JP2018176664A - Inkjet recording device, and liquid supply device as well as liquid supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording device that can make concentration of ink to be supplied from an ink tank uniform inexpensively.SOLUTION: A printer, which forms an image on a roll sheet by supplying ink I stored in a main tank 35 to a recording head 31 through a sub tank 36, comprises: a refilling tube 38 which suctions ink from a vicinity of a bottom surface 35b of the main tank using a suction pump 62 to refill the ink into the sub tank; and a refilling tube 39 which suctions ink from a vicinity of liquid level Iu in the tank using a suction pump 63 to refill the ink into the sub tank. A CPU controls the suction pumps so that ratios of the ink to be suctioned from the refilling tubes, then the ink is refilled into the sub tanks and supplied to the recording head.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ink jet recording apparatus which discharges a liquid such as ink stored in a tank and supplies the liquid to a recording head or the like, a liquid supply apparatus, and a liquid supply method.

  In recent years, a pigment ink used in an inkjet recording apparatus is a solution (liquid) which exists in a particulate form without being dissolved in a solvent. When the pigment ink is stored in the tank and stands by for a long time, the pigment settles in the solvent and a concentration difference occurs in the tank. As described above, when the pigment concentration difference occurs in the ink, the image of each recording medium on which an image is formed varies, and the image quality itself to be formed is also degraded.

  Furthermore, since the pigment ink is sent from the inside of the tank to the recording head through the tube and discharged from the nozzle, the pigment is accumulated and clogged in the tube forming the ink flow path or the nozzle depending on the concentration of the pigment. May occur.

  From this, Patent Document 1 discloses an ink jet recording apparatus including a tank having a structure in which the concentration of the pigment in the ink can be kept constant by installing a stirring member in the ink tank and driving it. ing.

JP, 2013-208760, A

  However, in the ink jet recording apparatus as described in Patent Document 1, in order to make the concentration of the pigment of the ink in the tank uniform, it is necessary to secure the stirring time before the execution of the image forming process. It takes time. In addition, since the stirring member is installed for each ink tank to be set, there is a problem that the tank to be replaced as the consumable becomes expensive.

  An object of the present invention is to provide an inkjet recording apparatus that can equalize the density of ink supplied from an ink tank at low cost.

  One aspect of the invention of an inkjet recording apparatus that solves the above-mentioned problems can take in ink from a recording head that discharges ink and performs recording, and a first height of a tank that stores the ink supplied to the recording head. A first loading means, a second loading means capable of loading ink from a second height higher than the first height of the tank, and the ink loaded by the first loading means And ink supply means for mixing the ink taken in by the second take-in means and supplying the mixed ink to the recording head.

  As described above, according to one aspect of the present invention, the density of the ink supplied from the ink tank can be made uniform at low cost.

FIG. 1 is a conceptual schematic diagram for explaining an ink jet recording apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram for explaining the control system of the system. FIG. 3 is a conceptual structural view for explaining a flow path system for supplying the ink in the main tank. FIG. 4 is a conceptual structural view showing an example where the ink storage amount is different from that in FIG. FIG. 5 is a conceptual schematic diagram for explaining the sedimentation of the pigment according to the passage of time of the ink. FIG. 6 is a graph for explaining the sedimentation of the pigment according to the passage of time of the ink. FIG. 7 is a flowchart for explaining the ink replenishment control. FIG. 8 is a conceptual structural view for explaining an ink jet recording apparatus according to a second embodiment of the present invention. FIG. 9 is a conceptual structural view for explaining an ink jet recording apparatus according to a third embodiment of the present invention. FIG. 10 is a conceptual structural view for explaining an ink jet recording apparatus according to the fourth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 to 7 are diagrams for explaining an example of a printer to which an ink jet recording apparatus equipped with a liquid supply apparatus according to a first embodiment of the present invention is applied. FIG. 1 is an image recording system including the printer It is a conceptual schematic diagram explaining the whole structure of.

  In FIG. 1, a printer 10 is connected to a host apparatus 100 that outputs image data so as to be able to exchange various data, and constitutes an image recording system. The host device 100 is constituted by, for example, a so-called personal computer (PC: Personal Computer), and operates the image recording system by exchanging various data with an external device including the printer 10 . For example, the host device 100 processes the information received from an external device other than the printer 10 by executing software stored in a memory (not shown), and outputs the image data of the processing result generated to the printer 10 . The printer 10 forms an image by recording image data received together with a print command from the host device 100 on a roll paper (recording paper) P of a recording medium passing the image forming area Ar by an inkjet recording method described later. There is.

  Here, in the present embodiment, the case where the printer 10 is connected to the host apparatus 100 as one of the external apparatuses and the image forming system is constructed will be described as an example, but the present invention is not limited to this. For example, only the printer 10 may be connected to the host device 100 to construct an image forming system. Further, the present embodiment may be applied to a case where an image forming system is independently constructed by providing a mechanism for acquiring image data, such as a slot in which the printer 10 sets a memory card. Further, in the present embodiment, a roll paper P of recording paper is described as an example of a recording medium, but the invention is not limited thereto. For example, cut paper which has been cut into a predetermined size may be used. It may be in the form of fanfold paper or the like. Needless to say, the present invention may be applied to a printer that forms an image on a recording medium other than recording paper.

  The printer 10 is configured to include a sheet feeding unit 11, a conveyance unit 12, a recording unit 13, a tank unit 14, and a control unit 15.

  The paper feed unit 11 holds the roll paper P by sandwiching the roll paper P and rotating the paper storage unit 21 in which roll-shaped roll paper P on which an image is formed (hereinafter, simply referred to as printing) is set rotatably. And a paper feed roller pair 22 which is pulled out of the storage unit 21 and fed.

