JP2018114626A - Inkjet printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet printing device that can decrease exchange frequencies of waste liquid absorption members.SOLUTION: An inkjet printing device 1 comprises: an inkjet head 29; an ink circulation mechanism part 4 and a maintenance part 8 which perform operation for cleaning the inkjet head 29; a waste liquid sponge 9 for absorbing waste liquid resulting from the operation for cleaning the inkjet head 29; a waste liquid detection part 10 that detects absorbed waste liquid amounts by the waste liquid sponge 9; and a control part 12 that changes settings of the cleaning operation so that waste liquid amounts are reduced, when the absorbed waste liquid amounts detected by the waster liquid detection part 10 reach alert level.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inkjet printing apparatus that prints by ejecting ink from an inkjet head.

  In the ink jet printing apparatus, an ink jet head cleaning operation is performed in order to remove dust adhering to the ink jet head or to stabilize the physical properties of ink in the nozzle. The cleaning operation is performed, for example, every predetermined number of printed sheets.

  As one of the cleaning operations of the ink-jet head, a series of operations are known in which ink is forcibly discharged from a nozzle, so-called purging, and then the surface of the nozzle is wiped with a wiper.

  In such a cleaning operation, the ink discharged from the nozzles of the inkjet head by purging becomes waste liquid. The waste liquid is stored, for example, in a waste liquid tank provided in the apparatus (see, for example, Patent Document 1).

  There is also known an ink jet printing apparatus that stores waste liquid by absorbing it with a waste liquid absorbing member such as a sponge.

JP 2012-121229 A

  In the above-described inkjet printing apparatus that stores waste liquid in the waste liquid absorbing member, when the waste liquid absorption amount of the waste liquid absorbing member reaches the limit, if the apparatus is used continuously, when waste liquid is generated by the cleaning operation, the waste liquid absorbing member There is a risk that waste liquid that is not absorbed leaks from the device.

  Therefore, in such an ink jet printing apparatus, when the waste liquid absorption amount of the waste liquid absorbing member reaches a limit, printing is impossible until the waste liquid absorbing member is replaced. That is, when the waste liquid absorbing member is replaced, a period during which printing cannot be performed by the ink jet printing apparatus occurs. For this reason, it is desirable to reduce the replacement frequency of the waste liquid absorbing member by extending the period until the waste liquid absorption amount of the waste liquid absorbing member reaches the limit.

  The present invention has been made in view of the above, and an object thereof is to provide an ink jet printing apparatus capable of reducing the replacement frequency of the waste liquid absorbing member.

  In order to achieve the above object, a first feature of an ink jet printing apparatus according to the present invention is that an ink jet head, cleaning means for performing a cleaning operation of the ink jet head, and waste liquid absorption for absorbing waste liquid due to the cleaning operation of the ink jet head. A member, a detecting means for detecting a waste liquid absorption amount of the waste liquid absorbing member, and a control for changing the setting of the cleaning operation so as to reduce the waste liquid amount when the waste liquid absorption amount detected by the detecting means reaches a warning level. Means.

  A second feature of the ink jet printing apparatus according to the present invention is that, as a change in the setting of the cleaning operation for reducing the amount of waste liquid, the control unit removes ink from the ink jet head in the cleaning operation execution frequency and the cleaning operation. It is to change at least one of the purge pressures when purging to be discharged.

  A third feature of the ink jet printing apparatus according to the present invention is that, when the execution frequency of the cleaning operation is changed, the control unit changes at least one of the number of printed sheets and the power-off period as a cleaning operation execution condition. There is.

  According to the first feature of the inkjet printing apparatus according to the present invention, the control means performs the cleaning operation so as to reduce the waste liquid amount when the waste liquid absorption amount of the waste liquid absorbent detected by the detection means reaches a warning level. Change the settings. Accordingly, the amount of waste liquid due to the cleaning operation is reduced, and the period until the waste liquid absorption amount of the waste liquid absorbent reaches the limit level is extended, so that the replacement frequency of the waste liquid absorbing member can be reduced.

  According to the second feature of the ink jet printing apparatus according to the present invention, the control means is at least one of the frequency of execution of the cleaning operation and the purge pressure in the cleaning operation as a change in setting of the cleaning operation for reducing the amount of waste liquid. Change one. As described above, the amount of waste liquid can be effectively reduced by changing at least one of the cleaning operation execution frequency and the purge pressure related to the amount of waste liquid.

  According to the third feature of the ink jet printing apparatus according to the present invention, the control means changes at least one of the number of printed sheets and the power shut-off period as a cleaning operation execution condition when changing the execution frequency of the cleaning operation. To do. This makes it possible to easily change the frequency of execution of the cleaning operation in the inkjet printing apparatus that employs at least one of the number of printed sheets and the power-off period as the execution condition of the cleaning operation.

1 is a schematic configuration diagram of an inkjet printing apparatus according to a first embodiment. It is a principal part front view of the printing part of the inkjet printing apparatus shown in FIG. It is a principal part top view of the printing part of the inkjet printing apparatus shown in FIG. It is a perspective view of the maintenance part of the inkjet printing apparatus shown in FIG. It is a top view of the maintenance part of the inkjet printing apparatus shown in FIG. FIG. 2 is a perspective view of a waste liquid sponge and a waste liquid detection unit of the ink jet printing apparatus shown in FIG. 1. It is a control block diagram of the inkjet printing apparatus shown in FIG. It is a figure which shows an example of the cleaning mode table in 1st Embodiment. It is a figure which shows the state which has a belt platen part and a maintenance part in a standby position. It is a figure which shows the state which has a belt platen part in a standby position, and a maintenance part exists in a retracted position. It is a figure which shows the state which a belt platen part exists in a printing position, and a maintenance part exists in a retracted position. It is a figure which shows the state which has a belt platen part and a maintenance part in a cleaning position. It is a flowchart of a cleaning mode setting process. It is a flowchart of a cleaning mode setting process. It is a figure which shows an example of the cleaning mode table in 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals.

