JP2007268794A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an undersize imaging device which can easily maintain a recording head especially, even in such a state that a recording medium is loaded so as to position it opposite to the recording head, with regard to the imaging device which prints data in the recording medium by discharging ink from a plurality of nozzles installed in the recording head. <P>SOLUTION: A medium opening 10a is formed in the recording medium using a cutting-out blade 20a of an opening formation mechanism 20, to a web such as rolled paper. Then, the medium opening 10a is transferred and thereby, is made to coincide with a support part opening 23a opened in a platen 23. After that, a maintenance head 24 is inserted into the medium opening 10a and the support part opening 23a, and the tip of the maintenance head 24 is attached tightly to a nozzle plate 9 on which the nozzles of the recording head are formed, in the state that the recording medium is brought into contact with the platen 23. Next, maintenance services such as capping procedure, no-load discharge procedure and suction/purge procedure, are performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that performs printing on a recording medium by discharging ink from a plurality of nozzles provided in a recording head.

  Inkjet image forming apparatuses, for example, have a high speed by ejecting ink to a recording medium such as recording paper or plastic film from a plurality of nozzles provided in the recording head when being conveyed by a recording medium conveying unit. In addition, a high-quality image is formed.

  In such an image forming apparatus, when conveying the recording medium, dust such as paper dust generated by contact between the recording media may adhere to the ink discharge port of the recording head and cause clogging. In addition, bubbles may enter the ink discharge port and reduce the surface tension of the ink. For these reasons, problems such as ink ejection failure and bending in the ink ejection direction occur. Therefore, a maintenance mechanism for quickly eliminating the cause is indispensable.

  On the other hand, the recording system includes a recording system in which both the recording head and the recording medium are moved, and a fixed line head system in which the recording head is fixed in, for example, a line and only the recording medium is conveyed and recorded. In the former, maintenance can be easily performed by moving the recording head to face a maintenance mechanism arranged on the side of the recording medium. On the other hand, in the latter line head system, various devices that face the maintenance mechanism have been proposed.

  For example, in Patent Document 1, the following apparatus is proposed. That is, a recovery unit for stabilizing the head performance is arranged on the upstream side in the transport direction of the roll paper for the ink jet print head that forms an image on the roll paper, and the ink jet print head is moved upward at the time of maintenance. The recovery unit is opposed to the ink jet print head by horizontally moving below the ink jet print head.

For example, Patent Document 2 proposes the following apparatus. In other words, the ink jet recording apparatus enables high-speed printing by electrostatically attracting a sheet onto an endless belt and passing it under a recording head corresponding to the sheet width (non-scanning type). On the other hand, the conveyor belt unit is configured by attaching an endless belt between two endless belts stretched between a driving roller and a driven roller, and a portion where the endless belt is not provided between the endless belts is an opening. It is said that. A maintenance device is disposed inside the conveyance belt unit so as to face the recording head, and maintenance is performed by facing the maintenance device to the recording head through the opening.
Japanese Unexamined Patent Publication No. 7-47670 JP 2004-262020 A

  However, in the invention of Patent Document 1, it is necessary to dispose the recording head and the maintenance mechanism so that they do not completely overlap in the conveyance direction of the recording medium. The size is increased in the recording medium conveyance direction.

  In Patent Document 2, the recording medium cannot be positioned between the recording head and the maintenance mechanism during maintenance. For this reason, for example, when the same mechanism is applied to image formation on continuous paper, the continuous paper loaded so that the maintenance mechanism is opposed to the recording head during maintenance is temporarily cut, and between the recording head and the maintenance mechanism. The recording medium needs to be removed. For this reason, in order to resume printing after maintenance, it is necessary to reload the continuous paper.

  An object of the present invention is to provide an image forming apparatus that can easily perform maintenance of a recording head even when the recording medium is loaded so as to face the recording head.

  According to the image forming apparatus of the present invention, the above-described problem is a recording head having a nozzle that discharges ink to a recording medium, a maintenance head that performs maintenance on the recording head, and a transport unit that transports the recording medium. And an image forming apparatus having a medium opening forming portion for forming a medium opening in the recording medium and performing maintenance using the medium opening.

The recording head is a line-shaped head that is fixed to the recording medium at the time of image formation, and the recording medium is continuous paper.
With this configuration, even in an image forming apparatus that uses a fixed line head as a recording head and uses continuous paper such as roll paper, the recording head can be easily maintained.

  According to the means for solving the above problems, in an image forming apparatus using a fixed line head and using continuous paper, the recording head can be maintained while the recording medium is loaded on the recording head, and the movement of the maintenance can be performed. A small image forming apparatus can be provided without increasing the size of the mechanism.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, in the drawing, the conveyance direction of the recording medium is the X-axis direction or the sub-scanning direction, and the direction orthogonal to the conveyance direction is the Y-axis direction, the main scanning direction, or the width direction of the recording medium. Furthermore, the direction orthogonal to the X-axis and Y-axis directions is defined as the Z-axis direction or the vertical direction.

