged on the first conveyor belt according to the pattern. FIG. 7 is an explanatory diagram schematically showing still another example of the pattern and sheets arranged on the first conveyor belt according to the pattern. It is a top view which shows the other example of a structure of the said 1st conveyance belt. FIG. 16 is an explanatory diagram schematically showing an example of the pattern when the first conveyance belt of FIG. 15 is used, and sheets arranged on the first conveyance belt according to the pattern. FIG. 7 is an explanatory diagram schematically showing another example of the pattern and sheets arranged on the first conveyor belt according to the pattern. FIG. 7 is an explanatory diagram schematically showing still another example of the pattern and sheets arranged on the first conveyor belt according to the pattern. FIG. 7 is an explanatory diagram schematically showing still another example of the pattern and sheets arranged on the first conveyor belt according to the pattern.

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

A paper feed device 3 is disposed 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. The paper feed device 3 separates the paper sheets P one by one and sends them out toward the upper right of the paper feed cassette 2 in FIG.

The printer 100 includes a first paper conveyance path 4a therein. 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 conveyed vertically upward along the side surface of the printer main body 1 by the first paper conveyance path 4a.

A registration roller pair 13 is provided at the downstream end of the first paper transport path 4a in the paper transport direction. Furthermore, the first transport unit 5 and the recording section 9 are arranged immediately downstream of the pair of registration rollers 13 in the paper transport direction. The paper P sent out from the paper feed cassette 2 passes through the first paper transport path 4a and reaches the pair of registration rollers 13. The pair of registration rollers 13 feeds the paper P toward the first transport unit 5 while correcting the oblique feeding of the paper P, timing the ink ejection operation executed by the recording section 9.

The paper P sent out to the first transport unit 5 is transported by the first transport belt 8 (see FIG. 2) to a position opposite to the recording section 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 ejection of ink in the recording section 9 is controlled by a control section 110 inside the printer 100. The control unit 110 is configured by, for example, a CPU (Central Processing Unit).

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

A decurler section 14 is provided downstream of the second transport unit 12 and near the left side of the printer main body 1 in the paper transport direction. The paper P on which the ink has been dried by the second transport unit 12 is sent to the decurler section 14, and curls generated on the paper P are corrected.

In the paper transport direction, a second paper transport path 4b is provided downstream of the decurler section 14 (above in FIG. 1). If double-sided recording is not performed, the paper P that has passed through the decurler unit 14 passes through the second paper transport path 4b and is discharged to a paper discharge tray 15 provided outside the left side of the printer 100.

A reversing conveyance path 16 for double-sided recording is provided at the top of the printer body 1 above the recording section 9 and the second conveyance unit 12. When double-sided recording is performed, after the recording on one side (first side) of the paper P has been completed and the paper P has passed through the second transport unit 12 and decurler section 14, the paper P passes through the second paper transport path 4b and is reversed. It is sent to the conveyance path 16.

The conveyance direction of the paper P sent to the reversing conveyance path 16 is then switched in order to record 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, is sent toward the right side, passes through a pair of registration rollers 13, and is sent again to the first transport unit 5 with the second side facing upward. In the first transport unit 5, the paper P is transported to a position facing the recording section 9, and an image is recorded on the second surface by ink ejection from the recording section 9. The paper P after double-sided recording is ejected to the paper ejection tray 15 via the second transport unit 12, the decurler section 14, and the second paper transport path 4b in this order.

Further, below the second transport unit 12, a maintenance unit 19 and a cap unit 20 are arranged. When performing purging, the maintenance unit 19 moves horizontally below the recording section 9, wipes off the ink pushed out from the ink ejection ports of the recording head, and collects the wiped ink. Note that purge refers to an operation of forcibly pushing out ink from the ink ejection ports of the recording head in order to discharge thickened ink, foreign matter, and air bubbles from the ink ejection ports. The cap unit 20 moves horizontally below the recording section 9 when capping the ink ejection surface of the recording head, moves further upward, and is attached to the lower surface of the recording head.

FIG. 2 is a plan view of the recording section 9. The recording section 9 includes a head housing 10 and line heads 11Y, 11M, 11C, and 11K. The line heads 11Y to 11K are arranged at a predetermined interval (for example, 1 mm) with respect to the conveying surface of an endless first conveying belt 8 stretched over a plurality of rollers including a driving roller 6a, a driven roller 6b, and another roller 7. ) is held in the head housing 10 at a height that forms a.

The line heads 11Y to 11K each have a plurality of (here, three) 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 conveyance 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 at regular intervals in the width direction of the recording head, that is, in the paper width direction (arrow BB' direction). Ink of each color of yellow (Y), magenta (M), cyan (C), and black (K) is first transported from the line heads 11Y to 11K through the ink ejection ports 18 of the recording heads 17a to 17c. They are each discharged toward the paper P conveyed by the belt 8.

FIG. 3 schematically shows the configuration around the conveyance path of paper P from the paper feed cassette 2 to the second conveyance unit 12 via the first conveyance unit 5. Further, FIG. 4 is a block diagram showing the hardware configuration of the main parts of the printer 100. In addition to the above configuration, the printer 100 further includes a registration sensor 21, a first paper sensor 22, a second paper sensor 23, and belt sensors 24 and 25.

The registration sensor 21 detects the paper P conveyed from the paper cassette 2 by the paper feeder 3 and sent to the registration roller pair 13. The control unit 110 can control the rotation start timing of the registration roller pair 13 based on the detection result by the registration sensor 21. For example, the control unit 110 can control the timing of supplying the paper P to the first conveyor belt 8 after the skew (oblique feeding) has been corrected by the pair of registration rollers 13 based on the detection result of the registration sensor 21 .

The first paper sensor 22 is a line sensor that detects the position in the width direction of the paper P sent from the registration roller pair 13 to the first conveyor belt 8 . Based on the detection result from the first paper sensor 22, the control unit 110 injects ink 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. An image can be recorded on the paper P by discharging it.

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 upstream of the recording unit 9 and downstream of the first paper sensor 22 in the paper conveyance direction. Based on the detection result of the second paper sensor 23, the control unit 110 determines the timing of ejecting ink to the paper P that reaches a position facing the line heads 11Y to 11K (recording heads 17a to 17c) by the first conveyor belt 8. can be controlled.

