JP2016221796A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove ink accumulated on/adhering to an ink discharge surface while preventing damage on the ink discharge surface of an ink jet head.SOLUTION: An ink jet printer comprises: first maintenance control means 81 which performs control so as to cause a wiper blade 432 to wipe color ink on an ink discharge surface after the color ink is discharged from a color ink head 31 after causing the wiper blade 432 to wipe clear ink along the ink discharge surface on the ink discharge surface after the clear ink is discharged from a clear ink discharge part 321b when the first maintenance condition is reached; and second maintenance control means 82 which performs control so as to cause the wiper blade 432 to wipe the color ink along the ink discharge surface on the ink discharge surface after the color ink is discharged from the color ink head 31 after causing the wiper blade 432 to wipe washing ink on the ink discharge surface after the washing ink is discharged from a washing ink discharge part 331b when the second maintenance condition is reached.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an inkjet printing apparatus that removes ink deposited and fixed on an ink ejection surface while preventing damage to the ink ejection surface of an inkjet head.

  In an inkjet printing apparatus, maintenance is periodically performed in order to maintain a normal ejection state of the inkjet head. For example, a purge for forcibly discharging ink from an ink discharge surface of an ink jet head in which a plurality of nozzles is formed is performed, and dust and the like adhering to the ink discharge surface are wiped with a wiper blade together with the discharged ink.

  Here, in the ink jet printing apparatus, when a predetermined time or more has passed since the previous maintenance, that is, the maintenance operation of the ink jet head, the ink attached to the wiper blade may be dried and solidified, or dust or the like may adhere to the wiper blade. . When maintenance of the ink jet head is performed in such a state, the newly purged ink is wiped off without sufficiently reaching the wiper blade at the head wiping start portion on the ink ejection surface of the ink jet head. Ink repellent film may be peeled off, and the ink ejection surface may be damaged.

  Therefore, Patent Document 1 discloses a technique related to a maintenance method for an ink jet recording apparatus. Specifically, an ink set including at least one pigment ink and a clear ink containing at least one water-soluble organic solvent for the pigment ink is mounted on the recording head. A wiper for wiping the discharge surface on which the pigment ink discharge port and the clear ink discharge port of the recording head are disposed is provided. When the discharge surface is wiped with the wiper, the clear ink is transferred from the clear ink discharge port to the wiper. Is discharged. Thereby, the frictional force between the wiper surface and the ejection surface can be reduced, and the durability of the ink repellent film on the ink ejection surface can be improved.

JP 2007-253391 A

  However, when a large number of prints such as 20,000 sheets are printed, or when left for a long time from the previous printing operation, the discharged ink may accumulate on the ink discharge surface and stick. In such a case, when the discharge surface is wiped with the wiper described in Patent Document 1, the ink that has accumulated and adhered to the ink discharge surface is removed only by discharging the clear ink from the clear ink discharge port to the wiper. It was difficult.

  The present invention has been made in view of the above, and an object of the present invention is to provide an inkjet printing apparatus that removes ink deposited and fixed on an ink ejection surface while preventing damage to the ink ejection surface of an inkjet head.

  In order to achieve the above object, the first feature of the ink jet printing apparatus according to the present invention is that a color ink ejecting means for ejecting color ink from an ink ejection surface on which a plurality of nozzles are formed and a plurality of nozzles are formed. A clear ink discharge means for discharging colorless and transparent clear ink from the ink discharge surface, a cleaning ink discharge means for discharging cleaning ink having higher cleaning ability than the clear ink from an ink discharge surface on which a plurality of nozzles are formed, and a first When the maintenance condition is reached, after the clear ink is discharged from the clear ink discharge means, the ink discharge surface is wiped by the ink wiping member along the ink discharge surface, and then the color ink The ink discharge surface after discharging the color ink from the discharge means is colored along the ink discharge surface by the ink wiping member. First maintenance control means for controlling the ink to be wiped off, and discharging the cleaning ink from the cleaning ink ejection means when the second maintenance condition set to be less frequent than the first maintenance condition is reached. The ink discharge surface after the ink ink wiping member is wiped off the cleaning ink along the ink discharge surface by the ink wiping member, and the ink discharge surface after discharging the color ink from the color ink discharge means, And a second maintenance control unit that controls the ink wiping member to wipe the color ink along the ink ejection surface.

  Here, the “first maintenance condition” is a condition for performing a maintenance operation using clear ink. For example, the first maintenance condition is counted and stored, and the first maintenance is performed every time 1000 sheets are printed. Set to meet the conditions.

  The “second maintenance condition” is a condition for performing a strong maintenance operation using a cleaning ink having a higher cleaning ability than the clear ink. For example, the number of printed sheets is counted and stored, and 20,000 sheets are stored. Is set so as to satisfy the second maintenance condition when printing is not performed for a predetermined period such as one week.

  In order to achieve the above object, a second feature of the ink jet printing apparatus according to the present invention is that the clear ink is a functional ink for adjusting the density of the color ink, and an instruction for adjusting the density of the color ink. Print control means for controlling to discharge the clear ink superimposed on the color ink from the clear ink discharge means before or after discharging the color ink from the color ink discharge means based on the print job Is to further provide.

  Here, the “clear ink” is a colorless and transparent ink having a weak detergency, and is a functional ink that is ejected so as to be superimposed on the color ink in order to improve the glossiness and storability of the printed matter.

  In order to achieve the above object, a third feature of the ink jet printing apparatus according to the present invention is that a plurality of color inks are ejected onto a sheet to be conveyed for each color ink on the ink ejection surface of the color ink ejection means. Are arranged at predetermined intervals in the main scanning direction orthogonal to the paper transport direction, and a plurality of nozzles for discharging clear ink onto the paper to be transported are predetermined in the main scanning direction on the ink ejection surface of the clear ink ejection means. The ink wiping members are arranged at intervals, and below the color ink ejection unit and the clear ink ejection unit, the ink wiping member is provided in a maintenance unit that is movable in the conveyance direction and in the vertical direction perpendicular to the conveyance direction. A plurality of color ink discharge means and a clear ink discharge means are provided at least one of the plurality of provided ink wiping members. When wiping the ink discharge surface of the ejecting means, the other ink wiping members are provided so as to be in a vertical position that does not contact the ink discharge surface of the color ink discharge means, and the first maintenance control means conveys the maintenance section After wiping the ink discharge surface of the clear ink discharge means by the ink wiping member by moving in the direction, a plurality of ink wiping members contact the ink discharge surface of the color ink discharge means corresponding to each color ink Control is performed so that each color ink is wiped along the ink ejection surface of the color ink ejection means by the ink wiping member by moving in the conveyance direction and up to the position and then moving the maintenance unit in the conveyance direction. .

