JP2008119835A - Inkjet recorder and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder which is free from sensing error due to bubbles of ink and can exactly and correctly grasp an ink residual quantity also during the carriage movement, and to provide an inkjet recording method. <P>SOLUTION: The inkjet recorder comprises a sub tank 50 which stores the ink, and a carriage 1 which carries a recording head 5 that ejects the ink supplied from within the sub tank 50. The inkjet recorder comprises a residual quantity sensor 314 which is energized when a negative pressure is generated by an ink flow in the sub tank 50, and which is released from the energization while the negative pressure is not generated. Moreover, the inkjet recorder comprises a CPU 301 which judges that there is no ink remaining in the sub tank 50 when the state that the energization of the residual quantity sensor 314 is released is maintained for a fixed time or longer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method using the ink jet recording apparatus.

  The ink jet method is a method of forming an image by discharging droplets from a nozzle using an electrothermal conversion element or an electromechanical conversion element. In order to stably supply ink to the recording head provided in the carriage, it is effective to provide a sub tank near the head. In general, ink is supplied from an ink tank to a sub tank through an ink tube and flows to a recording head. It is preferable that all the ink in the ink tank is used, but in order to use up all of the ink, a detection means for accurately determining the remaining amount of ink is required.

On the other hand, in the conventional ink remaining amount detecting means, the ink remaining amount in the sub tank is determined by electrical energization through the ink liquid level (see Patent Document 1).
JP-A-4-244854

  However, although the technology described in Patent Document 1 can detect the remaining amount of ink in the sub tank, the liquid level vibrates during false detection or a carry operation due to ink bubbles generated in the sub tank. Cannot be detected.

  The present invention has been made based on the above-described viewpoint, and there is no erroneous detection due to ink bubbles, and an ink jet recording apparatus and an ink jet capable of accurately grasping the remaining amount of ink even during carriage operation An object is to provide a recording method.

  In order to achieve the above object, an inkjet recording apparatus of the present invention includes a sub tank that stores ink, a carriage on which a recording head that discharges ink supplied from the sub tank is mounted, and ink for supplying ink to the sub tank. In an ink jet recording apparatus having an ink cartridge for storing ink, an ink remaining amount detecting means that is energized when a negative pressure is generated by ink flow in the sub tank and is de-energized when no negative pressure is generated, and an ink And determining means for determining that the ink in the ink cartridge that supplies ink into the sub-tank is exhausted when the state where the energization of the remaining amount detecting means is released is maintained for a certain time or longer.

  According to the present invention, using the negative pressure in the sub-tank generated by the ink flow, the determination unit determines the presence or absence of ink in the energized state of the energization type ink remaining amount detection unit. By adopting such a method, it is possible to determine the presence or absence of ink in the ink cartridge without being affected by erroneous detection due to ink bubbles generated in the sub-tank or liquid level vibration during carriage operation. Further, when the energization release state is maintained for a certain time or more, it is possible to make the ink remaining amount in the ink cartridge almost zero by determining that there is no ink. As a result, even when there is a variation in the ejection amount due to variations in the shape of the head or a variation in the ejection amount due to environmental differences, it is possible to use up the ink stably.

(Embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a top view showing an ink jet recording apparatus according to an embodiment of the present invention.

  The ink jet recording apparatus of this embodiment performs recording on a relatively large recording sheet (recording medium), and the apparatus main body 2 includes a paper transport system unit.

  The carriage 1 moves with the six recording heads 5 mounted thereon, thereby enabling reciprocal scanning of the recording head 5 with respect to the recording paper. That is, the carriage 1 is guided and supported by the guide shaft 33 so as to be movable along the guide shaft 33, and can be reciprocated by a driving force transmitted through the belt 34. In addition to the cyan, magenta, yellow, and black ink used, a total of six colors including light cyan and light magenta for the purpose of reducing graininess are employed.

  The recovery mechanisms 30A and 30B have caps and perform a suction operation using a pump (not shown) of each recording head 5 as a driving source, and protect the recording head when the recording head is not used. The recording head uses an electrothermal conversion element or an electromechanical conversion element to eject ink from the nozzles to form an image, and the preliminary ejection ink receiving box 31 receives the ink ejected by the preliminary ejection operation of each recording head 5. To do. The wiping mechanism 32 performs a wiping operation on the ejection port surface of each recording head 5.