Belt sensors 24 and 25 detect the positions of a plurality of opening groups 82 (see FIG. 10), which will be described later, provided on the first conveyor belt 8. That is, the belt sensors 24 and 25 are detection sensors that detect passage of at least one of the opening group 82 due to the running of the first conveyor belt 8. The belt sensor 24 is located downstream of the recording section 9 in the paper conveyance direction (travel direction of the first conveyance belt 8). The belt sensor 25 is located between the driven roller 6b that stretches the first conveyor belt 8 and another roller 7. The driven roller 6b is located upstream of the recording section 9 in the running direction of the first conveyor belt 8. Note that the belt sensor 24 has the same function as the second paper sensor 23. The control unit 110 can control the pair of registration rollers 13 to feed the paper P to the first conveyor belt 8 at a predetermined timing based on the detection result by 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 conveyor belt 8 is detected by a plurality of sensors (belt sensors 24 and 25). This makes it possible to correct errors in detected positions and detect abnormalities.

The first paper sensor 22, second paper sensor 23, and belt sensors 24 and 25 described above may be configured with a transmission type or reflection type optical sensor, or a CIS sensor (Contact Image Sensor). Further, a mark corresponding to the position of the opening group 82 is formed at the end of the first conveyor belt 8 in the width direction, and when the belt sensors 24 and 25 detect the mark, the position of the opening group 82 is The location may also be detected.

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

Further, the printer 100 further includes an operation panel 27, a storage section 28, and a communication section 29. The operation panel 27 is an operation section for receiving various setting inputs from the user. For example, the user can operate the operation panel 27 to input information about 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 transported by the first transport belt 8. The storage unit 28 is a memory that stores the operating program of the control unit 110 as well as various types of information, and includes ROM (Read Only Memory), RAM (Random Access Memory), nonvolatile memory, etc. There is. Information set using the operation panel 27 (for example, information on the size of paper P) is stored in the storage section 28. The communication unit 29 is a communication interface for transmitting and receiving information with an external device (for example, a personal computer (PC)). For example, when a user operates a PC and sends a print command along with image data to the printer 100, the image data and print command are input to the printer 100 via the communication unit 29. In the printer 100, the control unit 110 can record an image on the paper P by controlling the recording heads 17a to 17c to eject ink based on the image data.

Further, as shown in FIG. 3, the printer 100 includes ink receiving portions 31Y, 31M, 31C, and 31K on the inner peripheral surface side of the first conveyor belt 8. When the ink receiving parts 31Y to 31K perform flushing to the recording heads 17a to 17c, the ink is ejected from the recording heads 17a to 17c and the ink receiving parts 31Y to 31K are connected to the openings 80 of the opening group 82 (described later in FIG. 10) of the first conveyor belt 8. Collect and collect the ink that has passed through the 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 with the first conveyor belt 8 in between. Note that the ink collected in the ink receiving sections 31Y to 31K is sent to, for example, a waste ink tank and discarded.

Here, flushing refers to ejecting ink at a timing different from the timing contributing to image formation (image recording) on the paper P for the purpose of reducing or preventing clogging of the ink ejection ports 18 due to ink drying. say. Execution of flushing in the recording heads 17a to 17c is controlled by the control unit 110.

The second conveyance unit 12 described above includes a second conveyance belt 12a and a dryer 12b. The second conveyor belt 12a is stretched by two driving rollers 12c and a driven roller 12d. The paper P, which is transported by the first transport unit 5 and on which an image is recorded by ink ejection by the recording section 9, is transported by the second transport belt 12a, and is dried by the dryer 12b during transport, and then sent to the decurler section 14 described above. transported.

FIG. 5 schematically shows another configuration around the transport path of the paper P. As shown in the figure, in the printer 100 of the present embodiment, the ink collected in the ink receiving sections 31Y to 31K may be sent to the recording heads 17a to 17c of the line heads 11Y to 11K by the liquid feeding mechanism 30. . Such a liquid feeding mechanism 30 is configured to include, for example, a pump and a liquid feeding pipe. In this case, the ink collected by the ink receivers 31Y to 31K can be reused (effectively used) as ink for image recording. Note that the liquid sending mechanism 30 may further include a tank that temporarily stores the collected ink, and may send the ink to the recording heads 17a to 17c via the pump and the tank.

[2. Details of the first transport unit]
(2-1. Example of configuration of first transport unit)
In this 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 conveyor belt 8 and conveyed by negative pressure suction.

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 with the first conveyance belt 8 interposed therebetween. During negative pressure suction, if the suction force in the area where the ink receiving parts 31Y to 31K are provided is strong, the ink ejected from the recording heads 17a to 17c during flushing will force the opening 80 of the first conveyor belt 8. In some cases, the mist passes through the ink well and collides with the surface of the ink already stored in the ink receiving parts 31Y to 31K, causing mist to scatter the ink around it. When the mist is generated, the scattered ink adheres to the inner peripheral surface of the first conveyor belt 8 and stains the inner peripheral surface. As a result, the surface of the roller that stretches the first conveyor belt 8 becomes dirty, and there is a risk that the first conveyor belt 8 may experience uneven conveyance (for example, meandering or slipping).

Therefore, in this embodiment, as shown in FIG. By making the area weaker than the upstream and downstream areas in the paper conveyance direction, the above-mentioned inconvenience caused by mist is reduced. Specifically, regions with different attraction forces are generated by the following configuration.

Hereinafter, for convenience, the section where the recording heads 17a to 17c of the line heads 11Y to 11K and the ink receiving sections 31Y to 31K face each other (the conveyance section of the paper P) will be referred to as a facing section _E1 . Further, a section on the upstream side or downstream side in the conveying direction of the paper P with respect to the opposing section _E1 (transporting section of the paper P) is referred to as a non-opposing section _E2 .

FIG. 7 is an explanatory diagram schematically showing an example of the configuration of the first transport unit 5. As shown in FIG. The first transport unit 5 has a negative pressure generating section 50. The negative pressure generating section 50 generates negative pressure for sucking the paper P through the suction hole 8a of the first conveyor belt 8. The negative pressure generating section 50 includes a suction member 53, first suction chambers 51a to 51e, and second suction chambers 52a to 52d.

