JP2012192635A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform agitation of liquid in a tank in a relatively short time while reducing the load on a mechanism.SOLUTION: A relatively high target acceleration α is set when an ink residual ratio Q is less than a first ratio Q1 (for example, 30%), a medium degree target acceleration α is set when the ink residual ratio Q is equal to or more than the first ratio Q1 and less than a second ratio Q2 (for example, 50%), and a relatively low target acceleration α is set when the ink residual ratio Q is equal to or more than the second ratio Q2 (S110-S150), and a carriage is moved to the same direction by repeating acceleration and deceleration of the carriage with the set target acceleration α (S160-S240). Thus, the ink in the ink cartridge can be agitated by uniform impact regardless of the ink residual ratio while the large load is prevented from frequently acting on a carriage motor or the like.

Description

  The present invention relates to an image forming apparatus that forms an image on a medium by discharging liquid stored in a tank from a discharge head.

  Conventionally, as this type of image forming apparatus, by reciprocating the carriage in the main scanning direction, the ink in the ejection head or the tank mounted on the carriage is agitated (for example, see Patent Document 1), There has also been proposed one that stirs ink in a tank by repeating acceleration, deceleration, and stop of a carriage a plurality of times (for example, see Patent Document 2). Since the pigment ink is obtained by dispersing pigment particles in a solution, if the pigment ink is left for a long period of time, the pigment particles settle, and the pigment concentration becomes non-uniform between the upper part and the lower part of the tank. For this reason, the ink density can be made uniform by moving the carriage without ejecting ink from the recording head (empty scan).

JP 2004-1411 A JP 2009-73091 A

  In the image forming apparatus described above, the number of times of stirring is set according to parameters such as the remaining amount of ink. Although the effect of stirring can be obtained by increasing the number of times of stirring, a long waiting time is imposed on the user. On the other hand, by setting the movement acceleration of the carriage to the maximum acceleration that can be driven by the carriage motor, the stirring of the ink can be completed in a short time, but the load on the mechanism such as the carriage belt and the carriage guide increases. This is disadvantageous in terms of durability.

  The main object of the image forming apparatus of the present invention is to stir the liquid in the tank in a relatively short time while reducing the load on the mechanism.

  The image forming apparatus of the present invention employs the following means in order to achieve the main object described above.

The image forming apparatus of the present invention includes:
An image forming apparatus that forms an image on a medium by discharging liquid stored in a tank from a discharge head,
A carriage mounted with the tank and the discharge head and reciprocating;
Moving means for moving the carriage;
A remaining amount acquisition means for acquiring a remaining amount of liquid in the tank;
When stirring of the liquid in the tank is requested, the target acceleration of the carriage is set based on the acquired remaining amount of liquid, and the acceleration and deceleration of the carriage are repeated by the set target acceleration. Stirring control means for controlling the moving means so that the carriage moves in the same direction;
It is a summary to provide.

  In the image forming apparatus according to the present invention, when stirring of the liquid in the tank is requested, the target acceleration of the carriage is set based on the remaining amount of the liquid in the tank, and the acceleration and deceleration of the carriage are set according to the set target acceleration. By repeating the above, the moving means is controlled so that the carriage moves in the same direction. As a result, the load on the carriage mechanism can be reduced, and the liquid in the tank can be appropriately stirred regardless of the remaining amount of liquid in the tank. Also, the liquid in the tank can be agitated in a shorter time compared to a carriage reciprocating between one end and the other end in the scanning direction.

  In such an image forming apparatus of the present invention, the stirring control means is a means for controlling the moving means by setting the target acceleration so that the acceleration decreases as the remaining amount of the acquired liquid increases. You can also In this way, when the remaining amount of liquid in the tank is large, the load on the carriage mechanism can be further reduced while maintaining the effect of stirring the liquid in the tank.

  In the image forming apparatus according to the aspect of the invention, the stirring control unit may be configured such that the degree of impact acting on the liquid in the tank due to the deceleration after the acceleration of the carriage is substantially constant regardless of the remaining amount of the liquid in the tank. It can also be a means for setting the target acceleration. In this way, the effect of stirring the liquid can be made uniform regardless of the remaining amount of liquid in the tank. In the image forming apparatus according to the aspect of the invention, the stirring control unit may be configured such that the product of the total weight of the carriage including the liquid remaining in the tank and the acceleration of the carriage is substantially constant regardless of the remaining amount of the liquid. Means for setting the target acceleration to be

  Further, in the image forming apparatus of the present invention, the stirring control unit controls the moving unit so that the carriage moves forward from one end to the other end in the scanning direction while repeating acceleration and deceleration, and the carriage is the other After reaching the end, the carriage may be a means for controlling the moving means so that the carriage moves backward from the other end to the one end. In this way, the liquid in the tank can be efficiently stirred.