  As a result, in the sheet feeding unit 11, the roll sheet P in the storage unit 21 is nipped by the sheet feeding roller pair 22 and is fed to the conveyance unit 12 from the leading end side. The sheet feeding unit 11 is configured such that a roll motor (not shown) assists the rotation of the roll sheet P in the storage unit 21 and supports sheet feeding and conveyance of the roll sheet P by the sheet feeding roller pair 22. .

  The conveyance unit 12 includes a conveyance belt 25, a conveyance roller pair 26, a carry-out roller pair 27, a conveyance motor 28, and a tension pulley 29. The transport belt 25 is made of an endless belt so as to be capable of cyclic rotation. The pair of transport rollers 26 is disposed on the upstream side (the side of the sheet feeding unit 11) in the transport direction of the image forming area Ar, and is supported in a rotatable manner in a state of sandwiching the transport belt 25. The delivery roller pair 27 is disposed on the downstream side of the image forming area Ar in the transport direction (the opposite side of the sheet feeding unit 11) like the transport roller pair 26 and is freely rotatable in a state of sandwiching the transport belt 25. It is supported by The conveyance motor 28 feeds the conveyance belt 25 wound around the rotation shaft 28 a together with the conveyance roller pair 26 and the discharge roller pair 27 in the rotational direction by rotational power. The tension pulley 29 applies a constant tension to the transport belt 25 in a wound state.

  Thereby, in the conveyance unit 12, the image forming area Ar is positioned on the upper surface of the conveyance belt 25 stretched between the conveyance roller pair 26 and the discharge roller pair 27, and the conveyance belt 25 is It is cyclically rotated repeatedly by the rotation of the rotation shaft 28a. Therefore, in the transport unit 12, the roll paper P fed from the paper feed unit 11 is nipped between the transport roller pair 26 and fed together with the transport belt 25 so as to pass through the image forming area Ar and transport direction It is transported to A. Thereafter, in the transport unit 12, the roll paper P passing through the image forming area Ar is delivered to the delivery roller pair 27 and delivered from the transport belt 25 onto the delivery unit 30. Although the paper discharge unit 30 omits the detailed description of the structure, for example, the paper discharge unit 30 may be structured to roll up and store the image-formed roll paper P, or a table to be cut into a predetermined size and stacked. May be provided.

  The recording unit 13 is constructed by a plurality of recording heads 31 which eject ink, and recording heads 31 K and 31 C for each color ink of black (K), cyan (C), magenta (M) and yellow (Y). , 31M, 31Y. The recording units 13 are arranged in parallel such that the recording heads 31 K, 31 C, 31 M, and 31 Y are sequentially arranged in the conveyance direction A of the conveyance belt 25 of the conveyance unit 12. The recording unit 13 forms a full color image on one side of the roll paper P by sequentially ejecting the ink of each color toward the image forming area Ar on each of the recording heads 31. Needless to say, the number of recording heads 31 and the color tone described in the present embodiment are merely examples, and the present invention is not limited to this.

  The recording head 31 of the recording unit 13 extends in the width direction of the conveyance belt 25 (direction orthogonal to the conveyance direction A), and is a so-called line head in which nozzles (not shown) for discharging (jetting) ink are arranged. It is made in the form of The recording head 31 is manufactured such that the discharge range of the ink is longer than the width of the roll paper P. The recording head 31 is not limited to the form of a line head. For example, the recording head 31 may be compact, and may be of a type that reciprocates while discharging ink in the width direction of the roll paper P.

  Here, the recording head 31 of the recording unit 13 of the present embodiment is held by a mechanism (not shown) movable in the conveyance direction A and the vertical direction B, and utilizes the driving force of the motors 33 and 34 shown in FIG. Is movably supported. As a result, the recording head 31 can slide and reciprocate in the transport direction A of the roll paper P, and can move up and down in the vertical direction B with respect to the roll paper P.

  Further, the removable cap 32 is disposed adjacent to each other in the transport direction A on the side of the formation surface 31 a of the nozzle that ejects the ink. The recording head 31 is slid in the horizontal direction to advance in the transport direction A and then lowered in the vertical direction B while avoiding a collision with the cap 32 by raising it in the vertical direction B, so that the cap 32 It is attached to the nozzle formation surface 31a. For example, when the nozzle forming surface 31a is exposed to the atmosphere during storage of the printer 10 or printing standby, for example, the solvent of the ink in the vicinity of the outlet of the nozzle is volatilized to increase the viscosity. Solidification occurs. Further, in the recording head 31, dust adheres to the ink, and the discharge quality of the ink is lowered, and the image quality is deteriorated. By attaching the cap 32 to the recording head 31, the occurrence of these inconveniences can be prevented in advance. The recording head 31 may be restored to the operable state by the reverse procedure. That is, the recording head 31 discharges the ink onto the roll paper P by raising the recording head 31 in a direction away from the cap 32 and slidingly moving it in the reverse horizontal direction and then lowering it and fitting it into a positioning opening (not shown). Positioning is fixed at the image forming position.

  Further, as described above, the recording head 31 of the present embodiment has a function of recovering the quality of the discharged ink, in addition to the attachment and detachment of the cap 32 in order to avoid the inconvenience due to the exposure of the nozzle forming surface 31a. It is done. The recording unit 13 is, for example, ink in the vicinity of the discharge port of the nozzle by applying a negative pressure by a pump (not shown) to a space formed between the recording head 31 and the cap forming surface 31a. Is equipped with a recovery mechanism (not shown) to recover the quality by The recovery mechanism is not limited to this, and for example, the quality of the ink at the time of operation may be recovered by causing the recording head 31 to perform the preliminary ink discharge operation before the operation. Further, in addition to the cap 32, a wiper blade made of rubber or the like for wiping the nozzle formation surface 31a of the recording head 31 may be attached to execute the cleaning operation before the operation.