  The following embodiments exemplify devices for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, arrangement, etc. of each component. Is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an inkjet printing apparatus according to a first embodiment of the present invention. FIG. 2 is a front view of an essential part of a printing unit of the inkjet printing apparatus shown in FIG. FIG. 3 is a plan view of the main part of the printing unit. FIG. 4 is a perspective view of a maintenance unit of the ink jet printing apparatus shown in FIG. FIG. 5 is a plan view of the maintenance unit. 6 is a perspective view of a waste liquid sponge and a waste liquid detection unit of the ink jet printing apparatus shown in FIG. FIG. 7 is a control block diagram of the ink jet printing apparatus shown in FIG. In the following description, the direction orthogonal to the paper surface of FIG. 1 is the front-rear direction, and the front surface direction is the front. Also, the top, bottom, left, and right of the paper surface in FIG.

  In FIG. 1, a path indicated by a thick line is a transport path through which the paper P that is a print medium is transported. Among the transport routes, a route indicated by a solid line is a normal route RC, a route indicated by a one-dot chain line is a reverse route RR, a route indicated by a broken line is a paper discharge route RD, and a route indicated by a two-dot chain line is a paper feed route RS.

  As shown in FIGS. 1 and 7, the inkjet printing apparatus 1 according to the first embodiment includes a paper feeding unit 2, a printing unit 3, an ink circulation mechanism unit 4, an upper surface transport unit 5, and a paper discharge unit 6. A reversing unit 7, a maintenance unit 8, a waste liquid sponge (corresponding to the waste liquid absorbing member in the claims) 9, a waste liquid detection unit (corresponding to the detection means in the claims) 10, an operation panel 11, and a control unit ( (Corresponding to the control means of the claims) 12 and a housing 13 for storing or holding each part.

  The paper feeding unit 2 feeds the paper P to the printing unit 3. The paper feed unit 2 includes an external paper feed base 21, an external paper feed roller 22, a plurality of internal paper feed stands 23, a plurality of internal paper feed rollers 24, and a plurality of pairs of vertical transport rollers 25.

  The external paper feed tray 21 is used for loading paper P used for printing. The external paper feed tray 21 is partly exposed outside the housing 13. The external paper feed roller 22 takes out the paper P one by one from the external paper feed tray 21 and conveys the paper P toward a registration roller 26 described later.

  The internal paper feed table 23 is used for loading paper P used for printing. The internal paper feed table 23 is disposed inside the housing 13. The internal paper feed roller 24 takes out the paper P one by one from the internal paper feed tray 23 and sends it out to the paper feed path RS. The vertical conveyance roller 25 conveys the paper P taken out from the internal paper feed table 23 by the internal paper feed roller 24 toward the registration roller 26 along the paper feed path RS.

  The printing unit 3 prints an image on the paper P while conveying the paper P. The printing unit 3 includes a registration roller 26, a belt platen unit 27, and line heads 28C, 28K, 28M, and 28Y. In addition, the alphabetic suffixes in the reference numerals of the line heads 28C, 28K, 28M, and 28Y may be omitted to collectively describe them.

  The registration roller 26 temporarily stops the paper P conveyed from the paper feeding unit 2 or the reversing unit 7 and then conveys the paper P toward the belt platen unit 27.

  The belt platen unit 27 conveys the sheet P conveyed from the registration roller 26 while adsorbing and holding the sheet P on the belt. The belt platen portion 27 is configured to be movable up and down by a motor (not shown). Thus, the belt platen unit 27 can be arranged at the printing position, the standby position (see FIG. 9), and the cleaning position (see FIG. 12), which are the positions of the belt platen unit 27 in FIG.

  The line heads 28 </ b> C, 28 </ b> K, 28 </ b> M, 28 </ b> Y eject ink onto the paper P conveyed by the belt platen unit 27 to print an image. The line heads 28C, 28K, 28M, and 28Y are disposed above the belt platen portion 27. The line heads 28C, 28K, 28M, and 28Y eject cyan (C), black (K), magenta (M), and yellow (Y) inks, respectively. Each of the line heads 28C, 28K, 28M, 28Y has six inkjet heads 29 as shown in FIG.

  In each line head 28, six inkjet heads 29 are arranged in a staggered manner. That is, in each line head 28, six inkjet heads 29 arranged along the front-rear direction are arranged with their positions in the left-right direction alternately shifted.

  The inkjet head 29 has a plurality of nozzles (not shown) arranged along the main scanning direction (front-rear direction), and ejects ink from the nozzles. A nozzle is opened in a nozzle surface 29 a which is the lower surface of the inkjet head 29.

  The ink circulation mechanism 4 supplies ink to the inkjet head 29 of the line head 28 while circulating the ink. The ink circulation mechanism 4 has an ink circulation path (not shown) for each color ink, and supplies each color ink to the line heads 28C, 28K, 28M, and 28Y while circulating each color ink. The ink circulation mechanism 4 includes a pressure generation mechanism (not shown) that generates pressure for circulating the ink of each color along the respective ink circulation paths. With this pressure generation mechanism, a purge pressure at the time of purging in a cleaning operation described later can be generated in the inkjet head 29. The ink circulation mechanism part 4 constitutes a part of the cleaning means of the claims.