1 is a configuration diagram showing an outline of the configuration of an inkjet printer 20 according to the present embodiment. FIG. 3 is an external view illustrating an external appearance in a state where a printer cover 52 is opened. 6 is a flowchart illustrating an example of an ink agitation processing routine of the present embodiment. FIG. 6 is an explanatory diagram showing a relationship between a remaining ink amount and a carriage acceleration coefficient k. Explanatory drawing which shows the mode of ink stirring. FIG. 6 is an explanatory diagram showing a relationship between a remaining ink amount and a carriage acceleration coefficient k.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of the configuration of an ink jet printer 20 as an embodiment of the present invention, and FIG. 2 is an external view showing the appearance of the ink jet printer 20 with a printer cover 52 opened.

  As shown in FIG. 1, the ink jet printer 20 of the present embodiment transports a sheet P in the sub-scanning direction (the direction from the back to the front in the figure), and transports it onto the platen 46 by the sheet transport mechanism 41. A printer mechanism 21 that performs printing by ejecting ink droplets from nozzles formed in the print head 24 with movement in the main scanning direction (left and right directions in the figure) with respect to the printed paper P, and the entire apparatus are controlled. And a controller 60. A capping device 50 that seals the nozzle surface of the print head 24 is installed at one end (right end in FIG. 1) of the platen 46, and the other end (left end in FIG. 1) of the platen 46 in the main scanning direction. ) Is provided with a flushing area 48 for performing flushing for ejecting ink droplets from the nozzles of the print head 24 on a regular basis in order to prevent nozzle clogging.

  As shown in FIG. 1, the printer mechanism 21 includes a carriage 22 that can be reciprocated in the main scanning direction while being guided by a carriage guide 28, a carriage motor 34 installed on one end side and the other end side of the carriage guide 28, and A carriage belt 32 that is stretched over the driven roller 35, the carriage motor 34, and the driven roller 35 and attached to the carriage 22, and cyan (C), which is mounted on the carriage 22 and in which pigment particles are dispersed in water as a solvent. An ink cartridge 26 that stores light cyan (LC), magenta (M), ride magenta (LM), yellow (Y), and black (K) inks that can be replaced independently for each color; Pressurize each ink supplied from each to eject ink droplets Includes a print head 24 in the number of nozzles are formed, a. The carriage 22 is reciprocated in the main scanning direction by driving the carriage belt 32 by a carriage motor 34. A carriage position sensor 36 for detecting the position of the carriage 22 in the main scanning direction is attached to the back side of the carriage 22. The carriage position sensor 36 is a linear optical scale 36a disposed on the frame 58 along the carriage guide 28. The carriage position sensor 36 is attached to the back surface of the carriage 22 so as to oppose the optical scale 36a, and optically reads the optical scale 36a. And a sensor 36b. Further, although not shown, a chip IC that can read and write data by the controller 60 is attached to the ink cartridge 26. The chip IC stores manufacturing information of the ink cartridge 26, data such as an initial ink amount at the time of shipment, and an ink remaining amount. Here, the ink remaining amount calculated by the ink remaining amount calculating process (not shown) executed by the controller 60 is written. For example, the remaining ink amount is calculated by multiplying the ink ejection amount calculated by multiplying the number of shots, which is the number of times ink droplets are ejected from the nozzles in printing processing or flushing processing, and the amount of ink droplets ejected for each shot. This is performed by subtracting the value obtained by adding the required amount of cleaning consumed by the cleaning executed by the capping device 50 from the ink remaining amount written last time.

  As shown in FIG. 1, the paper feed mechanism 41 includes a transport roller 42 that transports the paper P onto the platen 46, and a transport motor 44 that rotationally drives the transport roller 42. The transport motor 44 is provided with a rotary encoder 49 that detects the amount of rotation on its rotation shaft, and is driven and controlled based on the amount of rotation from the rotary encoder 49. Although not shown, the rotary encoder 49 includes a rotary scale that is graduated at predetermined rotation angle intervals and a rotary scale sensor that reads the scale of the rotary scale.

