JP2015051595A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder capable of maintaining an ink state supplied to an ink tank in a more proper state.SOLUTION: The ink jet recorder for forming an image on a record medium by discharging an ink from plural nozzles comprises: an ink tank for storing an ink supplied from outside; a detection part for detecting completion of ink supply to the ink tank; an agitation part for agitating the ink stored in the ink tank; and a control part for making the agitation part perform agitation operation over a predetermined period after detection of completion of ink supply by the detection part.

Description

  The present invention relates to an ink jet recording apparatus.

  Conventionally, there is an ink jet recording apparatus that forms an image on a medium by discharging ink from a plurality of nozzles. This ink jet recording apparatus is used in various fields. For example, some of those used for industrial use can be used while adding supplementary ink to an ink tank that supplies ink to nozzles as needed. .

  In addition, some inks used in such an ink jet recording apparatus have components separated by being left for a long time. Therefore, such an ink has a problem that it is not supplied to the nozzle at an appropriate ratio as it is.

  On the other hand, Patent Document 1 discloses a technique for keeping the ink supplied to the nozzles from being separated by stirring the ink in the ink tank at regular intervals in the ink tank. Patent Document 2 discloses a technique for stirring ink by applying pressure to the ink in the ink flow path and causing the ink to flow back to the ink tank when closing the shielding valve of the ink flow path.

  On the other hand, Patent Document 3 discloses that when a replaceable ink tank is mounted on an ink tank holder, the stirring portion of the ink tank is swung to perform stirring.

JP-A-8-276599 JP 2007-245350 A JP 2011-121243 A

  However, in the conventional configuration, when ink for replenishment is injected into the ink tank, if the ink components are injected in a separated state, stirring in the ink tank is not performed until the predetermined stirring timing is reached. In this state, there is a problem that ink is not supplied to the nozzle.

  An object of the present invention is to provide an ink jet recording apparatus capable of keeping ink replenished in an ink tank in a more appropriate state.

In order to achieve the above object, the present invention described in claim 1
In an inkjet recording apparatus that forms an image on a recording medium by discharging ink from a plurality of nozzles,
An ink tank for storing ink injected from the outside;
A detection unit for detecting the end of ink injection into the ink tank;
A stirring unit for stirring the ink in the ink tank;
And a control unit that causes the stirring unit to perform a stirring operation for a predetermined period after the end of ink injection is detected by the detection unit.

According to a second aspect of the present invention, in the ink jet recording apparatus of the first aspect,
The detection unit detects removal of an ink injection container attached to the ink tank.

The invention according to claim 3 is the ink jet recording apparatus according to claim 1 or 2,
The detector is
A measuring unit that measures the amount of ink in the ink tank;
A stop of the increase in the ink amount measured by the measurement unit is detected.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the third aspect,
The measuring unit is a weight sensor that measures the weight of the ink tank.

  According to the present invention, there is an effect that the ink replenished in the ink tank can be maintained in a more appropriate state.

1 is a side view illustrating an overall configuration of an ink jet recording apparatus according to an embodiment of the present invention. It is a perspective view which shows the external appearance of an ink supply part. It is the schematic diagram which looked at the ink supply part from the front and the side. An example of a change in ink viscosity as the ink temperature rises and falls is shown. FIG. 3 is a diagram illustrating ink flow paths in the ink jet recording apparatus. It is a block diagram which shows the internal structure of an inkjet recording device. It is a figure which shows the period which performs the stirring operation of ink. 3 is a flowchart illustrating a control procedure of ink agitation processing in the ink jet recording apparatus according to the first embodiment. It is a flowchart which shows the control procedure of the ink stirring process in the inkjet recording device of 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall schematic view of an inkjet recording apparatus 1 according to the present embodiment as viewed from the side.