  FIG. 1 shows a schematic configuration of an image forming apparatus of the present embodiment. The image forming apparatus 1 includes an image forming unit 2, an ink supply unit 3, an opening forming unit 4, a maintenance unit 5, and a roll paper transport unit 6.

  The image forming unit 2 includes four recording heads 2K, 2C, 2M, and 2Y that can handle black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the recording medium conveyance direction. Configured. For example, in the yellow (Y) recording head 2Y, as shown in FIG. 2, four inkjet heads 2Y-1, 2Y-2, 2Y-3, 2Y-4 that are short in the Y direction are arranged in a staggered manner in the Y direction. And fixed to the holding plate 8. Each inkjet head 2Y-1, 2Y-2, 2Y-3, 2Y-4 has a nozzle row 12 in which a number of nozzles 11 for ejecting ink onto a recording medium are formed in a row on a nozzle plate 9. .

  Further, when the four ink jet heads 2Y-1, 2Y-2, 2Y-3, 2Y-4 are viewed from the X-axis direction, the four nozzle row end portions are arranged so as to slightly overlap each other. 2Y forms one nozzle row having a recording width in the Y-axis direction. The other recording heads 2K, 2C, and 2M have the same configuration, and the four recording heads 2K, 2C, 2M, and 2Y are arranged in the X-axis direction while maintaining the same pitch P. As a result, the image forming unit 2 configured by a linear recording head fixed to the recording medium 10 at the time of image formation is configured.

  Next, the ink supply unit 3 includes an ink bottle 13, a sub tank 14, an ink supply electromagnetic valve 15, and the like. The ink bottle 13 is provided at the uppermost position in the height direction. Ink is replenished. The sub tank 14 is provided with a liquid level detection sensor (not shown), and controls the ink liquid level in the sub tank 14 to be constant. In this case, the liquid level is at a position about 10 cm below the surface of the nozzle plate 9 of the inkjet heads 2K-1, 2K-2, 2K-3, 2K-4,. is there.

  The inside of the sub tank 14 is normally opened to the atmosphere by an atmosphere opening electromagnetic valve 16. An ink flow path is connected to each inkjet head 2K-1, 2K-2, 2K-3, 2K-4,... Further, a replenishment path valve 17 is provided between the sub tank 14 and the inkjet heads 2K-1, 2K-2, 2K-3, 2K-4, ... 2Y-4. Further, a pressurizing pump 18 for sending compressed air to the sub tank 14 is provided with a pressurizing valve 19 on the way and connected to the sub tank 14.

  The pressurizing pump 18 is used when the ink-jet heads 2K-1, 2K-2, 2K-3, 2K-4,. After the supply path valve 17 is tightened to increase the pressure in the sub-tank 14, the supply path valve 17 is opened to fill the ink at once.

  The ink bottle 13, the sub tank 14, the ink supply electromagnetic valve 15, the air release electromagnetic valve 16, the supply path valve 17, the pressurization pump 18, and the pressurization valve 19 are configured as black (K), cyan (C), It is provided for each color of magenta (M) and yellow (Y).

  Next, the opening forming unit 4 includes an opening forming mechanism 20, a tube 21, and a negative pressure source 22. The opening forming mechanism 20 is disposed on the upstream side in the transport direction of the recording medium 10 of the image forming unit 2, and the opening forming mechanism 20 has a hollow cutting blade 20a having a rectangular tip and movable in the Z-axis direction. Similar to the recording heads 2K, 2C, 2M, and 2Y described above, four are arranged in a zigzag manner in the Y-axis direction, and the internal space is connected to the negative pressure source 22 via the tube 21. Further, the punching blade 20a is provided with a moving mechanism that is movable in the Z-axis direction (not shown).

  Next, the maintenance unit 5 is disposed in a downward direction, which is a space opposite to the recording heads 2K, 2C, 2M, and 2Y with respect to the recording medium 10 supported by the platen 23. The maintenance unit 5 includes a maintenance head 24 corresponding to the recording heads 2K, 2C, 2M, and 2Y, a holding member 25 that holds the maintenance head 24, and a moving mechanism 26 that moves the holding member 25. The maintenance heads 24 are arranged in a staggered manner in the Y-axis direction so as to correspond to the respective inkjet heads 2K-1, 2K-2, 2K-3, 2K-4,... 2Y-4. Four sets are arranged in the X-axis direction. A negative pressure source 27 of the suction pump is connected to each maintenance head 24 through a tube formed in the holding member 25. The front ends of the maintenance heads 24 are positioned in the support opening 23a of the platen 23, respectively.

  As shown in FIG. 3, the maintenance head 24 has an outer peripheral portion 28 which is in contact with the nozzle plate 9, a recessed portion 29 slightly recessed from the outer peripheral portion 28, and a recessed portion 29. 27 has a suction hole 30 leading to 27.