  The tank unit 14 is provided with a plurality of main tanks 35 for storing the ink which the recording head 31 of the recording unit 13 discharges onto the roll paper P. The tank unit 14 has main tanks 35K, 35C, 35M and 35Y for each color of black (K), cyan (C), magenta (M) and yellow (Y), and recording heads 31K, 31C, 31M, Each color ink is supplied to 31Y.

  As shown in FIG. 2, the control unit 15 is connected to the CPU 41 so that the program ROM 42, the image memory 43, the work RAM 44 and the operation panel 45 can exchange various information. The CPU 41 executes the control program stored in the program ROM 42, and based on various sensor information temporarily stored in the work area of the work RAM 44, various setting instruction information input from the operation panel 45, etc. Control overall. Thus, the CPU 41 carries out an image forming process for recording the image data received from the host device 100 on the roll paper P by the inkjet recording method. The program ROM 42 stores a processing program for executing an ink replenishment procedure, which will be described later, and the like, and various tables for storing necessary fixed data.

  The control unit 15 is connected to the CPU 41 so that the host apparatus 100 can exchange various information via the interface controller 46. In addition, a sensor group 50 installed in each of the paper feed unit 11, the conveyance unit 12, the recording unit 13, and the tank unit 14 constituting the printer 10 is connected to the CPU 41 so that various information can be acquired via the input port 47. ing. The sensor group 50 detects and acquires various information in order to perform a required operation. For example, a paper leading edge sensor 50p that detects the leading edge of the roll paper P, and an ink remaining amount sensor that detects the remaining amount of ink 50i etc. are installed appropriately.

  The control unit 15 is connected to the CPU 41 so that the recording unit 13 can exchange various information via the recording head control circuit 48. The print head control circuit 48 generates drive signals for each color ink based on image data sent from the CPU 41 and controls the print heads 31 K, 31 C, 31 M, and 31 Y to appropriately eject each color ink. . The CPU 41 receives various information on the recording head 31 side via the recording head control circuit 48, for example, sensor information for detecting the movement of the recording head 31, the attachment of the cap 32, etc., and drives the motor group described later. It is supposed to control.

  The CPU 41 of the control unit 15 relays each color image data to be processed by the recording head 31 by performing bit map development and raster division while temporarily storing image data received together with a print command from the host device 100 in the image memory 43. Do. The CPU 41 controls the recording head control circuit 48 to drive the respective color recording heads 31 K, 31 C, 31 M, and 31 Y to which the respective color image data is allocated, thereby discharging the respective color inks toward the roll paper P to form an image.

  At this time, the CPU 41 controls the discharge timing of each color ink of the recording head 31 based on the detection information of the paper leading edge sensor 50p of the sensor group 50 that detects the leading edge of the roll paper P carried into the image forming area Ar. The CPU 41 sequentially relays the image data developed in the image memory 43 and discharges the ink of each color of the recording head 31 so as to synchronize with the roll paper P carried into the image forming area Ar. Image formation on paper P. Note that on the roll paper P, each color ink of black (K), cyan (C), magenta (M) and yellow (Y) is selectively selected sequentially from the recording head 31K to the recording heads 31C, 31M, and 31Y. The full-color image is formed by being ejected and superimposed.

  The CPU 41 is connected to the motor drive unit 51 via the output port 49 so as to be able to output various types of information. Various motors such as the above-described transport motor 28 are connected to the motor drive unit 51 so as to be able to receive drive signals. The motor drive unit 51 drives the elevation motor 33 to move the recording head 31 of the recording unit 13 in the vertical direction B, and the slide motor 34 to slide the recording head 31 in the conveyance direction A based on various instructions from the CPU 41 It is connected to be able to receive a signal. Thereby, the motor drive unit 51 generates a drive signal based on, for example, the conveyance instruction of the roll paper P from the CPU 41, and drives the conveyance motor 28 of the conveyance unit 12 to make the roll paper P in the image forming area Ar. Transport to pass through. The motor drive unit 51 generates an elevation signal and a slide signal of the recording head 31 based on the attachment / detachment instruction of the cap 32 from the CPU 41, and drives the elevation motor 33 and the slide motor 34 to form the nozzles of the recording head 31. The cap 32 is attached to and detached from the surface 31a.

  Incidentally, in the tank unit 14, as shown in FIG. 3, the sub tank 36 is disposed between the recording head 31 and the main tank 35. The sub tank 36 is connected to the recording head 31 so as to be able to flow the ink I through one supply tube 37, and is connected to the main tank 35 so as to be able to flow the ink I by two replenishment tubes 38 and 39. That is, the tank unit 14 is constructed to receive the ink I replenished from the main tank 35 via the replenishment tubes 38 and 39 by the sub tank 36 and supply it to the recording head 31 while temporarily storing it. In short, the ink I in the main tank 35 is relayed to the sub tank 36 and supplied to the recording head 31. That is, the ink I in the main tank 35 is supplied through the refilling tubes 38 and 39 with the sub tank 36 and the recording head 31 as supply destinations.

  The sub tank 36 is manufactured in a volume capable of storing a small volume of ink I, since the ink I replenished via the replenishment tubes 38 and 39 is supplied to the recording head 31 at any time via the supply tube 37. . The main tank 35 is manufactured in a volume capable of storing a large volume of ink I.

