JP7258597B2 - printer - Google Patents

Description

The present invention relates to a printer capable of reducing the load on an ink ejection unit.

2. Description of the Related Art Printers are known that send ink from an ink tank to an ink ejection unit through a liquid supply tube and eject the ink from the ink ejection unit onto a medium for printing. There is a technique disclosed in Japanese Patent Application Laid-Open No. 2002-300018 as a conventional technique related to such a printer.

A printer, such as that disclosed in Japanese Unexamined Patent Application Publication No. 2002-100003, includes a rail extending substantially perpendicularly to the direction in which a medium is conveyed, a carriage provided movably on the rail, and supported by the carriage to eject ink onto the medium. An ink ejection unit, an ink cartridge filled with ink to be ejected onto a medium, a liquid delivery tube connected from the ink cartridge to the ink ejection unit, and an ink ejection unit provided on the liquid delivery tube from the ink cartridge. and a pump for sending ink to.

A sensor is provided in the ink ejection unit to detect whether or not the amount of ink stored is equal to or less than a predetermined amount. When the amount of stored ink falls below a predetermined amount, the pump operates to send ink from the ink cartridge to the ink ejection unit.

JP 2018-111214 A

The sensor disclosed in Patent Document 1 can also be used, for example, to detect whether or not the amount of ink stored in the ink ejection unit has reached or exceeded a predetermined amount. By stopping the pump when the predetermined amount is exceeded, the pressure of the ink in the ink ejection unit can be reduced to a predetermined value or less. As a result, the load on the ink ejection unit can be reduced.

However, if a sensor fails in such a printer, the pump may continue to operate. Ink continues to be sent to the ink ejection unit, and a heavy load is applied to the ink ejection unit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printer that can more reliably reduce the load on the ink ejection unit.

According to the present invention, a carriage supported by a rail and provided movably on the rail;
an ink ejection unit that is supported by the carriage and ejects ink onto the medium;
an ink remaining amount detection sensor provided in the ink ejection unit and capable of detecting that the ink filled in the ink ejection unit has reached a predetermined amount;
an ink cartridge filled with the ink to be ejected onto the medium;
a liquid feeding tube connected from the ink cartridge to the ink ejection unit;
a pump provided in the liquid-sending tube and capable of sending the ink from the ink cartridge to the ink ejection unit;
a control unit that controls the pump based on the detection signal of the ink remaining amount detection sensor;
A bypass passage having one end connected to the upstream side of the pump of the liquid-sending tube and the other end of the liquid-sending tube connected to the downstream side of the pump, with reference to the direction in which the ink flows. and,
Provided on the bypass passage, only when the differential pressure between the pressure on the upstream side of the pump and the pressure on the downstream side of the pump reaches a predetermined pressure or more, and a valve that opens to return said ink.

In the present invention, the printer returns ink from the downstream side to the upstream side only when the differential pressure between the pressure on the upstream side of the pump and the pressure on the downstream side of the pump reaches or exceeds a predetermined pressure. A valve is provided on the bypass passage to open the valve. For example, if the remaining ink sensor fails, ink continues to be supplied to the ink ejection unit. By continuing to supply ink to the ink ejection unit, the pressure of the ink on the downstream side of the pump increases. When the pressure exceeds a predetermined pressure, the valve is opened allowing ink to flow through the bypass. Ink that has flowed through the bypass is returned to the upstream side of the pump. By flowing the ink through the bypass and returning it to the upstream side of the pump, the pressure on the downstream side of the pump can be reduced. It is possible to reduce the load on the ink ejection unit even when the ink remaining amount detection sensor fails. It is possible to provide a printer that can more reliably reduce the load on the ink ejection unit.

1 is a schematic diagram of a printer according to an embodiment; FIG. FIG. 2 is a diagram showing a main part of the printer shown in FIG. 1; FIG. 3(a) is a diagram for explaining the valve when the pressure on the downstream side of the pump rises, and FIG. 3(b) is a diagram for explaining the action when the valve operates from the state of FIG. 3(a). 3(c) is a diagram for explaining the valve when positive pressure is applied to the downstream side of the pump and negative pressure is applied to the upstream side of the pump, and FIG. 3(d) is the state of FIG. 3(c). FIG. 10 is a diagram for explaining the action when the valve is operated from .

An embodiment of the present invention will be described below with reference to the accompanying drawings. In the figure, Fr indicates the front, Rr the rear, Le the left, Ri the right, Up the top, and Dn the bottom.
<Example>

[Configuration of Printer 10]
Please refer to FIG. The printer 10 is an inkjet printer capable of forming a color image on the medium Me. The printer 10 can print large signboards and posters, for example.