  Further, a planar platen 23 is disposed to face the recording heads 2K, 2C, 2M, and 2Y. On the platen 23, four inkjet heads 2K-1, 2K-2, 2K-3, 2K-4,... 2Y-4, and four in a staggered manner in the Y-axis direction so as to correspond to the maintenance head 24 Furthermore, four support openings 23a are formed in which four sets are arranged in the X-axis direction.

Next, the roll paper transport unit 6 includes transport rollers 31 to 34, an original winding roller 35, and a winding roller 36. The recording medium 10 is a continuous paper wound in a roll shape around the original winding roller 35, and is unwound from the original winding roller 35 by the conveying rollers 31, 32, 33, 34, conveyed on the platen 23, and taken up. It is wound up by a roller 36.

Next, an image forming operation by the image forming apparatus having the above configuration will be described.

  First, the conveyance rollers 31, 32, 33, and 34 are driven to unwind the recording medium 10 from the original winding roller 35, and the image forming unit 2 in which the four recording heads 2K, 2C, 2M, and 2Y are arranged is provided. On the other hand, the platen 23 is conveyed. At this time, image data is supplied to the recording head 2, and black (K), cyan (C), magenta (M), and yellow (Y) inks are respectively supplied from the four recording heads 2K, 2C, 2M, and 2Y. An image is formed on the recording medium 10 by being ejected onto the recording medium 10. Thereafter, the recording medium 10 is taken up by the take-up roller 36. During this time, ink supply to the recording heads 2K, 2C, 2M, and 2Y is performed by the ink supply unit 3 having the above-described configuration. At this time, the maintenance head 24 is located at a position 24 indicated by a solid line in FIG. 4 where the outer peripheral portion 28 is positioned below the surface of the platen 23 that supports the recording medium 10 so as not to interfere with the recording medium 10. Is at position 25, also indicated by a solid line. Note that reference numeral 23 a shown in the figure is a support opening formed in the platen 23.

On the other hand, the maintenance is performed as follows.
First, the conveyance of the recording medium 10 is stopped, and the opening operation to the recording medium 10 by the opening forming unit 4 is performed. In this operation, the negative pressure source 22 is first driven to generate a negative pressure. Next, as shown in FIG. 4, the punching blade 20a is pressed onto the platen 23 by a moving mechanism (not shown), and the recording medium 10 is punched into a square shape to form a medium opening 10a. The generated extracted residue 10b is sucked to the negative pressure source 22 through the tube 21 by the negative pressure. The portion 23b of the platen 23 against which the punching blade 20a is pressed is recessed, for example, by 0.1 to 0.5 mm as shown in the figure. Even if the flatness of the platen surface deteriorates due to the punching blade 20a, recording is performed. It does not hit the medium 10 and does not affect the conveyance performance.

  By the punching process, four medium openings 10a arranged in a staggered manner in the Y-axis direction are formed. Thereafter, the recording medium 10 is moved in the transport direction by the pitch P of the arrangement between the adjacent recording heads 2K, 2C, 2M, and 2Y, and the punching process is continued. The same process is repeated three times to form four rows of medium openings 10a in the X-axis direction.

  Thereafter, the recording medium 10 is conveyed by the distance between the punching blade 20a and the recording head 2K, and each medium opening 10a is moved to the respective inkjet heads 2K-1, 2K-2, 2K-3, 2K-4,. It is located directly under the nozzle plate 9.

  Next, the maintenance mechanism 24 and the holding member 25 are moved in the Z-axis (+) direction by the moving mechanism 26, and the outer peripheral portion 28 at the front end of each maintenance head 24 is moved to each inkjet head 2K-1, 2K-2, 2K-3. 2K-4,... 2Y-4 are brought into contact with the surface of the nozzle plate 9. At this time, the maintenance head 24 is at a position 24 ′ indicated by a two-dot chain line in FIG. 4, and the holding member 25 is at a position 25 ′ also indicated by a two-dot chain line. Note that reference numeral 23 a shown in the figure is a support opening formed in the platen 23.

  As described above, the maintenance head 24 corresponding to the nozzle plate 9 of each inkjet head 2K-1, 2K-2, 2K-3, 2K-4,. .

Next, a specific example of the maintenance process will be described below.
<Capping process>
The capping process is performed when the image forming process is not performed for a long time or when the image forming apparatus 1 is turned off. First, as described above, the maintenance head 24 and the holding member 25 are moved in the Z-axis (+) direction by the moving mechanism 26, and the outer peripheral portion 28 at the tip of each maintenance head 24 is moved to each inkjet head 2K-1, 2K-2. 2K-3, 2K-4,... 2Y-4 are brought into contact with the surface of the nozzle plate 9. At least the outer peripheral portion 28 of the maintenance head 24 is made of an elastic member such as fluoro rubber, and the outer peripheral portion 28 is in close contact with the surface of the nozzle plate 9.

  By this processing, all the nozzles 11 are configured to be located inside the above-described recessed portion 29 while the image forming apparatus 1 is not used, so that thickening and drying of ink in the nozzles 11 can be prevented, and further to the periphery of the nozzles 11 It is possible to prevent the adhering of trash etc.