  In the sub tank 36, the suction port 37i at the opposite end of the supply tube 37 connected to the recording head 31 is inserted to the vicinity of the bottom surface 36b so as to be able to suction the ink I. Further, the sub tank 36 is positioned and fixed so that the discharge ports 38o, 39o at one end side of the refilling tubes 38, 39 are positioned in the vicinity of the liquid level iu of the ink I of a fixed amount. Thereby, in the sub tank 36, the ink I ejected from the ejection ports 38o and 39o of the replenishment tubes 38 and 39 is replenished (supplied) from the liquid surface iu side and sucked from the suction port 37i of the supply tube 37 on the bottom surface 36b . Therefore, the sub tank 36 can supply the recording head 31 with stirring (mixing) a small amount of stored ink I.

  The refilling tube 38 has the discharge port 38o at one end located near the liquid surface iu of the sub tank 36, while the suction port 38i at the other end moves the ink I up to near the bottom surface 35b of the main tank 35. It is plugged in for retrieval. In the refilling tube 38, the suction pump 62 is disposed between the discharge port 38o and the suction port 38i, and is taken in by suctioning the ink I near the bottom of the main tank 35 (first height). It is installed to supply (replenish) to The term “near the bottom surface 35 b of the main tank 35” is also referred to simply as “bottom surface vicinity (near the bottom surface 35 b)” below.

  Similar to the refilling tube 38, the refilling tube 39 has the discharge port 39 o at one end located near the liquid level iu of the sub tank 36, while the suction port 39 i at the other end is above the bottom surface 35 b of the main tank 35. The ink I is placed so as to be located near (the second height) near the liquid level Iu. In the refilling tube 39 as well, the suction pump 63 is installed between the discharge port 39o and the suction port 39i so that the ink I on the liquid level Iu side of the main tank 35 is suctioned and supplied (replenished) to the sub tank 36. is set up. The term “near the vicinity of the liquid level Iu of the ink I” is also referred to simply as “liquid level vicinity (near the liquid level Iu)” below.

  That is, the suction port 38i of the refilling tube 38 constitutes a bottom intake port (first loading means), and the suction port 39i of the refilling tube 39 constitutes a liquid level loading port (second loading means). The replenishment tubes 38 and 39 and the suction pumps 62 and 63 constitute an ink supply means and a liquid supply means.

  The refilling tube 39 includes a tube body 39 b, a bellows tube 64 and a float 61. The tube main body 39 b is connected to the upper surface 35 u of the main tank 35. The bellows-like tube 64 is formed to be stretchable, and is suspended from the upper surface 35 u of the main tank 35 in communication with the tube main body 39 b. The float 61 has a through hole 61 h communicating with the bellows tube 64 and floats on the liquid level Iu (above the liquid level) of the ink I in the main tank 35. The replenishment tube 39 is capable of suctioning the ink I through the bellows tube 64, and the end of the through hole 61h opens as a suction port 39i in the bottom surface (bottom) 61b of the surface of the float 61 located below the liquid level Iu. doing.

  Here, the bellows-like tube 64 expands and contracts according to the float 61 located at the lower end moving up and down on the liquid surface according to the height of the liquid level Iu of the ink I in the main tank 35. Thereby, even if the level Iu of the ink I in the main tank 35 drops, as shown in FIG. 4, for example, the bellows-like tube 64 allows the float 61 to drop together with the level Iu. . Therefore, the refilling tube 39 is maintained in a state where the ink I in the main tank 35 can be sucked by the suction pump 63 from the suction port 39i of the float 61.

  In addition, the communication pipe 40 which makes the inside and the outside communicate with the upper surface 35 u is installed in the main tank 35. Thus, when the ink I stored in the main tank 35 is sucked through the refilling tubes 38 and 39, the outside air is allowed to flow into the inside through the communication pipe 40 and becomes negative pressure. It is avoided and suction of the ink I is not prevented.

  By the way, since the supply of the ink I is also stopped when the image forming operation is stopped, the tank unit 14 is in a state where the ink I is filled in the sub tank 36 and the replenishment tubes 38 and 39, etc. It is supposed to wait from.

  At this time, as shown in FIG. 5, the ink I stored in the main tank 35 or the sub tank 36 is a solution (liquid) in which the particulate pigment c is dispersed in the solvent s. In the ink I, the pigment c is dispersed in the solvent s, and the colors of black (K), cyan (C), magenta (M) and yellow (Y) are developed. In the ink I, the pigment c tends to descend, that is, settle, in the solvent s with the passage of time in the resting state. For this reason, in the ink I, the pigment c gradually precipitates with the passage of time in a resting state of approximately monthly units, and the pigment c precipitates in the vicinity of the bottom surface 35b and the concentration becomes high. Concentration decreases. For example, when the main tank 35 is shaken and set in the tank unit 14 of the printer 10, as shown in FIG. 5A, the pigment c is in a substantially uniformly dispersed state. After this, as shown in FIG. 5 (b) to FIG. 5 (c), the concentration change of pigment c is shown, the pigment c is gradually precipitated and precipitated as time passes in the resting state, and spreads in the vertical direction Concentration distribution will occur. The dispersion state of the pigment c shown in FIG. 5 of the ink I is merely an example, and generally differs depending on the viscosity of the solvent s and the particle size and shape of the pigment c.

  For example, as shown in FIG. 6, the ink I in the main tank 35 changes so that the density α of the pigment c in the vicinity of the bottom surface 35b follows a density change line Lb indicated by an alternate long and short dash line in the figure. Further, in the ink I, the concentration α of the pigment c in the vicinity of the liquid level Iu changes so as to follow a concentration change line Lu indicated by a two-dot chain line in the drawing. The concentration α of the pigment c of the ink I follows the dispersion characteristics of the pigment c in the solvent s.