  The ink jet recording apparatus 1 includes a paper feeding unit 10, an image forming unit 20, a paper discharge unit 30, a control unit 40 (see FIG. 6), an ink supply unit 50 (see FIGS. 2 and 3), and the like. In the inkjet recording apparatus 1, the image forming unit 20 uses the ink supplied from the ink supply unit 50 to the recording medium P conveyed from the paper supply unit 10 to the image forming unit 20 based on the control of the control unit 40. After the image is formed, the recording medium P is discharged to the paper discharge unit 30.

  The paper feeding unit 10 holds the recording medium P on which image formation is performed, and supplies the recording medium P to the image forming unit 20 before image formation. The paper feed unit 10 includes a paper feed tray 11 and a transport unit 12.

  The paper feed tray 11 is a plate-like member provided so that one or a plurality of recording media P can be placed thereon. The paper feed tray 11 is provided so as to move up and down according to the amount of the recording medium P placed thereon, and is held at a position where the uppermost recording medium P is transported by the transport unit 12.

  The conveyance unit 12 is mounted on the sheet feeding tray 11 and a conveyance mechanism that conveys the recording medium P on the belt 123 by rotationally driving a ring-shaped belt 123 by a plurality of (for example, two) rollers 121 and 122. A supply unit for transferring the uppermost recording medium P to the belt 123 is provided. The transport unit 12 transports the recording medium P delivered to the belt 123 by the supply unit as the belt 123 rotates.

  The image forming unit 20 forms an image by ejecting ink onto the recording medium P. The image forming unit 20 includes an image forming drum 21, a delivery unit 22, a paper heating unit 23, a head unit 24, an irradiation unit 25, a delivery unit 26, an ink chamber 27, an ink heating unit 28, and the like. .

  The image forming drum 21 carries the recording medium P along a cylindrical outer peripheral surface, and conveys the recording medium P as it rotates. The conveyance surface of the image forming drum 21 faces the paper heating unit 23, the head unit 24, and the irradiation unit 25, and performs processing related to image formation on the conveyed recording medium P.

  The delivery unit 22 is provided at a position between the transport unit 12 of the paper feed unit 10 and the image forming drum 21, and delivers the recording medium P transported by the transport unit 12 to the image forming drum 21. The delivery unit 22 is a swing arm unit 221 that supports one end of the recording medium P conveyed by the conveyance unit 12, and a cylindrical delivery drum that delivers the recording medium P carried on the swing arm unit 221 to the image forming drum 21. The recording medium P on the transport unit 12 is picked up by the swing arm unit 221 and transferred to the transfer drum 222 to guide the recording medium P in the direction along the outer peripheral surface of the image forming drum 21 to form an image. Delivered to drum 21.

  The paper heating unit 23 heats the recording medium P carried on the image forming drum 21. The sheet heating unit 23 includes, for example, an infrared heater and generates heat in response to energization. The sheet heating unit 23 is provided in the vicinity of the outer peripheral surface of the image forming drum 21 and on the upstream side of the head unit 24 in the conveyance direction of the recording medium P by the rotation of the image forming drum 21. Heat generation of the sheet heating unit 23 is controlled by the control unit 40 so that the recording medium P carried on the image forming drum 21 and passing through the vicinity of the sheet heating unit 23 has a predetermined temperature.

The head unit 24 discharges ink to the recording medium P carried on the image forming drum 21 to form an image. The head unit 24 is individually provided for each color of C (cyan), M (magenta), Y (yellow), and K (black). In FIG. 1, head units 24 corresponding to the colors Y, M, C, and K are provided in order from the upstream with respect to the conveyance direction of the recording medium P that is conveyed along with the rotation of the image forming drum 21.
The head unit 24 of this embodiment is provided with a length (width) that covers the entire recording medium P in a direction (width direction) perpendicular to the conveyance direction of the recording medium P. That is, the ink jet recording apparatus 1 is a one-pass line head type ink jet recording apparatus. The head unit 24 can constitute a line head by arranging a plurality of recording heads 24a (see FIG. 5).