<Empty discharge processing>
In the idle ejection process, a voltage is applied to the electrodes in each inkjet head 2K-1, 2K-2, 2K-3, 2K-4,. The idle ejection drive is performed, and the ink is ejected from each nozzle 11 to the recess 29. By this process, the thickened ink and foreign matter around each nozzle 11 can be removed from the nozzle, and the ejection performance can be recovered.

Further, the ink discharged to the recessed portion 29 is sucked from the suction hole 30 through the tube formed in the holding member 25 to the negative pressure source 27 and stored in a waste liquid tank (not shown).
<Pressure purge process>
In the pressure purge process, the ink replenishing solenoid valve 15, the air release solenoid valve 16, and the replenishment path valve 17 are tightened to open the pressure valve 19, and the pressure pump 18 is driven to drive the sub tank 14 to a predetermined pressure. After that, the supply path valve 17 is opened, and the pressure is applied to the ink chamber (not shown) in the inkjet heads 2K-1, 2K-2, 2K-3, 2K-4,. In addition, the ink is pushed out from the nozzle 11. The ink pushed out by this process is sucked through the suction holes 30.

Also by this maintenance process, the thickened ink and foreign matter around each nozzle 11 can be removed from the nozzle, and the ejection performance can be recovered.
<Suction purge process>
The suction purge process is a process of operating the negative pressure source 27 to generate a negative pressure in the recess 29 and sucking ink in the nozzles 11 and ink remaining on the surface of the nozzle plate 9.

  By this maintenance process, for example, thickened ink around the nozzles 11 and foreign matter can be removed from the nozzles 11, unnecessary ink on the surface of the nozzle plate 9 can be removed, and the ejection performance can be recovered. Note that the negative pressure level of the negative pressure source 27 may be changed in the idle discharge process, the pressure purge process, and the suction purge process.

  Next, when image forming processing is performed after each maintenance described above, the maintenance head 24 and the holding member 25 are moved in the Z-axis (−) direction, the recording medium 10 is conveyed, and all the medium openings 10a are imaged. After moving to the downstream side of the forming unit 2, the image forming process is started.

  In post-processing such as cutting of the recording medium 10 taken up by the take-up roller 36, a mark printed simultaneously on a necessary image is detected and post-processed. If necessary, marks indicating the first and last positions where the medium opening 10a is formed are printed and detected, or the medium opening 10a is directly detected by an optical sensor or the like, and the medium opening 10a is formed. The part may be configured to perform a process different from the part where the necessary image is formed in a post-processing step.

  With this configuration, maintenance of the recording heads 2K, 2C, 2M, and 2Y using continuous paper can be performed while the continuous paper is loaded on the image forming unit 2. For this reason, the time until the image forming process after the maintenance is started can be shortened, and the throughput can be improved. Further, since it is not necessary to cut the continuous paper halfway during maintenance, winding can be performed on one continuous roll, and post-processing after image formation is facilitated. In addition, even when printing is interrupted for a long time in the middle of one roll, the above-described capping process can be performed, and the handling becomes easy.

  Further, since the maintenance unit 5 is disposed in the space opposite to the recording heads 2K, 2C, 2M, and 2Y with respect to the recording medium 10, the maintenance head 24 and the holding member 25 are slightly moved in the Z-axis direction during maintenance. Just do it. For this reason, a moving mechanism can be reduced in size and an image forming apparatus can also be comprised small. For example, the minimum value of the movement amount may be about 0.5 to 3 mm, for example, between the recording heads 2K, 2C, 2M, and 2Y and the surface of the platen 23 that supports the recording medium 10.

  Further, since there is no need to move the recording heads 2K, 2C, 2M, and 2Y for maintenance, the positional accuracy of the recording heads 2K, 2C, 2M, and 2Y can be maintained high, and high-quality image formation can be performed. .

  Further, the portion of the platen 23 against which the punching blade 20a is pressed is recessed by 0.1 to 0.5 mm as described above, and even if the flatness of the belt platen surface is deteriorated by the punching blade 20a, the portion of the platen 23 is not in the recording medium 10. It does not hit and does not affect the transport performance.

The maintenance process can be performed in the same manner even when the recording medium 10 is not on the platen 23. In this case, an operation necessary for forming a medium opening in the recording medium 10 can be omitted.
Further, the shape of the punching blade 20a is substantially equal to the shape of each maintenance head 24. However, for example, a plurality of maintenance heads 24 are located in one medium opening as indicated by a two-dot chain line in FIG. It is good also as a structure. Further, for example, a single opening 20a may be moved in the Y-axis direction to form a medium opening arranged in the Y-axis direction. In this case, the number of punching blades can be reduced.

  Moreover, you may make it attract | suck the extraction waste 10b extracted with the extraction blade 20a from the belt platen 23 side. Further, although the punching blade 20 a is arranged on the upstream side of the image forming unit 2, it may be arranged on the downstream side of the image forming unit 2. In this case, after the medium opening is formed by the punching blade 20a, the recording medium 10 is transported in the opposite direction to the image formation, and the medium opening 10a is opposed to the maintenance head 24 and the recording heads 2K, 2C, 2M, and 2Y. Move to the desired position.

