JP2010030086A - Liquid droplet delivering apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use a cartridge capable of more printing with the same cartridge size. <P>SOLUTION: An IC chip for identifying whether the cartridge 101 is a new product or not is provided. When the cartridge 101 is determined to be new, liquid in the cartridge is sent to a head tank 35 while the pressure of the cartridge 101 is detected by a pressure sensor 210 until the pressure of the liquid in the cartridge reaches at least at a pressure difference P generated by the water head difference h of the head and the cartridge 101 or lower. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge device and an image forming apparatus, and in particular, a cartridge mounting portion in which a cartridge for storing liquid is installed, a liquid supply mechanism for supplying liquid from the cartridge installed in the cartridge mounting portion, and a liquid supply The present invention relates to a droplet discharge device including a liquid supply path for supplying a liquid from a mechanism to a head tank provided on a head for discharging the liquid, and an image forming apparatus including the droplet discharge device.

  In general, a printer, a fax machine, a copier, or an image forming apparatus that combines these functions, for example, a recording head composed of a liquid ejection head that ejects liquid droplets of a recording liquid is used to perform recording while conveying a medium. 2. Description of the Related Art A liquid discharge type image forming unit that forms an image by attaching liquid droplets to a sheet is known.

  In such a liquid (droplet) discharge type image forming apparatus, as a system for supplying a recording liquid to the recording head, a recording liquid cartridge which is a recording liquid storage means for storing the recording liquid in a carriage on which the recording head is mounted. Is mounted detachably, and a recording liquid is supplied from the recording liquid cartridge to the recording head, and a small-capacity head tank which is a second liquid storage means for supplying the recording liquid to the recording head is mounted on the carriage. A system in which a large-capacity recording liquid cartridge (main tank) as a first liquid storage means is replaceably mounted on the apparatus main body side, and the recording liquid (ink) is replenished and supplied to the head tank from the recording liquid cartridge on the apparatus main body side; ,It has been known.

  In the latter liquid supply apparatus using the two liquid storage means described above, the liquid is supplied to the second liquid storage means by driving the supply pump in a state where there is no liquid in the main first liquid storage means. The supply operation is performed. At this time, the supply pump continues to be driven until the amount of liquid in the second liquid storage means reaches a specified amount. If it is not detected that the amount of liquid in the second liquid storage means has reached the specified amount even when the supply pump is driven for a predetermined time, the first liquid storage means is empty. The replacement of the liquid storage means is instructed.

  As described above, the following has been proposed as a droplet discharge device that replenishes and supplies liquid from the first liquid storage means to the second liquid storage means. In Patent Document 1, when there is a high possibility that air has entered the ink supply path, an air mixing flag is set, air is sent to the head tank together with ink, and the head tank is opened to the atmosphere until bubbles in the head tank disappear. There is a description that restricts the ink supply in a state where the ink is discharged.

  Patent Document 2 has a function of detecting the load of the drive motor of the supply pump, and prevents the air from entering the supply pump by stopping the supply pump when the load is detected.

Further, Patent Document 3 describes that when the cartridge is replaced when the power is turned off, the ink supply operation is resumed when the power is turned on.
JP 2007-223230 A JP 2007-105935 A JP-A-2005-41085

  However, when it is detected that the first liquid storage means is empty when it is not possible to detect that the liquid amount in the second liquid storage means has reached the specified amount even if the supply pump is driven for a predetermined time, A state occurs in which the supply pump is driven even though the liquid storage means is empty. At this time, the pressure in the supply pump increases excessively, and the first liquid storage means When the instruction is issued, the supply pump is in a strong negative pressure state.

  At this stage, when the first liquid storage means is replaced, the portion connecting the first liquid storage means and the supply pump (for example, the joint between the rubber plug and the hollow needle) is removed, and the first liquid storage means The air will be sucked into the supply pump which is in a negative pressure at the moment of removing.

  When such a situation occurs, the air sucked into the supply pump does not escape, and when a new first liquid storage means is installed and the supply operation is started, the air passes through the supply tube and the second liquid. The air sent to the storage means becomes foamed on the liquid surface in the second liquid storage means, and the bubbles increase. And the bubble in this 2nd liquid storage means will malfunction the sensor which detects the liquid level of a 2nd liquid storage means.

  Therefore, when replenishing and supplying the liquid in a state in which the second liquid storage means is opened to the atmosphere, liquid leakage from the atmosphere opening mechanism occurs, or the valve means constituting the atmosphere opening mechanism becomes dirty and malfunctions. There is a problem of causing a slow leak.

  In addition to the bubbles sucked by the supply pump when the cartridge is replaced, for example, when bubbles are mixed due to air permeation in the ink supply path, the above-mentioned problem can be caused.