Also refer to FIG. The printer 10 includes a transport unit 11 capable of transporting the medium Me to be printed in the front-rear direction, a bed 12 on which the medium Me transported from the transport unit 11 can be placed, and above the bed 12 extending in the left-right direction. A rail 13, a carriage 14 supported by the rail 13 and movably provided on the rail 13, an ink ejection unit 15 supported by the carriage 14 for ejecting ink onto the medium Me, and ink filled with ink. a cartridge 16, a liquid-sending tube 17 connected from the ink cartridge 16 to the ink ejection unit 15, a pump 18 provided on the liquid-sending tube 17 for sending ink from the ink cartridge 16 to the ink ejection unit 15, A bypass passage 19 bypassing the pump 18 and connected to the liquid feeding tube 17, a valve 30 provided on the bypass passage 19 and allowing ink to flow in an open state, It has a flow rate detection sensor 21 that detects the flow rate of ink flowing inside, and a control section 50 that can control the transport section 11 , carriage 12 , ink discharge unit 15 and pump 18 .

Please refer to FIG. The printer 10 sends the medium Me forward by the conveying unit 11, moves the carriage 14 in the left-right direction, and ejects ink onto the medium Me passing below the ink ejection unit 15 to perform printing.

Note that the printer 10 can be equipped with any device such as a cutter device for cutting the medium Me.

[About Media Me]
The medium Me is, for example, a roll medium wound on a roll, and the material of the medium may be paper such as plain paper, resin such as polyvinyl chloride or polyester, or aluminum. It may be made of various materials such as metals, iron materials, and the like. The medium Me is transported from the rear to the front by the transport section 11 .

[Regarding the ink ejection unit 15]
The ink ejection unit 15 has ejection units 15C, 15M, 15Y, and 15K capable of ejecting ink, respectively. The ejection units 15C, 15M, 15Y, and 15K include a cyan unit 15C that ejects cyan ink, a magenta unit 15M that ejects magenta ink, a yellow unit 15Y that ejects yellow ink, and a black unit 15K that ejects black ink. , consisting of

Also refer to FIG. FIG. 2 shows only the cyan unit 15C among the ejection units 15C, 15M, 15Y, and 15K. The ejection units 15C, 15M, 15Y, and 15K employ the same configuration, but differ in the color of the ink that is ejected. The cyan unit 15C will be described below as an example, but since the configurations of the other discharge units 15M, 15Y, and 15K are the same, detailed description will be omitted.

The ejection unit 15C includes a damper 15d filled with ink, a head 15h for ejecting the ink supplied from the damper 15d, and a built-in damper 15d capable of detecting when the ink in the damper 15d reaches a predetermined amount. and an ink remaining amount detection sensor 15s.

A filler sensor or a photointerrupter can be used for the remaining ink detection sensor 15s. The ink remaining amount detection sensor 15s detects whether or not the amount of ink in the damper 15d exceeds a predetermined amount. The detected information is sent to the control unit 50 .

[Regarding the ink cartridge 16]
Please refer to FIG. The ink cartridge 16 is filled with ink to be ejected onto the medium Me. The ink cartridge 16 includes a cyan cartridge 16C filled with cyan ink, a magenta cartridge 16M filled with magenta ink, a yellow cartridge 16Y filled with yellow ink, and a black cartridge 16K filled with black ink. Become.

The number and color of cartridges constituting the ink cartridge 16 can be arbitrarily selected. The ink to be filled in the ink cartridge 16 is preferably water-based resin ink, which is excellent in fixability to media. In order to print a lot in a short time, it is also preferable to select an ink that dries quickly. In addition, any water-based ink or organic solvent-based ink can be selected.

Also refer to FIG. FIG. 2 shows only the cyan cartridge 16C among the cartridges 16C, 16M, 16Y, and 16K that make up the ink cartridge 16. As shown in FIG. The cartridges 16C, 16M, 16Y, and 16K have the same configuration, but are filled with different colors of ink. The cyan cartridge 16C will be described below as an example, but since the other cartridges 16M, 16Y, and 16K have the same configuration, detailed description thereof will be omitted.

[Regarding the liquid sending tube 17]
Please refer to FIG. The liquid-feeding tube 17 has a liquid-feeding fixing portion 17a that is fixed (not displaced) regardless of the position of the carriage 14, and a liquid-feeding moving portion 17b that follows when the carriage 14 moves.