  The capping device 50 prevents the ink in the nozzles from drying or seals the nozzle surface by sealing the nozzle surface while the print head 24 is moved to a position facing the capping device 50 (so-called home position). The print head 24 is cleaned by sucking the ink in the nozzles in a stopped state. The capping device 50 is attached to a tube (not shown) connected to the bottom of the cap 51, in addition to a substantially rectangular parallelepiped cap 51 having an upper opening for sealing the nozzle surface of the print head 24. And a suction pump (not shown). When cleaning the print head 24, the capping device 50 drives the suction pump while the nozzle surface of the print head 24 is sealed by the cap 51, so that the nozzle surface of the print head 24 and the cap 51 The formed internal space is set to a negative pressure, and ink in the nozzle is forcibly sucked.

  The controller 60 is configured as a microprocessor centered on the CPU 61, and includes a ROM 62 that stores processing programs, a RAM 63 that temporarily stores data, and a flash memory that is rewritable and retains data even when the power is turned off. 64 and an interface (I / F) 65. The controller 60 receives the position of the carriage 22 from the carriage position sensor 36, the rotation amount of the transport roller 42 from the rotary encoder 49, the power-on signal from the power button 68, and the like via the I / F 65. The controller 60 outputs a drive signal to the print head 24, a drive signal to the transport motor 44, a drive signal to the carriage motor 34, a drive signal to the suction pump, and the like via the I / F 65. In addition, the controller 60 receives a print instruction or print data from the user PC 10 via the I / F 65. The RAM 63 is provided with a print buffer area. When print data is received from the user PC 10, the received print data is stored in the print buffer area.

  As shown in FIG. 2, the ink jet printer 20 of the present embodiment has a cartridge replacement opening 54 for mounting and replacing the ink cartridge 26 at this position on the upper surface of the printer cover 52 opened. A replacement cartridge confirmation opening 56 is formed for confirming that the ink cartridge 26 that needs to be replaced moves to the position of the mark 55 by a button operation from the user. In this embodiment, the replacement cartridge confirmation opening 56 is formed to be wide, and the print head 24 (carriage 22) is connected to one end side of the cartridge replacement opening 54 or replacement cartridge confirmation opening 56 ( The state of reciprocating from the home position to the other end side (flushing area 48) can also be confirmed.

  In this embodiment, pigment ink is used as the ink, and the pigment in the solvent easily settles. Therefore, by moving the carriage 22 on which the ink cartridge 26 is mounted without ejecting ink from the print head 24, the ink cartridge The pigment in 26 is agitated to make the concentration uniform.

  Next, the operation of the ink jet printer 20 of the present embodiment configured as described above, particularly the operation for stirring the ink in the ink cartridge 26 to make the ink density uniform will be described. FIG. 3 is a flowchart illustrating an example of an ink agitation processing routine executed by the CPU 61 of the controller 60. This routine is executed when ink agitation is requested. In this embodiment, the ink agitation is requested immediately after the power is turned on, when the elapsed time since the power is turned on is a predetermined time or more, or when the ink cartridge 26 is newly installed, the ink cartridge 26 is replaced. It was supposed to be made when it was done.

  When the ink stirring process routine is executed, the CPU 61 of the controller 60 first inputs the remaining ink ratio Q (step S100). Here, the remaining ink ratio Q is calculated as the ratio of the current remaining ink amount to the capacity of the ink cartridge 26. Note that the remaining ink amount can be obtained by reading the remaining ink amount recorded on the IC chip attached to the ink cartridge 26 as described above.

  When the remaining ink ratio Q is thus input, the input remaining ink ratio Q is compared with the first ratio Q1 (for example, 30%) and the second ratio Q2 (for example, 50%) (step S110). ). When the remaining ink ratio Q is less than the first ratio Q1, a value khi is set for the acceleration coefficient k (step S120), and the remaining ink ratio Q is equal to or greater than the first ratio Q1 and less than the second ratio Q2. In this case, the value kmid is set to the acceleration coefficient k (step S130), and when the remaining ink ratio Q is equal to or greater than the second ratio Q2, the value klo is set to the acceleration coefficient k (step S140). A value obtained by multiplying the set acceleration coefficient k by the maximum acceleration A that can move the carriage 22 is set as the target acceleration α of the carriage 22 for stirring the ink (step S150). Here, FIG. 4 shows an example of the relationship between the remaining ink ratio Q and the acceleration coefficient k. As shown, the acceleration coefficient k is 100% when the remaining ink ratio Q is 0% to 30% (first ratio Q1), and the remaining ink ratio Q is 30% to 50% (second). The ratio Q2) is 90%, and the remaining ink ratio Q is 50% to 100%, 80%.

