JP6342744B2 - Ink jet recording apparatus and preliminary discharge method - Google Patents

Description

The present invention relates to an ink jet recording apparatus that performs recording by discharging ink and a preliminary discharge method .

  Inkjet recording technology has been widely researched and developed due to the advantage that it is possible to manufacture a color recording device capable of producing color recording at a relatively low cost. Inkjet recording devices are widely used as consumer and industrial equipment such as printers. It is popular. In an ink jet recording apparatus, generally, a recording head having a plurality of ejection openings for ejecting a plurality of colors of ink is used. In such a recording head, when the solvent in the ink evaporates from the ejection port and the viscosity of the ink in the vicinity of the ejection port increases, the so-called twisting in which the ejection direction of the ink droplet is deflected, or so-called non-ejection in which the ink droplet is not ejected. It is known that a failure occurs.

  As countermeasures against such problems, the ink jet recording apparatus includes a capping unit for suppressing evaporation of the solvent in the ink from the ejection port and a preliminary ejection unit for performing so-called preliminary ejection for ejecting thickened ink. It has been.

  If there is a location (retention location) where it is difficult for the ink flow to occur in the liquid chamber of the recording head, preliminary ejection is performed to eliminate the retention location, and the amount of ink used for the preliminary ejection may increase. Are known. In Japanese Patent Laid-Open No. 2004-228688, ink discharge, interruption, and ink discharge are performed once or more to diffuse mixed color inks having different densities and colors in the liquid chamber of the recording head, and ink necessary for eliminating mixed colors. It is described that the consumption is suppressed.

JP-A-4-255360

  However, in the long line head, when a plurality of top plates (ribs) are provided on the top plate constituting the discharge element portion of the recording head in order to ensure the strength, the ink flow is below the top plate. It is hard to occur. According to the method of Patent Document 1, the ink flow at the place where the supply port and the common liquid chamber communicate with each other is preferential, and the mixed color ink staying at the bottom of the top plate is difficult to be discharged. A large amount of ink must be consumed by preliminary ejection in order to completely discharge the retained mixed color ink and eliminate the mixed color.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording apparatus that efficiently discharges ink staying in a lower part of a top plate or the like where ink flow is unlikely to occur, and suppresses ink consumption necessary to eliminate ink stay. And

Therefore the ink-jet recording apparatus of the present invention includes a recording head including a plurality of discharge ports for discharging ink, a flow path forming member that forms a supply channel of the ink to the plurality of discharge ports, a, from the recording head Preliminary ejection means for performing preliminary ejection for ejecting ink that does not contribute to recording, and among the plurality of ejection ports, ejection ports corresponding to regions where the flow of ink toward the ejection ports is blocked by the flow path forming member And preliminary ejection means for performing partial preliminary ejection.

  According to the present invention, the ink jet recording apparatus can efficiently discharge the ink stagnating at the lower part of the top plate or the like where the ink flow is difficult to occur, and can suppress the ink consumption necessary for eliminating the ink retention.