  The upper surface transport unit 5 transports the paper P transported by the belt platen unit 27 to the paper discharge unit 6 or the reversing unit 7. The upper surface transport unit 5 includes a plurality of pairs of ascending transport rollers 31 and a plurality of pairs of horizontal transport rollers 32.

  The ascending conveyance roller 31 conveys the sheet P conveyed by the belt platen unit 27 to the upper horizontal conveyance roller 32. The horizontal conveyance roller 32 conveys the paper P conveyed by the ascending conveyance roller 31 to the paper discharge unit 6 or the reversing unit 7.

  The paper discharge unit 6 discharges the printed paper P. The paper discharge unit 6 includes a switching unit 36, a paper discharge roller 37, and a paper discharge stand 38.

  The switching unit 36 switches the transport path of the paper P between the paper discharge path RD and the reverse path RR. The paper discharge roller 37 conveys the paper P guided to the paper discharge path RD by the switching unit 36 and discharges it to the paper discharge tray 38. The paper discharge tray 38 is a stack on which printed paper P discharged by the paper discharge roller 37 is stacked.

  The reversing unit 7 reverses the single-side printed paper P and re-feeds it to the printing unit 3 during duplex printing. The reversing unit 7 includes a reversing roller 41, a switchback unit 42, a refeed roller 43, and a switching gate 44.

  The reverse roller 41 temporarily transports the paper P transported by the horizontal transport roller 32 to the switchback unit 42 and then transports it to the refeed roller 43. The switchback unit 42 is a space for the reversing roller 41 to carry in the paper P temporarily. The switchback unit 42 is formed in the lower part of the paper discharge tray 38. The refeed roller 43 conveys the paper P conveyed by the reversing roller 41 to the registration roller 26. The switching gate 44 guides the sheet P conveyed by the horizontal conveyance roller 32 to the reverse roller 41. Further, the switching gate 44 guides the paper P carried out from the switchback unit 42 by the reversing roller 41 to the refeed roller 43.

  The maintenance unit 8 wipes the nozzle surface 29 a in the cleaning operation of the inkjet head 29. The maintenance unit 8 constitutes a part of the cleaning means in the claims.

  The maintenance unit 8 is configured to be movable between a retracted position, which is the position of the maintenance unit 8 shown in FIG. 1, and a standby position described later (see FIG. 9) by a motor (not shown). The maintenance unit 8 is disposed at a cleaning position (see FIG. 12) described later during cleaning.

  As shown in FIGS. 4 and 5, the maintenance unit 8 includes an ink receiving member 46, a wiper unit 47, and a wiper drive unit 48. 4 and 5 are diagrams in a state where the maintenance unit 8 is disposed at the cleaning position.

  The ink receiving member 46 receives ink that has been removed from the nozzle surface 29a of the inkjet head 29 during the cleaning operation. The ink receiving member 46 is formed in a rectangular parallelepiped shape. A recess 46 a for receiving ink is formed at the center of the ink receiving member 46. The recess 46a is formed so as to be larger than a region where the inkjet heads 29 of the line heads 28C, 28K, 28M, and 28Y are disposed in a plan view. The upper side of the ink receiving member 46 is opened.

  The wiper unit 47 wipes the nozzle surface 29 a of the inkjet head 29. The wiper unit 47 includes a mounting base 49 and eight wipers 50.

  The mounting base 49 is to which the wiper 50 is attached. The mounting base 49 is formed in a rectangular parallelepiped shape. Screw holes 49 a and 49 b are formed in the mounting base 49. Screw screw gears 54A and 54B, which will be described later, pass through and are screwed into the screw holes 49a and 49b, respectively. Due to the rotation of the screw gears 54A and 54B, the mounting base 49 moves in the front-rear direction.

  The wiper 50 is a member that wipes the nozzle surface 29 a of the inkjet head 29. The wiper 50 is made of a material such as elastically deformable rubber and is formed in a rectangular plate shape. The lower end portion of the wiper 50 is fixed to the mounting base 49 by a fixture (not shown). As shown in FIG. 5, the eight wipers 50 are arranged so as to be positioned on the extended lines of the respective rows along the front-rear direction of the staggered inkjet head 29 in a state where the maintenance unit 8 is arranged at the cleaning position. Has been.

  In the state where the maintenance unit 8 is disposed at the cleaning position, the upper end of the wiper 50 is at a position higher than the nozzle surface 29 a of the inkjet head 29. When the wiper 50 is moved in the front-rear direction and comes into contact with the inkjet head 29, the wiper 50 is elastically deformed and the upper end portion slides (wipes) the nozzle surface 29a.

  The wiper drive unit 48 moves the wiper unit 47 in the front-rear direction. The wiper drive unit 48 includes a wiper motor 51, a drive belt 52, drive pulleys 53A and 53B, and screw gears 54A and 54B.

  The wiper motor 51 generates a rotational driving force for moving the wiper unit 47. The wiper motor 51 is disposed outside the rear wall of the ink receiving member 46. The wiper motor 51 has an output gear 51a. The output gear 51 a transmits the rotational driving force of the wiper motor 51 to the drive belt 52. The output gear 51 a is disposed at the center of the drive belt 52.

  The driving belt 52 transmits the rotational driving force transmitted from the wiper motor 51 to the driving pulleys 53A and 53B. The drive belt 52 is stretched between the drive pulley 53A and the drive pulley 53B.

  The drive pulleys 53A and 53B transmit the rotational driving force transmitted from the drive belt 52 to the screw gears 54A and 54B. The drive pulley 53A and the drive pulley 53B are spaced apart from each other in the left-right direction and are disposed at the same height. The drive pulleys 53 </ b> A and 53 </ b> B are rotatably supported on the rear wall of the ink receiving member 46.