  Further, a minute hole is formed in the platen 23 on the entire surface facing the recording heads 2K, 2C, 2M, and 2Y, and the minute hole is connected to a negative pressure source, thereby making the minute hole a negative pressure. The recording medium 10 can also be adsorbed on the surface of the platen 23. In this case, the recording medium 10 can be brought into close contact with the surface of the platen 23, and better image formation is possible.

  When the recording medium 10 is continuous paper, the platen 23 other than the portion facing the punching blade 20a can be deleted, and the recording medium 10 can be transported by the transport rollers 31 to 34. In this case, since there is no platen 23 between the maintenance head 24 and the recording heads 2K, 2C, 2M, and 2Y, the support part opening 23a is not necessary in the platen 23.

  The medium openings 10a are provided corresponding to all the ink jet heads 2K-1, 2K-2, 2K-3, 2K-4,... 2Y-4, but are arranged in a staggered manner in the Y-axis direction, for example. Only the four openings are formed in the recording medium 10, and the recording head 2K is first maintained with the medium opening 10a facing the recording head 2K, and then the recording medium 10 is transported, and the medium opening 10a is connected to the recording head 2C. Correspondingly, the recording head 2C may be maintained. In this case, since only the medium openings corresponding to a part of the recording heads 2K, 2C, 2M, and 2Y are formed in the recording medium 10, the number of medium openings 10a to be formed is reduced, and the waste of the recording medium 10 is reduced.

  Further, the maintenance unit 5 may have a configuration shown in FIG. 5, for example. In this modification, the maintenance head 24 is configured to be short in the Y-axis direction and movable in the Y-axis direction. A wiper 40 made of, for example, elastic rubber is disposed at the end of the maintenance head 24 in the Y-axis direction. With the outer peripheral portion 28 at the tip of the maintenance head 24 in contact with the surface of the nozzle plate 9 of each inkjet head 2K-1, 2K-2, 2K-3, 2K-4,. The maintenance head 24 is moved in the Y-axis (−) direction. At this time, the tip of the wiper 40 in contact with the surface of the nozzle plate 9 cleans the ink on the surface of the nozzle plate 9. Furthermore, both the maintenance head shown in FIG. 3 and the maintenance head shown in FIG. 5 can be configured as a switchable mechanism, and both are arranged on the holding member 25 so that both can be selectively used.

  Further, the medium opening may be formed separately for one recording head 2K composed of a plurality of inkjet heads 2K-1, 2K-2, 2K-3, 2K-4, and the like. For example, in the example shown in FIG. 6, first, medium openings 10a corresponding to 2Y-1, 2Y-3, etc. are formed for four recording heads (a shown in the figure), and then 2Y-2, 2Y-. The medium openings 10a corresponding to 4 etc. are formed for four recording heads (b shown in the figure), and the maintenance is performed by dividing the ink jet heads corresponding to the above a and b twice. In this case, the maintenance unit 5 has a moving mechanism that selectively moves the maintenance head 24 corresponding to a and b in the Z-axis direction.

In the case of this modification, since the area ratio of the medium opening 10a to the recording medium 10 is small, it is possible to suppress a decrease in rigidity of the recording medium 10.
Further, when the recording heads 2K, 2C, 2M, and 2Y are constituted by a single inkjet head that is long in the width direction of the recording medium 10 as shown in FIG. 7, the recording head 10 is long in the width direction. A medium opening 10a is formed.

  Further, according to the present example, in the case of maintenance only for empty discharge as maintenance, the maintenance head 24 and the holding member 25 do not move in the Z-axis direction as shown in FIG. You may carry out in the state away from. In this case, the opening area of the medium opening 10a and the support portion opening 23a of the platen 23 may be such that the ink ejected from the nozzle 11 passes and can be a narrow slit. For this reason, the rigidity reduction of the recording medium 10 and the platen 23 can be reduced. Further, since the support opening 23a facing the recording heads 2K, 2C, 2M, and 2Y can be made small, the recording medium 10 can be favorably supported.

Further, the capping can be performed by moving the recording head 2 to the platen 23 side in FIG. 8 and bringing the nozzle plate 9 into close contact with the surface of the recording medium 10 or the surface of the platen 23.

Next, a second embodiment of the present invention will be described.

In addition, about description of 2nd Embodiment, description is abbreviate | omitted about the same component as the above-mentioned 1st Embodiment, and only a different component is demonstrated.
FIGS. 9A, 9B, and 9C are diagrams illustrating the configuration of this example. In the present embodiment, the support portion opening 23a of the platen 23 is not located at the position 10c where the ink ejected from the nozzle 11 such as the ink jet head 2K-1 lands on the recording medium 10, and is shifted downstream from this position. It is arranged at the position. In addition, a minute hole (not shown) for sucking the recording medium 10 is arranged in the platen 23 just below the position 10c where the ink lands.