The suction member 53 is composed of a fan or a compressor that generates negative pressure (including a drive mechanism (for example, a motor)). The first suction chambers 51a to 51e and the second suction chambers 52a to 52d are located on the inner peripheral surface side of the first conveyor belt 8, respectively, and are formed in an elongated shape in the belt width direction of the first conveyor belt 8. At the same time, the side opposite to the first conveyor belt 8 is open. The first suction chambers 51a to 51e use negative pressure generated by the suction member 53 to suction the paper P conveyed in the non-opposed section E ₂ . The second suction chambers 52a to 52d suck the paper P conveyed through the opposing section _E1 . Note that in FIG. 7, illustration of the ink receiving portions 31Y to 31K is omitted for convenience.

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

The interiors of the first suction chamber 51a and the second suction chamber 52a are suctioned by a common suction member 53. Further, the interiors of the first suction chamber 51b and the second suction chamber 52b are suctioned by a common suction member 53. Similarly, the insides of the first suction chamber 51c and the second suction chamber 52c are suctioned by a common suction member 53, and the insides of the first suction chamber 51d and the second suction chamber 52d are suctioned by a common suction member 53. Ru. The first suction chamber 51e is independently suctioned by the suction member 53.

Further, the first suction chambers 51a to 51e each have a low flow resistance section 54, and the second suction chambers 52a to 52d each have a high flow resistance section 55. In the low flow path resistance section 54, the flow path resistance of the suction air generated by the negative pressure of the adsorption member 53 is relatively low, and in the high flow path resistance section 55, the flow path resistance of the suction air is relatively high. The low flow resistance section 54 and the high flow resistance section 55 are configured, for example, by filters having different internal pore diameters and densities. For example, the filter constituting the low flow resistance section 54 has a coarser mesh than the filter constituting the high flow resistance section 55.

Note that the low flow resistance section 54 and the high flow resistance section 55 are composed of tubes that serve as passages for suction air generated by negative pressure, and the low flow resistance section 54 has a relatively large cross-sectional area of the tube. By making the cross-sectional area of the tube relatively small in the high flow resistance section 55, a low flow resistance section 54 with a relatively low flow resistance and a high flow resistance section 55 with a relatively high flow resistance are formed. may be configured respectively.

In such a configuration, when each suction member 53 is driven to generate negative pressure, the inside of the first suction chambers 51a to 51e is sucked through the low flow resistance section 54, and the inside of the second suction chambers 52a to 52d is suctioned. The inside is sucked through the high flow path resistance section 55. As a result, air is sucked through the suction holes 8a or the opening group 82 provided in the first conveyor belt 8, and the paper P is conveyed while being attracted to the first conveyor belt 8.

Here, since the low flow path resistance section 54 has a relatively low flow path resistance of the suction air compared to the high flow path resistance section 55, when each suction member 53 is driven with the same driving force, the first suction chamber The insides of the second suction chambers 51a to 51e are suctioned with a relatively strong suction force, and the insides of the second suction chambers 52a to 52d are suctioned with a relatively weak suction force. Therefore, the suction force generated by the negative pressure is stronger in the non-opposing section E ₂ than in the opposing section E ₁ .

That is, in the opposing section _E1 , the attraction force is relatively weaker than in the non-opposing section _E2 . As a result, when performing flushing, ink ejected from the recording heads 17a to 17c is suppressed from passing forcefully through the openings 80 of the opening group 82 of the first conveyor belt 8 in the opposing section _E1 . Ru. Therefore, it is possible to suppress the generation of mist in which the ink collides with the liquid surface of the ink already contained in the ink receivers 31Y to 31K and scatters ink droplets around it. As a result, it is possible to prevent the inner circumferential surface of the first conveyor belt 8 from being contaminated by the mist, and it is possible to suppress uneven conveyance of the first conveyor belt 8 due to the stain.

Further, the first suction chambers 51a to 51e have a low flow resistance section 54, and the second suction chambers 52a to 52d have a high flow resistance section 55. In this configuration, the amount of suction air flowing through the second suction chambers 52a to 52d is smaller than that of the first suction chambers 51a to 51e. As a result, the attraction force is weaker in the opposing section E ₁ than in the non-opposing section E ₂ . Therefore, generation of mist during flushing and uneven conveyance of the first conveyor belt 8 caused by the mist can be reliably suppressed.

FIG. 8 shows an enlarged view of the ink receiving sections 31Y to 31K of the first transport unit 5. As shown in FIG. A filter 56 may be arranged on the first conveyance belt 8 side (recording head 17a to 17c side) with respect to the ink receiving parts 31Y to 31K. The filter 56 is made of, for example, a PVA (polyvinyl alcohol) filter, and has water absorption properties. The filter 56 is arranged to be replaceable, that is, replaceable, with respect to the ink receiving parts 31Y to 31K.

By arranging the filter 56 as described above, the filter 56 allows ink ejected from the recording heads 17a to 17c to pass through during flushing, and also allows the ink to collide with the liquid surface of the ink receiving portions 31Y to 31K to prevent external damage. absorbs ink droplets that are scattered on the surface. Therefore, while the ink ejected during flushing is collected by the ink receivers 31Y to 31K via the filter 56, the ink during flushing collides with the liquid surface of the ink receivers 31Y to 31K and tries to scatter to the outside. The ink droplets are absorbed by the filter 56, and the generation of mist can be reliably suppressed.

In addition, since the filter 56 is arranged to be replaceable, even if the filter 56 becomes clogged due to absorption of ink droplets and prevents ink from passing through during flushing, or if the mist absorption function deteriorates due to long-term use, , these problems can be solved by replacing the filter 56.

(2-2. Other configuration examples of the first transport unit)
FIG. 9 is an explanatory diagram schematically showing another example of the configuration of the first transport unit 5. As shown in FIG. The first conveyance unit 5 in FIG. 9 has the same filter 54 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 suctioned by a separate suction member 53. In such a configuration, by switching the driving force of each suction member 53 that sucks the inside of the second suction chambers 52a to 52d, the suction force of the second suction chambers 52a to 52d is switched between strong suction and weak suction. . Note that the driving of each suction member 53 is controlled by, for example, the control unit 110.