  The irradiation unit 25 irradiates energy rays for curing the ink ejected on the recording medium P. The irradiation unit 25 includes, for example, a fluorescent tube such as a low-pressure mercury lamp, and emits energy rays such as ultraviolet rays by causing the fluorescent tube to emit light. The irradiation unit 25 is provided in the vicinity of the outer peripheral surface of the image forming drum 21 and on the downstream side of the head unit 24 in the conveyance direction of the recording medium P by the rotation of the image forming drum 21. The irradiation unit 25 irradiates the recording medium P carried on the image forming drum 21 and ejects the ink with energy rays, and cures the ink ejected onto the recording medium P by the action of the energy rays.

  As a fluorescent tube emitting ultraviolet rays, in addition to a low-pressure mercury lamp, a mercury lamp having an operating pressure of about several hundred Pa to 1 MPa, a light source usable as a germicidal lamp, a cold cathode tube, an ultraviolet laser light source, a metal halide lamp, a light emitting diode, etc. Is mentioned. Among these, a light source (for example, a light emitting diode) that can irradiate ultraviolet rays with higher illuminance and consumes less power is more desirable. The energy rays are not limited to ultraviolet rays, but may be any energy rays having a property of curing the ink according to the properties of the ink, and the light source is replaced according to the wavelength of the energy rays.

  The delivery unit 26 conveys the recording medium P irradiated with energy rays from the irradiation unit 25 from the image forming drum 21 to the paper discharge unit 30. The delivery unit 26 rotates the annular belt 263 by a plurality of (for example, two) rollers 261 and 262 and conveys the recording medium P on the belt 263, and the recording medium P from the image forming drum 21. A cylindrical delivery drum 264 and the like are provided to the transport mechanism. The delivery unit 26 conveys the recording medium P transferred to the belt 263 by the transfer drum 264 by the belt 263 and sends it to the paper discharge unit 30.

  The ink chamber 27 stores the ink pumped from the ink tank 51 of the ink supply unit 50. The ink stored in one or a plurality of ink chambers 27 is supplied to a plurality of nozzles of each recording head 24a via an ink flow path. The ink chamber 27 is provided with a float sensor 27a (see FIG. 5), and the control unit 40 operates the pump 53 and the pump 27b based on the detection data of the liquid surface position by the float sensor 27a, thereby supplying a predetermined amount of ink. Are to be stored.

  The ink heating unit 28 heats the ink chamber 27, the ink flow path, and each nozzle to change and maintain the ink in a liquid (sol) state. As the ink heating unit 28, for example, a heating wire or a heat conduction plate is used, and when energized, Joule heat is generated to heat the ink.

  The paper discharge unit 30 stores the recording medium P sent out from the image forming unit 20 by the delivery unit 26. The paper discharge unit 30 includes a plate-shaped paper discharge tray 31 and the like, and the recording medium P after image formation is placed on the paper discharge tray 31.

  The control unit 40 controls the operation of each unit of the inkjet recording apparatus 1 and controls the overall operation. The control unit 40 includes a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, and the like (see FIG. 6). In the control unit 40, the program read from the ROM 402 by the CPU 401 is executed on the RAM 403, and various control processes are executed.

The ink supply unit 50 supplies ink to the head unit 24 of the image forming unit 20 so that ink of each color can be ejected from the nozzles of the head unit 24.
FIG. 2 is a perspective view of the ink supply unit 50. FIG. 3 is a schematic view of the ink supply unit 50 as seen from the front and side. Here, the configuration for two of the four colors is shown. In FIG. 3, the inside of the ink tank 51 is shown through.

  The ink supply unit 50 includes an ink tank 51, a weight sensor 52, a pump 53, a supply pipe 54, a housing 55, and the like.

  The ink tank 51 is a container that stores ink of each color used for image formation. The ink pumped from the ink tank 51 by the pump 53 is sent to the head unit 24. The ink tank 51 can be additionally replenished with ink via a supply pipe 54.