  The maintenance head 24 has a notch 24b formed on the X-axis (−) side, and the tip 24a of the maintenance head 24 protrudes on the X-axis (−) side. Further, the outer peripheral portion 28, the recessed portion 29, and the suction hole 30 as described above are formed at the tip 24 a of the maintenance head 24.

At the time of image formation, the tip 24a of the maintenance head 24 is positioned within the support opening 23a of the platen 23 as shown in FIG.
At the time of maintenance, as shown in FIG. 9B, the inkjet head 2k-1 and the like are moved in the Z-axis (+) direction so as to be separated from the recording medium 10. At the same time, the maintenance head 24 and the holding member 25 are moved in the Z-axis (+) direction by the moving mechanism 26, and the tip 24a of the maintenance head 24 is moved from the medium opening 10a to the ink jet head 2K-1 and the like.

  Next, as shown in FIG. 9C, the maintenance head 24 and the holding member 25 are moved to the X-axis (−) side by the moving mechanism 26, and the tip 24a of the maintenance head 24 is moved below the inkjet head 2K-1. To be located. Then, the inkjet head 2K-1 and the like are moved in the Z-axis (−) direction, and the nozzle plate 9 is brought into contact with the outer peripheral portion 28 of the tip 24a of the maintenance head 24 to perform the above-described maintenance process such as suction purge.

As described above, in the present embodiment, the support portion opening 23a of the platen 23 is not located at the position 10c where the ink ejected from the nozzle 9 such as the inkjet head 2K-1 lands on the recording medium 10, but this position. And a minute hole (not shown) for sucking the recording medium 10 on the platen 23 is also disposed immediately below the position 10c where the ink lands. For this reason, even at the time of image formation, the upper surface of the platen 23 can support the position 10c where the ink lands on the recording medium 10, so that the flatness of the recording medium 10 at the landing position can be ensured and good image formation can be performed. it can.

Next, a third embodiment of the present invention will be described.

In addition, about description of 3rd Embodiment, description is abbreviate | omitted about the same component as the above-mentioned 1st, 2nd embodiment, and only a different component is demonstrated.
FIG. 10 is a diagram illustrating the configuration of this example. In the present embodiment, a notch 24c is formed on the Y axis (+) side, which is the direction in which the maintenance head 24 moves during maintenance, and the tip 24a of the maintenance head 24 is formed to protrude on the Y axis (+) side. Yes.

  At the time of maintenance, the inkjet head 2k-1 and the like are moved in the Z-axis (+) direction so as to be separated from the recording medium 10. At the same time, the maintenance head 24 and the holding member 25 are moved from the positions 24 and 25 to the Z-axis (+) side by the moving mechanism 26 and are positioned at 24 ′ and 25 ′, and the outer peripheral portion 28 of the tip 24a of the maintenance head 24. Is brought into contact with the nozzle plate 9.

  Next, while the maintenance head 24 is moved to the Y axis (+) side, the maintenance such as the aforementioned suction purge and the cleaning of the nozzle 11 and the nozzle plate 9 by the wiper 41 are performed. Further, at the position 24 ″ where the maintenance head 24 has moved most to the Y-axis (+) side, the blade 41 wipes all the nozzle rows 12 and is located closer to the Y-axis (+) side than the nozzle rows 12, and the maintenance head At least a part of the tip 24a of 24 is in a position protruding to the Y-axis (+) side from the medium opening 10a and the support opening 23a.

  After the maintenance is completed, the inkjet head 2k-1 and the like are moved in the Z-axis (+) direction so as to be separated from the tip 24a of the maintenance head 24, and the maintenance head 24 and the holding member 25 are moved to the Y-axis (−) side. Further, it is moved to the Z-axis (−) side and returned to the initial position.

  With this configuration, the maintenance head 24 is formed with the notch 24c on the Y axis (+) side, which is the direction in which the maintenance head 24 moves during maintenance. It can be located in the position which protruded in the Y-axis (+) side rather than the opening 10a and the support part opening 23a. For this reason, the length of the medium opening 10a and the support opening 23a in the moving direction of the maintenance head 24 can be shortened, and a decrease in rigidity of the recording medium 10 and the platen 23 can be suppressed.

  Even when the interval between the recording width end of image formation and both ends of the recording medium 10 is short or not, the length from the medium opening 10a to both ends in the Y direction of the recording medium 10 can be increased, and the rigidity of the recording medium 10 can be increased. The decrease can be suppressed.

The cutouts 24c may be formed on both sides where the maintenance head 24 moves during maintenance. In this case, at both ends where the maintenance head 24 moves, both ends in the Y-axis direction of the tip 24a of the maintenance head 24 may be positioned at positions projecting more in the Y-axis direction than the medium opening 10a and the support portion opening 23a. it can. For this reason, the length of the medium opening 10a and the support opening 23a in the moving direction of the maintenance head 24 can be further shortened.

Next, a fourth embodiment of the present invention will be described.