  Specifically, the concentration α of the pigment c of the ink I in the main tank 35 changes so as to gradually precipitate and precipitate according to the elapsed time t from the concentration α 0 at which the pigment c is uniformly dispersed in the resting state Do. For this reason, the concentration α u (t) of the pigment c near the liquid level I u changes in the direction of becoming thinner according to the elapsed time t, and becomes stable at the concentration α u (Tu) after the elapsed time Tu and is stabilized. . Also, the concentration αb (t) of the pigment c near the bottom surface 35b changes in the direction of becoming thicker according to the elapsed time t, and becomes stable at the concentration αb (Tb) after the elapsed time Tb.

  Here, the concentration change lines Lu and Lb of the pigment c as shown in FIG. 6 are previously obtained respectively by experiment, calculation, etc. by the concentration αu near the liquid level Iu and the concentration αb near the bottom surface 35b. It may be mapped inside or stored as an arithmetic expression. In this embodiment, the elapsed time Tu in which the concentration αu (t) of the pigment c near the liquid surface Iu stabilizes and the elapsed time Tb in which the concentration αb (t) of the pigment c near the bottom surface 35b stabilizes are Tu < It is a relationship of Tb.

For example, concentration change lines Lu and Lb in FIG. It can be calculated and expressed by an arithmetic expression. The density change line Lu in the vicinity of the liquid surface Iu of the ink I can be expressed as in the following equation (1) using a coefficient “−A” corresponding to the amount of sedimentation of the pigment c according to the elapsed time t. The density change line Lb in the vicinity of the bottom surface 35b of the ink I can be expressed by the following equation (2) using a coefficient "B" corresponding to the amount of precipitation of the pigment c according to the elapsed time t.
Lu (t) =-At + .alpha.0 Lu (Tu.ltoreq.) =. Alpha.u (Tu) (1)
Lb (t) = Bt + α0 Lb (Tb ≦) = αb (Tb) (2)

  Therefore, the CPU 41 of the control unit 15 drives the suction pumps 62, 63 of the refilling tubes 38, 39 to drive the ink I of the concentration αb (t) near the bottom surface 35b of the main tank 35 and the concentration αu near the liquid level Iu. The ink I of (t) is replenished into the sub tank 36. At this time, the CPU 41 controls the drive of the suction pumps 62, 63 to mix the ink I near the bottom surface 35b of the main tank 35 and the ink I near the liquid level Iu in the sub tank 36. The uniform density α0 is adjusted. That is, the CPU 41 of the control unit 15 constitutes a control means.

  Specifically, when the CPU 41 starts the process of replenishing the ink I from the main tank 35 to the sub tank 36, the CPU 41 controls the drive of the suction pumps 62, 63 according to the elapsed time t after being set in the printer 10. Do. At this time, the CPU 41 controls the drive of the suction pumps 62 and 63 to adjust the replenishment ratio of the ink I near the bottom surface 35 b of the main tank 35 and near the liquid level Iu, and the concentration α of the pigment c of the ink I Adjust the For example, the CPU 41 performs suction based on an elapsed time t after being set in the printer 10 so that the ink I replenished from the replenishment tubes 38 and 39 into the sub tank 36 has the density .alpha.0 of the pigment c in the uniformly dispersed state. The drive of the pumps 62, 63 is controlled. Here, an elapsed time t after setting in the printer 10 is a state in which the ink I is retained without stirring and the pigment c can settle, and hereinafter, it is also simply referred to as a residence time t.

The CPU 41 has a timer function for clocking the current time, and stores the set time of the main tank 35 in the work RAM 44, so that the residence time t of the ink I is calculated from the set time of the main tank 35 and the current time. Calculate (acquire). The CPU 41 sucks each of the replenishment tubes 38 and 39 so that the concentration α (t) of the pigment c of the ink I in the sub tank 36 becomes a uniform concentration α0 from the following equation (3) using the residence time t The ratio (ratio) Ru, Rb (Ru + Rb = 1) is determined. The CPU 41 is configured to control the drive of the suction pumps 62 and 63 based on the suction ratios Ru and Rb of the refilling tubes 38 and 39, respectively.
α0 = (Ru · Lu (t) + Rb · Lb (t)) / (Ru + Rb) (3)

The above equation (3) is as follows when the residence time of the pigment c near the liquid level Iu of the main tank 35 is less than the residence time Tu stabilized at the concentration αu, ie, when the residence time t <the residence time Tu.
α0 = (Ru (−At + α0) + Rb (Bt + α0)) / (Ru + Rb) (3-1)
Further, in the case where the pigment c in the vicinity of the bottom surface 35b of the main tank 35 is stable at the concentration αb, ie, residence time Tu ≦ retention time t <retention time Tb, the following occurs.
α0 = (Ru · αu + Rb (Bt + α0)) / (Ru + Rb) (3-2)
Furthermore, in the case of residence time Tb or more in which the pigment c near the bottom surface 35b of the main tank 35 is stabilized at the concentration αb, ie, residence time t ≦ retention time Tb, the following occurs.
α0 = (Ru · αu + Rb · αb) / (Ru + Rb) (3-3)

  Here, when the CPU 41 drives the suction pumps 62, 63 in accordance with the suction ratios Ru, Rb of the replenishment tubes 38, 39, for example, the ink I is sucked and discharged at a flow rate of the suction ratios Ru, Rb. The drive of the suction pumps 62, 63 is controlled so that Alternatively, when the replenishment amount of the ink I to the sub tank 36 is known in advance, the CPU 41 can operate the suction pump 62 for sucking and discharging the replenishment amount of the ink I for each suction time Ru. It may be controlled to be Rb.