  As a countermeasure against this, in the device described in Patent Document 1, the air release valve is prohibited from being opened, and then an ink feeding sequence for sending bubbles into the head tank is performed to eliminate bubbles inside the head tank. However, in this operation, it is necessary to put extra ink necessary for liquid feeding in the cartridge, and in order to prevent natural replenishment when the cartridge is set, the head and the cartridge head When filling so as not to exceed the difference, there is a problem that the capacity of the cartridge that can be used for printing decreases as a result.

  In addition, in the device described in Patent Document 2, in order to effectively prevent air from being mixed, when the ink cartridge becomes empty, it is detected instantaneously and the pump is stopped. However, it is difficult to make an accurate determination without erroneous detection. In the unlikely event that the supply pump is driven even though the ink cartridge is empty even if it is erroneously detected, air will be mixed into the supply path. It is necessary to take measures such as

  Furthermore, the problem described in Patent Document 3 does not consider the problem: mixing of air into the ink supply path, and does not consider the ink pressure in the cartridge.

  Accordingly, an object of the present invention is to provide a droplet discharge device that can use a cartridge that can print more with the same cartridge size.

  The invention of claim 1 includes a detection means capable of detecting from the outside whether or not it is a new article, a cartridge mounting portion where a cartridge for storing the liquid is installed, and a liquid from the cartridge installed in the cartridge mounting portion. A liquid supply mechanism for supplying liquid, a liquid supply path for supplying liquid from the liquid supply mechanism to a head tank provided on a head for discharging liquid, and a detecting means for detecting whether or not the cartridge is a new cartridge And when it is detected that the cartridge installed by the detection means is a new cartridge, the pressure of the liquid in the cartridge is at least equal to or less than the pressure difference P generated by the head difference between the head and the cartridge. A liquid droplet ejection apparatus comprising liquid feeding control means for feeding a liquid to the head tank.

  According to a second aspect of the present invention, in the liquid droplet ejection apparatus according to the first aspect, a pressure sensor is provided between the liquid supply mechanism and the cartridge mounting portion, and the liquid supply control means uses a pressure sensor to end the liquid supply. It is determined by the detection result of

  According to a third aspect of the present invention, in the liquid droplet ejection device according to the first or second aspect, the liquid feeding control means includes a liquid droplet ejection device that feeds a predetermined liquid amount V1, and the cartridge includes The liquid volume Va is equal to or larger than the filling volume V2 at which the liquid pressure in the cartridge is equal to the pressure difference P, and satisfies Va ≦ V1 + V2.

  According to a fourth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first to third aspects, the cartridge includes an IC chip as a detected unit, and the detection unit includes a reading device for the IC chip. Features.

  According to a fifth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first to fourth aspects, the head tank is disposed and an atmosphere release valve capable of communicating with the atmosphere, and when air is mixed at the end of the cartridge. And an invalid setting control means for invalidating the storage contents of the air mixing storage means after elapse of a predetermined time. When the storage contents of the air mixing storage means are valid, the air release valve is An open valve control means for prohibiting communication with the atmosphere is provided.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus comprising the droplet discharge device according to any one of the first to fifth aspects.

  According to the droplet discharge device and the image forming apparatus according to the present invention, in the initial state of the cartridge, by setting a positive pressure rather than the head difference between the head and the cartridge, more printing can be performed with the same cartridge size. Can do.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view of the image forming apparatus according to the embodiment. The image forming apparatus according to the present embodiment is an ink jet recording apparatus. The ink jet recording apparatus is attached to and detached from the apparatus main body 1, a paper feed tray 2 for loading paper loaded in the apparatus main body 1, and the apparatus main body 1. A paper discharge tray 3 is provided for stocking paper that is freely mounted and on which images are recorded (formed).

  Furthermore, the front end of the apparatus main body 1 has a cartridge loading section 4 for loading an ink cartridge as a first liquid storage means on one end side (side of the paper supply / discharge tray section). The upper surface of 4 is an operation / display unit 5 provided with operation buttons and a display.

  The cartridge loading unit 4 contains a plurality of recording liquids (inks) that are different color materials, for example, black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink. Ink cartridges (main tanks) 10k, 10c, 10m, 10y (referred to as “ink cartridge 10” when colors are not distinguished) as recording liquid cartridges as the first liquid storage means A front cover (cartridge cover) 6 that is opened when the ink cartridge 10 is attached or detached is provided on the front side of the cartridge loading portion 4 so as to be openable and closable.

Further, the ink cartridges 10k, 10c, 10m, and 10y are configured to be loaded side by side in a vertical state.