  According to the first feature of the ink jet printing apparatus according to the present invention, the first maintenance control means sets the ink ejection surface after discharging the clear ink from the clear ink ejection means when the first maintenance condition is reached. After the clear ink is wiped along the ink discharge surface by the ink wiping member, the color ink is discharged along the ink discharge surface by the ink wiping member after the color ink is discharged from the color ink discharge means. When the second maintenance control means reaches the second maintenance condition, the ink ejection surface after discharging the cleaning ink from the cleaning ink ejection means is changed to the ink ejection surface by the ink wiping member. The ink ejection surface after the color ink is discharged from the color ink ejection means is removed by the ink wiping member. Along the click ejection surface controls to wipe color ink.

  Therefore, when the first maintenance condition is reached, after the ink wiping member is wetted by the ink droplets formed by discharging the clear ink from the nozzles on the ink ejection surface, the ink wiping member moves the ink ejection surface to a predetermined level. When the second maintenance condition is reached, the ink wiping member is wetted by the ink droplets formed by discharging the cleaning ink from the nozzles on the ink ejection surface and then the ink wiping member is moved to the ink ejection surface. Are wiped at a predetermined speed.

  As described above, since the cleaning ink has a higher cleaning ability than the clear ink, the cleaning ink contains more components having a greater influence on the ink repellent film on the ink ejection surface than the clear ink. Therefore, for example, when frequent maintenance is performed at a short maintenance interval such as when 1000 sheets are printed (first maintenance condition), the first maintenance control unit uses clear ink that has a small influence on the ink repellent film on the ink ejection surface. The ink is discharged and the clear ink is wiped along the ink ejection surface by the ink wiping member.

  On the other hand, for example, when printing 20000 sheets or when printing is not performed for a predetermined period such as one week, it is expected that ink is accumulated and fixed on the ink ejection surface (second maintenance condition). The second maintenance control unit discharges the cleaning ink having a strong cleaning power in order to melt and wash the ink fixed on the ink discharge surface, and wipes the cleaning ink along the ink discharge surface by the ink wiping member.

  In this way, the following effects can be obtained by properly using the two types of maintenance control in accordance with the cleaning ability (the degree of influence on the ink repellent film) of the two types of ink used for maintenance. That is, while preventing damage to the ink discharge surface of the ink jet head, dust or the like attached to the ink discharge surface can be removed, and when a large number of prints such as 20,000 sheets are performed, or from the previous print operation, Even if colored ink accumulates and adheres to the ink ejection surface when left for a long period of time, such as a week, the ink that adheres together with the dust adhering to the ink ejection surface is prevented while preventing damage to the ink ejection surface of the inkjet head. Can be removed.

  Further, according to the second feature of the ink jet printing apparatus according to the present invention, when the print control unit receives a print job including an instruction for adjusting the density of the color ink, the color ink discharge unit performs color printing based on the print job. Control is performed so that clear ink is ejected from the clear ink ejecting means before or after ejecting ink.

  Therefore, the clear ink discharged from the clear ink discharge means prevents the ink discharge surface from being damaged by ensuring the wet state of the ink wiping member during the maintenance operation, and improves the glossiness and storage stability of the color ink during the printing operation. And can be used to realize both functions simultaneously. For example, in the maintenance operation of the clear ink discharge unit, the ink liquid formed by discharging the clear ink from the nozzle on the ink discharge surface before the tip of the ink wiping member contacts the ink discharge surface of the color ink discharge unit. The contact surface at the tip of the ink wiping member can be wetted by the droplets. At the same time, the clear ink, which is a functional ink, is ejected from the clear ink ejection means during the printing operation, so that the glossiness and storability of the color ink ejected from the color ink ejection means and landed on the printing paper can be improved. it can.

  Further, according to the third feature of the ink jet printing apparatus according to the present invention, the first maintenance control means wipes the ink ejection surface of the clear ink ejection means by the ink wiping member by moving the maintenance section in the transport direction. After that, the plurality of ink wiping members are moved in the transport direction and upward until they come into contact with the ink ejection surface of the color ink ejection unit corresponding to each color ink, and then the maintenance unit is moved in the transport direction. Thus, the ink wiping member is controlled to wipe the color ink along the ink ejection surface of the color ink ejection means.

  Therefore, the clear ink discharged from the clear ink discharge means prevents the ink discharge surface from being damaged by ensuring the wet state of the ink wiping member during the maintenance operation, and improves the glossiness and storage stability of the color ink during the printing operation. In addition, a plurality of ink wiping members provided for each color ink of the color ink discharge means wipe each color ink, thereby preventing ink color mixing. be able to.

It is a schematic block diagram of the inkjet printing apparatus which concerns on Example 1 of this invention. It is a top view of the maintenance unit provided in the inkjet printing apparatus which concerns on Example 1 of this invention shown in FIG. 1 is an exploded perspective view of a maintenance unit and an inkjet head provided in an inkjet printing apparatus according to Embodiment 1 of the present invention. It is sectional drawing along the AA line in FIG. It is a block diagram which shows the function structure of the inkjet printing apparatus which concerns on Example 1 of this invention. It is explanatory drawing explaining the normal maintenance operation | movement in the inkjet printing apparatus which concerns on Example 1 of this invention. It is explanatory drawing explaining the strong maintenance operation | movement in the inkjet printing apparatus which concerns on Example 1 of this invention. It is a top view of the maintenance unit provided in the inkjet printing apparatus which concerns on Example 2 of this invention. It is explanatory drawing explaining the normal maintenance operation | movement and the strong maintenance operation | movement in the inkjet printing apparatus which concerns on Example 2 of this invention. It is explanatory drawing explaining the normal maintenance operation | movement and the strong maintenance operation | movement in the inkjet printing apparatus which concerns on Example 2 of this invention. It is explanatory drawing explaining the normal maintenance operation | movement and the strong maintenance operation | movement in the inkjet printing apparatus which concerns on Example 2 of this invention. It is explanatory drawing explaining the normal maintenance operation | movement and the strong maintenance operation | movement in the inkjet printing apparatus which concerns on Example 2 of this invention.