  When the target acceleration α is thus set, the counter C is initialized to 0 (step S160), and the number of agitation Cref is set (step S170). Here, the number of times of stirring Cref is a relatively large number of times when there is a high possibility that the ink cartridge 26 has been left for a long period of time, such as when the ink cartridge 26 is newly installed or when the ink cartridge 26 is replaced. (For example, 250 times, 270 times, 300 times, etc.) and the ink cartridge 26 is left for a long period of time such as immediately after the power is turned on or when the elapsed time since the power is turned on is longer than a predetermined time. A relatively small number of times (for example, 60 times, 70 times, 80 times, etc.) is set when there is a low possibility of being present. It is considered that the longer the ink cartridge 26 is left, the more the ink settles down. For example, the manufacturing time is read from an IC chip attached to the ink cartridge 26 to calculate the time left. By doing so, it may be set based on the calculated standing time. Further, since the progress of pigment settling may differ depending on the ink color, a different number of stirring times Cref may be set for each color of the replaced ink cartridge.

  Then, the carriage motor 34 is driven and controlled so that the carriage 22 is accelerated and decelerated with the set target acceleration α (steps S180 and S190). The deceleration drive of the carriage 22 may be performed until the carriage 22 is completely stopped, or may be decelerated to such an extent that the carriage 22 is not completely stopped. When the carriage 22 is accelerated and decelerated, the counter C is incremented by 1 (step S200), and it is determined whether or not the value of the counter C has reached the number of agitation Cref (step S210). If the value of the counter C has not reached the number of agitation Cref, the carriage position from the carriage position sensor 36 is input (step S220), and the carriage 22 is moved to the moving end (home position or flushing area 48) based on the input carriage position. ) Is determined (step S230). If the carriage 22 has not reached the moving end, the process returns to step S180 and the processes of steps S180 to S230 are repeated. If the carriage 22 has reached the moving end, the moving direction of the carriage 22 is changed to the reverse direction (step S240), the process returns to step S180, and the processes of steps S180 to S230 are repeated. In this way, the carriage 22 is moved in the same direction from the home position to the flushing area 48 while repeating acceleration driving and deceleration driving. When the carriage 22 reaches the flushing area 48, the direction is changed and acceleration and deceleration are repeated again. However, by moving the carriage 22 in the same direction from the flushing area 48 to the home position, the ink in the ink cartridge 26 mounted on the carriage 22 is stirred. When the value of the counter C reaches the number of stirring times Cref in step S210, this routine is finished.

  FIG. 5 is an explanatory diagram showing how ink is stirred. As shown in the figure, when the carriage 22 is accelerated, the ink in the ink cartridge 26 is pulled in the direction opposite to the moving direction due to inertia, and when the carriage 22 is at a constant speed, the ink in the ink cartridge 26 is in a state during acceleration. Maintained. When the carriage 22 decelerates, the ink in the ink cartridge 26 is pushed out in the moving direction, and the ink in the ink cartridge 26 is stirred by the impact at this time. Therefore, the higher the acceleration of the carriage 22, the greater the impact level, and the stirring of the ink is promoted. Therefore, it is better to set the target acceleration α as high as possible. However, if the movement of the carriage 22 with high acceleration is frequently repeated, the load on the carriage motor 34, the carriage guide 28, and the carriage belt 32 becomes excessive, and there is a possibility of causing problems such as breakage. Since the degree of impact acting on the ink in the ink cartridge 26 increases as the remaining amount of ink in the ink cartridge 26 increases, in the embodiment, the target acceleration α is set so as to decrease as the remaining ink ratio Q increases. By repeatedly accelerating and decelerating the carriage 22, the ink in the ink cartridge 26 is agitated by a substantially uniform impact regardless of the remaining amount of ink while preventing frequent heavy loads from acting on the carriage motor 34 and the like. -ing

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The carriage 22 of the present embodiment corresponds to the “carriage” of the present invention, the carriage motor 34 and the carriage belt 32 correspond to “moving means”, and the controller 60 that calculates the remaining ink amount becomes the “liquid remaining amount acquiring means”. The controller 60 that executes the ink stirring process routine of FIG. 3 corresponds to “stirring control means”.

