JP3692526B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, pressurized air generated by an air pressure pump is applied to a main tank in which ink is stored, and ink is applied from the main tank to a recording head mounted on a carriage by the action of the pressurized air. The present invention relates to an ink jet recording apparatus configured to replenish.
[0002]
[Prior art]
Inkjet recording apparatuses are used for many printing including color printing in recent years because noise during printing is relatively small and small dots can be formed with high density. Such an ink jet recording apparatus is generally mounted on a carriage and moved in the width direction of the recording paper, and the recording paper is moved relatively in a direction perpendicular to the moving direction of the recording head. Paper feeding means is provided, and recording is performed on the recording paper by ejecting ink droplets from the recording head based on the print data.
[0003]
A recording head capable of ejecting, for example, black, yellow, cyan, and magenta inks is mounted on the carriage, enabling not only text printing with black ink but also full-color printing by changing the ejection ratio of each ink. Yes.
[0004]
On the other hand, in this type of recording apparatus provided for office use or business use, it is necessary to provide a large-capacity ink cartridge in order to cope with a relatively large amount of printing. For example, a recording apparatus of a type in which a main tank is loaded into a mounting apparatus (cartridge holder) disposed on the apparatus main body side is provided.
[0005]
A sub tank is disposed on the carriage on which the recording head is mounted, and each main tank supplies ink to each sub tank via an ink supply tube, and each sub tank supplies ink to each recording head. Is configured to supply.
[0006]
[Problems to be solved by the invention]
Nowadays, there is a demand for a large recording apparatus having a long carriage scanning distance capable of printing on a large sheet. In such a printing apparatus, in order to improve the throughput, the number of nozzles is increasingly increased in the printing head. Furthermore, in order to improve throughput, it is possible to replenish ink sequentially from the main tank to each sub-tank mounted on the carriage while printing is performed, so that ink can be stabilized from each sub-tank to the recording head. And a recording apparatus that can be supplied.
[0007]
In such a recording apparatus, it is necessary to connect an ink supply tube corresponding to each ink from the main tank to the sub tank on the carriage, and the scanning distance of the carriage is inevitably large. Will increase. In addition, as described above, since the number of nozzles in the recording head is increased, the amount of ink consumed is large, and the dynamic pressure (pressure loss) of the ink in each ink supply tube connected from the main tank to the sub tank is high. Increasingly, there is a technical problem that the amount of ink replenished to the sub tank is insufficient.
[0008]
As one means for solving such a problem, for example, air pressure is applied to the main tank side and a forced ink flow is generated from the main tank to the sub tank by the air pressure. A configuration for replenishing ink may be employed.
[0009]
When trying to adopt such a configuration, an air pressurizing pump for applying pressurized air to the main tank side is required. The air pressurizing pump can stably apply pressurized air to the main tank side by constantly driving the driving power supply to the recording apparatus when the power is turned on. Operation can be ensured.
[0010]
However, when the pressure pump is always driven, noise generated by the pressure pump becomes a problem, and the durability of the pressure pump is also a problem. Therefore, another problem of cost increase for these countermeasures also occurs. Therefore, it is desirable to configure the pressurizing pump to be intermittently driven within a range in which an appropriate air pressure for each main tank can be maintained. In this case, a pressure detector that detects the air pressure applied to each main tank and controls the driving operation of the pressurizing pump by the detection output is suitably employed.
[0011]
On the other hand, the ink replenished from the main tank to the sub tank has a temperature-dependent characteristic in which the viscosity changes depending on the environmental temperature. That is, when the environmental temperature is low, the viscosity of the ink is high, and the viscosity decreases as the environmental temperature increases. Therefore, the ink replenishment flow rate from the main tank to the sub tank has a temperature-dependent characteristic that increases as the temperature increases.
[0012]
As described above, in a recording apparatus that employs a mode in which ink is replenished from the main tank to the sub tank, the ink replenishment flow rate from the main tank to the sub tank can be suppressed to a certain range without depending on the environmental temperature. desired. In this case, it is possible to suppress the change in the ink replenishment flow rate from the main tank to the sub tank within a predetermined range by controlling the set pressure of the pressurized air applied to the main tank according to the temperature change. Become.