  The ink used in the ink jet recording apparatus 1 of the present embodiment has a predetermined temperature, for example, a phase change temperature of about 40 degrees to 100 degrees, and is uniformly liquefied by being heated and raised above the phase change temperature. (Solation). On the other hand, the ink gels below the predetermined temperature including about normal room temperature (0 degree to 30 degree). In this ink, separation of the ink component and other components gradually proceeds in a gelled state, but once the stirring is performed, the separation proceeds more rapidly (for example, within a day). . The composition and manufacturing method of this ink will be described in detail later.

  As shown in FIG. 3, the ink tank 51 includes a stirring unit having a stirring screw 51a and a rotation motor 51b. The ink in the ink tank 51 is stirred by the rotation of the stirring screw 51a by the rotation motor 51b. Each component is mixed. For example, the ink tank 51 can store 20 liters of ink.

  The weight sensor 52 (measurement unit) is provided below the ink tank 51, measures the weight of the ink tank 51, performs digital conversion at a predetermined sampling rate, and then outputs measurement value data to the control unit 40.

  The pump 53 draws ink from the ink tank 51 and sends it to the image forming unit 20. The ink pumped out by the pump 53 is a mixture of components in a gel state, and has sufficient lift to pump out the gel ink.

  The supply pipe 54 is an ink inlet for replenishing the ink tank 51. Normally, the upper portion of the supply tube 54 can be closed with a lid or the like, and when the ink is replenished, the lid member is removed and the external ink pack 60 is stably placed on the upper portion. It can be attached. Alternatively, a structure in which the supply pipe 54 opens and closes according to the attachment / detachment of the ink pack 60 without separately providing a lid member may be employed. An attachment / detachment sensor 54a (detection unit, see FIG. 6) for detecting attachment / detachment of the ink pack 60 is provided at the opening of the supply pipe 54.

The ink in the ink pack 60 (injection container) is once stirred and sheared after gelation. This facilitates the injection of ink from the ink pack 60 into the ink tank 51 via the supply pipe 54, while the ink components are easily separated inside the ink pack 60.
The ink in the gelled state does not sufficiently flow into the ink tank 51 from the inside of the ink pack 60 attached to the supply pipe 54 only by gravity. The ink pack 60 is a variable shape container or a box body in which such a variable shape container is housed, and applies force from the outside of the container using a user's hand or a pressing device (for example, air pressure). Thus, the gel-like ink remaining inside the container of the ink pack 60 can be squeezed out.

  The housing 55 holds each part of the ink supply unit 50 in a fixed manner. The housing 55 has a plurality of wheels and support legs that can be expanded and contracted or moved up and down at the lower part thereof, and the length of the support legs is adjusted as necessary, and the casing 55 can be moved by the wheels or predetermined by the support legs. It can be fixedly arranged at the position.

Next, the ink supplied by the ink supply unit 50 of this embodiment will be described.
The ink used in this embodiment is an ultraviolet (UV) curable ink. This UV curable ink undergoes a phase change between a gel state and a liquid (sol) state according to temperature in a state where UV is not irradiated. This ink is manufactured as follows.

  First, two kinds of compounds of 5 parts of Solspers 32000 (manufactured by Lubrizol) and 80 parts of HD-N (1,6-hexanediol dimethacrylate, Shin-Nakamura Chemical Co., Ltd.) are placed in a stainless beaker and stirred. While dissolving. Then, after cooling to room temperature, 15 parts of carbon black (# 56, manufactured by Mitsubishi Chemical Corporation) was added thereto, sealed in a glass bottle with 0.5 mm zirconia beads, dispersed in a paint shaker for 10 hours, and then zirconia. What removed the bead is obtained as a pigment dispersion.

  Including the obtained pigment dispersion, the composition is adjusted as in the examples shown in Tables 1 to 6.

  And the composition after filtration which filtered with the Teflon (trademark) 3 micrometer membrane filter made from ADVATEC company with respect to the composition shown in Table 1 to Table 6 is obtained as an ink.