  The screw gears 54A and 54B move the wiper unit 47 in the front-rear direction by the rotational driving force transmitted from the drive pulleys 53A and 53B. The screw gears 54A and 54B extend over substantially the entire length of the recess 46a in the front-rear direction. The rear ends of the screw gears 54A and 54B are fixed to drive pulleys 53A and 53B, respectively. The front ends of the screw gears 54A and 54B are rotatably supported by the front wall of the ink receiving member 46. Thereby, the screw gears 54A and 54B rotate together with the drive pulleys 53A and 53B, respectively.

  The waste liquid sponge 9 is a sponge that absorbs waste liquid due to the cleaning operation of the inkjet head 29. When the maintenance unit 8 is retracted to the retracted position, the ink receiving member 46 is tilted, so that the waste liquid in the ink receiving member 46 falls and is absorbed by the waste liquid sponge 9. The color of the waste liquid sponge 9 is a white color. The waste liquid sponge 9 is disposed in a recess 13 b formed in the bottom plate 13 a of the housing 13. The waste liquid sponge 9 is formed in a rectangular parallelepiped shape.

  The waste liquid detection unit 10 is for detecting the amount of waste liquid absorbed by the waste liquid sponge 9. The waste liquid detection unit 10 includes four dirt sensors 61. The four dirt sensors 61 are respectively disposed above the four corners of the waste liquid sponge 9 in plan view. The dirt sensor 61 includes a reflective optical sensor having a light emitting part and a light receiving part (both not shown). The dirt sensor 61 receives the light reflected by the waste liquid sponge 9 from the light emitted from the light emitting unit at the light receiving unit. As the amount of waste liquid absorbed by the waste liquid sponge 9 increases, the degree of contamination of the waste liquid sponge 9 increases and the amount of light received by the light receiving portion of the contamination sensor 61 decreases. Therefore, the amount of waste liquid absorbed by the waste liquid sponge 9 can be determined from the amount of light received by the light receiving unit of the dirt sensor 61.

  The operation panel 11 displays various input screens and accepts input operations by the user. The operation panel 11 includes a display unit 66 and an input unit 67.

  The display unit 66 displays images such as various input screens. The display unit 66 includes a liquid crystal display panel and the like.

  The input unit 67 receives an input operation by the user and outputs an operation signal corresponding to the operation. The input unit 67 includes various operation keys, a touch panel, and the like.

  The control unit 12 controls the operation of each unit of the inkjet printing apparatus 1. The control unit 12 includes a CPU, a RAM, a ROM, a hard disk, and the like.

  The control unit 12 stores a cleaning mode table 71 shown in FIG. The cleaning mode table 71 is a table in which the normal mode and the suppression mode provided as the cleaning mode in the inkjet printing apparatus 1, the number of printed sheets as a cleaning operation execution condition, and the purge pressure in the cleaning operation are associated with each other.

  The normal mode is a mode in which the cleaning operation of the inkjet head 29 is executed with a standard frequency. In the example of FIG. 8, in the normal mode, the cleaning operation is performed for every 1000 printed sheets. In the normal mode, the purge pressure in the purge performed in the cleaning operation of the inkjet head 29 is set to “strong”.

  The suppression mode is a mode for reducing the amount of waste liquid due to the cleaning operation as compared with the normal mode. In the example of FIG. 8, in the suppression mode, the cleaning operation is performed for every 3000 printed sheets, which is larger than in the normal mode. Thereby, in the suppression mode, the execution frequency of the cleaning operation is suppressed as compared with the normal mode, and the amount of waste liquid is reduced. Further, in the suppression mode, the amount of waste liquid is reduced compared to the normal mode by setting the purge pressure to “weak”.

  Here, the “strong” purge pressure in the normal mode is set as a purge pressure sufficient to discharge the thickened ink in the nozzles of the inkjet head 29 together with the ink. The “weak” purge pressure in the suppression mode is set as a purge pressure smaller than the “strong” purge pressure in the normal mode. The smaller the purge pressure, the smaller the amount of ink discharged in the purge, so the amount of waste liquid in the cleaning operation decreases.

  The control unit 12 sets the cleaning mode to the normal mode until the waste liquid absorption amount of the waste liquid sponge 9 detected by the waste liquid detection unit 10 reaches a warning level. When the waste liquid absorption amount of the waste liquid sponge 9 reaches a warning level, when the suppression mode is selected by the user, the control unit 12 changes the cleaning mode to the suppression mode. That is, in this case, the control unit 12 changes the setting of the cleaning operation for reducing the amount of waste liquid to change the number of printed sheets to be the execution condition of the cleaning operation to the number of printed sheets in the suppression mode, and set the purge pressure to “ Change from “strong” to “weak”.

  Next, the printing operation of the inkjet printing apparatus 1 will be described.

  In the standby state before starting the printing operation, the belt platen unit 27 and the maintenance unit 8 are respectively disposed at the standby positions shown in FIG. The standby position of the belt platen unit 27 is below the line heads 28C, 28K, 28M, and 28Y and below the printing position that is the position of the belt platen unit 27 shown in FIG. The standby position of the maintenance unit 8 is a position on the belt platen unit 27 at the standby position.

  From the state of FIG. 9, first, the control unit 12 moves the maintenance unit 8 to the retracted position as shown in FIG. Next, as shown in FIG. 11, the control unit 12 raises the belt platen unit 27 and moves it to the printing position. As a result, the maintenance unit 8 is retracted to the retracted position, and the belt platen unit 27 is disposed at the printing position.