  Specifically, the CPU 41 executes an image forming process of recording the image data received from the host device 100 on the roll paper P by the inkjet recording method in accordance with a control program in the program ROM 42. At the same time, the CPU 41 executes a control process (liquid supply method) shown in the flowchart of FIG. 7 for replenishing the ink I from the main tank 35 to the sub tank 36. Here, the CPU 41 has a calendar timer function that prompts to set the current time when power is turned on. The printer 10 shakes the main tank 35 to be set or the like at the time of power-on or replacement of the main tank 35 to promote the stirring operation of the pigment c in the ink I, and then, for each ink color of the main tank 35. The set time to the tank unit 14 is held in the work RAM 44.

  First, as shown in FIG. 7, the CPU 41 acquires the remaining amount of each color ink I in the sub tank 36 from the sensor information of the ink remaining amount sensor 50i of the sensor group 50 (step S11). Next, the CPU 41 repeatedly checks whether the remaining amount of the ink I in the sub tank 36 falls below a preset threshold and is consumed to such a degree that replenishment is necessary (step S12).

  In step S12, the CPU 41 that has confirmed the ink I that needs to be replenished to the sub tank 36 reads the set time of the main tank 35 of the ink I of the corresponding color from the work RAM 44 (step S13). Next, the CPU 41 calculates the retention time t of the ink I in the main tank 35 of the corresponding color from the set time and the current time (step S14).

  Next, the CPU 41 determines suction ratios Ru and Rb for each of the replenishment tubes 38 and 39 that suction the ink I from the main tank 35 based on the residence time t (step S15). Thereafter, the CPU 41 drives the suction pumps 62 and 63 at the suction ratios Ru and Rb to execute a process of replenishing the ink I of the replenishment amount set in advance from the main tank 35 to the sub tank 36 (step S16). ), End this process. Here, in this step S15, the bottom portion taking-in step and the liquid level taking-in step are performed by suctioning and taking in the ink I in the main tank 35 from the suction ports 38i, 39i of the refilling tubes 38, 39 at adjustment ratios. At this time, a liquid supply process is also performed in which the ink I adjusted in proportion into the sub tank 36 from the discharge ports 38o and 39o of the replenishment tubes 38 and 39 is discharged and supplied.

  As a result, the ink I is sucked and replenished to the sub tank 36 from the vicinity of the liquid level Iu and the vicinity of the bottom surface 35b at suction ratios Ru and Rb at a ratio according to the residence time t of the ink I in the main tank 35. .

  As described above, in the printer 10 according to the present embodiment, the ink I in the main tank 35 can be supplied to the sub tank 36 via the replenishment tubes 38 and 39. As a result, in the printer 10, even if there is a difference between the concentrations αu and αb of the pigment c between the vicinity of the liquid level Iu and the bottom surface 35b in the main tank 35, the ink I is adjusted to the uniform concentration c0 of the pigment c. The sub tank 36 can be replenished and supplied to the recording head 31.

  For this reason, in the printer 10, the ink I of the pigment c having a uniform concentration α0 is provided without setting the stirring function of the ink I in the main tank 35 and without securing the stirring time at the supply timing of the ink I. The recording head 31 can be stably and quickly supplied. Therefore, in the printer 10, it is possible to form a high quality image without variation even with the ink I in which the pigment c which is likely to generate a density difference is uniformly dispersed in the solvent s.

  Therefore, the main tank 35 is not expensive with the stirring member of the ink I, and it does not take time for stirring, and a high quality image is rolled with the ink I having the pigment c stable at the uniform density α0. An inexpensive printer 10 that can be formed on P can be provided.

  Next, FIG. 8 is a view for explaining an example of a printer to which an ink jet recording apparatus equipped with a liquid supply apparatus according to a second embodiment of the present invention is applied, and FIG. 8 explains replenishment of the ink. It is a conceptual block diagram. In addition, since the present embodiment is configured substantially the same as the above-described embodiment, the same reference numerals are given to the same configurations to describe the characteristic portions (the same applies to the other embodiments).

  In FIG. 8, in the tank unit 14 of the printer 10, the main tank 35 and the sub tank 36 are connected so that the ink I can flow through the refilling tubes 77, 78, 79.

  In the refilling tube 77, the discharge port 77o at one end is inserted so as to be able to discharge the ink I near the bottom surface 36b in the sub tank 36, and the other end is connected to one end of the refilling tubes 78 and 79 so that the ink I can flow. ing. Among them, the refilling tube 78 is inserted such that the suction port 78i on the other end side can suck the ink I to the vicinity of the bottom surface 35b of the main tank 35. Further, the refilling tube 79 includes the bellows-like tube 64 and the float 61 as in the above embodiment, and the suction port 79i capable of sucking the ink I to the bottom surface 61b of the float 61 floating on the liquid level Iu of the main tank 35. (Through hole 61h) is open.

  In the tank unit 14, one suction pump 73 is installed in the refilling tube 77, and on-off valves 74, 75 are installed in the refilling tubes 78, 79, respectively. The tank unit 14 drives the suction pump 73 to open and close the on-off valves 74 and 75 to suck the ink I in the main tank 35 from the suction ports 78i and 79i of the refill tubes 78 and 79 and discharge the refill tube 77. The fuel is discharged and replenished into the sub tank 36 from the outlet 77o. For this reason, the tank unit 14 of the present embodiment adjusts the drive of the suction pump 73 and the opening / closing timing and opening amount of the on / off valves 74 and 75 to thereby make the vicinity of the liquid surface Iu and the vicinity of the bottom surface 35b of the main tank 35 The replenishment amount of the ink I is adjustable.