  Hereinafter, an ink jet printing apparatus according to a first embodiment of the present invention will be described. In addition, each embodiment shown below illustrates the apparatus etc. for actualizing the technical idea of this invention, Comprising: The technical idea of this invention is arrangement | positioning of each component etc. below. It is not something specific. The technical idea of the present invention can be variously modified within the scope of the claims.

<Configuration of Embodiment 1 of the Present Invention>
FIG. 1 is a schematic configuration diagram of an inkjet printing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a plan view of a maintenance unit provided in the inkjet printing apparatus according to Embodiment 1 of the present invention shown in FIG. 3 is an exploded perspective view of the maintenance unit and the inkjet head provided in the inkjet printing apparatus according to the first embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along the line AA in FIG. In the following description, the paper surface direction of FIG. Moreover, as shown in FIG. 1, when viewed from the user, the vertical and horizontal directions are the vertical and horizontal directions.

  As shown in FIG. 1, the inkjet printing apparatus 1 according to the first embodiment of the present invention includes a transport unit 2, a head unit 3, and a maintenance unit 4.

  The conveyance unit 2 includes a conveyance belt 21 provided to face the head unit 3, a driving roller 22 that drives the conveyance belt 21 to rotate, and driven rollers 23, 24, and 25 that are driven by the driving roller 22.

  The conveying belt 21 is stretched over the driving roller 22 and the driven rollers 23, 24, and 25, and moves endlessly by driving of the driving roller 22 during printing, and is supplied from a paper supply stand (not shown) provided on the left side. Hold and transport.

  The transport unit 2 includes a printing position for performing paper transport processing at the time of printing by a vertical motor 44 described later, a retreat position for moving the maintenance unit 4 on a position lower than the printing position, a maintenance unit 4 is configured to be movable between a maintenance position that rises above the retracted position and causes the maintenance unit 4 to perform maintenance of the head unit 3. The transport unit 2 is moved to the retracted position in order to move the maintenance unit 4 between the transport unit 2 and the head unit 3 when the head unit 3 is maintained.

  The head unit 3 includes line-type inkjet heads 31C, 31K, 31M, and 31Y. Based on a print job, the head unit 3 ejects ink onto a sheet conveyed from the left to the right by the conveyance belt 21 to form an image. It is something to print. The inkjet heads 31C, 31K, 31M, and 31Y are arranged at predetermined intervals in the left-right direction above the transport unit 2. The inkjet heads 31C, 31K, 31M, and 31Y eject inks of different types of C (cyan), K (black), M (magenta), and Y (yellow) from the nozzles of each unit head 311 described later. To do.

  As shown in FIGS. 2 and 3, the inkjet head 31C is composed of six unit heads 311C arranged in a staggered matrix of 2 columns × 3 rows. Similarly, the inkjet heads 31K, 31M, and 31Y are each composed of six unit heads 311K, 311M, and 311Y.

  In addition, when it is not necessary to distinguish between colors, the alphabetic suffixes (C, K, M, Y) indicating the colors in the code are omitted. For example, the code of the inkjet head is “31” and the code of the unit head Is expressed as “311”.

  Further, the head unit 3 has an inkjet head 32 above the transport unit 2. In the inkjet head 32, unit heads 321 are arranged at a predetermined interval in the paper transport direction (left and right direction). As shown in FIG. 4, the unit head 321 includes a clear ink discharge unit 321b and a cleaning ink discharge unit. 331b.

  Then, the clear ink is discharged from the nozzle of the clear ink discharge unit 321b. Here, the clear ink is an ink having a weak detergency of colorless and transparent ink. For example, in order to improve the glossiness and storability of the printed matter, it has a function of being ejected so as to be superimposed on the color ink. Ink or the like is used.

  Further, the cleaning ink is discharged from the nozzles of the cleaning ink discharge unit 331b. Here, the cleaning ink is an ink having a stronger cleaning ability than the clear ink.

  On the ink ejection surface 321a of the clear ink ejection section 321b of the unit head 321 of the inkjet head 32, a plurality of nozzles are formed in two rows, for example, at predetermined intervals in the paper transport direction (left and right direction), and ink repellent A film is formed. The ink repellent film is made of a material having a property of repelling ink, for example, an amorphous fluororesin. Therefore, ink ejected from adjacent nozzles is combined by the ink repellent film on the ink ejection surface 321a to form ink droplets 9 as shown in FIG.

  Similarly, on the ink discharge surface 331a of the cleaning ink discharge portion 331b of the unit head 321 of the inkjet head 32, a plurality of nozzles are formed in two rows, for example, at predetermined intervals in the paper transport direction (left-right direction). An ink repellent film is formed. The ink repellent film is made of a material having a property of repelling ink, for example, an amorphous fluororesin. Therefore, ink ejected from adjacent nozzles is combined by the ink repellent film on the ink ejection surface 331a to form an ink droplet 11 as shown in FIG.

  Similarly, on the ink ejection surface 311a of the unit head 311 of the inkjet head 31, for example, a plurality of nozzles are formed in two rows, and an ink repellent film is formed. The ink repellent film is made of a material having a property of repelling ink, for example, an amorphous fluororesin. For this reason, the ink droplets 10 as shown in FIG. 6A are formed by the ink ejected from the adjacent nozzles being combined by the ink repellent film on the ink ejection surface 311a.

  The maintenance unit 4 performs maintenance on the ink ejection surface of the unit head 311. The maintenance unit 4 is arranged at a storage position indicated by a solid line in FIG. 1 during printing. The storage position is below the right side of the transport unit 2. When the maintenance unit 4 performs maintenance, the maintenance unit 4 is developed on the transport unit 2 and moved upward together with the transport unit 2 after the transport unit 2 has moved to the lower retreat position in FIG. It is moved to the maintenance position indicated by the broken line. The maintenance position is between the transport unit 2 and the inkjet head 31.