For example, when discharging ink onto the paper P transported by the first transport belt 8 (during 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 activated. Drive with the first driving force. On the other hand, during flushing, each suction member 53 that suctions the first suction chambers 51a to 51e is driven by the first driving force, and each suction member 53 that suctions the second suction chambers 52a to 52d is driven by the first driving force. The second driving force is lower than that of the second driving force. As a result, during image recording, the first suction chambers 51a to 51e and the second suction chambers 52a to 52d are strongly suctioned to transport the paper P, while during flushing, only the second suction chambers 52a to 52d are weakly suctioned. It can be done.

Here, the suction amount per unit time when the first suction chambers 51a to 51e are strongly suctioned is the first suction amount, and the suction member 53 that suctions the first suction chambers 51a to 51e with the first suction amount is , the first suction member 53a. In addition, the suction amount per unit time when the second suction chambers 52a to 52d are weakly suctioned is the second suction amount (however, smaller than the first suction amount), and the second suction chambers 52a to 52d are set to the first suction amount. The suction member 53 that sucks at the suction amount or the second suction amount is referred to as a second suction member 53b.

In the configuration of FIG. 9, the same filter 54 is disposed in the first suction chambers 51a to 51e and the second suction chambers 52a to 52d, so the flow path resistance of the suction air generated by negative pressure is reduced in the first suction chamber 51a. 51e and the second suction chambers 52a to 52d. In the configuration in which the first suction chambers 51a to 51e and the second suction chambers 52a to 52d are suctioned by separate suction members (first suction member 53a, second suction member 53b), the suction amount by the second suction member 53b is By switching between the first suction amount and the second suction amount, during flushing, the amount of suction air flowing through the second suction chambers 52a to 52d is smaller than that of the first suction chambers 51a to 51e, and the non-opposing section E ₂ The suction force is weaker in the opposing section E1 than in the opposite section _E1 . Therefore, during flushing, generation of mist and uneven conveyance of the first conveyor belt 8 caused by the mist can be suppressed.

In particular, when the control unit 110 controls the drive of the second suction member 53b to selectively switch the suction amount of the second suction member 53b, that is, when flushing is performed by the recording heads 17a to 17c, the control unit 110 controls the drive of the second suction member 53b. , the second suction member 53b is driven with the second driving force to switch the suction amount of the second suction member 53b from the first suction amount to the second suction amount. On the other hand, when ejecting ink from the recording heads 17a to 17c onto the paper P, the control unit 110 drives the second suction member 53b with the first driving force to increase the suction amount of the second suction member 53b to the second suction amount. Switch from the suction amount to the first suction amount. As a result, during flushing, the amount of suction air flowing through the second suction chambers 52a to 52d is made smaller than that in the first suction chambers 51a to 51e, and the suction force is made weaker in the opposed section _E1 than in the non-opposed section _E2 . However, generation of mist can be suppressed, and uneven conveyance of the first conveyor belt 8 can be suppressed. On the other hand, when performing normal printing, it is possible to ensure the same suction force in the non-opposing section E ₂ and the opposing section E ₁ and to stably transport the paper P by the first transport belt 8.

[3. Details of the first conveyor belt]
(3-1. Example of configuration of first conveyor belt)
Next, details of the first conveyance belt 8 of the first conveyance unit 5 will be explained. FIG. 10 is a plan view showing an example of the configuration of the first conveyor belt 8. As shown in FIG. In this embodiment, as described above, the paper P is conveyed using the negative pressure suction method. For this reason, as shown in the figure, the first conveyor belt 8 is provided with numerous suction holes 8a through which the suction air generated by the negative pressure suction of the suction member 53 passes.

The first conveyor belt 8 is also provided with an opening group 82 . The opening group 82 is a collection of openings 80 through which ink ejected from each nozzle (ink ejection port 18) of the recording heads 17a to 17c passes during flushing. The opening area of the opening 80 is larger than the opening area of the suction hole 8a. The first conveyance belt 8 has a plurality of opening groups 82 in one period in the conveyance direction (direction A) of the paper P, and has six opening groups in this embodiment. In addition, when distinguishing each opening group 82 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 above-mentioned suction hole 8a is located between adjacent opening groups 82 in the A direction. That is, in the first conveyor belt 8, no suction holes 8a are formed in a region overlapping with the opening group 82.

The opening group 82 is irregularly located in the A direction during one cycle of the first conveyor belt 8 . That is, in the A direction, the distance between adjacent opening groups 82 is not constant, but changes (there are at least two types of the above-mentioned distances). At this time, the maximum distance between two adjacent aperture groups 82 in the A direction (for example, the distance between the aperture group 82A and the aperture group 82B in FIG. 10) is the minimum printable size (for example, A4 size (horizontal)). ) is longer than the length of the paper P in the A direction when it is placed on the first conveyor belt 8.

The opening group 82 described above 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 this embodiment, it has two opening rows 81. Note that when the two opening rows 81 are to be distinguished from each other, one is designated as the opening row 81a and the other is designated as the opening row 81b.

In one opening group 82, the openings 80 in one of the opening rows 81 (for example, the opening row 81a) are aligned with the openings 80 in the other opening rows 81 (for example, the opening row 81b) in the BB' direction. The openings 80 of the openings 80 of the other openings 81 (for example, the openings 81b) are positioned to be offset from each other and overlap with each other when viewed in the A direction. Further, in each opening row 81, the plurality of openings 80 are positioned 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 same as that of the recording heads 17a to 17c. is larger than the width of Therefore, the opening group 82 covers all the ink ejection areas in the BB' direction of the recording heads 17a to 17c, and the ink ejected from all the ink ejection ports 18 of the recording heads 17a to 17c during flushing is It passes through any opening 80 in the group 82 .

(3-2. Regarding the pattern of the opening group used during flushing)
In this embodiment, the control unit 110 drives the recording heads 17a to 17c based on image data transmitted from the outside (for example, a PC) while conveying the paper P using the first conveyance belt 8. An image is recorded on the paper P. At this time, by causing the recording heads 17a to 17c to perform flushing (inter-sheet flushing) between the sheets P being transported, clogging of the ink ejection ports 18 is reduced or prevented. .

Here, in the present embodiment, the control unit 110 adjusts the pattern (combination) of the plurality of opening groups 82 in the A direction used for flushing in one cycle of the first conveyor belt 8 to the size of the paper P to be used. Decide accordingly. Note that the control unit 110 can recognize the size of the paper P to be used based on information stored in the storage unit 28 (size information of the paper P input through the operation panel 27).