It is a front view which shows the outline of the internal structure of an inkjet recording device. It is a control block diagram of an inkjet recording device. FIG. 3 is an exploded perspective view of a recording head. It is a simple perspective view of a discharge element. (A), (b) is the perspective view and side surface sectional drawing which fractured | ruptured the top plate of the discharge element partially at the supply port. (A), (b) is the perspective view partially fractured | ruptured by the B section of FIG. 4, and side surface sectional drawing. The front sectional view from the discharge direction side at the time of cut | disconnecting by the C section of FIG. 4 is shown. FIG. 8 is a top cross-sectional view of the discharge element as viewed from the nozzle wall and the liquid chamber frame by cutting along the plane D of FIG. FIG. 8 is a top cross-sectional view showing the opening and the lower part of the top plate bar, in which the discharge element is cut along the plane E in FIG. 7 and the supply port of the top plate and the liquid chamber communicate with each other. FIG. 9 is a front cross-sectional view including a top plate from the discharge direction side of the discharge element of FIG. 7 and a top cross-sectional view when the discharge element of FIG. 8 is viewed from a nozzle wall and a liquid chamber frame. 5 is a flowchart of a general recording sequence in the ink jet recording apparatus. (A) to (c) are diagrams showing a wiping operation in which color mixing is expected to occur in order of operation. (A), (b) is a diagram showing a state diagram in which the mixed color inks are diffused into the ejection element after being left for a long time with the ejection port surface capped from the state of FIG. 12 (c). (A), (b) is the figure which showed the state which refreshes the ink in a discharge element from the state of Fig.13 (a), (b). FIGS. 14A and 14B show a state in which the mixed color ink remaining in the lower part of the top plate crosses again in the ejection element when left for a long period of time from the state of FIGS. FIG. It is the flowchart which showed the recording sequence. FIG. 6 is a diagram illustrating ink flow and diffusion of mixed-color ink when a region X corresponding to a lower part of a top plate is selected and preliminary ejection is performed. It is the figure which showed the ink flow at the time of implementing all nozzle preliminary discharge after FIG. It is the flowchart which showed the recording sequence. FIG. 6 is a diagram illustrating ink flow and diffusion of mixed color inks when a region Y not corresponding to a lower part of a top plate is selected and preliminary ejection is performed. It is the flowchart which showed the recording sequence. FIG. 6 is a diagram illustrating ink flow and diffusion of mixed-color ink when a region X corresponding to a lower part of a top plate is selected and preliminary ejection is performed. FIG. 10 is a diagram showing ink flow and diffusion of mixed color ink when a region Y not corresponding to the lower part of the top plate is selected and preliminary ejection is performed. It is a figure showing diffusion of mixed color ink. FIG. 5 is a diagram illustrating ink flow and diffusion of mixed-color ink when preliminary ejection is performed by all nozzles. 6 is a table showing a predetermined time T, an elapsed time Tn, and a predetermined number n.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing an outline of the internal structure of an ink jet recording apparatus (hereinafter also simply referred to as a recording apparatus) 200 to which the present invention can be applied. The ink jet recording apparatus 200 can be equipped with a plurality of recording heads 100, and the plurality of recording heads 100 can be replaced. The recovery unit 201 is provided corresponding to each recording head 100 individually, and the discharge state of the recording head 100 can be favorably maintained by the recovery process. The ink tank 202 is a cartridge-type tank that stores ink, and can be replaced by the user when the stored ink is exhausted. In addition, the user can handle various processes by operating the operation panel unit 203. Further, the recording apparatus 200 is provided with a transport unit 204 that transports the recording medium and a paper feeding unit 205 that feeds the recording medium to the recording apparatus main body.

  The ink jet recording apparatus 200 of the present embodiment is a so-called full line type recording apparatus, and ejects ink from the ejection port of the recording head 100 while continuously transporting a recording medium from right to left in FIG. By doing so, an image can be recorded on the recording medium. In this embodiment, yellow (Y), light magenta (LM), magenta (M), light cyan (LC), cyan (C), and black (K) ink supplied from the ink tank 202 is recorded corresponding to each color. The ink is discharged from the head 100. Thereby, a color image can be recorded. The recovery unit 201 is used for a recovery process that maintains the ink ejection state of the recording head 100 well. In the recovery process, the ink is circulated between the recording head 100 and the ink tank 201, and the ink is circulated through the circulation path. It includes a circulation recovery operation to remove dust and bubbles inside. Further, the recovery process includes a preliminary ejection operation in which ink that does not contribute to image recording is ejected from the ejection port into the cap, and pressurization of the ink in the recording head to forcibly eject the ink from the ejection port into the cap. Pressure recovery operation, etc. are included. Further, the recovery process includes a suction recovery operation for sucking and discharging ink from the discharge port into the cap, and a wiping operation for wiping the discharge port surface of the recording head 100 on which the discharge port is formed.

  FIG. 2 is a block configuration diagram of a control system of the recording apparatus 200 of FIG. The recording apparatus 100 includes a CPU (Central Processing Unit), a USB interface unit, a ROM, a recording mechanism including a recording head, and the like. The CPU 211 executes programs stored in the program ROM 212 and controls each unit of the recording apparatus 100. The program ROM 212 stores programs and data for controlling the recording apparatus 100. The processing of the recording apparatus 200 is realized by the CPU 211 reading and executing a program in the program ROM 212.

  The recording data transmitted from the host PC 206 is received by the interface controller 213 of the recording apparatus 200. A command for instructing the number, type, size, and the like of a recording medium as a recording medium is also received and analyzed by the interface controller 213. In addition to analyzing these commands, the CPU 211 executes arithmetic processing for controlling the entire recording apparatus 200 such as reception of recording data, recording operation, and handling of the recording medium. The processing of the CPU 211 is executed based on the processing program stored in the program ROM 212, and the program includes a program corresponding to the procedure shown in the flowcharts of FIGS. 11, 16, 19, and 21 described later. A work RAM 214 is used as a working memory for the CPU 211. The EEPROM 215 is a rewritable nonvolatile memory. The EEPROM 215 stores information such as the time when the previous recovery operation was performed, the distance between the plurality of recording heads, and correction values for finely adjusting the recording position in the transport direction (longitudinal registration). Unique parameters are stored.