From the ink cartridge 16 to the pump 18, only the liquid feeding fixing portion 17a is provided. The portion from the pump 18 to the ink ejection unit 15 is composed of a fixed liquid-feeding portion 17a and a moving liquid-feeding portion 17b. Based on the direction in which the ink flows, the liquid feeding moving part 17b is positioned only downstream of the pump 18 .

[Regarding the configuration of the pump 18]
A diaphragm pump, for example, is employed as the pump 18 . The pump 18 is provided on the liquid feeding fixing portion 17a. The pump 18 is operated by an electric signal received from the control section 50 to send the ink in the ink cartridge 16 to the ink ejection unit 15 .

The pump 18 may be a pump other than the diaphragm type.

[Regarding bypass 19]
The bypass 19 has one end 22a connected to the upstream side of the pump 18 in the liquid feeding tube 17, and the other end 22a to the downstream side of the pump 18 in the liquid feeding tube 17. 22b are connected.

The bypass path 19 consists only of a bypass fixing portion that is fixed (not displaced) regardless of the position of the carriage 14 .

[Regarding valve 30]
A valve 30 is provided on the bypass passage 19 . That is, the valve 30 is provided on the bypass fixing portion. The valve 30 includes a valve box 31 connected to the bypass passage 19, a partition wall 32 dividing the inside of the valve box 31 into two chambers and having a hole 32a in the center through which ink can pass, and this partition wall. A rubber valve seat 33 fixed to the upper surface of the nozzle 32 so as to surround the hole 32a, a valve body 34 that normally contacts the valve seat 33 to prevent ink from passing through the hole 32a, and the valve It has a guided portion 35 that extends downward from the body 34 through the hole 32a, and a guide portion 36 that surrounds the guided portion 35 and guides the guided portion 35 so that the valve body 34 moves up and down. are doing. The valve 30 is a mechanical valve that does not require electric power for opening and closing.

As the valve 30, an electric valve that opens and closes with the power of a motor can be used.

The valve body 34 is made of disk-shaped metal. The pressure at which the valve body 34 opens can be set by the weight of the valve body 34 . Details will be described later.

The guided portion 35 is formed integrally with the valve body 34 . The guided portion 35 includes a cylindrical rod portion 35a extending downward from the center of the lower surface of the valve body 34, a disk-shaped disk portion 35b integrally formed concentrically with the rod portion 35a, have

[Regarding the flow rate detection sensor 21]
The flow rate detection sensor 21 is provided on the downstream side of the pump 18 in the liquid feeding fixed portion 17a. More specifically, the flow rate detection sensor 21 faces the downstream side of the portion P1 where the other end 19b of the bypass passage 19 is connected to the liquid feeding tube 17 in the liquid feeding fixed portion 17a.

The flow rate detection sensor 21 detects the flow rate of ink. The detected information is sent to the control unit 50 .

[Regarding the control unit 50]
Please refer to FIG. The control unit 50 has a processing unit 51 , a storage unit 52 and a communication unit 53 . The processing unit 51, the storage unit 52, and the communication unit 53 are configured by, for example, microcomputers or microcontrollers. The processing unit 51, storage unit 52, and communication unit 53 can include, for example, a CPU (or MPU or MCU), ROM, RAM, and an input/output interface. For example, the ROM can store programs that cause the CPU to perform predetermined operations. The RAM can form the work area of the CPU. Note that the processing unit 51, the storage unit 52, and the communication unit 53 may be configured by ASIC, FPGA, or the like.

The control unit 50 further has an operation panel 54 as an operation unit that can be operated by the user. The operation panel 54 has operation buttons such as a power button and a setting button, operation switches, and the like.

Next, operation of the printer 10 will be described.

Please refer to FIGS. 2 and 3(a). Ink is supplied from the ink cartridge 16 to the damper 15d when the pump 18 is activated by receiving a signal from the control unit 50 . When the inside of the damper 15d is sufficiently filled with ink, the pressure inside the damper 15d, the liquid feeding tube 17, and the pressure below the partition wall 32 of the valve 30 rises. The ink remaining amount detection sensor 15 s detects that the amount of ink in the damper 15 d has reached a predetermined amount, and sends an electric signal to the control section 50 . Upon receiving the electrical signal, the controller 50 stops the pump 18 . In other words, the controller 50 can control the pump 18 based on the detection signal from the remaining ink detection sensor 15s. The valve 30 keeps the bypass 19 closed.