11 to 14 show examples of the above-mentioned patterns for each sheet P, respectively. For example, when the paper P used is A4 size (landscape) or letter size (landscape), the control unit 110 selects the pattern of the opening group 82 shown in FIG. 11. That is, the control unit 110 selects the opening groups 82A, 82C, and 82F from the six opening groups 82 shown in FIG. 10 as the opening group 82 used for flushing. When the paper P to be used is A4 size (vertical) or letter size (vertical), the control unit 110 selects the opening group 82 used for flushing from among the six opening groups 82, as shown in FIG. , the opening groups 82A and 82D are selected. When the paper P to be used is A3 size, B4 size, or legal size (all placed vertically), the control unit 110 selects an opening group to be used for flushing from among the six opening groups 82, as shown in FIG. As 82, opening groups 82A, 82B, and 82E are selected. When the paper P to be used has a size of 13 inches x 19.2 inches, the control unit 110 selects an opening from among the six opening groups 82 as the opening group 82 used for flushing, as shown in FIG. Groups 82A and 82D are selected. In each drawing, the openings 80 of the opening group 82 belonging to the above pattern are 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 positioned in the determined pattern faces the recording heads 17a to 17c as the first conveyor belt 8 runs. Here, the running speed of the first conveyor belt 8 (paper conveyance speed), the interval between the opening groups 82A to 82E, and the positions of the recording heads 17a to 17c with respect to the first conveyor 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 first conveyor belt 8, several seconds after that detection, the opening group 82A is detected. It can be seen whether the recording heads 82E to 82E pass through the positions facing the recording heads 17a to 17c. Therefore, based on the detection result of the belt sensor 24 or 25, 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. can be executed.

At this time, the control unit 110 causes the ink to pass through the same group of openings 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 results from the belt sensor 24 or 25. Flushing in the recording heads 17a to 17c is controlled so as to perform the following operations.

For example, when the paper P to be used is A4 size (horizontal) or letter size (horizontal) (first class), the control unit 110 uses the same opening shown in FIG. Flushing in the recording heads 17a to 17c is controlled so that ink passes through the subgroups 82A, 82C, and 82F. When the paper P to be used is A4 size (portrait orientation) or letter size (portrait orientation) (second class), the control unit 110 controls the same opening group shown in FIG. Flushing in the recording heads 17a to 17c is controlled so that ink passes through 82A and 82D. When the paper P to be used is A3 size, B4 size, or legal size (all placed vertically) (third class), the control unit 110 controls the use of the same opening shown in FIG. Flushing in the recording heads 17a to 17c is controlled so that ink passes through the groups 82A, 82B, and 82E. When the paper P to be used has a size of 13 inches x 19.2 inches (fourth class), the control unit 110 controls the same opening groups 82A and 82D shown in FIG. Flushing in the recording heads 17a to 17c is controlled so that the ink passes through.

Further, the control unit 110 controls the supply of the paper P to the first conveyor belt 8 so that it is shifted in the A direction from the opening group 82 located in the determined pattern. That is, the control unit 110 causes the registration roller pair 13 serving as a recording medium supply unit to supply the paper P between the plurality of opening groups 82 arranged in the A direction in the above pattern on the first conveyance belt 8 .

For example, when the paper P to be used is A4 size (horizontal) or letter size (horizontal), the control unit 110 controls the opening group 82A and the openings on the first conveyor belt 8, as shown in FIG. Two sheets of paper P are arranged between the group 82C and the opening group 82C, 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 registration roller pair 13 is controlled to supply the paper P to the first conveyor belt 8 at a predetermined supply timing so that one sheet of paper P is arranged. At this time, the control unit 110 controls a position on the first conveyor belt 8 that is a predetermined distance or more away from the opening groups 82A, 82C, and 82F located in the above pattern in the A direction (including both upstream and downstream directions). The pair of registration rollers 13 are controlled to supply the sheets P to the first conveyor belt 8 so that each sheet P is arranged at . In addition, the said predetermined distance is 10 mm here as an example.

Here, the timing at which the paper P is supplied by the registration roller pair 13 can be determined by the control unit 110 based on the detection result from the belt sensor 24 or 25. For example, when the belt sensor 24 or 25 detects that the reference aperture group 82 (for example, the aperture group 82A) has passed as the first conveyor belt 8 travels, the control unit 110 controls the registration process after several seconds from the detection point. If the paper P is supplied to the first conveyor belt 8 by the roller pair 13, it can be determined whether the paper P can be placed 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 registration roller pair 13 so that the paper P is supplied at the determined supply timing. Thereby, the sheets P can be arranged at approximately equal intervals on the first conveyor belt 8 at each position shown in FIG. In the example shown in FIG. 11, five sheets of paper P can be transported in one cycle of the first transport belt 8, and the number of sheets of paper P printed per minute (productivity) is 150 ipm (images per minute). be able to.

Further, as shown in FIG. 11, when A4 size (horizontally placed) paper P is fed to the first conveyor belt 8, there is a space between the opening group 82F and the opening group 82A of the first conveyor belt 8. Only one sheet of paper P is supplied. In this case, the control unit 110 operates based on the detection result of the belt sensor 24 or 25 so that the center Po of the paper P in the A direction is located at the intermediate position 8m between the opening group 82F and the opening group 82A. The registration roller pair 13 is controlled so that the paper P is supplied from the registration roller pair 13 to the first conveyor belt 8 .

On the other hand, when the paper P to be used is A4 size (vertical) or letter size (vertical), the control unit 110 controls the opening group 82A and the openings on the first conveyor belt 8, as shown in FIG. The registration roller pair 13 is controlled so that two sheets of paper P are placed between the group 82D and the opening group 82D, and two sheets of paper P are placed between the opening group 82D and the opening group 82A. The paper P is supplied to the first conveyor belt 8 at the supply timing. In the example of FIG. 12, four sheets of paper P can be transported in one cycle of the first transport belt 8, and productivity of 120 ipm can be achieved.

When the paper P to be used is A3 size, B4 size, or legal size (all placed vertically), the control unit 110 controls the opening group 82A and the opening group on the first conveyor belt 8, as shown in FIG. 82B, one sheet of paper P is placed between opening group 82B and opening group 82E, and one sheet of paper P is placed between opening group 82E and opening group 82A. The registration roller pair 13 is controlled to supply the paper P to the first conveyor belt 8 at a predetermined supply timing so that the paper P is arranged. In the example of FIG. 13, three sheets of paper P can be transported in one cycle of the first transport belt 8, and productivity of 90 ipm can be achieved. Note that the control unit 110 adjusts the detection results 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 pair of registration rollers 13 based on the above and cause the first conveyor belt 8 to feed the paper P.