  Specifically, after analyzing the received command, the CPU 211 renders the image data of each color component of the recording data by developing a bitmap on the image memory 216. The CPU 211 also controls a recovery unit motor 219 for driving the recovery unit 201 and a head motor 220 for moving the recording head 100 via an input / output port (I / O) 217 and a motor drive unit 218. To do. The recording head 100 is moved between a capping position capped by the recovery unit 201 and a recording position for recording an image and a recovery position for performing a recovery operation.

  When recording an image, the conveyance motor 204 drives the conveyance unit 204 to convey the recording medium at a constant speed. In synchronization with an encoder (not shown) signal due to conveyance of the recording medium by the conveyance unit 204, the CPU 211 sequentially reads out the image data for each color from the image memory 216 and outputs the image data via the recording head control circuit 222. Transfer to the corresponding recording head 100. Accordingly, the recording head 100 ejects ink based on the image data.

  The pump motors 223 for driving the pumps that perform the pressure recovery operation and the suction recovery operation are driven and controlled via an input / output circuit (I / O) 217 and a motor drive unit 218, respectively.

  The operator panel 203 is connected via an input / output circuit (I / O) 224.

  FIG. 3 is an exploded perspective view of the recording head 100. One side of the ejection element 101 that forms the main part of the recording head 100 is supported by a ceramic base plate 102. As will be described later, the discharge element 101 includes a top plate, a supply port, a top plate including a common liquid chamber, a plurality of discharge ports, and a plurality of nozzles communicating between the common liquid chamber and the discharge port. A discharge energy generating element. In the case of this embodiment, an electrothermal converter (heater) is provided as a discharge energy generating element. An electrical wiring board 103 is disposed on the other side surface of the ejection element 101, and the electrical wiring board 103 is an electrode portion of wiring (wiring for generating ejection energy and driving elements thereof) provided on the ejection element 101. Are electrically connected by wire bonding. The flow path forming member 104 is installed so that an internal flow path is connected to a supply port, which will be described later, provided in the discharge element 101, which will be described later.

  The ink supply path in the present embodiment forms a circulation path capable of circulating ink between the recording head 100 and the ink tank 202. That is, the ink in the ink tank 202 is transferred to the common liquid chamber in the ejection element 101 via the flow path forming member 104, and the transferred ink is distributed from the common liquid chamber to a plurality of nozzles. Ink in the common liquid chamber can be returned to the ink tank 202 via the flow path forming member 104.

  FIG. 4 is a simplified perspective view of the discharge element 101, and FIGS. 5A and 5B are a perspective view and a side cross-sectional view, respectively, of the top plate 300 of the discharge element being partially broken at a portion A in FIG. . 6 (a) and 6 (b) are a perspective view and a side cross-sectional view partially broken at B part in FIG. 4, and FIG. 7 is a discharge direction when cut at C part in FIG. The front sectional view from the side is shown. On the heater board (substrate) 301, electrothermal transducers (heaters) as discharge energy generating elements are arranged at positions corresponding to the plurality of nozzles. The ink in the nozzles is foamed by the heat generated by the heater, and the ink can be ejected from the ejection port using the foaming energy. As the heater, a resistor such as tantalum nitride is used, the thickness is 0.01 to 0.5 μm, and the sheet resistance is 10 to 350Ω per unit square. The heater may be made of a material other than tantalum nitride, such as hafnium boride, and the thickness and sheet resistance are not particularly limited.

  A pair of electrode wirings (not shown) made of aluminum or the like for energization is connected to both ends of the heater, and a switching transistor (not shown) for turning on / off energization is connected to one electrode wiring. ) Is connected. A control IC (not shown) including a circuit including a gate element or the like controls the switching transistor in accordance with a recording signal input from the outside of the recording head 100.

  On the heater board 301, a nozzle wall 302 is formed between adjacent heaters. A top plate 300 made of Si or the like is disposed on the upper surface of the nozzle wall 302 via a top plate adhesive layer 310 (shown in FIG. 5 and subsequent drawings) having a thickness of about 2 μm. As a result, a tubular nozzle 303 surrounded by the heater board 301, the nozzle wall 302, and the top plate adhesive layer is formed. In the top plate 300, a plurality of supply ports 305 and a top plate bar 304 are formed between the adjacent supply ports on the upstream side of the ink flow by a method such as anisotropic etching. By connecting the flow path forming member 104 to the supply port 305, ink can be introduced into the common liquid chamber 306.