  FIG. 4 shows an example of the change in the viscosity of the ink as the temperature of the ink increases and decreases. A broken line L1 indicates an example of change in the viscosity of the ink when the temperature rises, and a solid line L2 indicates an example of the change in the viscosity of the ink when the temperature decreases.

  This change in viscosity is obtained, for example, by measuring a change in dynamic viscoelasticity of the ink accompanying a change in temperature with a rheometer. Specifically, the ink is heated from 20 ° C. to 100 ° C. under a predetermined shear rate (for example, 11.7 [1 / s]) and a predetermined temperature change degree (for example, 0.1 ° C./s). The dynamic viscoelasticity of the ink is measured when the ink is raised and then lowered to 20 ° C.

  This ink changes phase between a gel state having a viscosity of 100 mPa · s or more and a liquid (sol) state having a viscosity of 100 mPa · s or less (mainly 10 mPa · s or less). At this time, the ink viscosity change curve when the temperature rises (broken line L1) is different from the ink viscosity change curve when the temperature drops (solid line L2). When the temperature rises, the ink viscosity is less than 100 mPa · s when the ink temperature is 60 ° C. or higher. On the other hand, when the temperature drops, the ink viscosity exceeds 100 mPa · s when the ink temperature falls below 45 ° C. That is, in this ink example, when the temperature of the ink is 60 ° C. (T1: first temperature) or higher, the viscosity becomes less than 100 mPa · s and becomes liquid, regardless of the temperature rise or fall, and 45 ° C. ( When the temperature is lower than (T2: second temperature), the viscosity exceeds 100 mPa · s and becomes a gel, regardless of the temperature rise or fall.

FIG. 5 is a diagram illustrating ink flow paths in the inkjet recording apparatus 1 of the present embodiment.
In the ink jet recording apparatus 1, the ink stirred by the stirring screw 51 a in the ink tank 51 is pumped by the pump 53 and supplied to the ink chamber 27. The ink stored in the ink chamber 27 is transferred by the ink heating unit 28. It is heated to a temperature equal to or higher than the first temperature T1 and is liquefied (phase change into a sol). The liquefied ink is sent to each recording head 24a of the head unit 24 through the ink flow path heated by the ink heating unit 28, and discharged from a plurality of nozzles.

  FIG. 6 is a block diagram showing an internal configuration of the inkjet recording apparatus 1 of the present embodiment.

  In the ink jet recording apparatus 1, the control unit 40 is connected via the bus 49 to the transport drive unit 41, the head drive unit 42, the communication unit 43, the operation display unit 44, the paper heating unit 23, the ink heating unit 28, the irradiation unit 25, and the pump 27 b. , The pump 53, the float sensor 27a, the rotation motor 51b, the weight sensor 52, the attachment / detachment sensor 54a, and the like.

  In the control unit 40, the CPU 401 reads out and executes various programs, data, and the like corresponding to the processing contents from a storage device such as the ROM 402, and controls the operation of each part of the inkjet recording apparatus 1 according to the executed processing contents. . The RAM 403 temporarily stores various programs and data processed by the CPU 401. The ROM 402 stores various programs and data read by the CPU 401 and the like.

  The transport drive unit 41 operates the paper feed unit 10, the image forming drum 21 of the image forming unit 20, the delivery unit 22, the delivery unit 26, and the paper discharge unit 30 based on a control signal from the control unit 40 to appropriately control The recording medium P is transported at timing and speed.

The head driving unit 42 operates the head unit 24 based on a control signal from the control unit 40 and causes the ink to be ejected from a plurality of nozzles at an appropriate timing to form an image on the recording medium P.
The control unit 40 outputs control signals to the transport driving unit 41, the head driving unit 42, the paper heating unit 23, and the irradiation unit 25 and operates them at appropriate timings, so that the recording medium P is subjected to the head unit 24 under appropriate conditions. The ink ejected onto the recording medium P is cured.

  The communication unit 43 controls communication between the inkjet recording apparatus 1 and an external device. A print job and various control signals transmitted from the external device are received via the communication unit 43 and sent to the control unit 40. The control unit 40 performs various processes for image formation according to the acquired print job. Note that processing such as image data analysis and rasterization may be performed by providing an image processing CPU or memory separately from the control unit 40.