  Further, the operation / display unit 5 has the remaining amounts of the ink cartridges 10k, 10c, 10m, and 10y of each color at the arrangement positions corresponding to the mounting positions (arrangement positions) of the ink cartridges 10k, 10c, 10m, and 10y of each color. The remaining amount display portions 11k, 11c, 11m, and 11y for each color for displaying the near end and the end are arranged.

  Further, the operation / display unit 5 is also provided with a power button 12, a paper feed / print resume button 13, and a cancel button 14. Next, the mechanism part of the ink jet recording apparatus will be described with reference to FIGS.

  FIG. 2 is a side view schematically showing the outline of the mechanism part of the ink jet recording apparatus, and FIG. 3 is a plan view schematically showing the mechanism part of the ink jet recording apparatus. A main guide rod 31 which is a main guide member horizontally mounted on the left and right side plates 21A and 21B constituting the frame 21 and a sub guide rod 32 hold the carriage 33 slidably in the main scanning direction, and a main scanning motor (not shown). Is moved and scanned in the direction indicated by the arrow in FIG. 3 (carriage main scanning direction) via the timing belt.

  As described above, the carriage 33 includes a recording head 34 including four droplet discharge heads that discharge ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). A plurality of ink ejection openings are arranged in a direction crossing the main scanning direction (paper feeding direction), and the ink droplet ejection direction is mounted downward.

  Note that it is also possible to employ one or a plurality of head configurations having nozzle arrays that eject droplets of each color. As an inkjet head constituting the recording head 34, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. It is possible to use a shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet.

  In addition, the carriage 33 is equipped with a head tank 35 for each color, which is a second liquid storage means for supplying each color ink to each recording head 34. As described above, each color head tank 35 is supplementarily supplied with ink of each color from the ink cartridge 10 of each color mounted in the cartridge loading unit 4 via the supply tube 36 having flexibility of each color.

  The cartridge loading unit 4 is provided with a supply pump unit 24 which is a liquid feeding means for feeding ink in the ink cartridge 10. On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (pressure plate) 41 of the paper feeding tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 one by one from the paper stacking unit 41. A separation pad 44 made of a material having a large friction coefficient is provided facing the paper roller 43) and the paper feed roller 43, and the separation pad 44 is urged toward the paper feed roller 43 side.

  In order to feed the paper 42 fed from the paper feeding unit to the lower side of the recording head 34, a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressure roller. And a holding belt 48 which is a conveying means for electrostatically attracting the fed paper 42 and conveying it at a position facing the recording head 34.

The transport belt 51 is an endless belt, and is configured to wrap around the transport roller 52 and the tension roller 53 and circulate in the belt transport direction (sub-scanning direction).
Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided.

  The charging roller 56 is disposed so as to come into contact with the surface layer of the transport belt 51 and to rotate following the rotation of the transport belt 51. Further, a guide member 57 is disposed on the back side of the conveyance belt 51 in correspondence with the printing area by the recording head 34.

  The transport belt 51 rotates in the belt transport direction of FIG. 3 when the transport roller 52 is rotationally driven through timing by a sub-scanning motor (not shown). Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61 for separating the paper 42 from the conveying belt 51, a paper discharge roller 62, and a paper discharge roller 63 are provided. The paper discharge tray 3 is provided below the paper discharge roller 62.

  A duplex unit 71 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the conveyance belt 51, reverses it, and feeds it again between the counter roller 46 and the conveyance belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

  Further, as shown in FIG. 3, a maintenance / recovery mechanism 81 including a recovery means for maintaining and recovering the nozzle state of the recording head 34 is arranged in the non-printing area on one side of the carriage 33 in the scanning direction. Yes.

  The maintenance / recovery mechanism 81 includes cap members (hereinafter referred to as “caps”) 82a to 82d (hereinafter referred to as “caps 82” when not distinguished from each other) for capping the nozzle surfaces of the recording head 34, and nozzle surfaces. A wiper blade 83 that is a blade member for wiping the ink, and an empty discharge receiver 84 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing.

  Here, the cap 82a is a suction and moisture retention cap, and the other caps 82b to 82d are moisture retention caps. Then, the waste liquid of the recording liquid generated by the maintenance / recovery operation by the maintenance / recovery mechanism 81, the ink discharged to the cap 82, the ink attached to the wiper blade 83 and removed by the wiper cleaner 85, and the idle ejection to the idle ejection receiver 94 The discharged ink is discharged and stored in a waste liquid tank (not shown).

  Further, as shown in FIG. 3, in the non-printing area on the other side in the scanning direction of the carriage 33, idle discharge is performed to discharge liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An empty discharge receiver 88 for receiving the liquid droplets at the time is disposed, and the empty discharge receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 34.