  An electric pad 311 for transmitting a recording signal to the heater is formed on the side opposite to the side where the nozzle 303 is formed on the heater board 301. The electric pad is electrically connected to the pad portion of the electric wiring board 103 by a wire.

  In the above configuration, the heater IC is turned on / off by the control IC driving and controlling the switching transistor in accordance with a recording signal input from the outside of the recording head 100. The ink supplied from the common liquid chamber 306 to each nozzle 303 is heated and foamed on the heater. Then, due to the pressure due to the foaming, the ink downstream of the heater in the ink supply direction is ejected from the ejection port. The ink droplets fly and land on the recording medium to form dots.

  FIG. 6 is a perspective view and a side sectional view in which the top plate of the discharge element is partially broken at the top plate bar. As described above, the top plate 300 is formed with a plurality of supply ports 305, a plurality of top plate bars 304, and a common liquid chamber 306 by a method such as anisotropic etching. Ink flows from the opening 307 communicating with the. However, the lower portion 308 of the top plate 304 provided to ensure the strength of the top plate 300 is blocked by the top plate 304 so that the ink flow from the upstream side in the ink flow does not occur. That is, in the lower portion 308 of the top plate 304, the flow in the direction of the arrow β intersecting the ink ejection direction of the arrow α becomes the main flow.

  FIG. 7 is a front sectional view of part C in FIG. The supply port 305 and the top plate bar 304 are alternately arranged in the direction perpendicular to the discharge direction in the ink flow upstream half of the top plate 300, and the common liquid chamber 306 is in the discharge direction in the ink flow downstream half of the top plate 300. It is connected in the right angle direction.

  FIG. 8 is a top cross-sectional view of the discharge element 101 taken along the plane D in FIG. 7 and viewed from the nozzle wall 302 and the liquid chamber frame 309. A plurality of discharge ports 400, a plurality of nozzles 303 communicating with the discharge ports 400, a plurality of nozzle walls 302 forming the nozzles 303, and a plurality of heaters 401 are arranged in a direction perpendicular to the discharge direction. A liquid chamber frame 309 is formed so as to surround the outer periphery.

  FIG. 9 is a top cross-sectional view showing the opening 307 and the top plate rail lower portion 308 where the discharge element 101 is cut along the plane E of FIG. 7 and the supply port 305 and the liquid chamber 306 of the top plate 300 communicate with each other. . An opening 307 that communicates the supply port 305 and the liquid chamber 306 and a top plate lower portion 308 are arranged in a direction perpendicular to the discharge direction.

  10 is a front cross-sectional view including the top plate 304 from the discharge direction side of the discharge element of FIG. 7, and a top cross-sectional view when the discharge element 101 of FIG. 8 is viewed from the nozzle wall and the liquid chamber frame. Hereinafter, various descriptions of the color mixing generation mechanism, preliminary ejection, and ink flow will be described with reference to FIG.

  FIG. 11 shows a flowchart of a recording sequence in a conventional ink jet recording apparatus. Hereinafter, a general recording sequence will be described with reference to this flowchart.

  When the recording sequence is started, the ink jet recording apparatus stands by until a recording instruction is issued in step S001. If there is a recording instruction, the cap is opened in step S002, and then a preliminary ejection operation is performed in step S003 to eject ink that does not contribute to image recording from the ejection port into the cap. The preliminary discharge here is performed by all nozzles (discharge ports). Thereafter, recording on the recording medium is performed in step S004, and after the recording is finished, whether or not the wiping operation is performed is determined in accordance with the recording content in step S005. If it is determined in step S005 that a wiping operation is necessary, wiping is performed on the discharge port surface with a wiper in step S006, and preliminary discharge (all discharge ports) is performed after wiping to stabilize the meniscus on the discharge port surface in step S007. carry out. In step S008, the cap is closed, and a series of recording sequences is completed. If it is determined in step S005 that the wiping operation is unnecessary, the process proceeds to step S008, where the cap is closed, and the recording sequence ends.