[0013]
The present invention has been made based on the above-described technical viewpoint, and has a function capable of maintaining the change amount of the ink flow rate sent from the main tank within a predetermined range even when the change in the environmental temperature is received. An object of the present invention is to provide an ink jet recording apparatus provided with a pressure detector.
[0014]
[Means for Solving the Problems]
  Inkjet recording apparatus according to the present invention made to achieve the above-described objectOne form ofPressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured as described above, wherein an air flow path between the air pressurizing pump and a main tank has a diaphragm that receives and displaces the pressurized air, and pressure detection based on a displacement amount of the diaphragm A pressure detector having a signal generating means for generating a signal, the diaphragm is made of a material whose hardness changes according to an environmental temperature, and is based on a pressure detection signal generated by the signal generating means Configured to control the drive of the air pressurization pumpAt the same time, the temperature dependency characteristic of the pressure value at which the pressure detection signal is generated by the signal generating means is substantially equal to the temperature dependency characteristic of the viscosity of the ink replenished from the main tank to the recording head side.Composed.
  In another embodiment of the ink jet recording apparatus according to the present invention, pressurized air generated by an air pressurizing pump is applied to a main tank in which ink is stored. An ink jet recording apparatus configured to replenish ink from a main tank to a recording head mounted on a carriage, wherein the pressurized air is provided in an air flow path between the air pressurizing pump and the main tank. A pressure detector including a diaphragm that is displaced in response to the diaphragm and a signal generation unit that generates a pressure detection signal based on a displacement amount of the diaphragm, and the diaphragm has a material whose hardness changes according to an environmental temperature. And configured to control driving of the air pressurizing pump based on a pressure detection signal generated by the signal generating means. In addition, the temperature dependency characteristic of the pressure value at which the pressure detection signal is generated by the signal generating unit is configured to be substantially equal to the temperature dependency characteristic of the pressure loss in the ink supply path supplied from the main tank. The
  In another embodiment of the ink jet recording apparatus according to the present invention, pressurized air generated by an air pressurizing pump is applied to a main tank in which ink is stored. An ink jet recording apparatus configured to replenish ink from a main tank to a recording head mounted on a carriage, wherein the pressurized air is provided in an air flow path between the air pressurizing pump and the main tank. A pressure detector including a diaphragm that is displaced by receiving and a signal generation unit that generates a pressure detection signal based on a displacement amount of the diaphragm, and the diaphragm is a material whose volume changes according to an environmental temperature. And configured to control driving of the air pressurizing pump based on a pressure detection signal generated by the signal generating means. In addition, the temperature dependency characteristic of the pressure value at which the pressure detection signal is generated by the signal generating means is configured to be substantially equal to the temperature dependency characteristic of the viscosity of the ink supplied from the main tank to the recording head. The
[0015]
  Also,In another embodiment of the ink jet recording apparatus according to the present invention, pressurized air generated by an air pressurizing pump is applied to a main tank in which ink is stored, and the main tank is operated by the action of the pressurized air. An ink jet recording apparatus configured to replenish ink from a recording head to a recording head mounted on a carriage, wherein the compressed air is received in an air flow path between the air pressure pump and the main tank. A pressure detector having a diaphragm that displaces and a signal generation means that generates a pressure detection signal based on a displacement amount of the diaphragm, and the diaphragm is made of a material whose volume changes according to an environmental temperature And configured to control driving of the air pressurizing pump based on a pressure detection signal generated by the signal generating means. In both cases, the temperature dependency characteristic of the pressure value at which the pressure detection signal is generated by the signal generation unit is configured to be substantially equal to the temperature dependency characteristic of the pressure loss in the ink supply path supplied from the main tank. .
  In another embodiment of the ink jet recording apparatus according to the present invention, pressurized air generated by an air pressurizing pump is applied to a main tank in which ink is stored. An ink jet recording apparatus configured to replenish ink from a main tank to a recording head mounted on a carriage, wherein the pressurized air is provided in an air flow path between the air pressurizing pump and the main tank. A pressure detector including a diaphragm that is displaced in response to the displacement of the diaphragm and a signal generation unit that generates a pressure detection signal based on a displacement amount of the diaphragm, and a movable unit that mechanically couples the diaphragm and the signal generation unit. The member is made of a material whose dimension in the movable direction changes according to the environmental temperature, and the pressure detection signal generated by the signal generating means And the temperature dependent characteristic of the pressure value at which the pressure detection signal is generated by the signal generating means is replenished from the main tank to the recording head side. The ink is configured to be approximately equal to the temperature-dependent characteristic in the viscosity of the ink.