  In the above apparatus configuration, the carriage 1 moves in a direction (main scanning direction) along the guide shaft 33 in order to record on recording paper sent by a paper transport unit (not shown) when receiving recording data from the host device. Controlled. Thereby, each recording head 5 is scanned, and an image for one band is recorded on the recording sheet. Then, the recording paper is transported by the paper transport unit for one band in the direction orthogonal to the carriage 1 (sub-scanning direction). An encoder film 35 for detecting the movement position of the carriage 1 is disposed along the movement path of the carriage 1, and the position of the carriage 1 is determined based on a signal detected by an encoder sensor mounted on the carriage 1. I can know. The movement of the carriage 1 to the home position is controlled based on the position detection of the encoder.

  Each recording head 5 has 1280 ejection openings arranged at a density of 1200 dpi (dots / inch) in the sub-scanning direction. An electromechanical transducer for ejecting ink by the pressure of the piezoelectric element by deforming the piezoelectric element is provided in the ink liquid path communicating with each ejection port.

  FIG. 2 is a block diagram showing the configuration of the control system circuit in this embodiment.

  The main control unit 300 includes a CPU 301 that executes processing operations such as calculation, control, determination, and setting, and the main control unit 300 includes a ROM 302 that stores a control program to be executed by the CPU 301. Further, the main control unit 300 includes a RAM 303 used as a recording data buffer, a work area for processing by the CPU 301, an input / output port 304, and the like.

  The input / output port 304 is connected to the respective drive circuits 305, 306, 307, and 309 such as the transport motor (LF motor) 312, the carriage motor (CR motor) 313, and the recording head 5 described above. Further, the input / output port 304 includes sensors such as a remaining amount detection sensor (remaining amount detection means) 314 that detects the remaining amount of ink stored in the sub tank and a home position sensor 310 that detects the home position of the carriage 1. It is connected. The main controller 300 is connected to a host computer (not shown) via an interface circuit 311. The remaining amount detection sensor (remaining amount detection means) 314 includes a supply valve 63, a supply valve cover 67, an ink remaining amount detection contact member 72, a negative pressure spring 60, and a constant current power source 73 which will be described later.

  FIG. 3 is an overall view of the ink supply path according to the embodiment of the present invention.

  An ink bag 54 is included in the ink cartridge 55 and is packed with a resin film 53. The ink in the ink bag 54 is supplied to the sub tank 50 in the carriage 1 through the ink tube 51 connected by the joint 52. The ink flows into the sub tank 50 by the negative pressure generated by the discharge for image formation from the recording head 5.

  FIG. 4 is a cross-sectional view of a sub tank according to an embodiment of the present invention.

  The sub tank 50 includes a filter storage chamber 80 for storing the filter 64, a valve storage chamber 81 for storing the supply valve 63, the valve spring 62 and the negative pressure spring 60, and an ink supply path 82 for supplying ink to the recording head 5. Have.

  The valve storage chamber 81 and the filter storage chamber 80 communicate with each other through a supply valve window 66, and the valve storage chamber 81 and the ink supply path 82 communicate with each other through a communication path 82a. An ink remaining amount detection contact member 72 is provided on a portion of the wall surface 50a constituting the supply valve window 66 that comes into contact with a supply valve lid 67 described later.

  The supply valve 63 is an L-shaped member generally constituted by a first arm portion 62b and a second arm portion 62c. A supply valve lid 67 for opening and closing the supply valve window 66 is provided at the distal end portion of the first arm portion 62b. The tip of the first arm portion 62b, which is opposite to the side where the supply valve lid 67 is provided, is urged toward the supply valve window 66 by the valve spring 62. A fulcrum 62a is formed in the vicinity of the root portion of the first arm portion 62b, that is, on the side close to the second arm portion 62c. The supply valve 63 is rotatably provided around a fulcrum 62a that is in contact with the wall surface 50a (see arrows 71a and 71b in the figure).

  A tip end portion 62c1 of the second arm portion 62c extending substantially perpendicularly from the base of the first arm portion 62b is in contact with the pressing member 62d. Further, the pressing member 62d is urged by the negative pressure spring 60 in a direction (left direction indicated by an arrow 70) for releasing the contact between the first arm portion 62b and the tip end portion 62c1 of the second arm portion 62c. Chamfer 62C2 is formed so that tip 62c1 is pushed downward in the figure (downward indicated by arrow 71a) by pressing member 62d moving in the direction of contracting negative pressure spring 60 (rightward indicated by arrow 70). Has been.

  Next, the ink supply method, the operation of the supply valve 63, and the ink remaining amount detection method in the sub tank 50 according to the present embodiment will be described.