  FIG. 11 is a diagram illustrating the configuration of this example. In the present embodiment, the maintenance head 24 is a combination of the above-described third embodiment and the second embodiment. That is, the maintenance head 24 is formed with a notch 24c on the Y-axis (+) side, and a notch 24b is also formed on the X-axis (−) side.

  The positional relationship between the maintenance head 24 and the inkjet head 2k-1 and the like is the same as the configuration shown in FIG. 9 when viewed from the Y-axis direction and the configuration shown in FIG. 10 when viewed from the X-axis direction.

  During maintenance, the nozzle plate 9 is brought into contact with the outer peripheral portion 28 of the tip 24a of the maintenance head 24 from the position shown in FIG. 9A through FIG. 9B and as shown in FIG. 9C. Next, as shown in FIG. 10, the maintenance head 24 is moved to the Y axis (+) side to perform maintenance such as suction purge and wiping.

By configuring as described above, an image forming apparatus having the effects of both the second embodiment and the third embodiment can be provided.

Next, a fifth embodiment of the present invention will be described.

  FIG. 12 is a diagram for explaining the configuration of this example. In the present embodiment, maintenance is performed by inserting the periphery of the nozzle 11 such as the inkjet head 2k-1 through the medium opening 10a and the support opening 23a.

  FIG. 12A shows the time of image formation. The support portion opening 23 a is shifted to the X axis (+) side with respect to the ink landing position 10 c of the recording medium 10. On the other hand, at the time of maintenance, as shown in FIG. 12B, the inkjet head 2k-1 and the like move to the X axis (+) side, and then move to the Z axis (−) side to move the nozzle plate 9 to the maintenance head 24. It is made to contact | abut to the outer peripheral part 28 of the front-end | tip. Next, as shown in FIG. 12C, the maintenance head 24 is moved to the Y-axis (+) side to perform maintenance such as suction purge processing and wipe.

With this configuration, maintenance is performed in a state where the nozzle 11 is positioned in the support portion opening 23a below the recording medium 10 and the platen 23 surface. For this reason, even if ink mist is generated due to maintenance, the recording medium 10 and the surface of the platen 23 supporting the recording medium 10 are less likely to be stained, and the surface of the recording medium 10 is not stained with ink during image formation.

Next, a sixth embodiment of the present invention will be described.

FIGS. 13 and 14 are diagrams for explaining this example. In the present embodiment, the recording medium 10 is conveyed by the belt platen 50 in the image forming unit 2.
A belt platen 50 that conveys the recording medium 10 includes a driving roller 51, a driven roller 52, a tension roller 53, an endless belt 54, pressing rollers 55 and 56, and a platen 23. A large number of holes (not shown) are formed on the entire surface of the platen 23 and the endless belt 54. Then, the recording medium 10 is sucked onto the endless belt 54 through the hole of the platen 23 and the hole of the endless belt 54 by a negative pressure source (not shown), and the recording medium 10 is pressed onto the endless belt 54 by the pressing rollers 55 and 56. Then, the recording medium 10 is conveyed.

  As shown in FIG. 14, in the endless belt 54, four belt openings 54a corresponding to the tip shape of the maintenance head 24 are arranged in a staggered manner in the Y-axis direction, and four sets thereof are arranged in the X-axis direction. . At the time of maintenance, a marking indicating the belt opening 54a of the endless belt 54 (not shown) is detected, and the medium openings 10a are sequentially formed by the punching blade 20a of the opening forming mechanism 20 in accordance with the belt opening 54a. Thereafter, maintenance is performed by moving the endless belt 54 such that the plurality of belt openings 54a and the medium openings 10a are respectively positioned corresponding to the tips of the maintenance heads 24.

With this configuration, even in the belt platen 50 using the endless belt 54 as the transport mechanism for the recording medium 10, the recording medium 10 is similarly connected to the recording heads 2K, 2C by forming the belt opening 54a in the endless belt 54. Maintenance can be performed in a loaded state so as to face 2M and 2Y.

Next, a seventh embodiment of the present invention will be described.

  FIG. 15 is a diagram for explaining this embodiment. In this embodiment, a cylindrical platen 60 is used instead of the planar platen. The recording heads 2 </ b> K, 2 </ b> C, 2 </ b> M, 2 </ b> Y and the maintenance head 24 are arranged radially so as to go toward the central axis of the cylindrical platen 60.

  As shown in FIG. 15, the support opening 60 a formed in the platen 60 is shifted in the circumferential direction with respect to the recording heads 2 </ b> K, 2 </ b> C, 2 </ b> M, 2 </ b> Y and the maintenance head 24 during image formation. The recording medium 10 is pressed against the surface of the platen 60 by the driving roller 62 and the driven roller 61, and the recording medium 10 is conveyed by sliding on the surface of the platen 60 by the driving roller 62.

  During maintenance, the platen 60 is rotated in the circumferential direction so that the support opening 60a is positioned at a position corresponding to the recording heads 2K, 2C, 2M, and 2Y and the maintenance head 24. Then, the medium opening 10a is sequentially formed by the punching blade 20a of the opening forming mechanism 20, and maintenance is performed through the support portion opening 60a.