  As shown in FIGS. 2 to 5, the maintenance unit 4 includes an ink receiving member 41, a drive unit 42, a wiper unit 43, a motor 44 of the maintenance unit 4, and an upper and lower motor 45 of the transport unit 2.

  The ink receiving member 41 receives ink or the like removed by maintenance. The ink receiving member 41 is formed in a rectangular parallelepiped shape and holds each member of the maintenance unit 4.

  The drive unit 42 moves the wiper unit 43 in the front-rear direction during maintenance. The drive unit 42 includes a wiper drive motor 421, a drive belt 422, a pair of drive pulleys 423a and 423b, and a pair of ball screws 424a and 424b.

  The wiper drive motor 421 generates a rotational drive force, and includes a stepping motor or the like, and is disposed outside the rear wall of the ink receiving member 41. The rotation direction of the wiper drive motor 421 can be switched, and the wiper drive motor 421 is moved forward when the wiper drive motor 43 is moved forward, and the wiper drive motor when the wiper drive 43 is moved backward. The rotation direction of 421 is the reverse rotation direction.

  The power of the wiper drive motor 421 is transmitted to the output gear 421a, the drive belt 422, and the drive pulleys 423a and 423b, and the pair of drive pulleys 423a and 423b receives the rotational driving force transmitted from the drive belt 422 as a ball screw 424a, 424b. The ball screws 424a and 424b move the wiper portion 43 in the front-rear direction by the rotational driving force transmitted from the wiper drive motor 421.

  The wiper unit 43 wipes the ink discharge surface (nozzle formation surface) 311a of the unit head 311 of the inkjet head 31 and removes ink, dust, etc. adhering to the ink discharge surface 311a and performs maintenance. 431 and a wiper blade 432 which is an ink wiping member of the present invention.

  The mounting base 431 is to which the wiper blade 432 is attached, and is composed of a prismatic member elongated in the left-right direction.

  The mounting base 431 is formed with a pair of screw holes 431a and 431b. Ball screws 424a and 424b are passed through and screwed into the screw holes 431a and 431b. Accordingly, when the ball screws 424a and 424b are rotated, the mounting base 431 moves in the front-rear direction.

  The wiper blade 432, which is an ink wiping member, removes ink, dust, and the like by sliding on the ink ejection surface 311a of the unit head 311 of the inkjet head 31, and cleans the ink ejection surface 311a. The wiper blade 432 is made of an elastically deformable material such as fluorine rubber. The wiper blade 432 is formed in an elongated rectangular thin plate shape.

  As shown in FIG. 2, the length of the wiper blade 432 is not less than the length in the left-right direction of the range in which the two unit heads 311 are arranged. Note that the wiper blade 432 of the first embodiment is not less than the length in the left-right direction of the range in which the unit head 311 is disposed as shown in FIG. 2, but the present invention is not limited to this. One wiper blade may be provided for each row of the heads 311.

  As shown in FIG. 4, the lower end portion of the wiper blade 432 is fixed to the front side surface of the mounting base 431 by a fixture (not shown). The upper end portion of the wiper blade 432 is configured to be higher than the upper surface of the mounting base 431, and is usually higher than the ink discharge surfaces 311a, 321a, and 331a of the unit heads 311 and 321 at the maintenance position. Is arranged. Accordingly, when the wiper blade 432 moves in the front-rear direction and comes into contact with the unit head 311, it is elastically deformed and slides on the ink ejection surfaces 311a, 321a, 331a.

  In the first embodiment, for example, the height of the wiper blade 432 can be adjusted in the vertical direction perpendicular to the transport direction by changing the overall height of the maintenance unit 4 using the vertical motor 45 or the like.

  The motor 44 moves the maintenance unit 4 between the storage position shown in FIG. 1 and the deployment position.

  The vertical motor 45 moves the maintenance unit 4 up and down together with the transport unit 2. Thus, the vertical motor 45 moves the transport unit 2 to the printing position, the retracted position, and the maintenance position shown in FIG. 1, while moving the maintenance unit 4 between the unfolded position and the maintenance position. In this manner, the height of the wiper blade 432 is adjusted in the vertical direction.

<Functional Configuration of Embodiment 1 of the Present Invention>
FIG. 5 is a block diagram illustrating a functional configuration of the ink jet printing apparatus according to the first embodiment of the present invention.

  As shown in FIG. 5, the ink jet printing apparatus 1 according to the first embodiment of the present invention includes a pressurizing unit 53, 52, 5C, 5K, 5M, 5Y, a storage unit 6, an operation panel unit 7, and a control unit. 8.

  The pressurizing units 53, 52, 5C, 5K, 5M, and 5Y pressurize the paths for supplying ink from ink bottles (not shown) of the respective colors to the inkjet heads 33, 32, 31C, 31K, 31M, and 31Y. It consists of a pump and the like. The pressure units 53, 52, 5C, 5K, 5M, and 5Y supply ink to the inkjet heads 33, 32, 31C, 31K, 31M, and 31Y when performing a purge that forcibly discharges the ink during the maintenance operation. Pressurize the path to discharge ink.

  The storage unit 6 is a non-volatile storage medium such as a hard disk, and stores a program for comprehensively controlling the operation of the entire inkjet printing apparatus 1 and a program for executing a maintenance operation and a printing operation described later. ing. In addition, predetermined conditions such as a first maintenance condition and a second maintenance condition described later when executing the maintenance operation are set and stored by a user or the like.

  The operation panel unit 7 includes various operation buttons, a touch panel (none of which is shown), receives an input operation by the user, and outputs an operation signal corresponding to the operation.

  The control unit 8 includes a CPU, a memory (none of which are shown), and the like. The control unit 8 executes a program stored in the storage unit 6 to comprehensively control the operation of the entire inkjet printing apparatus 1. Then, a printing operation is performed on a sheet conveyed based on a print job, or a maintenance operation is performed.

  The control unit 8 mounts a first maintenance control unit 81 and a second maintenance control unit 82 in terms of its functions.