  The ink supplied from the ink cartridge 55 is supplied from the direction of the arrow 68 into the sub tank 50. The seal rubber 65 has a role of preventing outside air from being mixed between the ink tube 51 and the sub tank 50. The ink flowing into the sub tank 50 passes through the supply valve window 66 through the filter 64, is supplied in the direction of the arrow 69, and is carried to the recording head 5. The seal rubber 61 has a role of preventing outside air from being mixed between the recording head 5 and the sub tank 5.

  When ink is ejected from the recording head 5, the ink in the sub tank 5 moves in the direction of the arrow 69. Due to the negative pressure generated by the movement of the ink, the negative pressure spring 60 exerts a force in a contracting direction (right direction indicated by an arrow 70). As a result, the second arm portion 62c is pushed downward in the figure (downward direction indicated by the arrow 71a). Then, the supply valve 63 rotates about the fulcrum 62 in the counterclockwise direction in the figure, so that the first arm portion 62b moves away from the supply valve window 66 while pushing and contracting the valve spring 62 (left direction indicated by an arrow 71b). Moving. That is, the supply valve 63 moves in the direction in which the supply valve cover 67 opens. When the supply valve lid 67 is opened, ink flows into the sub tank 5 from the direction of the arrow 68, and the negative pressure spring 60 that has been contracted by the negative pressure extends to return to the original state again. As the negative pressure spring 60 extends, the pressing member 62d moves in the left direction indicated by the arrow 70, and accordingly, the second arm portion 62c moves in the upward direction indicated by the arrow 71a. As a result, the supply valve 63 rotates in the clockwise direction in the drawing around the fulcrum 62, so that the first arm 62b is in contact with the supply valve window 66 while being urged by the valve spring 62 (the left direction indicated by the arrow 71b). Move to. That is, the supply valve 63 moves in the direction in which the supply valve lid 67 is closed. The supply valve window 66 closes when the supply valve lid 67 contacts the ink remaining amount detection contact member 72.

  The constant current power source 73 is electrically connected to the ink supply valve cover 67 and the ink remaining amount detection contact member 72. When the ink supply valve cover 67 and the ink remaining amount detection contact member 72 are in contact with each other, that is, when the supply valve 63 is closed, the energized state is established. When the ink supply valve lid 67 and the ink remaining amount detection contact member 72 are not in contact, that is, when the supply valve 63 is open, the energization is released.

  At the time of image formation, the supply valve lid 67 is repeatedly opened and closed according to the timing at which ejection is performed from the recording head 5. Similarly, the supply valve lid 67 is repeatedly opened and closed during the recovery operation. In other words, the ink supply valve cover 67 is repeatedly opened and closed discontinuously due to the ink discharge and recovery operation, and if it is detected that the energization and de-energization are repeated, the ink supply in the ink bag 54 in the ink cartridge 55 is detected. The CPU 301 determines that the ink is present.

  On the other hand, when the ink in the ink bag 54 in the ink cartridge 55 becomes empty, the ink supply into the sub tank 50 is stopped, and the ink supply valve cover 67 is kept open. In a state where an ejection pulse signal for ejecting ink is output or an ejection pulse signal for executing a recovery operation is output, the ink supply valve cover 67 is opened and the energization release state is maintained for a certain time or more. In this case, the CPU 301 determines that there is no ink.

  As described above, in this embodiment, the supply valve is opened and closed using the negative pressure in the sub tank generated by the flow of ink, and the CPU determines the presence or absence of ink in the energized state of the energization type ink remaining amount detecting means. By adopting such a method, it is possible to determine the presence or absence of ink without being affected by erroneous detection due to ink bubbles generated in the sub-tank or liquid level vibration during carriage operation. Further, when the energization release state is maintained for a certain time or more, it is possible to make the ink remaining amount in the ink cartridge almost zero by determining that there is no ink. As a result, even when there is a variation in the ejection amount due to variations in the shape of the head or a variation in the ejection amount due to environmental differences, it is possible to use up the ink stably.

  As long as the ink jet recording apparatus has a recording head having a plurality of ink discharge ports, the present invention can be similarly applied to a color recording apparatus that records using ink of the same or different colors, and achieves the same effect. To get. Furthermore, the present invention can be similarly applied to a gradation recording apparatus that records at the same color and at different densities, and also a recording apparatus that combines these, and the same effect can be achieved. .

  Furthermore, the present invention can be similarly applied to a configuration using a replaceable ink jet cartridge in which a recording unit and an ink tank are integrated, and the same effect can be obtained.

The present invention also provides an excellent effect in an inkjet recording apparatus that uses a recording unit that discharges ink using mechanical energy, among other inkjet recording systems. However, the same effect can be obtained in an ink jet recording apparatus that uses recording means that ejects ink using thermal energy.
(Example)
The present invention will be described in more detail with reference to the following examples, but the embodiment of the present invention is not limited thereto.