  In the ink jet recording apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feeding tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide member 45, and the conveyance belt 51 and the counter It is sandwiched between the rollers 46 and conveyed, and the leading end is guided by the conveying guide 37 and pressed against the conveying belt 51 by the leading end pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a charging voltage pattern in which a positive output and a negative output are alternately repeated from the AC bias supply unit of the control unit (not shown) to the charging roller 56, that is, an alternating voltage is applied and the conveying belt 51 alternates. That is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction which is the circumferential direction.

  When the paper 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the paper 42 is attracted to the conveyance belt 51, and the paper 42 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 51.

  Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line.

  Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3. Further, during printing (recording) standby, the carriage 33 is moved to the maintenance / recovery mechanism 81 side, and the recording head 34 is capped by the cap 82 to keep the nozzles in a wet state, thereby preventing ejection failure due to ink drying. .

  In addition, the recording liquid is sucked from the nozzle by a suction pump (not shown) with the recording head 34 capped by the cap 82 (referred to as “nozzle suction” or “head suction”), and the recovered recording liquid and bubbles are discharged. Perform the action. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. As a result, the stable ejection performance of the recording head 34 is maintained. Next, an outline of the control unit of the image forming apparatus will be described with reference to FIG.

  FIG. 4 is a block diagram illustrating the entire control unit of the image forming apparatus. The control unit controls the entire image forming apparatus, and includes a main control unit 301 configured by a microcomputer that also serves as a unit for performing control according to the present invention, and a print control unit configured by a microcomputer that controls print control. 302 is provided.

  The main control unit 301 then sets a main scanning motor driving circuit that moves the carriage 33 in the main scanning direction in order to form an image on the paper 42 based on the information of the printing process input from the communication circuit 300. A sub-scan motor that feeds the paper 42 is controlled to be driven via a sub-scan motor driving circuit 304 via 303, and control is performed such as sending print data to the print controller 302.

  The main control unit 301 receives a detection signal from a carriage position detection circuit 305 that detects the position of the carriage 23, and the main control unit 301 controls the movement position and movement speed of the carriage 23 based on the detection signal. To do.

  The carriage position detection circuit 305 detects the position of the carriage 23 by, for example, reading and counting the number of slits of an encoder sheet arranged in the scanning direction of the carriage 23 with a photosensor mounted on the carriage 23.

  The main scanning motor drive circuit 303 rotates the main scanning motor in accordance with the carriage movement amount input from the main control unit 301 to move the carriage 23 to a predetermined position at a predetermined speed.

  Further, the main control unit 301 receives a detection signal from a conveyance amount detection circuit 306 that detects the movement amount of the conveyance belt 51, and the main control unit 301 moves the movement amount and movement speed of the conveyance belt 51 based on the detection signal. To control.

  The conveyance amount detection circuit 306 detects the conveyance amount by, for example, reading and counting the number of slits of the rotary encoder sheet attached to the rotation shaft of the conveyance roller 52 with a photo sensor.

  The sub-scanning motor driving circuit 304 rotates the sub-scanning motor 58 in accordance with the conveyance amount input from the main control unit 301 to rotate the conveyance roller 52 to move the conveyance belt 51 to a predetermined position at a predetermined speed. Move with.

  The main control unit 301 rotates the sheet feeding roller 43 once by giving a sheet feeding roller driving command to the sheet feeding roller driving circuit 307. The main control unit 301 rotationally drives the motor of the maintenance / recovery mechanism 81 via the maintenance / recovery mechanism drive motor drive circuit 308, thereby raising and lowering the cap 82, raising and lowering the wiper blade 83, and driving the suction pump as described above. And so on.

  The main control unit 301 drives and controls a drive motor (supply motor) for driving the pump of the supply pump unit 24 via the supply pump drive circuit 311, and the head from the ink cartridge 10 loaded in the cartridge loading unit 4. Ink is replenished and supplied (filled) to the tank 35.

  At this time, the main control unit 301 controls replenishment supply (filling operation) based on a detection signal from the head tank full tank sensor 312 that detects that the head tank 35 is full. In this case, there are open air filling in which the air release mechanism 204 of the head tank 35 is opened to perform filling, and normal filling in which filling is performed with the air release mechanism 204 closed.

  Further, the main control unit 301 takes in information stored in the nonvolatile memory 316 which is a storage unit provided in each ink cartridge 10 mounted on the cartridge loading unit 4 through the cartridge communication circuit 314, and performs a necessary process. And stored in a non-volatile memory (for example, EEPROM) 315 which is a main body storage means.

  Further, the main control unit 301 receives a detection signal from an environmental sensor 313 that detects environmental temperature and environmental humidity.