Here, the mechanism of color mixing will be described.
FIGS. 12A to 12C are diagrams showing the wiping operation in which the color mixture is expected to be generated in the order of operation. FIG. 12A shows a state in which mixed color inks adhere to the wiper 400 before the wiping operation. There are several factors that cause the mixed color ink to adhere to the wiper 400. For example, when different color inks adhere to the wiper and mix, or when the mixed color ink adheres to the wiper by the cleaner that cleans the wiper, and when the ink mist adheres to the discharge port surface of another color and wipes, the wiper 400 may be mixed color ink. FIG. 12B shows a state during the wiping operation by the wiper 400 to which the mixed color inks are attached. The mixed color ink adhering to the wiper 400 enters the nozzle 303 (discharge port) from the discharge port surface by wiping, and at this time, a part of the mixed color ink also remains around the discharge port surface. FIG. 12C shows a state in which the mixed color ink that has entered from the discharge port surface is accumulated in the nozzle 303 by capillary force after the wiping operation is completed. By performing preliminary discharge (all discharge ports) from this state and discharging the mixed color ink in the nozzle, the mixed color in the nozzle 303 can be eliminated. However, as described above, a part of the mixed color ink also remains around the discharge port surface. ing. In this case, the mixed color ink remaining around the discharge port surface cannot be removed by preliminary discharge. Then, when the cap is closed and left in a state where the mixed color ink remains attached to the ejection port surface, a part of the mixed color ink that remains is again entered into the nozzle from the ejection port surface, leading to color mixing.

  FIGS. 13A and 13B show state diagrams in which the mixed color ink in the nozzles diffuses into the ink in the ejection element when left for a long time with the ejection port face capped from the state of FIG. 12C. It is a figure. A dotted line arrow in the figure indicates a state of diffusion of the mixed color ink. The mixed color ink diffuses from the nozzle 303 to the entire common liquid chamber 306 including the top plate lower portion 308, and the mixed color ink also diffuses to the supply port 305 side through the opening 307 that connects the common liquid chamber 306 and the supply port 305. To do.

  FIGS. 14A and 14B show a state in which preliminary ejection from all the nozzles 303 is performed from the states of FIGS. 13A and 13B and the ink in the ejection elements 101 is refreshed. Yes. The arrows in the figure indicate the flow of ink at the time of refreshing, the one-dot chain arrow indicates the ink flow from the flow path forming member 104 to the common liquid chamber 306, and the two-dot chain arrow indicates the ink flow from the common liquid chamber 306 to the nozzle 303. Ink flow is shown. When preliminary ink is discharged from all the nozzles 303 and ink starts to flow in the discharge element 101 as a whole, the flow of ink is given priority to the flow as indicated by the two types of arrows described above. Hardly occurs. Not only such preliminary ejection by all the nozzles 303, but also when ink is discharged by suction, pressurization, etc., and the ink in the ejection element 101 is refreshed, almost no ink flow occurs in the top plate lower portion 308. Ink stays. That is, in the refreshing (preliminary ejection) of the ejection elements 101 performed using all the nozzles 303, the interior of the ejection elements 101 cannot be completely refreshed, and the mixed color ink remains inside (the top plate lower portion 308). .

  FIGS. 15A and 15B show that the mixed color ink remaining in the top plate lower portion 308 diffuses again in the ejection element 101 when left for a long time from the state of FIGS. 14A and 14B. It is the figure which showed the state. When recording is performed in a state where the mixed color inks are diffused in the ejection element 101 in this way, the mixed color inks are ejected from all the ejection ports, and the ink in the common liquid chamber 306 is preferentially ejected at the early stage of ejection. Therefore, dark mixed-color ink is ejected from the nozzle 303 in the region X corresponding to the top plate rail 308, and as a result, streak-like recording is performed.

  Therefore, in the present embodiment, when a predetermined time has elapsed from the wiping operation, it is determined that the mixed color ink has diffused in the discharge element 101, and after the stirring operation has been performed in the discharge element 101, all the nozzles are discharged. Perform preliminary discharge. This method will be described in detail below.

  FIG. 16 is a flowchart showing a recording sequence in the present embodiment. Also, FIG. 17 shows the ink flow of the mixed color ink when the region X corresponding to the top plate lower portion 308 is selected and preliminary discharge (partial preliminary discharge) is performed from the discharge port (discharge port group) corresponding to the region X. It is the figure which showed diffusion. FIG. 18 is a diagram showing the ink flow when all-nozzle preliminary ejection is performed after FIG. Hereinafter, the recording sequence of the present embodiment will be described with reference to the flowchart of FIG.