  In Comparative Example 1, in the method of counting the amount of ink ejected from the recording head, continuous printing was performed, and the result of measuring the remaining amount of ink in the ink cartridge when the no-ink flag was set in the inkjet recording apparatus was measured. Table 1 shows. That is, Comparative Example 1 is not provided with the remaining amount detecting means by the energization method of the present invention.

  As the recording head, a large ejection amount head with 10% more ejection head and a smaller ejection amount head with 10% less than the medium ejection amount head with an average ink ejection amount were used. Each of these heads is continuously operated from a new ink tank to a no-ink flag under a temperature of 30 degrees, a humidity of 80%, a temperature of 20 degrees, a humidity of 50%, a temperature of 15 degrees, and a humidity of 10%. The amount of ink remaining when printing was measured.

  Due to variations in the ejection amount of the recording head and variations in the ejection amount due to the environment, the remaining amount of ink in the ink cartridge varies, and ink that cannot be used in the range of 6 ml to 49 ml is generated.

  On the other hand, Example 1 was provided with the remaining amount detection means by the energization method of the present invention, performed continuous printing, and measured the remaining amount of ink in the ink cartridge when the no ink flag was set in the ink jet recording apparatus. When the ink ejection drive signal or the recovery operation drive signal is in the ON state, the ink supply valve cover 67 is opened, the energization supplied from the constant current power supply 73 is released, and the state continues for 2 seconds or more. In this case, the CPU 301 determines that there is no ink. Table 2 shows the remaining amount of ink in Example 1.

  As the recording head, a large ejection amount head with 10% more ejection head and a smaller ejection amount head with 10% less than the medium ejection amount head with an average ink ejection amount were used. Each of these heads is in a temperature of 30 degrees, a humidity of 80% environment, a temperature of 20 degrees, a humidity of 50% environment, a temperature of 15 degrees and a humidity of 10% environment, from the new ink tank to the no ink flag The amount of ink remaining when continuous printing was performed was measured.

  Although there is a variation in the ejection amount of the recording head and a variation in the ejection amount due to the environment, there is almost no variation in the remaining amount of ink in the ink cartridge, and it is possible to stably use up the ink to a remaining amount of 3 ml or less.

1 is a top view showing an ink jet recording apparatus according to an embodiment of the present invention. It is a block diagram which shows the structure of the control system circuit concerning embodiment of this invention. 1 is an overall view of an ink supply path according to an embodiment of the present invention. It is sectional drawing of the sub tank concerning embodiment of this invention.

Explanation of symbols

1 Carriage 5 Recording head 50 Sub tank 301 CPU
314 Ink remaining amount detection sensor

Claims (8)

In an ink jet recording apparatus, comprising: a sub-tank for storing ink; a carriage having a recording head for discharging ink supplied from within the sub-tank; and an ink cartridge for storing ink for supplying ink to the sub-tank. ,
An ink remaining amount detecting means that is energized when a negative pressure is generated by the ink flow in the sub-tank and is de-energized when no negative pressure is generated;
An ink jet recording apparatus comprising: a determination unit that determines that the ink in the ink cartridge that supplies ink into the sub tank is exhausted when the energization of the ink remaining amount detection unit is released. 2. The ink jet recording apparatus according to claim 1, wherein the ink remaining amount detecting unit is a valve provided in the sub tank that opens when a negative pressure is generated and closes when the negative pressure is not generated. The inkjet recording apparatus according to claim 1, wherein the determination unit determines the presence or absence of ink in a state where an ejection pulse signal is output. The inkjet recording apparatus according to claim 1, wherein the determination unit determines the presence or absence of ink in a state where a drive signal for recovery operation is output. 3. The ink jet recording according to claim 1, wherein the determination unit determines that the ink in the ink cartridge has run out when the state where the energization of the ink remaining amount detection unit is released is maintained for a predetermined time or more. apparatus. The ink jet recording apparatus according to claim 1, wherein the recording head includes an electromechanical conversion element used for ejecting ink. The inkjet recording apparatus according to claim 1, wherein the recording head includes an electrothermal converter that generates thermal energy used to eject ink. An image is recorded using an ink jet recording apparatus that includes a sub tank for storing ink and performs recording by discharging ink from the recording head while reciprocally scanning a carriage on which a recording head for discharging ink supplied from the sub tank is mounted. In the ink jet recording method for forming
An ink jet recording method comprising forming an image using the ink jet recording apparatus according to claim 1.

Images