  The first maintenance control unit 81 causes the wiper blade 432 to wipe the clear ink along the ink discharge surface after the clear ink is discharged from the inkjet head 32 when the first maintenance condition is reached. After that, the ink discharge surface after discharging the color ink from the inkjet head 31 is controlled by the wiper blade 432 so that the color ink is wiped along the ink discharge surface.

  Here, the first maintenance condition is a condition for performing the maintenance operation using the clear ink. For example, the first maintenance condition is counted and stored, and the first maintenance condition is set every time 1000 sheets are printed. Set to meet.

  The second maintenance control unit 82 wipes the ink ejection surface after the cleaning ink is discharged from the inkjet head 32 when the second maintenance condition set so as to be less frequent than the first maintenance condition is reached. After the cleaning ink is wiped along the ink discharge surface by the blade 432, the color ink is wiped along the ink discharge surface by the wiper blade 432 on the ink discharge surface after the color ink is discharged from the inkjet head 31. To control.

  Here, the second maintenance condition is a condition for performing a strong maintenance operation using a cleaning ink having a higher cleaning ability than the clear ink. For example, the number of printed sheets is counted and stored, and 20,000 sheets are stored. When printing or when printing is not executed for a predetermined period such as one week, the second maintenance condition is set.

<Normal maintenance processing>
Next, the normal maintenance process of the ink jet printing apparatus according to the first embodiment of the present invention will be specifically described.

  For example, the first maintenance control unit 81 of the control unit 8 has reached the first maintenance condition when the number of printed sheets (first printed sheet number) counted since the previous normal maintenance process has exceeded 1000 sheets. Is determined. Then, the counted first number of printed sheets is reset to zero.

  When the first maintenance condition is reached, when the maintenance unit 4 performs maintenance, the maintenance unit 4 is deployed on the transport unit 2 and moved upward together with the transport unit 2 after the transport unit 2 has moved to the lower retreat position. Is moved to a maintenance position indicated by a broken line in FIG.

  When the movement of the maintenance unit 4 to the maintenance position is completed, the first maintenance control unit 81 of the control unit 8 causes the pressurizing unit 52 to discharge the clear ink from the clear ink discharge unit 321b of the inkjet head 32 by purging. On the other hand, it controls to pressurize the path for supplying the clear ink. As a result, as shown in FIG. 6A described later, the clear ink is pushed out from the plurality of nozzles formed on the ink discharge surface (nozzle formation surface) 321a of the unit head 321 and discharged from the adjacent nozzles. Clear ink is combined to form ink droplets 9 on the ink ejection surface 321a.

  Next, the first maintenance control means 81 of the control unit 8 drives the wiper drive motor 421 in the forward rotation direction so that the wiper blade 432 moves at a predetermined speed. Thereby, the rotational driving force of the wiper drive motor 421 rotates the ball screws 424a and 424b. As a result, the wiper blade 432 moves in the forward direction as shown in FIG. 2 together with the mounting base 431 screwed into the ball screws 424a and 424b.

  Then, as shown in FIG. 6A, the tip (upper part) of the wiper blade 432 protrudes above the ink discharge surface 321 a of the unit head 321, so that the tip of the wiper blade 432 is in contact with the unit head 321. The ink discharge surface 321a of the unit head 321 slides at a predetermined speed while being elastically deformed by being pressed by the ink discharge surface 321a. As a result, as shown in FIG. 6B, before the tip of the wiper blade 432 comes into contact with the ink ejection surfaces 311a of the ink jet heads 31C, 31K, 31M, and 31Y for the respective color inks, the nozzles on the ink ejection surface 321a The contact surface of the tip of the wiper blade 432 can be wetted by the ink droplet 9 formed by discharging the clear ink.

  Next, the first maintenance control means 81 of the control unit 8 supplies ink to the pressure units 5C, 5K, 5M, and 5Y in order to discharge ink from the inkjet heads 31C, 31K, 31M, and 31Y by purging. Control to pressurize the supply path. As a result, as shown in FIG. 6A described later, ink of each color is pushed out from a plurality of nozzles formed on the ink ejection surface (nozzle formation surface) 311a of each unit head 311 and from a plurality of adjacent nozzles 311b. The ejected inks are combined to form ink droplets 10 on the ink ejection surface 311a.

  Next, the first maintenance control means 81 of the control unit 8 drives the wiper drive motor 421 in the forward rotation direction so that the wiper blade 432 moves at a predetermined speed. Thereby, the rotational driving force of the wiper drive motor 421 rotates the ball screws 424a and 424b. As a result, the wiper blade 432 moves in the forward direction as shown in FIG. 2 together with the mounting base 431 screwed into the ball screws 424a and 424b.

  Then, since the tip (upper part) of the wiper blade 432 protrudes above the ink discharge surface 311a of the unit head 311, the tip of the wiper blade 432 is pressed against the ink discharge surface 311a of the unit head 311 and elastically deformed. While sliding the ink ejection surface 311a of the unit head 311 at a predetermined speed. Thus, the ink droplet 10 attached to the ink discharge surface 311a by the purge is removed together with dust or the like attached to the ink discharge surface 311a.

  Thus, after the contact surface of the tip of the wiper blade 432 is wetted by the ink droplet 9 formed by discharging the clear ink from the nozzle of the ink discharge surface 321a, the tip of the wiper blade 432 is moved to the unit head. Since the ink discharge surface 311a of the unit head 311 slides at a predetermined speed while being elastically deformed by being pressed by the ink discharge surface 311a of 311, the ink discharge surface 311a is prevented from being damaged while preventing the ink discharge surface of the inkjet head from being damaged. Adhering dust and the like can be removed.

<Strong maintenance processing>
Next, the powerful maintenance process of the ink jet printing apparatus according to the first embodiment of the present invention will be specifically described.

  The second maintenance control means 82 of the control unit 8 is, for example, a predetermined period such as one week when the number of printed sheets (second printed number) counted after executing the previous strong maintenance process exceeds 20000. When printing has not been executed, it is determined that the second maintenance condition has been reached. Then, the counted second number of printed sheets is reset to zero.