When the paper P to be used has a size of 13 inches x 19.2 inches, the control unit 110 controls the size of the paper P between the opening group 82A and the opening group 82D on the first conveyor belt 8, as shown in FIG. The registration roller pair 13 is controlled to feed the paper P at a predetermined timing so that one sheet of paper P is placed between the opening group 82D and the opening group 82A. It is supplied to the first conveyor belt 8. In the example of FIG. 14, two sheets of paper P can be transported in one cycle of the first transport belt 8, and productivity of 60 ipm can be achieved.

As described above, the control unit 110 determines the pattern (combination) of the plurality of opening groups 82 in the A direction to be used during flushing, depending on the size of the paper P to be used. As a result, no matter what size of paper P is used, as many papers P as possible can be placed on the first conveyor belt 8 without overlapping with the opening group 82 arranged in the above pattern. Therefore, no matter what size paper P is used, a decrease in productivity (a decrease in the number of printed sheets) can be avoided.

Furthermore, during one cycle of the first conveyor belt 8, flushing can be performed multiple times using the multiple opening groups 82 located in the above pattern. Therefore, no matter what size paper P is used, insufficient flushing and the resulting clogging of the nozzles (ink ejection ports 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 positioned in the above pattern faces the recording heads 17a to 17c as the first conveyor belt 8 runs. Thereby, flushing can be reliably performed a plurality of times during one period of the first conveyor belt 8, and the shortage of flushing can be solved.

Further, in order to eliminate the lack of flushing, there is no need to reduce the conveyance speed of the paper P as in the past, so this also contributes to improving productivity. Further, since there is no need to change the conveyance speed of the paper P, complicated conveyance control of the paper P (complex drive control of the first conveyance belt 8) is also unnecessary.

Further, in the present embodiment, the storage unit 28 stores information on the size of the paper P input in advance through the operation panel 27, that is, information on the size of the paper P conveyed by the first conveyance 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 may have a sensor that detects the size of paper P to be used, and the control unit 110 may determine the pattern of the opening group 82 according to the size detected by the sensor. , a dedicated sensor for detecting the size of paper P is required. In this embodiment, since the control unit 110 determines the pattern by recognizing the size of the paper P based on the information stored in the storage unit 28, a dedicated sensor for detecting the size of the paper P may be separately provided. The effects of this embodiment can be obtained by determining the above pattern without any modification.

Further, the control unit 110 causes the registration roller pair 13 to feed the paper P between the plurality of opening groups 82 arranged in the above pattern on the first conveyor belt 8 . As a result, even if the ink ejected from the recording heads 17a to 17c during flushing adheres to the openings 80 of the opening group 82 and the openings 80 become dirty, the paper P will not fit into the dirty openings 80. They are not transported together. Thereby, it is possible to reduce the situation in which the paper P is stained due to ink stains in the opening 80.

Further, on the first conveyor belt 8, the paper P is located at least a predetermined distance away from the opening group 82 in the A direction. As a result, for example, during flushing, ink ejected from the recording heads 17a to 17c may deviate from the path toward the opening group 82 for some reason (for example, due to the negative pressure suction of the paper P) and proceed in the A direction. Even if the ink collides with the periphery of the opening 80 of the opening group 82 and scatters (splash occurs), the scattered ink becomes difficult to reach the paper P. Therefore, it is possible to reduce the situation in which the paper P is stained due to ink splash during flushing. Note that the above-mentioned predetermined distance is appropriately set depending on the viscosity of the ink, the suction force of the paper P (the driving force of the suction member 53 described above), the running speed of the first conveyor belt 8 (the conveyance speed of the paper P), etc. However, it is not limited to the above-mentioned 10 mm.

Further, in the present embodiment, the control unit 110 controls the position on the first conveyor belt 8 between the plurality of opening groups 82 (from the opening group 82 in the A direction) based on the detection result of the belt sensor 24 or 25. The timing for supplying the paper P to a position separated by a predetermined distance or more is determined, and the paper P is supplied from the pair of registration rollers 13 to the first conveyor belt 8 at the determined timing. Thereby, the paper P can be reliably supplied to the position between the opening groups 82 of the first conveyor belt 8 by the pair of registration rollers 13, and the above-described effects can be reliably obtained.

Furthermore, in the present embodiment, as described above, the control unit 110 controls the first conveyance belt 8 in each cycle 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 ink passes through the same opening group 82. In this case, in each cycle of the first conveyor belt 8, the other opening groups 82 are not stained with ink during flushing. Therefore, even if the paper P of any class is transported so as to overlap with other opening groups 82 in each cycle of the first transport belt 8, there is no fear that the paper P will get dirty, and such paper P can be transported. . That is, for any class of paper P, it is possible to transport the paper P without staining it by arranging it in each cycle while avoiding the opening group 82 through which ink passes during flushing.

In addition, in this embodiment, as shown in FIG. 11, when one sheet of paper P is supplied from the pair of registration rollers 13 between the opening group 82F and the opening group 82A adjacent in the A direction, the control Based on the detection result of the belt sensor 24 or 25, the section 110 positions the center Po of the paper P in the A direction at the intermediate position 8m between the two adjacent opening groups 82F and 82A of the first conveyor belt 8. The pair of registration rollers 13 is controlled to supply the paper P from the pair of registration rollers 13 to the first conveyor belt 8 .

In this case, on the first conveyor belt 8, both the leading edge (the downstream end in the A direction) and the trailing edge (the upstream end in the A direction) of the paper P are located on the downstream side with respect to the paper P. The opening group 82F located on the upstream side and the opening group 82A located on the upstream side are separated by the same distance. As a result, 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, the scattered ink becomes difficult to reach the leading and trailing ends of the paper P. Therefore, it is possible to reliably reduce the situation in which the paper P is stained due to ink splashes.

Further, in this embodiment, the control unit 110 causes the paper P to be supplied from the registration roller pair 13 to the first conveyor belt 8 at regular intervals, as shown in FIGS. 11 to 14. In this case, the supply of the paper P from the pair of registration rollers 13 to the first conveyor belt 8 can be controlled at a constant timing, so that supply control of the paper P (control of the pair of registration rollers 13) becomes easy.