  That is, the suction port 78i of the refilling tube 78 constitutes a bottom intake port (first loading means), and the suction port 79i of the refilling tube 79 constitutes a liquid level loading port (second loading means). ing. In addition to the refilling tubes 78 and 79, the refilling tube 77, the suction pump 73, and the on-off valves 74 and 75 constitute an ink supply means and a liquid supply means.

  Therefore, the CPU 41 of the control unit 15 is configured to adjust the drive of the suction pump 73 and the open / close timing and the opening amount of the open / close valves 74, 75. Thus, as in the above-described embodiment, the CPU 41 substantially uniformly divides the ink I at a concentration αb (t) near the bottom surface 35b of the main tank 35 and the ink I at a concentration αu (t) near the liquid surface Iu. The subtank 36 is refilled while adjusting (mixing). At this time, the ink I in the main tank 35 is sucked from the suction ports 78i and 79i of the refilling tubes 78 and 79, and is discharged from the discharge port 77o while being mixed in the refilling tube 77.

  As a result, even in the sub tank 36 of the present embodiment, the ink I is sucked from the vicinity of the liquid surface Iu and the vicinity of the bottom surface 35b at suction ratios Ru and Rb at a ratio corresponding to the residence time t of the ink I in the main tank 35. , It is replenished while being adjusted to the pigment c of uniform density α0.

  As described above, in the printer 10 according to the present embodiment, in addition to the functions and effects of the above-described embodiment, the two suction pumps 62 and 63 are replaced with one suction pump 73 to make the installation space smaller and compact. Can.

  Next, FIG. 9 is a view for explaining an example of a printer to which an ink jet recording apparatus equipped with a liquid supply apparatus according to a third embodiment of the present invention is applied, and FIG. It is a conceptual block diagram.

  In FIG. 9, in the tank unit 14 of the printer 10, the main tank 35 and the sub tank 36 are connected so as to allow the ink I to flow, leaving the refilling tubes 38 and 39 as they are. Opening and closing valves 84 and 85 are respectively installed in the refilling tubes 38 and 39. Furthermore, a pressure pump 83 is installed in the communication pipe 40 of the present embodiment.

  The tank unit 14 is configured to push outside air into the main tank 35 and pressurize it by driving the pressure pump 83 and opening and closing the on-off valves 84 and 85. At this time, the CPU 41 discharges the ink I into the sub tank 36 from the discharge ports 38o and 39o of the refilling tubes 38 and 39 whose opening and closing valves 84 and 85 are opened and replenishes. Therefore, the tank unit 14 of the present embodiment adjusts the vicinity of the liquid level Iu and the vicinity of the bottom surface 35b of the main tank 35 by adjusting the drive of the pressure pump 83 and the opening / closing timing and opening amount of the on / off valves 84 and 85. It is configured to be able to adjust the replenishment amount of the ink I from.

  That is, in addition to the refilling tubes 38 and 39, the communication pipe 40, the pressure pump 83 and the on-off valves 84 and 85 constitute an ink supply means and a liquid supply means.

  Therefore, the CPU 41 of the control unit 15 controls the driving of the pressure pump 83 and the opening and closing of the on-off valves 84 and 85. Thereby, the CPU 41 controls the ink I of the concentration αb (t) near the bottom surface 35b of the main tank 35 and the ink I of the concentration αu (t) near the liquid level Iu in the sub tank 36 as in the above embodiment. The mixture is adjusted to a substantially uniform concentration α0 and replenished.

  As a result, even in the sub tank 36 of the present embodiment, the ink I is pushed in (taken in) from the vicinity of the liquid surface Iu and the vicinity of the bottom surface 35b at suction ratios Ru and Rb in proportions according to the residence time t of the ink I. , It is replenished while being adjusted to the pigment c of uniform density α0.

  As described above, in the printer 10 according to the present embodiment, in addition to the functions and effects of the above-described embodiment, the two suction pumps 62 and 63 are replaced by one pressure pump 83 without changing the configuration of the refilling tubes 38 and 39. Installation space can be reduced and made compact.

  Next, FIG. 10 is a view for explaining an example of a printer to which an ink jet recording apparatus equipped with a liquid supply apparatus according to a fourth embodiment of the present invention is applied. FIG. 10 shows a tank for storing the ink. It is a conceptual block diagram explaining a structure.

  In FIG. 10, the tank unit 14 of the printer 10 is formed in an inclined surface shape in which the bottom surface 35b of the main tank 35 is inclined such that the vicinity of the suction port 38i of the refilling tube 38 is the lowest. Is equipped. Thereby, the tank unit 14 of this embodiment can collect the pigment c which settles the inside of the ink I in the deepest part 35bm of the bottom face 35b of the inclined surface, and can secure a stable density change.

  Therefore, the main tank 35 having the deepest portion 35bm can improve the accuracy of the density change line Lb (t) of the pigment c in the vicinity of the bottom surface 35b of the ink I represented by the above equation (2). In addition, the main tank 35 further improves the accuracy of the suction ratios Ru and Rb (Ru + Rb = 1) of the ink I for each of the replenishment tubes 38 and 39 calculated (decided) using the above equation (3). it can.

  As described above, in the printer 10 according to the present embodiment, in addition to the effects of the above-described embodiment, the pigment c of the ink I can be more accurately made into the uniform density α0 and replenished in the sub tank 36. Further, in the printer 10, the image formed by the ink I ejected from the recording head 31 can be made more stable and high quality.