  The operation display unit 44 is, for example, a touch panel having a liquid crystal screen and a touch sensor. The control unit 40 outputs a display control signal to display a status, a menu, and the like on the liquid crystal screen. The touch sensor receives an input operation from the outside and outputs an input signal to the control unit 40. The control unit 40 performs various processes based on the input signal.

The control unit 40 operates the pump 27b and the pump 53 based on the amount of ink in the ink chamber 27 measured by the float sensor 27a, and supplies an appropriate amount of ink to the ink flow path and also supplies the ink flow path. The ink heating unit 28 is operated so as to keep the ink that has been discharged in a liquid state.
In addition, the control unit 40 operates the rotation motor 51b to stir the ink in the ink tank 51 periodically and based on input signals from the weight sensor 52 and the attachment / detachment sensor 54a, and the state where the components are mixed is determined. keep.

Next, the ink stirring operation in the inkjet recording apparatus 1 of the present embodiment will be described.
FIG. 7 is a diagram illustrating a period in which the ink stirring operation is performed in the inkjet recording apparatus 1.

  In the ink jet recording apparatus 1 of the present embodiment, as shown in FIG. 7A, the control unit 40 counts a clock signal having a predetermined frequency and activates the rotary motor 11b at a predetermined interval (t0), for example, an hour interval. The operation is performed for a predetermined period (t1) to stir the ink, and based on the signal of the attachment / detachment sensor 54a of the ink pack 60, the timing (q ), The ink is stirred for a period (r) until a predetermined period (t1, for example, 3 minutes) elapses. As the predetermined period t1, the effect of stirring appears even for a short time, but it is preferable that the predetermined period t1 is a time during which the separated components are sufficiently mixed.

  FIG. 8 is a flowchart showing the control procedure of the ink agitation process executed by the control unit 40 in the inkjet recording apparatus 1 of the present embodiment.

This ink agitation process is a process that is continuously performed while power is supplied to the ink supply unit 50.
When the ink agitation process is started, the control unit 40 (CPU) acquires an attachment / detachment signal from the supply pipe 54, and determines whether or not the ink pack is attached (step S101). If it is determined that it is in the mounted state (“YES” in step S101), the processing by the control unit 40 proceeds to step S105.

  When it is determined that the ink pack 60 is not attached ("NO" in step S101), the control unit 40 determines whether or not the ink pack is within a predetermined time after being removed (step S101). Step S102). If it is determined that the time is within the predetermined time (“YES” in step S102), the processing by the control unit 40 proceeds to step S105.

  When it is determined that the ink pack 60 is not within the predetermined time after the ink pack 60 is removed (“NO” in step S102), the control unit 40 is currently stirring the ink and the predetermined time since the start of the stirring. It is determined whether it is within the time (step S103). If it is determined that the time is within the predetermined time (“YES” in step S103), the process of the control unit 40 proceeds to step S105.

  If it is not within the predetermined time, that is, it is determined that the ink is not being stirred or the predetermined time has elapsed since the start of stirring (“NO” in step S103), the control unit 40 performs the previous stirring. It is determined whether or not a predetermined time has elapsed since the end (step S104). If it is determined that the predetermined time has elapsed (“YES” in step S104), the processing by the control unit 40 proceeds to step S105.

  If it is determined that the predetermined time has not elapsed since the end of stirring (“NO” in step S104), the processing by the control unit 40 returns to step S101.

  When the process proceeds from one of the determination processes of steps S101 to S104 to the process of step S105, the control unit 40 operates the rotary motor 51b to stir the ink (step S105). Then, the process by the control unit 40 returns to step S101.