  The print control unit 302 generates pressure for ejecting droplets of the recording head 34 based on the signal from the main control unit 301 and the carriage position and conveyance amount from the carriage position detection circuit 305 and the conveyance amount detection circuit 306. Data for driving the means is generated, and the above-mentioned image data is transferred to the head drive circuit 310 as serial data, and the transfer clock and latch signal necessary for transferring the image data and confirming the transfer, drop control, etc. In addition to outputting a signal (mask signal) etc. to the head drive circuit 310, it comprises a D / A converter, a voltage amplifier, a current amplifier, etc. for D / A converting the pattern data of the drive signal stored in the ROM. Drive waveform generation means and drive waveform selection means to be given to the head driver, one drive pulse (drive signal) or a plurality of drive parameters. Scan to generate a composed drive waveform (drive signal) to the head drive circuit 310.

  The head drive circuit 310 selectively selects a drive signal constituting a drive waveform supplied from the print control unit 302 based on image data corresponding to one row of the print head 34 that is input serially. The recording head 34 is driven by applying it to a driving element (for example, a piezoelectric element as described above) that generates energy for discharging the ink.

  At this time, by selecting a driving pulse constituting the driving waveform, for example, dots having different sizes such as large droplets (large dots), medium droplets (medium dots), and small droplets (small dots) can be distinguished. it can.

  Next, a liquid supply device that supplies ink as a recording liquid to the recording head 34 in the image forming apparatus will be described. FIG. 5 is a schematic view showing the liquid supply apparatus.

  The ink cartridge 10 as the first liquid storage means is configured by storing a flexible ink bag 102 that stores ink, which is a liquid, in a cartridge case 101, and supplying ink inside the ink bag 102. Ink supply port portion 103 is provided.

  The ink supply port 103 has an elastic member such as rubber inside. The head tank 35 serving as the second liquid storage means includes a tank case 201 for storing the ink 200, a negative pressure generation means (not shown), for example, a negative pressure generation mechanism including a film and an elastic member, and the inside of the tank case 201 is opened to the atmosphere. The recording head 34 is attached to the lower part of the tank case 201, and the liquid level of the ink 200 contained in the upper part of the tank case 202 is in a predetermined position. A full tank detecting means (head tank full sensor) 203 constituted by two detection electrodes to be detected is provided.

  The supply pump unit 24 includes a supply pump 241 for supplying ink of the ink cartridge 10 to the head tank 35, a cam 243 for reciprocating the piston 242 of the supply pump 241 in the vertical direction in FIG. A gear 244 for rotating and a gear 247 for rotating the gear 244 are provided with a drive motor 245 which is a pump driving means attached to the motor shaft 245a, and the hollow needle 246 provided on the supply pump 241 is attached to the ink bag 102 of the ink cartridge 10. By inserting into an elastic member (for example, a rubber plug) in the ink supply port portion 103, the inside of the supply pump 241 and the inside of the ink bag 102 are jointed.

  The main control unit 301, which is a control means for controlling the operation / stop of the supply pump 241, is based on a detection signal from the head tank full sensor 203 when supplying ink from the ink cartridge 10 to the head tank 35. The rotational drive and stop of the drive motor 245 are controlled via the supply pump drive circuit 311.

  In this liquid supply apparatus, one end of the supply tube 36 is along the liquid supply direction of the supply pump 241 (same as the reciprocating direction of the piston 242 in FIG. 4) with respect to the supply pump 241 as the liquid feeding means. Connected by joint part 249 in the direction.

  Next, in this liquid supply apparatus, when the head tank 35 is filled with the recording liquid (ink), the ink cartridge 10 is filled when the head tank 35 does not become full even if the supply pump 241 is operated until a predetermined time elapses. Next, description will be made on the mixing of air in the case of performing the process of treating ink as no ink.

  When the ink bag 102 of the ink cartridge 10 is empty, nothing is sucked out. As the supply pump 241 continues to be driven, the pressure in the supply pump 241 increases as the negative pressure (negative pressure) increases. Become.

For this reason, when an instruction to replace the ink cartridge 10 is issued, the supply pump 241 is in a strong negative pressure state.

  In order to replace the ink cartridge 10 in this state, the rubber plug of the ink supply port 103 and the joint of the hollow needle 246 of the supply pump 241 are temporarily removed. Air inhalation begins.

  The sucked air does not escape because the supply path from the supply pump 241 to the head tank 35 is a closed path. When a new ink cartridge 10 is installed and the supply operation starts, the air passes through the supply tube 36. It will be sent to the head tank 35 through.

  FIG. 6 is a cross-sectional view schematically showing a state in the head tank. As shown in FIG. 6, the air sent into the head tank 35 in this manner becomes bubbles B on the ink liquid level in the head tank 35, and the bubbles B increase as the supply operation proceeds further. It becomes.