  According to the ink jet printer 20 of the present embodiment described above, the target acceleration α is set so as to decrease as the remaining ink ratio Q increases, and the carriage 22 is repeatedly accelerated and decelerated and moved in the same direction. The ink in the ink cartridge 26 can be agitated by a substantially uniform impact regardless of the remaining amount of ink while preventing a large load from being frequently applied to the motor 34 and the like. In addition, the carriage 22 is moved in the same direction until the moving end reaches the moving end while repeating the acceleration driving and the deceleration driving, and when it reaches the moving end, the direction is changed to move in the same direction while repeating the acceleration driving and the deceleration driving again. Therefore, the ink in the ink cartridge 26 can be efficiently stirred.

  In the embodiment described above, the target acceleration α is set to three levels of high and low according to the ink remaining amount ratio Q. However, the present invention is not limited to this. It does not matter. FIG. 6 shows the total weight of the carriage 22 (including ink remaining in the ink cartridge 26), acceleration (acceleration coefficient k), and acceleration at each remaining ink ratio Q from 0% to 100% in increments of 10%. An example of the relationship between the degree of impact when the carriage 22 is accelerated and decelerated is shown. In this example, as shown in the drawing, the product of the total weight of the carriage 22 and the acceleration (acceleration coefficient k) is substantially constant so that the degree of impact is uniform regardless of the remaining ink ratio Q. The acceleration coefficient k is set to

  In the above-described embodiment, the ink cartridge 26 is applied to the so-called on-carriage inkjet printer 20 in which the carriage 22 is mounted. However, the ink cartridge is fixed to the frame 58 and a sub tank is mounted on the print head 24 to form an ink cartridge. It may be applied to a so-called off-carriage type ink jet printer that supplies ink by connecting a sub tank and a sub tank. Even in this case, the ink in the sub-tank of the print head can be stirred.

  In the above-described embodiment, the print head 24 employs a system in which a voltage is applied to the piezoelectric element to deform the piezoelectric element and pressurize the ink. However, the heating resistor (for example, a heater) has a voltage applied thereto. It is also possible to adopt a method in which the ink is pressurized by bubbles generated by heating the ink by applying.

  In the above-described embodiment, the image forming apparatus of the present invention is applied to the ink jet printer 20. However, the image forming apparatus is applied to a multi-function printer including a scanner capable of reading a document, or to a FAX apparatus having a FAX function. It may be applied.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  20 Inkjet printer, 21 Printer mechanism, 22 Carriage, 24 Print head, 26 Ink cartridge, 28 Carriage guide, 32 Carriage belt, 34 Carriage motor, 36 Carriage position sensor, 36a Optical scale, 36b Optical sensor, 41 Paper feed mechanism, 42 Transport roller, 46 Platen, 48 Flushing area, 49 Rotary encoder, 50 Capping device, 51 Cap, 52 Printer cover, 54 Cartridge replacement opening, 55 mark, 56 Replacement cartridge confirmation opening, 60 Controller, 61 CPU 62 ROM, 63 RAM, 64 Flash memory, 65 interface (I / F), 68 Power button.

Claims (5)

An image forming apparatus that forms an image on a medium by discharging liquid stored in a tank from a discharge head,
A carriage mounted with the tank and the discharge head and reciprocating;
Moving means for moving the carriage;
A remaining amount acquisition means for acquiring a remaining amount of liquid in the tank;
When stirring of the liquid in the tank is requested, the target acceleration of the carriage is set based on the acquired remaining amount of liquid, and the acceleration and deceleration of the carriage are repeated by the set target acceleration. Stirring control means for controlling the moving means so that the carriage moves in the same direction;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
The image forming apparatus, wherein the agitation control unit is a unit that controls the moving unit by setting the target acceleration such that the acceleration decreases as the remaining amount of the acquired liquid increases. The image forming apparatus according to claim 1, wherein:
The agitation control means is means for setting the target acceleration so that the degree of impact acting on the liquid in the tank by the deceleration after acceleration of the carriage is substantially constant regardless of the remaining amount of liquid in the tank. An image forming apparatus. The image forming apparatus according to claim 3, wherein
The agitation control means is a means for setting the target acceleration so that a product of the total weight of the carriage including the liquid remaining in the tank and the acceleration of the carriage is substantially constant regardless of the remaining amount of the liquid. Image forming apparatus. The image forming apparatus according to any one of claims 1 to 4, wherein
The agitation control means controls the moving means so that the carriage moves forward from one end to the other end in a scanning direction while repeating acceleration and deceleration, and after the carriage reaches the other end, the carriage An image forming apparatus, which is a means for controlling the moving means so as to move backward from the other end to the one end.