  As described above, the ink jet recording apparatus 1 according to the first embodiment detects the removal of the ink tank 51 that stores the ink injected from the outside, and the ink pack 60 that means the end of the injection of the ink into the ink tank 51. The detachable sensor 54a, the stirring screw 51a and the rotary motor 51b for stirring the ink in the ink tank 51, and the end of the ink injection are detected by the detachable sensor 54a, and then the stirring screw 51a is rotated for a predetermined period. And a control unit 40 that is operated to perform a stirring operation. Therefore, the ink injected from the ink pack 60 in a non-uniform state can be immediately stirred in the ink tank 51 by an easy configuration and an easy control process, and the ink can be kept in a more appropriately mixed state. . In particular, since it takes time to squeeze the ink gelled in the ink pack 60 into the ink tank 51, the stirring process is further performed for a necessary time after the injection is completed. It is possible to ensure that even the ink injected into the ink is mixed.

  Further, even during the operation of the image forming process by the image forming unit 20, it is possible to easily replenish ink without interrupting the process and keep the replenished ink in an appropriate state.

  Further, since the removal of the ink pack 60 attached to the ink tank 51 is detected using the attachment / detachment sensor 54a, detection signal processing and stirring control can be performed very simply.

[Second Embodiment]
Next, the ink jet recording apparatus 1 of the second embodiment will be described.
The configuration of the ink jet recording apparatus 1 according to the second embodiment is the same as that of the ink jet recording apparatus according to the first embodiment, and the description thereof is omitted by using the same reference numerals.

Next, the ink stirring operation by the inkjet recording apparatus 1 of the second embodiment will be described.
In the ink jet recording apparatus 1 of the second embodiment, the ink agitation operation is performed based on the measurement data of the weight sensor 52 instead of the attachment / detachment signal from the supply pipe 54.

  In the ink jet recording apparatus 1 of the present embodiment, as shown in FIG. 7B, the control unit 40 counts the clock signal having a predetermined frequency and turns the rotary motor 11b at a predetermined interval (t0), for example, an hour. The ink is stirred for a predetermined period (t1), and the weight increase is stopped from the timing (u) when the weight increase is detected based on the weight measurement data of the weight sensor 52 (v ), The ink is stirred for a period (w) until a predetermined period (t1, for example, 3 minutes) elapses without detecting an increase in weight again.

FIG. 9 is a flowchart illustrating the control procedure of the ink agitation process executed by the control unit 40 in the inkjet recording apparatus 1 of the second embodiment.
This flowchart is the same except that the process of step S110 is added and the processes of steps S101 and S102 are changed to the processes of steps S111 and S112, respectively, compared to the ink agitation process of the first embodiment. Therefore, the same processing contents are denoted by the same reference numerals, and detailed description thereof is omitted.

  When the ink agitation process of the present embodiment is started, the control unit 40 (CPU) acquires the latest measurement value from the weight sensor (step S110). The control unit 40 determines whether an increase in weight is detected as compared with the previous measurement value (step S111). If it is determined that an increase in weight is detected (“YES” in step S111), the processing by the control unit 40 proceeds to step S105.

  If it is determined that no weight increase has been detected ("NO" in step S111), the control unit 40 determines whether or not it is within a predetermined time since the most recent weight increase was detected (step S112). ). If it is determined that the time is within the predetermined time (“YES” in step S112), the processing by the control unit 40 proceeds to step S105. If it is determined that it is not within the predetermined time (“NO” in step S112), the processing by the control unit 40 proceeds to step S103.

  As described above, the ink jet recording apparatus 1 according to the second embodiment includes the weight sensor 52 that measures the weight of the ink tank 51 and continues stirring the ink for a predetermined time after the increase in the weight measurement value stops. Even when the ink injection from the ink pack 60 is interrupted in the middle or when there is a time from the completion of the injection to the removal of the ink pack 60, the injected ink is properly stirred and properly applied. In this state, the image can be supplied to the image forming unit 20.

  In addition, by using the weight sensor 52 to measure the amount of ink in the ink tank 51, gel-like ink is injected non-uniformly into the ink tank 51 and the stirring screw 51a is operating properly. In addition, an increase in the amount of ink can be detected.