  The bubbles B in the head tank 35 cause a misdetection result of the ink detection means 203, and when the filling operation is performed with the air release mechanism 204 opened with respect to the head tank 35, the full tank is detected. In some cases, the ink leaks out from the atmosphere release mechanism 204 to contaminate the recording head 34 or cause the recording head 34 to malfunction.

  Therefore, a process for dealing with a case where there is a high possibility that air (air) is mixed in the supply path to the head tank 35 is performed. FIG. 7 is a flowchart showing processing in the case of air mixing, FIG. 8 is a flowchart showing processing for setting an air mixing flag, and FIG. 9 is a flowchart showing a liquid feeding sequence.

  In this image forming apparatus, when there is a high possibility that air (air) is mixed in the supply path to the head tank 35, processing for setting the air mixing flag (= 1) is performed.

  That is, as shown in FIG. 7, the head tank filling process for driving the supply pump 241 to fill the head tank 35 with the recording liquid from the ink cartridge 10 to the head tank 35 (this is the above-described atmospheric release filling). In the case of carrying out normal filling, and there is also a filling operation that occurs in association with the head maintenance / recovery operation, the supply pump 241 is driven (SA1), and a predetermined time has passed before the filling is completed. When (timeout) occurs (Y in SA3), the recording liquid is exhausted in the ink cartridge 10, and therefore, as described above, it is considered that air is highly likely to be mixed in the supply path, and the air mixing flag is set. Is set (= 1) (SA4), and then the process proceeds to cartridge replacement processing.

  In addition, even when the device is not used for a predetermined period (predetermined time) (N in SA2), it is highly likely that air (air) is mixed into the supply path such as the supply pump 241 and the supply tube 36. The process of setting the air mixing flag (= 1) is performed.

  That is, as shown in FIG. 8, when the power of the apparatus is turned on, when the elapsed period from the power-off has reached a predetermined period (for example, 72 hours) (Y of SB1), the air mixing flag Is set (= 1) (SB2), and then the process proceeds to power-on. In this case, since the supply pump 241 has not been driven for a predetermined period, the supply pump 241 is treated as having a high possibility of air entering the supply path.

  Therefore, as shown in FIG. 9, the image forming apparatus determines whether or not the liquid feeding sequence has been performed when the air mixing flag is “1” (Y in SC1: viewed in units of heads). (SC2). If the liquid feeding sequence has not been performed (N in SC2), the liquid feeding sequence is performed (SC3), and the air mixed in the supply pump 241 and the supply tube 36 together with the recording liquid is recorded in the head tank 35. And the liquid feeding time is stored (SC4).

  In this liquid feeding sequence, for example, a larger amount of recording liquid than the normal filling amount is fed to the head tank 35 (overfilling), and the recording head 34 is capped with a cap 82 to perform nozzle suction. The negative pressure is formed in the head tank 35 by the above operation, and the operation of wiping the nozzle surface of the recording head 34 (the surface on which the nozzle for discharging droplets is formed) with the wiper blade 83 is performed a required number of times (2 to 3 times). This is an operation (sequence) in which the required cleaning operation is repeated and the recording head 34 is capped with the cap 82.

  On the other hand, if the air mixing flag is “1” and the liquid feeding sequence has been performed, a predetermined time until the bubbles due to the air sent into the head tank 35 disappear has elapsed from the liquid feeding time. If the predetermined time has elapsed (Y in SC5, the air mixing flag is reset (to 0) (SC6).

  As described above, when the possibility that air has entered the liquid supply path from the first liquid storage means to the second liquid storage means is high, the first liquid storage means to the second liquid storage means. By providing the means for supplying the liquid, the recording liquid leaks until the air in the supply path is sent to the second liquid storage means until the bubbles in the second liquid storage means disappear. Can be prohibited.

  In this case, the apparatus is used for a predetermined period when the second liquid storage means does not become full even if the liquid is replenished and supplied from the first liquid storage means to the second liquid storage means for a predetermined time. If there is no air, the possibility that air has entered the liquid supply path has become high, so even if air is mixed into the supply pump due to the replacement operation of the liquid storage means at the time of liquid supply timeout, the head The apparatus can be operated without failing (fail-safe function), and it is possible to cope with problems caused by air in the supply path, particularly in the pump.

  In the case of using the above-described liquid feeding sequence in the droplet discharge device having such a configuration, ink that can be used for printing is used to prevent the natural replenishment at the time of cartridge setting so as not to exceed the head-to-cartridge water head difference. Capacity will be reduced as a result.