  When the recording sequence is started, it is checked in step S1501 if there is a recording command from the host PC 206. If there is a recording command, the cap is opened in step S1502, and then the elapsed time from the previous wiping operation is compared with a predetermined time T in step S1503. When the elapsed time from the previous wiping operation is less than the predetermined time T, the sequence is the same as that after step S003 described in FIG. If the elapsed time from the previous wiping operation is equal to or longer than the predetermined time T in step S1503, the process proceeds to step S1504 to select the region X (see FIG. 17) corresponding to the top plate lower portion 308, and this selected region Preliminary discharge is performed with the nozzles. In the initial ejection in the preliminary ejection, the ink in the common liquid chamber is preferentially used. For this reason, the ink in the lower part of the top plate 308 is used for preliminary ejection, and an ink flow from the lower part of the top plate 308 to the nozzles occurs, so that the mixed-color ink flows in the ejection direction, giving priority to the preliminary ejection. used. At the same time, the diffusion of the mixed color ink from the top plate lower portion 308 to the surroundings due to the occurrence of ink flow in the top plate lower portion 308 is promoted. At this time, the preliminary ejection amount per unit time in the region X is set such that the ink flow develops and the ink flow from the opening communicating with the supply port and the common liquid chamber is not preferential. After a flow is generated in the ink in the top plate lower portion 308, in step S1505, all nozzles are preliminarily ejected (all preliminarily ejected) as shown in 18 to discharge the mixed color inks. In the all-nozzle preliminary discharge at this time, the flow is already generated in the top plate lower portion 308 by the preliminary discharge of the region X corresponding to the top plate lower portion 308 in step S1504. Therefore, by performing all nozzle preliminary discharge, the flow generated in the top plate lower portion 308 becomes the flow toward the nozzles as it is. Therefore, in the all-nozzle preliminary discharge after the preliminary discharge of the region X corresponding to the top plate rail 308, the mixed color ink is surely discharged with almost no ink remaining in the top plate rail 308. At that time, in order to surely discharge the mixed color ink, the total nozzle preliminary discharge amount is set to an amount larger than the ink volume in the discharge element. Thereafter, in step S1506, it is determined whether or not the elapsed time from the previous wiping operation is equal to or longer than the elapsed time Tn after preliminary discharge of all nozzles. If the elapsed time is equal to or longer than Tn, the process proceeds to step S1507. In step S1507, it is confirmed whether or not the top plate lower portion corresponding region X preliminary discharge → all nozzles preliminary discharge is performed n times or more. If it is n times or more, the process proceeds to step S1509 and described in FIG. The same sequence as that after step S004 is performed. In step S1507, if it is not n times or more, the process returns to step S1504 and repeats the top plate lower portion corresponding region X preliminary discharge → all nozzle preliminary discharge until n times or more (perform at least once). Here, the elapsed time Tn> the predetermined time T, and the predetermined number n is 1 or more. An example of the predetermined time T, the elapsed time Tn, and the predetermined number of times n is shown in the table of FIG. The predetermined time T is the time required for the mixed color inks to diffuse throughout the ink in the ejection elements, and the elapsed time Tn indicates the time during which the ink in the ejection elements increases in viscosity as n increases. The predetermined time T, the elapsed time Tn, and the predetermined number n are appropriately determined according to the ink physical properties and the apparatus configuration, and are not limited to the table of FIG.

  In this embodiment, the preliminary discharge is performed for all nozzles after the preliminary discharge by the nozzles (discharge ports) in the region X. However, depending on the configuration of the apparatus and the ink to be used, the nozzles (discharge ports) in the region X are used. Only preliminary discharge may be used.

  As described above, before the preliminary discharge of all nozzles is performed, the preliminary discharge of the top plate rail corresponding region X having a stirring effect is performed to generate a flow at the bottom of the top plate, and then the preliminary discharge of all nozzles is performed. Then, the mixed color ink is discharged. As a result, it was possible to realize an ink jet recording apparatus that suppresses the ink consumption necessary to eliminate the staying ink.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of the present embodiment is the same as that of the first embodiment, only the characteristic configuration will be described below.

  FIG. 19 is a flowchart showing a recording sequence in the present embodiment. FIG. 20 is a diagram showing the ink flow and diffusion of mixed-color inks when a region Y not corresponding to the top plate rail 308 is selected and preliminary ejection (partial preliminary ejection) is performed. Hereinafter, the recording sequence of the present embodiment will be described with reference to the flowchart of FIG.