Please refer to FIGS. 2 and 3(b). If the ink remaining amount detection sensor 15s is out of order, it may not be possible to detect that the amount of ink in the damper 15d has reached a predetermined amount. Therefore, the pump 18 continues to operate. At this time, the ink that has flowed inside the valve box 31 pushes up the valve body 34 . When the valve body 34 is pushed up, the ink passes through the hole 32 a and the bypass passage 19 and returns to the upstream side of the pump 18 . This suppresses an excessive increase in pressure inside the damper 15d.

Please refer to FIGS. 2 and 3(c). As the pump 18 continues to operate, the ink inside the ink cartridge 16 may become empty. If the pump 18 continues to operate in an empty state, the valve body 34 is subjected to a force that is pulled upward by the negative pressure and a force that is pushed upward by the positive pressure.

See FIG. 3(d). Since the force that pulls the valve body 34 upward is applied, the valve body 34 rises and the bypass passage 19 can be opened even when the upward force of the ink is small. Some ink passes through bypass 19 and returns upstream of pump 18 . As a result, the load applied to the ink cartridge 16 can be reduced.

Please refer to FIG. When the ink cartridge 16 becomes empty and part of the ink flows into the bypass passage 19, the flow rate of ink detected by the flow rate detection sensor 21 sharply decreases. This information is sent to the controller 50 by electrical signals. The controller 50 can detect that the ink cartridge 16 has become empty from the rapid decrease in the flow rate of ink. When the control unit 50 detects that the ink cartridge 16 is empty, the pump 18 is stopped. That is, the controller 50 can stop the pump 18 in operation based on the detection signal of the flow rate detection sensor 21 .

The valve 30 returns ink from the downstream side to the upstream side only when the differential pressure between the pressure on the upstream side of the pump 18 and the pressure on the downstream side of the pump 18 exceeds a predetermined pressure. It can be said to open up.

Printer 10 can be described as follows.

Please refer to FIGS. The printer 10
a carriage 14 supported by the rail 13 and provided movably on the rail 13;
an ink ejection unit 15 that is supported by the carriage 14 and ejects ink onto the medium Me;
an ink remaining amount detection sensor 15s provided in the ink ejection unit 15 and capable of detecting that the ink filled in the ink ejection unit 15 has reached a predetermined amount;
an ink cartridge 16 filled with ink to be ejected onto the medium Me;
a liquid feeding tube 17 connected from the ink cartridge 16 to the ink ejection unit 15;
a pump 18 provided in the liquid-sending tube 17 and capable of sending ink from the ink cartridge 16 to the ink ejection unit 15;
a control unit 50 that controls the pump 18 based on the detection signal of the remaining ink detection sensor 15s;
A bypass in which one end 19a of the liquid feeding tube 17 is connected upstream of the pump 18 and the other end 19b of the liquid feeding tube 17 is connected downstream of the pump 18, with reference to the direction of ink flow. Road 19 and
Provided on the bypass 19, only when the differential pressure between the pressure on the upstream side of the pump 18 and the pressure on the downstream side of the pump 18 becomes a predetermined pressure or more (the pressure difference is a predetermined value or more) , and a valve 30 that opens to return ink from downstream to upstream.

For example, if the ink remaining amount detection sensor 15 s fails, ink continues to be supplied into the ink ejection unit 15 . By continuing to supply ink to the ink ejection unit 15, the pressure of the ink on the downstream side of the pump 18 increases. When the pressure exceeds a predetermined pressure, valve 30 is opened and ink flows to bypass 19 . The ink that has flowed through the bypass 19 is returned to the upstream side of the pump 18 . By flowing the ink through the bypass passage 19 and returning it to the upstream side of the pump 18, the pressure downstream of the pump 18 can be reduced. Even when the ink remaining amount detection sensor 15s fails, the load on the ink ejection unit 15 can be reduced. It is possible to provide the printer 10 that can more reliably reduce the load on the ink ejection unit 15 .

In particular, the valve 30 preferably opens to return ink from the downstream side to the upstream side only when the pressure on the downstream side of the pump 18 exceeds a predetermined pressure.

The valve opening pressure is set so that the valve 30 is closed when the pressure in the ink ejection unit 15 falls below a certain level.

When the pressure inside the ink ejection unit 15 is below a certain level, the ink ejection unit 15 needs to be filled with ink immediately. By closing the valve 30, the ink is prevented from flowing to the bypass passage 19, and the ink ejection unit 15 can be quickly filled with ink.