  Therefore, in this example, it is provided with a detection means that can detect from the outside whether or not the cartridge is new, a cartridge mounting portion where the cartridge for storing the liquid is installed, and a means for detecting whether or not the cartridge is new. When it is detected that the cartridge is new, the liquid is supplied to the head tank until the pressure of the liquid in the cartridge becomes at least a pressure difference P generated by a head difference between the head and the cartridge.

  An IC chip is attached to the cartridge as a means to be detected, and an IC chip reader that exchanges data with the IC chip is disposed at the cartridge attachment portion. In this example, the IC chip and the IC chip reader exchange data in a non-contact state. Note that data may be exchanged in a contact state. Data indicating that the cartridge is new is recorded on the IC chip, and when the IC chip is set in the droplet discharge device, the IC chip reader confirms that the reading cartridge is new. The IC chip data is rewritten to record that it has been used.

  Further, in this example, the head tank 35 is provided with an atmosphere release mechanism 204 capable of communicating with the atmosphere, and an air mixing flag as a means for storing that air has been mixed at the end of the cartridge and an air mixing flag are predetermined. And a control means that becomes invalid in time. In this case, when the air mixing flag is valid, the atmosphere release valve is prohibited from communicating with the atmosphere, and ink adhesion to the atmosphere release valve due to bubbles in the head tank 35 can be prevented.

  FIG. 10 is a flowchart illustrating cartridge new article detection control processing of the droplet discharge device according to the embodiment. In this embodiment, it is determined whether or not the cartridge is new. When it is determined that the cartridge is new, liquid feeding is performed until the cartridge ink pressure becomes the pressure difference P or less.

  That is, in this example, when the cartridge of the ink jet recording apparatus is replaced with a new cartridge, the ink hydrostatic pressure of the cartridge is reduced to a value equal to or less than the water head difference h between the head and the cartridge. For this reason, in the initial state of the cartridge, it is possible to set a positive pressure (= increase the filling amount) rather than the head difference between the head and the cartridge. Therefore, it is possible to use a cartridge that can print more with the same cartridge size.

  Next, a specific example of control will be described. In the first example, control is performed using a pressure sensor. FIG. 11 is a schematic diagram showing a configuration of a droplet discharge device using a pressure sensor. In this example, a pressure sensor 210 is provided between the supply pump unit 24 which is a liquid supply mechanism and the cartridge case 101, and the detection result of the pressure sensor 210 is used for the end of liquid feeding. Other configurations are the same as those in FIG. In this example, the ink pressure in the cartridge at the end of the liquid feeding can be reliably made to be equal to or lower than the water head differential pressure between the head and the cartridge by this configuration, and ink dripping from the head due to natural ink replenishment can be effectively prevented. Control is performed in the following procedure.

  FIG. 12 is a flowchart showing the control of the droplet discharge device using the pressure sensor. First, it is determined whether the cartridge is new (SE1). If it is new (Y in SE1), ink feeding from the cartridge to the head tank is started (SE2), and this is performed until the detected pressure reaches P. (SE3, SE4, SE5).

  By controlling in this way, in the initial state of the cartridge, the filling amount can be increased by a positive pressure rather than the head difference between the head and the cartridge, and a cartridge that can print more with the same cartridge size can be used. it can.

  Next, a case where control is performed without using a pressure sensor will be described as a second example. In this case, the configuration of the droplet discharge device is the same as that shown in FIG. FIG. 13 is a flowchart showing control of a droplet discharge device that performs control without using a pressure sensor. In this example, it is assumed that the ink capacity Va of the cartridge is equal to or greater than the filling capacity V2 at which the liquid pressure in the cartridge is equal to the pressure difference P, and the condition Va ≦ V1 + V2 is satisfied. When a new cartridge is set, a predetermined amount V1 is fed. By doing so, it becomes possible to supply ink to the head tank until the pressure difference P caused by the head difference between the head and the cartridge becomes equal to or less, and the ink in the cartridge can be constructed at a low cost without using a pressure sensor. Prevention of natural replenishment due to pressure can be achieved.

  At this time, since the capacity required to send the air mixed at the time of cartridge replacement to the head tank is Q, the capacity V1 is preferably equal to or larger than the capacity Q of the ink supply path, and most preferably V1 = Q. .