  When the second maintenance condition is reached, when the maintenance unit 4 performs maintenance, the maintenance unit 4 is deployed on the transport unit 2 and moved upward together with the transport unit 2 after the transport unit 2 has moved to the lower retreat position. Is moved to a maintenance position indicated by a broken line in FIG.

  When the movement of the maintenance unit 4 to the maintenance position is completed, the second maintenance control unit 82 of the control unit 8 causes the pressurizing unit 53 to discharge the cleaning ink from the cleaning ink discharge unit 331b of the inkjet head 32 by purging. On the other hand, it controls to pressurize the path for supplying the cleaning ink. As a result, as shown in FIG. 7A described later, the cleaning ink is pushed out from the plurality of nozzles formed on the ink ejection surface (nozzle formation surface) 331a of the unit head 321 and ejected from the adjacent nozzles. Ink droplets 11 are formed on the ink discharge surface 331a by combining the cleaning inks.

  Next, the second maintenance control unit 82 of the control unit 8 drives the wiper drive motor 421 in the forward rotation direction so that the wiper blade 432 moves at a predetermined speed. Thereby, the rotational driving force of the wiper drive motor 421 rotates the ball screws 424a and 424b. As a result, the wiper blade 432 moves in the forward direction as shown in FIG. 2 together with the mounting base 431 screwed into the ball screws 424a and 424b.

  Then, as shown in FIG. 7A, the tip (upper part) of the wiper blade 432 protrudes above the ink discharge surface 331 a of the unit head 321, so that the tip of the wiper blade 432 is in contact with the unit head 321. The ink discharge surface 331a of the unit head 321 slides at a predetermined speed while being elastically deformed by being pressed by the ink discharge surface 331a. Accordingly, the ink formed by discharging the cleaning ink from the nozzles of the ink discharge surface 331a before the tip of the wiper blade 432 contacts the ink discharge surfaces 311a of the ink jet heads 31C, 31K, 31M, and 31Y of the respective color inks. The droplet 11 can wet the contact surface at the tip of the wiper blade 432.

  Next, the second maintenance control means 82 of the control unit 8 supplies ink to the pressure units 5C, 5K, 5M, and 5Y in order to discharge ink from the inkjet heads 31C, 31K, 31M, and 31Y by purging. Control to pressurize the supply path. As a result, as shown in FIG. 7B described later, ink of each color is pushed out from a plurality of nozzles formed on the ink discharge surface (nozzle formation surface) 311a of each unit head 311 and discharged from a plurality of adjacent nozzles. Ink droplets 10 are formed on the ink discharge surface 311a.

  Next, the second maintenance control unit 82 of the control unit 8 drives the wiper drive motor 421 in the forward rotation direction so that the wiper blade 432 moves at a predetermined speed. Thereby, the rotational driving force of the wiper drive motor 421 rotates the ball screws 424a and 424b. As a result, the wiper blade 432 moves in the forward direction as shown in FIG. 2 together with the mounting base 431 screwed into the ball screws 424a and 424b.

  Then, since the tip (upper part) of the wiper blade 432 protrudes above the ink discharge surface 311a of the unit head 311, the tip of the wiper blade 432 is pressed against the ink discharge surface 311a of the unit head 311 and elastically deformed. While sliding the ink ejection surface 311a of the unit head 311 at a predetermined speed.

  As described above, when a large number of prints such as 20,000 sheets are printed or when left for a long period of time such as one week from the previous printing operation, the color ink may be deposited on the ink discharge surface 311a and fixed. However, even in such a case, the contact surface at the tip of the wiper blade 432 is wetted by the ink droplets 11 formed by discharging the cleaning ink from the nozzles of the ink discharge surface 331a, and further powerful. The ink discharge surface 311a can be cleaned using a cleaning ink having a cleaning capability. Therefore, it is possible to remove dust adhered to the ink ejection surface 311a, adhered ink, and the like from the ink droplet 10 adhered to the ink ejection surface 311a without damaging the ink repellent film on the ink ejection surface 311a.

  In addition, after cleaning the ink discharge surface 311a using cleaning ink, the ink discharge surface 311a is further cleaned using clear ink in order to remove the cleaning ink remaining on the ink discharge surface 311a. Also good.

<Configuration of Embodiment 2 of the Present Invention>
FIG. 8 is a plan view of a maintenance unit provided in the ink jet printing apparatus according to the second embodiment of the present invention. In addition, description is abbreviate | omitted about the structure which attached | subjected the same code | symbol shown in FIG.

  As shown in FIG. 8, in the inkjet head 34, six unit heads 341 arranged in a zigzag matrix of 2 columns × 3 rows are arranged at predetermined intervals in the main scanning direction orthogonal to the transport direction. The clear ink and the cleaning ink are discharged from the nozzles of the unit head 341.

  The maintenance unit 4 includes an ink receiving member 41, a drive unit 42, and a wiper unit 43.

  Unlike the first embodiment, in the second embodiment, the drive unit 42 is provided on the right side of the ink receiving member 41, and moves the wiper unit 43 in the left-right direction during maintenance. The drive unit 42 includes a wiper drive motor 421, a drive belt 422, a pair of drive pulleys 423a and 423b, and a pair of ball screws 424a and 424b. Since these configurations are the same as those of the inkjet printing apparatus 1 according to the first embodiment, description thereof is omitted.

  The wiper unit 43 wipes the ink discharge surface (nozzle formation surface) 311a of the unit head 311 of the inkjet head 31 and removes ink, dust, etc. adhering to the ink discharge surface 311a and performs maintenance. 431C, 431K, 431M, 431Y and wiper blades 432C, 432K, 432M, 432Y which are ink wiping members.

  The mounting bases 431C, 431K, 431M, and 431Y are to which wiper blades 432C, 432K, 432M, and 432Y are attached for each color, and are constituted by prismatic members that are elongated in the left-right direction.

  As will be described later, the wiper blade 432C slides on the ink discharge surface 341a that discharges the clear ink of the unit head 341 of the inkjet head 34 and the ink discharge surface 351a that discharges the cleaning ink, thereby leading the tip of the wiper blade 432C. Make the contact surface of the part wet. Thereafter, the wiper blade 432C removes the adhered ink, dust, and the like by sliding on the ink ejection surface 311a of the unit head 311C of the inkjet head 31, and cleans the ink ejection surface 311a of the unit head 311C.