  In the above embodiment, the replenishment timing of the ink I from the vicinity of the liquid level Iu, the replenishment timing from the vicinity of the bottom surface 35b, and the respective replenishment amounts are not described in detail, but they are not particularly limited. A control process may be performed to adjust the density α of the ink I so as to satisfy the suction ratios Ru and Rb (Ru + Rb = 1) of the ink I determined by the above equation (3). For example, the replenishment timing of the ink I from the vicinity of the liquid level Iu and the replenishment timing from the vicinity of the bottom surface 35b may be performed once or plural times simultaneously or alternately (sequentially). Alternatively, one or both of the replenishments may be operated intermittently, or the drive of the pump and the opening and closing of the valves may be controlled to adjust the respective replenishment amounts appropriately.

  Here, “recording” and “image formation” used in the description of the above-described embodiment is not limited to the case of revealing significant information such as characters and figures, and may or may not be significant. In addition, “recording” and “image formation” mean to widely form an image, a pattern, a pattern, etc. on a recording medium, regardless of whether it is manifested so as to be perceived visually. Do. The recording may include processing of the medium.

  The recording medium is not limited to sheet-like paper used in office equipment and the like, and can widely be formed by the ink I, including cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc. What if it is

  In the embodiment described above, the ink I used in the inkjet recording method is described as an example, but the present invention is not limited to this. For example, as in the above-mentioned "recording", the ink is applied onto the recording medium to form an image, a pattern, a pattern, etc. or process the recording medium, or coagulate or insolubilize a coloring agent in the ink. The present embodiment may be applied, including a solution such as a liquid to be subjected to a treatment such as

  Furthermore, in the above-mentioned embodiment, although the case where the remaining amount of the ink I in the sub tank 36 is detected by the sensor is described as an example, the present invention is not limited to this. For example, the discharge amount of the ink I of the recording head 31 may be integrated and detected by subtracting the volume from the sub tank 36.

  Here, the present invention can be widely applied to liquid supply devices that supply various liquids, and liquid discharge devices that can discharge various liquids. For example, the present invention is not limited to the ink in which a pigment is dispersed in a solution, and can be suitably applied to a device that discharges a liquid in which precipitated particulate material is dispersed in a solvent. Further, the present invention is directed to an apparatus that performs various processing (recording, processing, coating, irradiation, reading, inspection, etc.) on various media such as sheets using a liquid discharge head capable of discharging liquid. Is also applicable. The medium (including the recording medium) includes various media to which the liquid including the ink is applied, regardless of the material, such as paper, plastic, film, fabric, metal, flexible substrate, and the like.

  While embodiments of the present invention have been disclosed, it will be apparent to one skilled in the art that modifications can be made without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

10 Printer (inkjet recording device)
31 Recording head (supply destination)
35 Main tank 35 b Bottom surface 36 Sub tank (supply destination)
37 Supply Tubes 38, 39, 77, 78, 79 Refill Tubes (Ink Supply Means, Liquid Supply Means)
38i, 78i Suction port (bottom intake port, first intake means)
39i, 79i Suction port (liquid level intake port, second intake means)
38o, 39o, 77o Discharge port 40 Connecting pipe (ink supply means, liquid supply means)
41 CPU (control means)
61 Float 61 b Bottom (bottom)
62, 63, 73 Suction pump (ink supply means, liquid supply means)
64 bellows tube 74, 75, 84, 85 open / close valve (ink supply means, liquid supply means)
83 Pressure pump (ink supply means, liquid supply means)
100 host device c pigment I ink (solution, liquid)
Iu Liquid level P Roll paper (recording medium)
s Solvent

Claims (9)

A recording head that discharges ink to perform recording;
A first capture unit capable of capturing ink from a first height of a tank that stores the ink supplied to the recording head;
A second capture means capable of capturing ink from a second height higher than the first height of the tank;
Ink supply means for mixing the ink taken in by the first take-in means and the ink taken in by the second take-in means and supplying the mixed ink to the recording head;
An inkjet recording apparatus comprising:   The apparatus further comprises control means for adjusting the ratio of the ink supplied from the first loading means to the ink supplied from the first loading means to the ink supplied to the recording head. The ink jet recording apparatus according to claim 1, characterized in that   The control means determines the ratio of the ink taken in from the first take-in means and the second take-in means based on the residence time of the ink in the tank. The inkjet recording device described in.   The said 2nd taking-in means has a float which floats on the liquid level of ink, and a taking-in port provided in the bottom of the float, according to any one of claims 1 to 3 characterized by the above-mentioned. Inkjet recording device.   The ink jet recording apparatus according to any one of claims 1 to 4, wherein the first take-in means is provided at the bottom of the tank. The tank has an inclined bottom surface,
6. The ink jet recording apparatus according to claim 5, wherein the first take-in means has a take-in port near the lowermost part of the bottom surface. A first capture means capable of capturing the liquid from a first height of a tank for storing the liquid;
A second capture means capable of capturing liquid from a second height higher than the first height of the tank;
Liquid supply means for mixing the liquid taken in by the first take-in means and the liquid taken in from the second take-in means, and supplying the mixed liquid to the supply destination;
The liquid supply device characterized by having. A first taking-in step for taking in the liquid from a first height of a tank for storing the liquid;
A second taking-in step for taking in liquid from a second height which is higher than the first height of the tank;
A liquid supplying step of mixing the liquid taken in the first taking-in step and the liquid taken in the second taking-in step and supplying the liquid to a supply destination;
A liquid supply method comprising:   The ratio of the liquid taken in by the first taking-in step to the liquid taken in by the second taking-in step is carried out simultaneously or alternately by performing the first taking-in step and the second taking-in step The liquid supply method according to claim 8, wherein the adjustment is performed.

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