Further, in this embodiment, the first conveyor belt 8 further includes a suction hole 8a in addition to the opening 80 described above. In the first conveyor belt 8, the size (opening area) of the opening 80 is larger than the size (opening area) of the suction hole 8a. For example, if the suction hole 8a is large, ink ejected from the recording heads 17a to 17c during flushing may deviate from the direction toward the opening 80 toward the suction hole 8a and collide with the periphery of the opening 80, resulting in splashing. There are concerns. Since the suction hole 8a is relatively smaller than the opening 80, it is possible to further reduce the occurrence of the above-mentioned splashes, and further reduce the staining of the paper P due to the splashes.

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

Further, as shown in FIG. 11, A4 size (landscape) and letter size (landscape) belong to the same class (first class). In this class, the opening group 82 used for flushing is a fixed pattern of opening groups 82A, 82C, and 82F. Further, as shown in FIG. 12, A4 size (vertical orientation) and letter size (vertical orientation) belong to the same class (second class). In this class, the opening group 82 used for flushing is a fixed pattern of opening groups 82A and 82D. Further, as shown in FIG. 13, A3 size, B4 size, and legal size (all vertically placed) belong to the same class (third class). In this class, the opening group 82 used for flushing is a fixed pattern of opening groups 82A, 82B, and 82E. Furthermore, as shown in FIG. 14, the size of 13 inches by 19.2 inches constitutes one class (fourth class). In this class, the opening group 82 used for flushing is a fixed pattern of opening groups 82A and 82D.

In this way, the pattern of the opening group 82 used during flushing is a constant pattern for each class determined according to the size of the paper P. In this case, during flushing, the control unit 110 can easily control the ejection of ink from the recording heads 17a to 17c in a pattern corresponding to the pattern of the opening group 82 for each class. Become.

Furthermore, the patterns of the opening group 82 used during flushing are different between FIGS. 11 and 12, between FIGS. 12 and 13, and between FIGS. 13 and 14. On the other hand, the above pattern is the same in FIGS. 12 and 14. From this, it can be said that the above patterns are different between at least two classes determined depending on the size of the paper P. By setting such a pattern, flushing can be performed using the opening group 82 of an appropriate pattern for any size (class) of paper P without reducing productivity.

Further, in the first conveyor belt 8, the opening group 82 has a plurality of opening rows 81 in the A direction. The openings 80 of one of the opening rows 81 (for example, the openings 81a) are positioned offset from the openings 80 of the other opening rows 81 (for example, the opening row 81b) in the belt width direction, and It is located so as to overlap with a portion of the openings 80 of other opening rows 81 when viewed in the A direction. In this case, ink is ejected from the nozzles (ink ejection ports 18) located at any position in the width direction of the recording heads 17a to 17c, and ink is ejected from the nozzles located at any position in the belt width direction on the first conveyor belt 8. Flushing can be performed by passing through the section 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 conveyor belt 8, the plurality of openings 80 in the opening row 81 are located at equal intervals in the belt width direction. In this configuration, by positioning the plurality of opening rows 81 shifted in the belt width direction, it becomes easy to partially overlap the openings 80 of adjacent opening rows 81 when viewed in the A direction. Therefore, it becomes easy to manufacture the first conveyor belt 8 having such a configuration.

Further, in this embodiment, the first conveyor belt 8 has six opening groups 82 in the A direction in one period. In this case, patterns of the opening group 82 in the A direction can be generated for the four classes classified according to the size of the paper P without reducing productivity. Note that the first conveyor 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 of the opening group 82 in the A direction without reducing productivity for five or more classes classified according to the size of the paper P.

(3-3. Other configuration examples of the first conveyor belt)
FIG. 15 is a plan view showing another example of the configuration of the first conveyor belt 8. As shown in FIG. The first conveyor belt 8 may have a configuration in which the above-mentioned opening groups 82 are positioned at equal intervals in the conveyance direction of the first conveyor belt 8, that is, in the A direction. At this time, the two opening groups 82 adjacent in the A direction are arranged at an interval shorter than the length of the paper P in the A direction when the smallest printable size paper P is placed on the first conveyor belt 8. To position. Furthermore, in the configuration of FIG. 15, the openings 80 forming the opening group 82 also serve as the suction holes 8a in the configuration of FIG. Note that 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 as shown in FIG. This is the same as the first conveyor belt 8 shown in FIG.

Even when the first conveyor belt 8 shown in FIG. 15 is used, the control unit 110 controls the timing of flushing according to the size of the paper P used, as in the case where the first conveyor belt 8 shown in FIG. 10 is used. 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 (landscape) or letter size (landscape), the control unit 110 selects the pattern of the opening group 82 shown in FIG. 16. When the paper P used is A4 size (portrait orientation) or letter size (portrait orientation), the control unit 110 selects the pattern of the opening group 82 shown in FIG. 17. When the paper P to be used is A3 size, B4 size, or legal size (all placed vertically), the control unit 110 selects the pattern of the opening group 82 shown in FIG. 18. When the paper P to be used has a size of 13 inches x 19.2 inches, the control unit 110 selects the pattern of the opening group 82 shown in FIG. 19. Note that in FIGS. 16 to 19, for convenience, the opening groups 82 located at positions corresponding to the opening groups 82A to 82F in FIG. 10 are shown as opening groups 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 positioned in the determined pattern faces the recording heads 17a to 17c as the first conveyor belt 8 runs.

Furthermore, the control unit 110 causes the registration roller pair 13 to move the paper sheet onto the first conveyor belt 8 at the positions shown in FIGS. be supplied. At this time, the control unit 110 places each paper P on the first conveyor belt 8 at a position that is a predetermined distance or more away from the opening group 82 located in the above pattern in the A direction (including both upstream and downstream directions). The registration roller pair 13 is controlled to supply the paper P to the first conveyor belt 8 so that the paper P is arranged.

As described above, even when the first conveyor belt 8 shown in FIG. 15 is used, the control unit 110 performs the same control (flushing control, paper P control, By performing the supply control), no matter what size paper P is used, it is possible to obtain the same effects as above, such as reducing nozzle clogging due to insufficient flushing while avoiding a decrease in productivity. I can do it.