  Furthermore, in another embodiment of the ink jet recording apparatus according to the present invention, pressurized air generated by an air pressurizing pump is applied to a main tank in which ink is stored. An ink jet recording apparatus configured to replenish ink from a main tank to a recording head mounted on a carriage, wherein the pressurized air is provided in an air flow path between the air pressurizing pump and the main tank. A pressure detector including a diaphragm that is displaced in response to the displacement of the diaphragm and a signal generation unit that generates a pressure detection signal based on a displacement amount of the diaphragm, and a movable unit that mechanically couples the diaphragm and the signal generation unit. The member is made of a material whose dimension in the movable direction changes according to the environmental temperature, and the pressure detection signal generated by the signal generating means. And a temperature-dependent characteristic of a pressure value at which a pressure detection signal is generated by the signal generating means is configured to control driving of the air pressurizing pump based on the ink supplied from the main tank. It is comprised so that it may become substantially equal to the temperature dependence characteristic of the pressure loss in the replenishment path.
[0016]
  In this case, the diaphragm is made of a material that changes so that the hardness is high at a low temperature and the hardness is low at a high temperature. The diaphragm may be made of a material that changes so that the volume contracts in a low temperature state and the volume expands in a high temperature state. Further, the diaphragm may be made of a material that changes so that the volume contracts in a low temperature state and the volume expands in a high temperature state.
[0017]
Preferably, ink is supplied from the main tank to a sub tank mounted on the carriage via an ink supply path, and ink is supplied from the sub tank to the recording head mounted on the carriage. . In addition, the ink supply path from the main tank to the sub tank is constituted by a flexible ink supply tube.
[0018]
In a preferred embodiment, the signal generating means includes a movable member that is advanced and retracted by the displacement of the diaphragm, and a photosensor that includes a light source and a light receiving element that are arranged so as to traverse the movement path of the movable member. And configured to generate the pressure detection signal based on an output of a light receiving element constituting the photosensor.
[0019]
In another preferred embodiment, the signal generating means includes a movable member that is advanced and retracted by a displacement of a diaphragm, a light source that projects light onto a movement path of the movable member, and the light source that is based on the movement of the movable member. And a light sensor that receives the reflected light, and is configured to generate the pressure detection signal based on an output of the light receiving element that constitutes the photo sensor.
[0020]
In any of the above-described embodiments, the diaphragm is made of an elastic material, and the movable member is advanced and retracted based on the displacement of the diaphragm due to the balance between the air pressure received by the diaphragm and the return force of the diaphragm. The made configuration can be adopted. The movable member further comprises a spring member that urges the diaphragm in the return direction, and the movable member is based on the displacement of the diaphragm due to the balance between the air pressure received by the diaphragm, the return force of the diaphragm, and the urging force of the spring member. It is also possible to adopt a configuration that is adapted to be advanced and retracted.
[0022]
According to the above-described ink jet recording apparatus, since the pressurized air generated by the pressure pump is applied to the main tank, the air pressure acts on the recording head mounted on the carriage. The amount of ink can be replenished. The pressure state of the main tank is monitored by a pressure detector arranged in the air flow path between the air pressure pump and the main tank, and the pressure is detected by a pressure detection signal generated by the pressure detector. The pump is controlled to be driven intermittently.
[0023]
In this case, the pressure detector is provided with a diaphragm that is displaced by receiving the air pressure of the pressurized air. Based on the displacement amount of the diaphragm, the signal generating means generates a pressure detection signal for controlling the driving of the pressure pump. appear. The signal generating means includes a movable member that is advanced and retracted by the displacement of the diaphragm, and a pressure detection signal for controlling the driving of the pressure pump is generated by detecting the movement state of the movable member by a photo sensor. The
[0024]
In this case, in response to a change in ink viscosity due to a change in environmental temperature, the flow rate of ink replenished from the main tank to the sub-tank is slow in the low temperature state and increases as the high temperature state is reached. Therefore, the diaphragm provided in the pressure detector is configured by using a material that changes in hardness so that the hardness is low in a low temperature state and low in a high temperature state, so that the diaphragm is displaced in a low temperature state. Since the driving of the movable member is suppressed, the pressure value when the moving state of the movable member is detected by the photosensor becomes high. Therefore, the air pressurization pump continues to be driven, and thereby the flow rate of ink replenished from the main tank to the sub tank is increased. On the other hand, in a high temperature state, the driving action of the movable member due to the displacement of the diaphragm is promoted, and the pressure value when the moving state of the movable member is detected by the photosensor becomes low. Accordingly, since the driving of the air pressurization pump is stopped early, this acts to reduce the flow rate of the ink replenished from the main tank to the sub tank.