  After the belt platen unit 27 is arranged at the printing position, the unprinted paper P is conveyed from any one of the external paper feed table 21 and the plurality of internal paper feed tables 23 of the paper feed unit 2 to the registration roller 26, 26 conveys the paper P to the belt platen unit 27. The paper P is printed by ink ejected from the line heads 28C, 28K, 28M, and 28Y while being conveyed by the belt platen unit 27. The printed paper P is conveyed from the belt platen unit 27 to the upper surface conveyance unit 5, and is conveyed by the upper conveyance roller 31 and the horizontal conveyance roller 32 in the upper surface conveyance unit 5.

  Here, in the case of single-sided printing, the paper P is guided from the normal route RC to the paper discharge route RD by the switching unit 36 of the paper discharge unit 6. Then, the paper P is discharged to a paper discharge tray 38 by a paper discharge roller 37.

  On the other hand, in the case of duplex printing, the paper P is guided from the normal route RC to the reverse route RR by the switching unit 36 of the paper discharge unit 6. The paper P guided to the reversing path RR is guided to the reversing roller 41 by the switching gate 44 in the reversing unit 7 and is carried into the switchback unit 42 by the reversing roller 41. Thereafter, the paper P is unloaded from the switchback unit 42 by the reverse roller 41 and guided to the refeed roller 43 by the switching gate 44. Then, the sheet P is conveyed to the registration roller 26 by the refeed roller 43 and is conveyed to the belt platen unit 27 by the registration roller 26.

  Here, since the paper P is reversed by the reversing unit 7, the unprinted surface is directed upward. While the sheet P is conveyed by the belt platen unit 27, an unprinted surface is printed by ink ejected from the line heads 28C, 28K, 28M, and 28Y. Then, the double-side printed paper P is transported to the paper discharge unit 6 by the upper surface transport unit 5 and is discharged to the paper discharge tray 38 in the paper discharge unit 6.

  When printing for the designated number of pages is completed, the control unit 12 moves the belt platen unit 27 from the printing position to the standby position. Thereafter, the control unit 12 moves the maintenance unit 8 from the retracted position to the standby position.

  Next, the cleaning operation of the inkjet head 29 in the inkjet printing apparatus 1 will be described.

  The cleaning operation is executed when the cumulative number of prints from the previous cleaning operation reaches the number of prints that is the execution condition of the cleaning operation in the normal mode or the suppression mode currently set as the cleaning mode.

  When performing the cleaning operation, the control unit 12 places the belt platen unit 27 and the maintenance unit 8 at the cleaning position. Specifically, the control unit 12 lowers the belt platen unit 27 from the printing position to the standby position. Next, the control unit 12 moves the maintenance unit 8 from the retracted position to the standby position. And the control part 12 raises the belt platen part 27, and moves the belt platen part 27 and the maintenance part 8 to the cleaning position shown in FIG.

  The cleaning position of the belt platen unit 27 is above the standby position and below the printing position. The cleaning position of the maintenance unit 8 is a position on the belt platen unit 27 at the cleaning position.

  When the belt platen unit 27 and the maintenance unit 8 are disposed at the cleaning position, the control unit 12 performs a purge. Specifically, the control unit 12 controls the ink circulation mechanism unit 4 to generate a purge pressure in the ink jet head 29 in the normal mode or the suppression mode currently set as the cleaning mode and to discharge ink from the nozzles. As a result, the ink is pushed out from the nozzles of the inkjet head 29, and the ink adheres to the nozzle surface 29a.

  Next, the control unit 12 performs a wipe operation. Specifically, the control unit 12 drives the wiper motor 51 to start moving the wiper unit 47 forward. Here, when the maintenance unit 8 moves to the cleaning position, the wiper unit 47 is at the initial position behind the rearmost inkjet head 29.

  When the wiper unit 47 moves forward and the wiper 50 contacts the inkjet head 29, the wiper 50 is pressed by the inkjet head 29 and elastically deformed. When the wiper unit 47 further moves forward in this state, the upper end portion of the wiper 50 slides (wipes) the nozzle surface 29a. Thereby, the ink adhering to the nozzle surface 29a is removed together with dust and the like on the nozzle surface 29a. Ink or the like removed from the nozzle surface 29a by the wiping operation is received by the ink receiving member 46 as waste liquid.

  When the wiper 50 moves further forward than the frontmost inkjet head 29, the control unit 12 stops the wiper motor 51. Thereby, the wiper unit 47 stops. As a result, the wiping operation ends and the cleaning operation ends.

  When the printing operation is resumed after the cleaning operation is completed, the control unit 12 moves the maintenance unit 8 to the retracted position and moves the belt platen unit 27 to the printing position. Specifically, the control unit 12 first lowers the belt platen unit 27 and moves the belt platen unit 27 and the maintenance unit 8 from the cleaning position to the standby position. The control unit 12 drives the wiper motor 51 to move the wiper unit 47 to the initial position. Next, the control unit 12 moves the maintenance unit 8 from the standby position to the retracted position. Then, the control unit 12 raises the belt platen unit 27 and moves it from the standby position to the printing position. Thereafter, the printing operation is resumed. Here, when the maintenance unit 8 moves to the retracted position, the ink receiving member 46 tilts, so that the waste liquid in the ink receiving member 46 falls and is absorbed by the waste liquid sponge 9.

  When the printing operation is not resumed, the control unit 12 lowers the belt platen unit 27 after the cleaning operation is completed, and moves the belt platen unit 27 and the maintenance unit 8 from the cleaning position to the standby position. The control unit 12 drives the wiper motor 51 to move the wiper unit 47 to the initial position. Thereby, the inkjet printing apparatus 1 will be in a standby state. In this case, when the next printing operation is performed, the maintenance unit 8 moves to the retracted position, so that the waste liquid in the ink receiving member 46 falls and is absorbed by the waste liquid sponge 9.