  From step S1801 to step S1803, the same processing as the processing from step S1501 to step S1503 in FIG. 16 is performed. If it is determined in step S1803 that the elapsed time from the previous wiping operation is equal to or longer than the predetermined time T, the process proceeds to step S1804 to select a region Y (see FIG. 20) that does not correspond to the top plate lower portion 308, and this selected region Preliminary discharge is performed with the nozzle (discharge port group). Accordingly, an ink flow is generated in the top plate lower portion 308, and thereby, the diffusion of mixed color ink from the top plate lower portion 308 to the surroundings is promoted. Since step S1805 and subsequent steps are the same as those in the first embodiment, description thereof is omitted.

  As described above, before the preliminary discharge of all the nozzles is performed, the preliminary discharge of the region Y not corresponding to the lower part of the top plate having a stirring effect is performed, and the flow is generated in the lower part of the top plate, and then the preliminary discharge of all the nozzles is performed. Is performed to discharge mixed color ink. As a result, it was possible to realize an ink jet recording apparatus that suppresses the ink consumption necessary to eliminate the staying ink.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of the present embodiment is the same as that of the first embodiment, only the characteristic configuration will be described below.

  FIG. 21 is a flowchart showing a recording sequence in the present embodiment. FIG. 22 is a diagram showing the ink flow and diffusion of the mixed color inks when the region X corresponding to the top plate rail 308 is selected and preliminary ejection is performed. FIG. 23 is a diagram showing the ink flow and diffusion of mixed-color inks when a region Y not corresponding to the top plate rail 308 is selected and preliminary ejection is performed. FIG. 24 is a diagram showing the flow of ink while the preliminary ejection is interrupted, and FIG. 25 is a diagram showing the preliminary ejection by all the nozzles. Hereinafter, the recording sequence of this embodiment will be described with reference to the flowchart of FIG.

  From step S2001 to step S2003, processing similar to the processing from step S1501 to step S1503 in FIG. 16 is performed. In step S2003, when the elapsed time from the previous wiping operation is equal to or longer than the predetermined time T, the process proceeds to step S2004 to select the region X (see FIG. 22) corresponding to the top plate lower portion 308, and this selected region. Preliminary discharge is performed with the nozzles. Thereafter, in step S2005, a region Y (see FIG. 30) that does not correspond to the top plate lower portion 308 is selected, and preliminary ejection is performed using the nozzles in the selected region. As a result, the ink in the region adjacent to the top plate lower part 308 is used for preliminary ejection, so that ink flows mainly from the lower part of the top plate cross to the nozzle arrangement direction and the region Y. In addition, since the ink flow in the lower part of the top plate is newly generated in the direction orthogonal to the preliminary discharge in the region X corresponding to the lower part of the top plate, there is no stagnation in the subsequent preliminary discharge of all the nozzles. The mixed color ink can be discharged. Note that the total of the preliminary discharge amount in the region X and the preliminary discharge amount in the region Y is an amount in which the ink flow is developed and the ink flow from the opening communicating with the supply port and the common liquid chamber is not preferential. Furthermore, the preliminary discharge amount per unit time is set as region X> region Y.

  In step S2004 and step S2005, after an ink flow is generated in the ink below the top plate, in step S2006, all nozzles are preliminarily ejected as shown in FIG. At that time, in order to surely discharge the mixed color ink, the total discharge amount of the ink by the preliminary discharge is set to an amount equal to or larger than the ink volume in the discharge element. Thereafter, in step S2007, it is determined whether or not the elapsed time from the previous wiping operation is equal to or greater than the elapsed time Tn after preliminary discharge of all nozzles. If the elapsed time is equal to or greater than Tn, the process proceeds to step S2008. In step S2008, the above-described cycle of the top plate lower portion corresponding region X preliminary discharge → the top plate lower portion corresponding region Y preliminary discharge → preliminary discharge interruption → all nozzle preliminary discharge is performed. Here, the preliminary discharge is interrupted between the top plate lower portion corresponding area Y preliminary discharge and all the nozzles preliminary discharge. This is because it is considered that the mixed color ink stays in the lower part 308 of the top plate not less than after all the nozzles have been preliminarily discharged in step S2006. Therefore, stirring is performed by the operation of the preliminary ejection at the lower part of the top plate X to the preliminary ejection at the lower part of the upper part of the top plate Y, and then the interruption is interrupted for the purpose of promoting the stirring effect of the mixed color ink by stirring. Pre-discharge with all nozzles is carried out after inserting.

  Thereafter, in step S2009, it is confirmed whether or not the top plate rail corresponding area X preliminary discharge → the top plate bottom corresponding area Y preliminary discharge → preliminary discharge interruption → all nozzle preliminary discharge has been performed n times or more. If it is n times or more, the process proceeds to step S2011, and the same sequence as that after step S004 described in FIG. 11 is performed. Here, the elapsed time Tn> the predetermined time T, and the predetermined number n is 1 or more. The predetermined time T, the elapsed time Tn, and the predetermined number n are appropriately determined according to the ink physical properties and the apparatus configuration.