  The maintenance head 24 moves radially and faces the recording heads 2K, 2C, 2M, and 2Y. Further, although the cylindrical platen 60 is fixed when the recording medium 10 is conveyed, it may be rotated. In this case, at the time of maintenance, the position of the support portion opening 60 a of the platen 60 is moved to a position corresponding to the position of the maintenance head 24.

The present invention is not limited to the first to seventh embodiments described above. For example, the following configuration may be used.
First, the means for forming the medium opening in the recording medium may be anything as long as the medium opening can be formed in the recording medium. For example, if a CO2 laser or the like is used for forming the medium opening 10a instead of the punching blade, the medium opening can be formed without contact with the recording medium. When the recording medium is a resin such as a plastic film, the medium opening 10a may be formed by melting with heat.

  Further, the configuration of the recording head and the maintenance mechanism is not limited to the above-described embodiment. Further, not only continuous paper but also cut paper is applicable. Furthermore, the recording head is not limited to the ink jet head, and any maintenance mechanism can be applied as long as the maintenance mechanism is brought close to or in contact with the recording head.

Further, four recording heads that can handle four colors of black (K), cyan (C), magenta (M), and yellow (Y) are used. However, the present invention is applicable to recording heads of one color or more.
Further, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the gist thereof in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an exemplary embodiment. It is a figure explaining the arrangement structure of four inkjet heads short in the Y-axis direction. It is a perspective view which shows the front-end | tip structure of a maintenance head. FIG. 5 is a diagram illustrating a connection configuration between a recording head and a maintenance head when forming an opening for the recording medium and performing a maintenance process. It is a figure explaining the structure of the maintenance head of a modification, and the movement of a maintenance head. It is a figure explaining the modification of 1st Embodiment. It is a figure explaining the modification of 1st Embodiment. It is a figure explaining the modification of 1st Embodiment. (A), (b), (c) is a figure explaining 2nd Embodiment. It is a figure explaining 3rd Embodiment. It is a figure explaining 4th Embodiment. It is a figure explaining 5th Embodiment. It is a figure explaining 6th Embodiment using a belt platen. It is a figure explaining 6th Embodiment. It is a figure explaining 7th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Image forming part 2Y-1, 2Y-2, 2Y-3, 2Y-4 ... Inkjet head 3 ... Ink supply part 4 ... Opening formation part 5 ... Maintenance unit 6 ... roll paper transport unit 8 ... holding plate 9 ... nozzle plate 10 ... recording medium 11 ... nozzle 12 ... nozzle row 13 / ink bottle 14 ... sub tank 15 ...... ink replenishment electromagnetic Valve 16 .. Open air solenoid valve 17. Replenishment path valve 18 Pressurizing pump 19 Pressurizing valve 20 Opening mechanism 20a Extracting blade 21 Tube 22 Negative pressure source 23 Platen 24. Maintenance head 25. Holding member 26. Movement mechanism 27. Negative pressure source 28. Outer periphery 29. Recess 30. Suction holes 31 to 34. Conveying roller 35. Original winding roller 36. ..Winding rollers 40, 41 Ipa 50 ... belt platen 51 ... driving roller 52 ... driven roller 53 ... tension roller 54 ... endless belt 55 ... pressing roller 60 ... cylindrical platen 61 ... driven roller 62 ... driving roller

Claims (11)

A recording head having a nozzle for ejecting ink to the recording medium;
A maintenance head for performing maintenance on the recording head;
A transport unit for transporting the recording medium;
A medium opening forming part for forming a medium opening in the recording medium,
An image forming apparatus that performs maintenance using the medium opening.   The image forming apparatus according to claim 1, wherein the medium opening portion faces the recording head and / or the maintenance head during maintenance of the recording head.   The image forming apparatus according to claim 1, wherein the recording head is a line-shaped head that is fixed to the recording medium during image formation.   The image forming apparatus according to claim 1, wherein the recording medium is continuous paper.   The image forming apparatus according to claim 1, wherein maintenance is performed to eject ink from the recording head to the opening of the medium.   The image forming apparatus according to claim 1, wherein the first portion of the maintenance head is inserted into the medium opening during maintenance and faces the recording head.   The image forming apparatus according to claim 1, wherein the recording head is inserted into the medium opening during maintenance and faces the maintenance head.   The image forming apparatus according to claim 1, wherein the conveyance unit includes the recording medium support unit facing the recording head, and the recording medium support unit includes a support unit opening corresponding to the maintenance head. apparatus.   9. The image forming apparatus according to claim 8, wherein the position of the ink ejected and landed from the recording head to the recording medium is the recording medium support portion other than the support portion opening.   The image forming apparatus according to claim 6, wherein the first portion of the maintenance head has a cutout portion in the transport direction.   The image forming apparatus according to claim 6, wherein the first portion of the maintenance head has a cutout portion in a width direction of the recording medium orthogonal to the transport direction.