  Next, the cleaning mode setting process in the inkjet printing apparatus 1 will be described.

  The cleaning mode setting process is a process for setting the cleaning mode to the normal mode or the suppression mode with reference to the waste liquid absorption amount of the waste liquid sponge 9. In the initial state of the inkjet printing apparatus 1, the cleaning mode is set to the normal mode.

  13 and 14 are flowcharts of the cleaning mode setting process. The process of this flowchart is started when the waste liquid amount confirmation timing comes. The waste liquid amount confirmation timing is set, for example, at a timing when the power of the inkjet printing apparatus 1 is turned on or when a print job is input to the inkjet printing apparatus 1.

  In step S1 of FIG. 13, the control unit 12 determines whether the waste liquid absorption amount of the waste liquid sponge 9 is less than the limit level (maximum absorption amount) based on the light reception amounts of the four dirt sensors 61 of the waste liquid detection unit 10. to decide. Here, the control unit 12 determines that the waste liquid absorption amount of the waste liquid sponge 9 is less than the limit level when there is at least one dirt sensor 61 whose received light amount is equal to or greater than the threshold (the degree of dirt is small). In other words, the control unit 12 determines that the amount of waste liquid absorbed by the waste liquid sponge 9 has reached the limit level when the amount of light received by all the dirt sensors 61 is less than the threshold value.

  When it is determined that the waste liquid absorption amount of the waste liquid sponge 9 is less than the limit level (step S1: YES), in step S2, the control unit 12 absorbs the waste liquid of the waste liquid sponge 9 based on the received light amounts of the four dirt sensors 61. Determine whether the amount has reached the alert level. Here, when the number of the dirt sensors 61 whose received light amount is less than the threshold is two or three, the control unit 12 determines that the waste liquid absorption amount of the waste liquid sponge 9 has reached a warning level.

  When it is determined that the amount of waste liquid absorbed by the waste liquid sponge 9 has reached the warning level (step S2: YES), in step S3, the control unit 12 determines whether or not the near-full flag is “0”.

  Here, the near full flag indicates whether or not the waste liquid absorption amount of the waste liquid sponge 9 has reached a warning level. When the waste liquid absorption amount of the waste liquid sponge 9 has reached the warning level, the near full flag is “1”, and when the waste liquid absorption amount is less than the warning level, the near full flag is “0”. The near full flag is stored in the control unit 12.

  When it is determined that the near full flag is “0” (step S3: YES), in step S4, the control unit 12 changes the near full flag to “1”.

  Here, the waste liquid absorption amount of the waste liquid sponge 9 has reached a warning level (step S2: YES) and the near full flag is “0” (step S3: YES). This means that it has been detected for the first time at the timing of checking the amount of waste liquid that the amount of absorbed waste liquid has reached a warning level. In this case, the cleaning mode is set to the normal mode when it is detected that the waste liquid absorption amount of the waste liquid sponge 9 has reached the warning level at the current waste liquid amount confirmation timing.

  Next, in step S <b> 5, the control unit 12 calculates a predicted replacement date for the waste liquid sponge 9. The predicted replacement date of the waste liquid sponge 9 is a date on which the amount of waste liquid absorption is predicted to reach a limit level in the normal mode.

  Specifically, the control unit 12 calculates the period of the cleaning operation based on the average number of printed sheets per day in the inkjet printing apparatus 1 and the number of printed sheets used as the execution condition of the cleaning operation in the normal mode. Next, the control unit 12 performs the cleaning operation cycle, the amount of waste liquid in one cleaning operation in the normal mode, and the allowable additional waste liquid amount of the waste liquid sponge 9 according to the number of dirt sensors 61 whose received light amount is less than the threshold. Based on the above, the period until the amount of waste liquid absorption reaches the limit level is calculated. And the control part 12 calculates the replacement | exchange estimated date of the waste liquid sponge 9 based on the period until a waste liquid absorption amount reaches a limit level, and the present date.

  Next, in step S <b> 6, the control unit 12 notifies the user by displaying the calculated estimated replacement date of the waste liquid sponge 9 on the display unit 66.

  Next, in step S <b> 7, the control unit 12 causes the display unit 66 to display a cleaning mode selection screen (not shown). The cleaning mode selection screen is a screen for allowing the user to select either the normal mode or the suppression mode. When the cleaning mode selection screen is displayed on the display unit 66, the user selects either the normal mode or the suppression mode by operating the input unit 67.

  Here, in the suppression mode, the cleaning operation is performed less frequently than in the normal mode, and the purge pressure is low, so that the inkjet head 29 is not sufficiently cleaned, and problems such as non-ejection of ink from the nozzles are eliminated. There is a risk that it cannot be done. For this reason, when the suppression mode is set, the print image quality may be lower than that in the normal mode. Therefore, the user may be notified by displaying on the cleaning mode selection screen that the print image quality may be lower in the suppression mode than in the normal mode.

  Further, the control unit 12 may calculate a predicted replacement date of the waste liquid sponge 9 when the mode is changed to the suppression mode, and display the predicted replacement date on the cleaning mode selection screen.

  Next, in step S8, the control unit 12 determines whether or not the suppression mode is selected by a user operation.

  If it is determined that the suppression mode has been selected (step S8: YES), in step S9, the control unit 12 changes the cleaning mode from the normal mode to the suppression mode. Specifically, the control unit 12 refers to the cleaning mode table 71 and changes the setting of the number of printed sheets as the execution condition of the cleaning operation from the number of printed sheets in the normal mode to the number of printed sheets in the suppression mode. In addition, the control unit 12 changes the setting of the purge pressure in the cleaning operation from “strong” to “weak”. As a result, the cleaning mode setting process ends.