  Similarly, the wiper blades 432K, 432M, and 432Y clean the ink ejection surfaces 311a of the unit heads 311K, 311M, and 311Y for each color.

  Further, the length of the wiper blades 432C, 432K, 432M, and 432Y is set to be longer than the length in the front-rear direction of the range in which the unit head 311 is disposed. Note that the wiper blades 432C, 432K, 432M, and 432Y of Example 2 have a length in the front-rear direction within the range in which the unit heads 311 are arranged as shown in FIG. 8, but the present invention is not limited to this. For example, one wiper blade may be provided for each column of the unit heads 311.

<Normal Maintenance Processing of Embodiment 2 of the Present Invention>
When the first maintenance condition is reached, the first maintenance control means 81 of the control unit 8 first drives the vertical motor 45 to move the transport unit 2 from the printing position to the lower retreat position as shown in FIG. Next, the motor 44 is driven to move the maintenance unit 4 from the storage position so that the wiper blades 432C, 432K, 432M, and 432Y are moved from the ink discharge surface 341a of the unit head 341 of the inkjet head 34 and the ink as shown in FIG. The ejection surface 351a is moved to a sliding position. Here, as shown in FIG. 9, the vertical positions of the ink ejection surfaces 341a and 351a of the inkjet head 34 are t greater than the vertical positions of the ink ejection surfaces 311a of the inkjet heads 31C, 31K, 31M, and 31Y. It is provided so as to be lower by (mm).

  Then, the first maintenance control unit 81 of the control unit 8 controls the pressurizing unit 52 to pressurize the path for supplying the clear ink in order to discharge the clear ink from the inkjet head 34 by purging. As a result, the clear ink is pushed out from a plurality of nozzles formed on the ink discharge surface (nozzle formation surface) 341a of the unit head 341, and the clear ink discharged from a plurality of adjacent nozzles is combined, and the ink liquid is applied to the ink discharge surface 341a. Drops are formed.

  Thereafter, the motor 44 is driven to move the maintenance unit 4 to the left, so that the wiper blades 432C, 432K, 432M, and 432Y slide on the ink ejection surface 341a of the unit head 341 of the inkjet head 34. As a result, the clear ink is discharged from the nozzles of the ink discharge surface 341a before the tips of the wiper blades 432C, 432K, 432M, and 432Y come into contact with the ink discharge surfaces 311a of the ink jet heads 31C, 31K, 31M, and 31Y of the respective color inks. The contact surface at the tip of the wiper blades 432C, 432K, 432M, and 432Y can be wetted by the ink droplets thus formed.

  Next, the first maintenance control means 81 of the control unit 8 supplies ink to the pressure units 5C, 5K, 5M, and 5Y in order to discharge ink from the inkjet heads 31C, 31K, 31M, and 31Y by purging. Control to pressurize the supply path. As a result, the ink of each color is pushed out from the plurality of nozzles formed on the ink ejection surface (nozzle formation surface) 311a of each unit head 311 and the ink ejected from the plurality of adjacent nozzles is combined to form ink on the ink ejection surface 311a. A droplet is formed.

  Thereafter, the first maintenance control means 81 of the control unit 8 further maintains the maintenance unit 4 until the wiper blades 432C, 432K, 432M, and 432Y are at the lower right positions of the ink jet heads 31C, 31K, 31M, and 31Y of the respective color inks. Move to the left. As described above, the vertical positions of the ink discharge surfaces 341a and 351a of the inkjet head 34 are lower by t (mm) than the vertical positions of the ink discharge surfaces 311a of the inkjet heads 31C, 31K, 31M, and 31Y. Therefore, when the maintenance unit 4 is moved in the left direction, the wiper blades 432C, 432K, 432M, and 432Y are in contact with the ink ejection surface 311a of the inkjet heads 31C, 31K, 31M, and 31Y. Moved without.

  Then, as shown in FIG. 11, when the maintenance unit 4 is moved to a position where the wiper blades 432C, 432K, 432M, and 432Y are at the lower right positions of the ink-jet heads 31C, 31K, 31M, and 31Y for the respective color inks. The vertical motor 45 is driven to move the transport unit 2 and the maintenance unit 4 upward.

  Thereafter, as shown in FIG. 12, the first maintenance control means 81 of the control unit 8 further moves the maintenance unit 4 leftward. As a result, the front end portions of the wiper blades 432C, 432K, 432M, and 432Y in a wet state are pressed against the ink ejection surfaces 311a of the ink jet heads 31C, 31K, 31M, and 31Y of the respective color inks, and are elastically deformed to be unit head 311. The ink ejection surface 311a is slid at a predetermined speed. As a result, the ink droplets attached to the ink discharge surface 311a by the purge are removed together with the dust and the like attached to the ink discharge surface 311a.

  When the normal maintenance process is completed, the control unit 8 moves the transport unit 2 to the retracted position, places the maintenance unit 4 at the storage position, and then moves the transport unit 2 to the printing position (not shown).

<Strong maintenance process of embodiment 2 of the present invention>
When the second maintenance condition is reached, the second maintenance control unit 82 of the control unit 8 moves the transport unit 2 and the maintenance unit 4 as shown in FIGS. 9 to 12 as in the normal maintenance process.

  At this time, in the strong maintenance process, instead of discharging the clear ink from the ink discharge surface 341a of the inkjet head 34 by the purge, the cleaning ink is discharged from the ink discharge surface 351a by the purge. Specifically, the second maintenance control unit 82 of the control unit 8 controls the pressurizing unit 53 to pressurize the path for supplying the cleaning ink. As a result, the cleaning ink is pushed out from a plurality of nozzles formed on the ink discharge surface (nozzle formation surface) 351a of the unit head 341, and the cleaning ink discharged from a plurality of adjacent nozzles is combined to form an ink liquid on the ink discharge surface 351a. Drops are formed.