A flow rate detection sensor 21 capable of detecting the flow rate of ink is provided downstream of the pump 18,
The control unit 50 can stop the operating pump 18 based on the detection signal of the flow rate detection sensor 21 .

When the ink cartridge 16 is empty, the valve 30 is opened and some of the ink flows through the bypass passage 19 . As a result, the amount of ink flowing downstream from the pump 18 sharply decreases. The controller 50 can quickly detect that the ink cartridge 16 is empty by detecting a sudden change in the amount of ink flowing. In this case, the ink cartridge 16 does not need to be equipped with an ink remaining amount sensor, which is advantageous.

The flow rate detection sensor 21 is further connected downstream of the portion P1 where the other end 19b of the bypass passage 19 is connected to the liquid feeding tube 17 .

The amount of decrease in ink when the ink cartridge 16 is empty becomes more pronounced on the downstream side of the portion P1 where the other end 19b of the bypass passage 19 is connected to the liquid feeding tube 17 . By arranging the flow rate detection sensor 21 downstream of the portion P1 connected to the liquid feeding tube 17, it is possible to more reliably detect that the ink cartridge 16 is empty.

The liquid-feeding tube 17 has a liquid-feeding moving portion 17b that follows the movement of the carriage 14, and a liquid-feeding fixed portion 17a that is fixed regardless of the position of the carriage 14,
The flow rate detection sensor 21 faces the liquid feeding fixed portion 17a.

When the flow rate detection sensor 21 is arranged in the liquid transfer moving portion 17 b , the flow rate detection sensor 21 also moves together with the liquid transfer tube 17 . In this case, it is necessary to increase the size of the power (for example, motor) for moving the liquid feeding tube 17 by the weight of the flow rate detection sensor 21 . Since the flow rate detection sensor 21 faces the liquid-feeding fixed portion 17a, the liquid-feeding tube 17 and/or the power for moving the liquid-feeding tube 17 can be reduced in size. This contributes to miniaturization of the printer 10 as a whole.

It should be noted that the present invention is not limited to the examples as long as the action and effects of the present invention are exhibited.

The printer of the present invention is suitable for inkjet printers.

DESCRIPTION OF SYMBOLS 10... Printer 11... Conveyance part 13... Rail 14... Carriage 15... Ink ejection unit 15s... Ink residual amount detection sensor 16... Ink cartridge 17... Liquid sending tube 17a... Liquid sending fixed part 17b... Liquid sending moving part 18... Pump 19 Bypass path 19a One end 19b Other end 21 Flow rate detection sensor 30 Valve 50 Control unit P1 A portion where the other end is connected to a liquid feeding tube Me Media

Claims (4)

a carriage supported by a rail and provided movably on the rail;
an ink ejection unit that is supported by the carriage and ejects ink onto a medium ;
an ink remaining amount detection sensor provided in the ink ejection unit and capable of detecting that the ink filled in the ink ejection unit has reached a predetermined amount;
an ink cartridge filled with the ink to be ejected onto the medium;
a liquid feeding tube connected from the ink cartridge to the ink ejection unit;
a pump provided in the liquid-sending tube and capable of sending the ink from the ink cartridge to the ink ejection unit;
a control unit that controls the pump based on the detection signal of the ink remaining amount detection sensor;
A bypass passage having one end connected to the upstream side of the pump of the liquid-sending tube and the other end of the liquid-sending tube connected to the downstream side of the pump, with reference to the direction in which the ink flows. and,
Provided on the bypass passage, only when the differential pressure between the pressure on the upstream side of the pump and the pressure on the downstream side of the pump becomes equal to or greater than a predetermined pressure, from the downstream side to the upstream side a valve that opens to return the ink ,
A printer according to claim 1, wherein the valve is set to open when the ink inside the ink cartridge is empty . a flow rate detection sensor capable of detecting the flow rate of the ink is provided downstream of the pump;
2. The printer according to claim 1 , wherein the controller can stop the pump in operation based on the detection signal of the flow rate sensor. 3. A printer according to claim 2 , wherein said flow rate detection sensor is further connected downstream of a portion where the other end of said bypass is connected to said liquid feeding tube. The liquid-feeding tube has a liquid-feeding moving part that follows the movement of the carriage and a fixed liquid-feeding part that is fixed regardless of the position of the carriage,
4. The printer according to claim 2 , wherein said flow rate detection sensor faces said liquid feeding fixed portion.

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