The present invention is not limited to the above-described embodiment, and various modifications can be made.
For example, in the above embodiment, the ink is stirred by rotating the stirring screw 51a by the rotary motor 51b, but other methods may be used.

  In the above embodiment, the operation control of the ink supply unit 50 is performed by the control unit 40 of the inkjet recording apparatus 1. However, the ink supply unit 50 may be separately performed by mounting a microcomputer or the like. good.

  Further, in the above embodiment, after the stirring operation related to ink replenishment is performed, the next periodic stirring operation is performed after a predetermined period of time has passed. The stirring operation related to ink replenishment may be interrupted during the stirring operation. Further, the stirring time may be set to a different length between the periodic stirring and the stirring after ink replenishment.

  In the above-described embodiment, the example using the detection of attachment of the ink pack and the example of detecting the increase in the amount of ink by the weight sensor have been described. However, these may be used in combination. Further, the method for detecting the increase in the amount of ink is not limited to the weight sensor, and for example, a sensor for detecting the liquid surface position may be used.

  In the above embodiment, the control unit 40 determines whether the ink pack 60 is removed or the weight increase is stopped based on the attachment / detachment signal of the attachment / detachment sensor 54a or the measurement data of the weight sensor 52. 52 may be configured to output a notification signal to the control unit 40 for a predetermined period only when the ink pack 60 is removed by each signal output circuit or when the increase in weight is stopped.

  In the above embodiment, the UV curable ink that is softened by heat has been described as an example. However, the present invention is not limited to this. The present invention can be applied to any type of ink that separates ink components from other components.

In the above embodiment, the inkjet recording apparatus 1 has been described by taking a line head that forms an image on paper as an example. However, the present invention is not limited to this. An ink jet recording apparatus that prints on a fabric may be used, or a serial head ink jet recording apparatus. Further, the mechanism related to the conveyance of the recording medium P is not limited to the one using a rotating drum. An image may be formed by ejecting ink from the nozzles of the head unit 24 to the recording medium P placed on the belt.
In addition, specific details such as the configuration, structure, processing procedure, and numerical values shown in the above embodiment can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 10 Paper feed part 11 Paper feed tray 11b Rotation motor 12 Conveyance part 121, 122 Roller 123 Belt 20 Image formation part 21 Image formation drum 22 Delivery unit 221 Swing arm part 222 Delivery drum 23 Paper heating part 24 Head unit 24a Recording head 25 Irradiation unit 26 Delivery unit 261, 262 Roller 263 Belt 264 Transfer drum 27 Ink chamber 27a Float sensor 27b Pump 28 Ink heating unit 30 Paper discharge unit 31 Paper discharge tray 40 Control unit 401 CPU
402 ROM
403 RAM
41 Transport Drive Unit 42 Head Drive Unit 43 Communication Unit 44 Operation Display Unit 49 Bus 50 Ink Supply Unit 51 Ink Tank 51a Stirring Screw 51b Rotation Motor 52 Weight Sensor 53 Pump 54 Supply Pipe 54a Detachment Sensor 55 Housing 60 Ink Pack P Recording Medium

Claims (4)

In an inkjet recording apparatus that forms an image on a recording medium by discharging ink from a plurality of nozzles,
An ink tank for storing ink injected from the outside;
A detection unit for detecting the end of ink injection into the ink tank;
A stirring unit for stirring the ink in the ink tank;
An ink jet recording apparatus comprising: a control unit that causes the stirring unit to perform a stirring operation over a predetermined period after completion of ink injection is detected by the detection unit.   The inkjet recording apparatus according to claim 1, wherein the detection unit detects removal of an ink injection container attached to the ink tank. The detector is
A measuring unit that measures the amount of ink in the ink tank;
The ink jet recording apparatus according to claim 1, wherein a stop of an increase in the ink amount measured by the measuring unit is detected.   The inkjet recording apparatus according to claim 3, wherein the measurement unit is a weight sensor that measures the weight of the ink tank.

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