1 is a perspective view of an ink jet recording apparatus according to an embodiment. It is a side view which shows typically the outline | summary of the mechanism part of an inkjet recording device. It is a top view which shows typically the mechanism part of an inkjet recording device. 2 is an overall block diagram of a control unit of the image forming apparatus. FIG. 3 is an explanatory diagram schematically showing a liquid supply device of the image forming apparatus. FIG. It is sectional drawing which shows the state in a head tank typically. It is a flowchart which shows the process in the case of air mixing. It is a flowchart which shows the set process of an air mixing flag. It is a flowchart which shows a liquid feeding sequence. It is a flowchart which shows the cartridge new article detection control process of the droplet discharge apparatus which concerns on an Example. It is a schematic diagram which shows the structure of the droplet discharge apparatus using a pressure sensor. It is a chart showing control of a droplet discharge device using a pressure sensor. It is a flowchart which shows control of the droplet discharge apparatus which performs control without using a pressure sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed tray 3 Paper discharge tray 4 Cartridge loading part 5 Display part 6 Front cover (cartridge cover)
10 Ink cartridge 10k, 10c, 10m, 10y Ink cartridge (...)
11k, 11c, 11m, 11y Remaining amount display unit 12 Power button 13 Print restart button 14 Cancel button 21 Frame 21A, 21B Side plate 23 Carriage 24 Supply pump unit 31 Main guide rod 32 Sub-guide rod 33 Carriage 34 Recording head 35 Head tank 36 Supply tube 37 Transport guide 41 Paper stacking unit (pressure plate)
42 paper 43 half moon roller (paper roller)
44 Separating pad 45 Guide member 46 Counter roller 47 Conveying guide member 48 Holding member 49 Tip pressure roller 51 Conveying belt 52 Conveying roller 53 Tension roller 56 Charging roller 57 Guide member 58 Sub-scanning motor 61 Separating claw 62 Discharging roller 63 Discharging Roller 71 Double-sided unit 72 Tray 81 Maintenance / recovery mechanism 82 Cap 82a to 82d Cap member (hereinafter referred to as “cap”)
83 Wiper blade 84 Empty discharge receiver 85 Wiper cleaner 88 Empty discharge receiver 89 Opening 94 Empty discharge receiver 101 Cartridge case 102 Ink bag 103 Ink supply port 200 Ink 201 Tank case 202 Tank case 203 Full tank detection means (head tank full sensor) )
204 Atmospheric release mechanism 210 Pressure sensor 241 Supply pump 242 Piston 243 Cam 244 Gear 245 Drive motor 245a Motor shaft 246 Hollow needle 247 Gear 249 Joint unit 300 Communication circuit 301 Main control unit 302 Print control unit 303 Main scan motor drive circuit 304 Sub scan Motor drive circuit 305 Carriage position detection circuit 306 Carrying amount detection circuit 307 Paper feed roller drive circuit 308 Maintenance drive mechanism drive motor drive circuit 310 Head drive circuit 311 Supply pump drive circuit 312 Head tank full sensor 313 Environmental sensor 314 Cartridge communication circuit 315 Non-volatile memory (eg EEPROM)
316 Nonvolatile memory

Claims (6)

A cartridge mounting portion provided with a detection means capable of detecting from the outside whether or not it is a new article and a cartridge for storing a liquid is installed;
A liquid supply mechanism for supplying a liquid from a cartridge installed in the cartridge mounting portion;
A liquid supply path for supplying liquid from a liquid supply mechanism to a head tank provided on the upper side of the head for discharging liquid;
Detecting means for detecting whether or not the cartridge is new;
When it is detected that the cartridge installed by the detection means is a new cartridge, the liquid in the cartridge is discharged until the pressure of the liquid in the cartridge becomes at least a pressure difference P generated by a water head difference between the head and the cartridge. A liquid droplet ejection apparatus comprising a liquid feeding control means for feeding liquid to the head tank.   2. The liquid droplet according to claim 1, further comprising a pressure sensor between the liquid supply mechanism and the cartridge mounting portion, wherein the liquid supply control unit determines the end of the liquid supply based on a detection result of the pressure sensor. Discharge device. The liquid feeding control means includes a droplet discharge device for feeding a predetermined liquid volume V1,
2. The droplet discharge device according to claim 1, wherein the cartridge has a liquid volume Va that is equal to or larger than a filling volume V <b> 2 at which a liquid pressure in the cartridge is equal to the pressure difference P, and satisfies Va ≦ V <b> 1 + V <b> 2. The cartridge includes an IC chip as a detected means,
4. The liquid droplet ejection apparatus according to claim 1, wherein the detection unit includes an IC chip reader. An air release valve disposed in the head tank and capable of communicating with the atmosphere;
Air mixing storage means for storing when air is mixed at the end of the cartridge;
Invalid setting control means for invalidating the storage content of the air mixing storage means after a predetermined time,
5. The droplet discharge device according to claim 1, further comprising an open valve control unit that prohibits the atmosphere release valve from communicating with the atmosphere when the stored contents of the air mixing storage unit are valid. . An image forming apparatus comprising the droplet discharge device according to claim 1.