  When it is determined that the normal mode is selected (step S8: NO), in step S10, the control unit 12 maintains the cleaning mode in the normal mode. As a result, the cleaning mode setting process ends.

  When it is determined in step S1 that the waste liquid absorption amount of the waste liquid sponge 9 has reached the limit level (step S1: NO), in step S11 in FIG. Is displayed on the display unit 66. When the user who has confirmed this screen notifies the serviceman, the serviceman replaces the waste liquid sponge 9.

  Here, the control unit 12 puts the inkjet printing apparatus 1 into a non-printable state when it is determined that the waste liquid absorption amount of the waste liquid sponge 9 has reached the limit level.

  Next, in step S12, the control unit 12 determines whether or not the replacement of the waste liquid sponge 9 has been completed. For example, the control unit 12 can determine that the replacement of the waste liquid sponge 9 has been completed based on an operation of notifying the input unit 67 of the replacement of the waste liquid sponge 9 by a serviceman. When it is determined that the replacement of the waste liquid sponge 9 has not been completed (step S12: NO), the control unit 12 repeats step S12.

  If it is determined that the replacement of the waste liquid sponge 9 has been completed (step S12: YES), in step S13, the control unit 12 resets the near-full flag to “0”.

  Further, the control unit 12 returns the inkjet printing apparatus 1 to a printable state when it is determined that the replacement of the waste liquid sponge 9 has been completed.

  Next, in step S14, the control unit 12 determines whether or not the normal mode is set as the cleaning mode. Here, the cleaning mode set at this time point (when the replacement of the waste liquid sponge 9 is completed) is selected when it is detected for the first time that the waste liquid absorption amount reaches the warning level in the waste liquid sponge 9 before replacement. Mode.

  When it is determined that the normal mode is set (step S14: YES), in step S15, the control unit 12 maintains the cleaning mode in the normal mode. As a result, the cleaning mode setting process ends.

  When it is determined that the suppression mode is set (step S14: NO), in step S16, the control unit 12 returns the cleaning mode to the normal mode. Specifically, the control unit 12 refers to the cleaning mode table 71 and returns the setting of the number of printed sheets as a cleaning operation execution condition from the number of printed sheets in the suppression mode to the number of printed sheets in the normal mode. Further, the control unit 12 returns the setting of the purge pressure in the cleaning operation from “weak” to “strong”. As a result, the cleaning mode setting process ends.

  If it is determined in step S2 of FIG. 13 that the waste liquid absorption amount of the waste liquid sponge 9 has not reached the alert level (step S2: NO), the control unit 12 ends the cleaning mode setting process as it is.

  Here, when the waste liquid absorption amount of the waste liquid sponge 9 has not reached the warning level, the normal mode is set as the cleaning mode. For this reason, when it is determined that the waste liquid absorption amount of the waste liquid sponge 9 has not reached the warning level (step S2: NO), the control unit 12 maintains the normal mode and ends the cleaning mode setting process.

  If it is determined in step S3 that the near-full flag is “1” (step S3: NO), the control unit 12 maintains the currently set cleaning mode and ends the cleaning mode setting process.

  Here, the amount of waste liquid absorbed by the waste liquid sponge 9 has reached a warning level (step S2: YES), and the near full flag is “1” (step S3: NO), before the previous waste liquid amount confirmation timing, This means that the amount of waste liquid absorbed has reached a warning level. In this case, the currently set cleaning mode is the cleaning mode selected when it is first detected that the amount of waste liquid absorbed by the current waste sponge 9 has reached the warning level.

  As described above, in the first embodiment, the control unit 12 changes the cleaning mode to the suppression mode when the suppression mode is selected by the user when the waste liquid absorption amount of the waste liquid sponge 9 reaches the warning level. To do. Thereby, in the suppression mode, the amount of waste liquid by the cleaning operation can be reduced, and the period until the waste liquid absorption amount of the waste liquid sponge 9 reaches the limit level can be extended. As a result, the replacement frequency of the waste liquid sponge 9 can be reduced.

  In addition, in the suppression mode, the controller 12 changes the execution frequency of the cleaning operation from the execution frequency in the normal mode, and reduces the amount of waste liquid due to the cleaning operation by changing the purge pressure from the purge pressure in the normal mode. Yes. As described above, the amount of waste liquid can be effectively reduced by changing the cleaning operation execution frequency and the purge pressure related to the amount of waste liquid.

  Further, the control unit 12 changes the execution frequency of the cleaning operation by changing the number of printed sheets as a cleaning operation execution condition. Thereby, in the inkjet printing apparatus 1 that employs the number of printed sheets as the execution condition of the cleaning operation, the execution frequency of the cleaning operation can be easily changed.

  In addition, even when the waste liquid absorption amount of the waste liquid sponge 9 reaches a warning level, the control unit 12 does not change the cleaning mode to the suppression mode when the normal mode is selected by the user. Thereby, it is possible to respond to a user's desire to avoid a decrease in print image quality due to insufficient cleaning of the inkjet head 29 by the suppression mode.

(Second Embodiment)
Next, a second embodiment in which a part of the first embodiment described above is changed will be described.

  In the second embodiment, the cleaning mode table 71 of the first embodiment described above is replaced with a cleaning mode table 72 shown in FIG.

  The cleaning mode table 72 is obtained by changing the number of printed sheets, which is the execution condition of the cleaning operation in the cleaning mode table 71 of the first embodiment described above, to the power-off period. The power cut-off period is a period during which the power supply of the inkjet printing apparatus 1 is cut off.