In particular, the configuration in which the opening group 82 is located at equal intervals in the A direction of the first conveyor belt 8 can be easily realized by making holes in the first conveyor belt 8 at regular intervals in the A direction. Therefore, the first conveyor belt 8 can be manufactured easily and its manufacturing cost can be reduced.

Furthermore, in the configuration in which the opening 80 of the first conveyor belt 8 also functions as the suction hole 8a shown in FIG. Only one hole size is required. In this respect as well, the first conveyor belt 8 is easier to manufacture than the configuration shown in FIG. 10 in which two types of holes of different sizes are formed.

In addition, in the configuration in which the paper P is conveyed by the first conveyor belt 9 using the negative pressure suction method, in order to avoid a decrease in productivity and to obtain effects such as reducing nozzle clogging due to insufficient flushing, the first The conveyor belt 8 may have the configuration shown in FIG. 10 or the configuration shown in FIG. 15. Therefore, to summarize the configurations of FIGS. 10 and 15, it can be said that in the first conveyor belt 8, the size of the opening 80 should be equal to or larger than the size of the suction hole 8a.

Note that in the first conveyor belt 8 having the configuration shown in FIG. 15, a large number of openings 80 for flushing are formed over the entire surface of the belt. By performing flushing using the opening 80 at a position that does not overlap with P, productivity can be significantly improved. However, when the paper P is transported in this way, the opening 80 that is contaminated by the passage of ink during flushing tends to overlap with the paper P being transported in each cycle of the first transport belt 8, and the paper P becomes dirty. It becomes easier.

Even in the configuration using the first conveyor belt 8 of FIG. 15, as described above, the pattern of the opening group 82 used during flushing is determined according to the size of the paper P, and the openings are positioned according to the determined pattern. By performing flushing using the opening group 82, flushing is performed using the same opening group 82 in each cycle, and the paper P is placed at a position different from the opening group 82 used for flushing and transported. can do. Thereby, it is possible to reduce stains on the paper P when printing is carried out by transporting the paper P over a plurality of cycles while ensuring productivity. In this respect, even when the first conveyor belt 8 having the configuration shown in FIG. 15 is used, the flushing control and paper P supply control described in this embodiment are effective.

Note that when the paper P is transported by the first transport belt 8 shown in FIG. 15, the pattern of the opening group 82 used during flushing is different from the pattern when the first transport belt 8 shown in FIG. 10 is used. It may be a pattern. For example, flushing may be performed on a group of openings located between the sheets P being transported at the positions shown in FIGS. 16 to 19.

Above, we have explained an example using a color printer that records color images using four color inks as an inkjet recording device, but when using a monochrome printer that records monochrome images using black ink However, it is possible to apply the control described in this embodiment.

INDUSTRIAL APPLICABILITY The present invention can be used in an inkjet recording device that records an image by ejecting ink onto a storage medium.

8 First conveyor belt (conveyor belt)
8a Suction hole 17a-17c Recording head 18 Ink discharge port (nozzle)
30 Liquid feeding mechanism 31Y, 31M, 31C, 31K Ink receiving section 50 Negative pressure generating section 51a, 51b, 51c, 51d, 51e First suction chamber 52a, 52b, 52c, 52d Second suction chamber 53 Suction member 53a First suction Member 53b Second suction member 54 Low flow path resistance section 55 High flow path resistance section 56 Filter 80 Opening section 100 Printer (inkjet recording device)
110 Control unit E ₁ Opposing section E ₂ Non-opposing section P Paper (recording medium)

Claims (7)

a recording head having a plurality of nozzles that eject ink;
An inkjet recording apparatus comprising: an endless conveyor belt that conveys a recording medium to a position facing the recording head,
a negative pressure generating section that generates negative pressure for suctioning the recording medium through the suction hole of the conveyor belt;
The recording head is disposed opposite to the recording head via the conveyor belt, and when flushing is performed in which the ink is ejected at a timing different from the timing at which the recording head contributes to image formation on the recording medium, the recording further comprising an ink receiving section that receives the ink ejected from the head and passing through the opening of the conveyor belt,
The suction force generated by the negative pressure is greater in the non-opposing section on the upstream or downstream side in the conveyance direction of the recording medium with respect to the opposing section than in the opposing section where the recording head and the ink receiving section face each other. is strong,
The negative pressure generating section is
a suction member that generates the negative pressure;
a first suction chamber that suctions the recording medium conveyed through the non-opposed section by the negative pressure;
An inkjet recording apparatus comprising: a second suction chamber that suctions the recording medium conveyed through the opposing section by the negative pressure . the ink receiving section is arranged in the second suction chamber,
The first suction chamber has a low flow resistance section in which the flow resistance of the suction air generated by the negative pressure is relatively low;
The inkjet recording apparatus according to claim 1, wherein the second suction chamber has a high flow path resistance portion where the flow path resistance is relatively high. the ink receiving section is arranged in the second suction chamber,
The flow path resistance of the suction air generated by the negative pressure is the same in the first suction chamber and the second suction chamber,
The suction member is
a first suction member that suctions the first suction chamber at a first suction amount;
2. A second suction member that sucks the second suction chamber with the first suction amount or a second suction amount that is smaller than the first suction amount. inkjet recording device. further comprising a control unit that controls the flushing by the recording head and selectively switches the suction amount of the second suction member between the first suction amount and the second suction amount;
The control unit is configured to switch the suction amount of the second suction member from the first suction amount to the second suction amount when the recording head performs the flushing, and the control unit is configured to switch the suction amount of the second suction member from the first suction amount to the second suction amount when the recording head performs the flushing. 4. The inkjet recording apparatus according to claim 3, wherein the second suction amount is switched to the first suction amount when ejecting. further comprising a filter disposed on the conveyor belt side with respect to the ink receiving section,
The filter is characterized in that it allows ink ejected from the recording head to pass through during the flushing, and absorbs ink droplets that are scattered to the outside when the ink collides with the liquid surface of the ink receiving portion. The inkjet recording apparatus according to any one of claims 1 to 4. The inkjet recording apparatus according to claim 5, wherein the filter is arranged to be replaceable. 7. The inkjet recording apparatus according to claim 1, further comprising a liquid sending mechanism that sends the ink collected by the ink receiving section to the recording head.

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