  In this way, before the preliminary discharge of all nozzles is performed, the preliminary discharge of the area X corresponding to the lower part of the top plate with the stirring effect and the preliminary discharge of the area Y not corresponding to the lower part of the upper part of the top plate are generated. The mixed color ink is discharged by performing preliminary discharge for all the nozzles after being diffused. As a result, it was possible to realize an ink jet recording apparatus that suppresses the ink consumption necessary to eliminate the staying ink.

DESCRIPTION OF SYMBOLS 100 Recording head 101 Discharge element 200 Inkjet recording device 201 Recovery unit 300 Top plate 301 Heater board 303 Nozzle 304 Top plate cross 305 Supply port 306 Common liquid chamber 307 Opening part 308 Bottom of top plate cross

Claims (8)

A plurality of discharge ports for discharging ink, a recording head including a flow path forming member that forms a supply channel of the ink to the plurality of discharge ports,
Preliminary ejection means for performing preliminary ejection for ejecting ink that does not contribute to recording from the recording head, and among the plurality of ejection ports, in a region where the flow of ink toward the ejection port is blocked by the flow path forming member Preliminary ejection means for performing partial preliminary ejection by a corresponding ejection port ;
An ink jet recording apparatus comprising:   A plurality of ejection openings for ejecting ink, and a flow path forming member having ribs for forming a flow path for supplying ink to the plurality of ejection openings and partitioning the plurality of supply openings provided in the flow path. Including a recording head;
  Preliminary ejection means for performing preliminary ejection for ejecting ink that does not contribute to recording from the recording head, and among the plurality of ejection ports, by ejection ports corresponding to the ribs in a direction of ink flow toward the ejection ports. Preliminary ejection means for performing partial preliminary ejection;
  An ink jet recording apparatus comprising:   A recording head comprising: a plurality of ejection openings for ejecting ink; and a flow path forming member that forms a flow path for supplying ink to the plurality of ejection openings and has a rib in the flow path;
  Preliminary ejection means for performing preliminary ejection for ejecting ink that does not contribute to recording from the recording head, and among the plurality of ejection ports, other than ejection ports corresponding to the ribs in a direction of ink flow toward the ejection port Preliminary discharge means for performing partial preliminary discharge by the discharge port;
  An ink jet recording apparatus comprising:   The preliminary discharge means includes
  A first partial preliminary discharge by a discharge port for performing the partial preliminary discharge;
  A second partial preliminary discharge by a discharge port other than the discharge port for performing the partial preliminary discharge;
  The inkjet recording apparatus according to any one of claims 1 to 3, wherein the inkjet recording apparatus is switched. Said preliminary discharge means, and the partial preliminary discharge, according to any one of claims 1 to 4, characterized in that by switching, and all preliminary ejection for ejecting ink from all of the discharge port Inkjet recording apparatus.   Recording from the recording head in an ink jet recording apparatus having, as recording means, a recording head that includes a plurality of ejection ports that eject ink and a flow path forming member that forms a flow path for supplying ink to the plurality of ejection ports. A preliminary ejection method for ejecting ink that does not contribute to
  A preliminary ejection method comprising: a preliminary ejection step of ejecting from an ejection port corresponding to a region where an ink flow toward the ejection port is blocked by the flow path forming member among the plurality of ejection ports.   An ink jet having a recording head including a plurality of discharge ports for discharging ink and a flow path forming member having a flow path for supplying ink to the plurality of discharge openings and having a rib in the flow path as a recording unit A preliminary ejection method for ejecting ink that does not contribute to recording from the recording head in a recording apparatus,
  A preliminary ejection method comprising: a preliminary ejection step of performing ejection from an ejection port corresponding to the rib in a direction of ink flow toward the ejection port among the plurality of ejection ports.   An ink jet having a recording head including a plurality of discharge ports for discharging ink and a flow path forming member having a flow path for supplying ink to the plurality of discharge openings and having a rib in the flow path as a recording unit A preliminary ejection method for ejecting ink that does not contribute to recording from the recording head in a recording apparatus,
  A preliminary ejection method comprising: a preliminary ejection step of ejecting from a plurality of ejection ports other than the ejection ports corresponding to the ribs in a direction of ink flow toward the ejection port.