  As described above, when a large number of prints such as 20,000 sheets are printed, or when a long-term notification such as one week is issued from the previous print operation, the color ink may be deposited on the ink discharge surface 311a and may be fixed. However, even in such a case, the contact surface at the tip of the wiper blades 432C, 432K, 432M, and 432Y is wetted by the ink droplets formed by discharging the cleaning ink from the nozzles of the ink ejection surface 351a. Furthermore, the ink discharge surfaces 311a of the inkjet heads 31C, 31K, 31M, and 31Y can be cleaned using cleaning ink having a strong cleaning ability. Therefore, dust attached to the ink discharge surface 311a, adhered ink, and the like can be removed from the ink droplets attached to the ink discharge surface 311a without damaging the ink repellent film on the ink discharge surface 311a.

<Printing Process of Example 2 of the Present Invention>
As described above, in the inkjet head 34 that discharges clear ink, six unit heads 341 arranged in a zigzag matrix of 2 columns × 3 rows are arranged at predetermined intervals in the main scanning direction orthogonal to the transport direction. Has been.

  Therefore, when a print job including an instruction for adjusting the density of color ink, that is, an instruction to discharge clear ink is received in the print job, the control unit 8 performs the process on the conveyed paper based on the received print job. After ejecting each color ink from the inkjet head 31, the clear ink is ejected from the inkjet head 34 so as to be superimposed on each color ink landed on the paper.

  This prevents clear ink discharged from the inkjet head 34 from damaging the ink discharge surface due to the wet state of the wiper blade during the maintenance operation, and improves the glossiness and storability of the color ink during the printing operation. It can be used to realize both of these functions simultaneously. Specifically, during the maintenance operation of the inkjet head 34, before the tip portions of the wiper blades 432C, 432K, 432M, and 432Y come into contact with the ink ejection surfaces 311a of the inkjet heads 31C, 31K, 31M, and 31Y of the respective color inks, The contact surface at the tip of the wiper blades 432C, 432K, 432M, and 432Y can be wetted by ink droplets formed by discharging clear ink from the nozzles of the ink ejection surface 341a. At the same time, since clear ink, which is a functional ink, is ejected from the inkjet head 34 during printing operation, the glossiness and storability of the color ink ejected from the inkjet heads 31C, 31K, 31M, and 31Y and landing on the printing paper are excellent. Can be.

  In the inkjet printing apparatus according to the first and second embodiments, the configuration including the clear ink discharge unit and the cleaning ink discharge unit that discharge clear ink to one inkjet head has been described as an example. However, the present invention is not limited to this, and may be configured to include a clear ink head that discharges clear ink and a cleaning ink head that discharges cleaning ink.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printing apparatus 2 ... Conveying part 3 ... Head unit 4 ... Maintenance unit 5 ... Pressurizing part 6 ... Memory | storage part 7 ... Operation panel part 8 ... Control part 31 ... Inkjet head (color ink discharge means)
32 ... Inkjet head 33 ... Inkjet head 41 ... Ink receiving member 42 ... Drive unit 43 ... Wiper unit 44 ... Motor 45 ... Vertical motor 81 ... First maintenance control means 82 ... Second maintenance control means 311 ... Unit head 311a ... Ink ejection Surface 311b ... Nozzle 314 ... Discharged ink holding part 321b ... Clear ink discharge part (clear ink discharge means)
331b: Cleaning ink discharge section (cleaning ink discharge means)
432 ... Wiper blade (ink wiping member)

Claims (3)

Color ink ejection means for ejecting color ink from an ink ejection surface on which a plurality of nozzles are formed;
Clear ink discharge means for discharging colorless and transparent clear ink from an ink discharge surface on which a plurality of nozzles are formed;
Cleaning ink discharge means for discharging cleaning ink having higher cleaning ability than the clear ink from an ink discharge surface on which a plurality of nozzles are formed;
When the first maintenance condition is reached, the ink ejection surface after the clear ink is discharged from the clear ink ejection means is wiped off the clear ink along the ink ejection surface by an ink wiping member; First maintenance control means for controlling the ink discharge surface after discharging color ink from the color ink discharge means so that the color ink is wiped along the ink discharge surface by the ink wiping member;
When the second maintenance condition set so as to be less frequent than the first maintenance condition is reached, the ink discharge surface after the cleaning ink is discharged from the cleaning ink discharging means is moved by the ink wiping member. After the cleaning ink is wiped along the ink discharge surface, the color ink is discharged along the ink discharge surface by the ink wiping member after the color ink is discharged from the color ink discharge means. Second maintenance control means for controlling to wipe away;
An ink jet printing apparatus comprising: The clear ink is a functional ink for adjusting the density of the color ink,
When a print job including a color ink density adjustment instruction is received, the color ink is ejected from the clear ink ejecting unit before or after the color ink is ejected based on the print job. Print control means for controlling to eject clear ink,
The inkjet printing apparatus according to claim 1, further comprising: On the ink ejection surface of the color ink ejection means, for each color ink, a plurality of nozzles that eject the color ink onto the conveyed paper are arranged at predetermined intervals in the main scanning direction orthogonal to the paper conveyance direction,
On the ink ejection surface of the clear ink ejection means, a plurality of nozzles for ejecting clear ink onto the conveyed paper are arranged at the predetermined interval in the main scanning direction,
The ink wiping member is provided below the color ink ejection unit and the clear ink ejection unit, in a maintenance unit that is movable in the conveyance direction and in the vertical direction perpendicular to the conveyance direction, for each color ink of the color ink ejection unit. A plurality of
The color ink ejection unit and the clear ink ejection unit are other ink wiping members when at least one of the plurality of ink wiping members wipes the ink ejection surface of the clear ink ejection unit. Is provided at a vertical position that does not contact the ink ejection surface of the color ink ejection means,
The first maintenance control means includes
The plurality of ink wiping members corresponding to the respective color inks after the maintenance unit is moved in the transport direction to wipe the ink ejection surface of the clear ink ejection unit by the ink wiping member. The ink of the color ink discharge means is moved by the ink wiping member by moving the color ink discharge means in the transport direction and upward to a position in contact with the ink discharge surface of the color ink discharge means, and then moving the maintenance unit in the transport direction. It controls so that each color ink may be wiped off along an ejection surface. The inkjet printing apparatus of Claim 2 characterized by the above-mentioned.

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