  In the example of FIG. 15, in the normal mode, the cleaning operation is performed when the inkjet printing apparatus 1 is turned on when the power cutoff period is 4 hours or more. In the suppression mode, when the power shut-off period is 6 hours or longer, the cleaning operation is performed when the inkjet printing apparatus 1 is turned on. Thus, in the suppression mode, the power shut-off period, which is a condition for executing the cleaning operation, is longer than that in the normal mode, so that the frequency of execution of the cleaning operation is suppressed and the amount of waste liquid is reduced.

  When changing the cleaning mode from the normal mode to the suppression mode, the control unit 12 changes the power-off period as a condition for executing the cleaning operation to the power-off period in the suppression mode and changes the purge pressure setting from “strong” to “ Change to “Weak”.

  In the second embodiment, the cleaning mode setting process is performed according to the procedure of the flowcharts of FIGS. 13 and 14 as in the first embodiment.

  Here, in the second embodiment, the calculation of the predicted replacement date of the waste liquid sponge 9 in step S5 of FIG. 13 is performed as follows. First, the control unit 12 sets the frequency at which the power is shut off for the power-off period or longer, which is a condition for executing the cleaning operation in the normal mode, and the amount of waste liquid and the amount of received light in one cleaning operation in the normal mode. Based on the allowable additional waste liquid amount of the waste liquid sponge 9 corresponding to the number of dirt sensors 61 having a threshold value less than the threshold, a period until the waste liquid absorption amount reaches a limit level is calculated. And the control part 12 calculates the replacement | exchange estimated date of the waste liquid sponge 9 based on the period until a waste liquid absorption amount reaches a limit level, and the present date.

  In step S9 of FIG. 13, when the cleaning mode is changed from the normal mode to the suppression mode, the control unit 12 refers to the cleaning mode table 72 and sets the power-off period as a cleaning operation execution condition. Change from the power-off period in the normal mode to the power-off period in the suppression mode. Further, similarly to the first embodiment, the control unit 12 changes the setting of the purge pressure in the cleaning operation from “strong” to “weak”.

  In step S16 of FIG. 14, when the cleaning mode is returned from the suppression mode to the normal mode, the control unit 12 refers to the cleaning mode table 72 and suppresses the setting of the power shut-off period as a cleaning operation execution condition. Return from the mode power-off period to the normal mode power-off period. As in the first embodiment, the control unit 12 returns the setting of the purge pressure in the cleaning operation from “weak” to “strong”.

  As described above, in the second embodiment, the execution frequency of the cleaning operation is changed by changing the power-off period as the execution condition of the cleaning operation. Thereby, in the inkjet printing apparatus 1 that employs the power-off period as the execution condition of the cleaning operation, the frequency of executing the cleaning operation can be easily changed.

(Other embodiments)
As described above, the present invention has been described according to the first and second embodiments. However, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the first and second embodiments described above, the execution frequency of the cleaning operation and the purge pressure are changed as a setting change of the cleaning operation for reducing the amount of waste liquid. However, as a setting change of the cleaning operation for reducing the amount of waste liquid, only one of the execution frequency of the cleaning operation and the purge pressure may be changed. That is, at least one of the cleaning operation execution frequency and the purge pressure may be changed.

  In the first embodiment described above, the execution frequency of the cleaning operation is changed by changing the number of printed sheets as the cleaning operation execution condition. In the second embodiment, the execution frequency of the cleaning operation is changed by changing the power-off period as the cleaning operation execution condition. However, both the number of printed sheets and the power-off time are used as the cleaning operation execution conditions, and the frequency of the cleaning operation is changed by changing both the number of printed sheets and the power-off time as the cleaning operation execution conditions. It may be. In other words, it is only necessary to change the execution frequency of the cleaning operation by changing at least one of the number of printed sheets and the power-off period as the cleaning operation execution condition.

  In the first and second embodiments described above, the cleaning mode is changed to the suppression mode when the suppression mode is selected by the user when the waste liquid absorption amount of the waste liquid sponge 9 reaches the warning level. However, when the waste liquid absorption amount of the waste liquid sponge 9 reaches a warning level, the normal mode may be changed to the suppression mode unconditionally.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Paper feed part 3 Printing part 4 Ink circulation mechanism part 5 Upper surface conveyance part 6 Paper discharge part 7 Inversion part 8 Maintenance part 9 Waste liquid sponge 10 Waste liquid detection part 11 Operation panel 12 Control part 28, 28C, 28K, 28M , 28Y Line head 29 Inkjet head 46 Ink receiving member 47 Wiper unit 48 Wiper drive unit 61 Dirt sensor 71, 72 Cleaning mode table

Claims (3)

An inkjet head;
Cleaning means for performing a cleaning operation of the inkjet head;
A waste liquid absorbing member that absorbs the waste liquid from the cleaning operation of the inkjet head;
Detecting means for detecting a waste liquid absorption amount of the waste liquid absorbing member;
An ink jet printing apparatus comprising: control means for changing setting of the cleaning operation so as to reduce the amount of waste liquid when the amount of waste liquid absorption detected by the detection means reaches a warning level.   The control means, as a change in setting of the cleaning operation for reducing the amount of waste liquid, at least one of the execution frequency of the cleaning operation and the purge pressure when performing a purge for discharging ink from the inkjet head in the cleaning operation The inkjet printing apparatus according to claim 1, wherein the inkjet printing apparatus is changed.   3. The inkjet printing apparatus according to claim 2, wherein, when changing the execution frequency of the cleaning operation, the control unit changes at least one of a number of printed sheets and a power-off period as a cleaning operation execution condition. .