[0025]
In addition, the diaphragm provided in the pressure detector is made of a material that changes in volume so that the volume contracts in a low temperature state and expands in a high temperature state, so that the diaphragm contracts in a low temperature state. Thus, since the movable member is substantially shifted away from the detection region of the photosensor, the pressure value when the moving state of the movable member is detected by the photosensor becomes high. Therefore, the air pressurization pump continues to be driven, and thereby the flow rate of ink replenished from the main tank to the sub tank is increased. On the other hand, in a high temperature state, the diaphragm expands and the movable member is shifted so as to substantially approach the detection area of the photosensor. Therefore, the pressure when the moving state of the movable member is detected by the photosensor is increased. The value becomes lower. Accordingly, since the driving of the air pressurization pump is stopped early, this acts to reduce the flow rate of the ink replenished from the main tank to the sub tank.
[0026]
Furthermore, the movable member that mechanically couples the diaphragm and the signal generating means is configured by using a material whose dimension in the movable direction contracts in a low temperature state and expands in a high temperature state. In the temperature state, the movable member contracts and the tip of the movable member is shifted so as to be far from the detection area of the photosensor. The value becomes higher. Therefore, the air pressurization pump continues to be driven, and thereby the flow rate of ink replenished from the main tank to the sub tank is increased. On the other hand, when the movable member expands in a high temperature state and is shifted so that the tip of the movable member substantially approaches the detection area of the photosensor, the movement state of the movable member is detected by the photosensor. The pressure value becomes low. Accordingly, since the driving of the air pressurization pump is stopped early, this acts to reduce the flow rate of the ink replenished from the main tank to the sub tank.
[0027]
By adopting the pressure detector having the above-described action, the change amount of the ink flow rate replenished from the main tank to the sub tank can be maintained within a predetermined range even when the environmental temperature changes. Since the above-described function can be obtained with a relatively simple configuration using a diaphragm and a photosensor, this can be realized at a relatively low cost.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a top view showing an example of an ink jet recording apparatus to which the present invention can be applied. In FIG. 1, reference numeral 1 denotes a carriage. The carriage 1 is guided by a scanning guide member 4 via a timing belt 3 driven by a carriage motor 2, in the longitudinal direction of the paper feeding member 5, that is, in the width direction of the recording paper. It is configured to reciprocate in a certain main scanning direction. Although not shown in FIG. 1, an ink jet recording head 6 described later is mounted on the surface of the carriage 1 that faces the paper feeding member 5.
[0029]
The carriage 1 is equipped with sub tanks 7a to 7d for supplying ink to the recording head. In this embodiment, four sub-tanks 7a to 7d are provided corresponding to each ink in order to temporarily store each ink therein. A flexible ink supply tube 10 that constitutes an ink supply path from main tanks 9a to 9d as ink cartridges loaded in a cartridge holder 8 disposed at the end of the apparatus with respect to the sub tanks 7a to 7d. , 10,..., Black, yellow, magenta and cyan inks are supplied.
[0030]
On the other hand, a capping unit 11 capable of sealing the nozzle forming surface of the recording head is disposed in a non-printing area (home position) on the movement path of the carriage 1, and further on the upper surface of the capping unit 11. Is provided with a cap member 11a formed of a flexible material such as rubber that can seal the nozzle forming surface of the recording head. Then, when the carriage 1 moves to the home position, the nozzle forming surface of the recording head is sealed by the cap member 11a.
[0031]
The cap member 11a functions as a lid that seals the nozzle forming surface of the recording head and prevents the nozzle openings from drying during the rest period of the recording apparatus. Although not shown in the figure, one end of a tube in a suction pump (tube pump) is connected to the cap member 11a, and a negative pressure by the suction pump is applied to the recording head so that ink is discharged from the recording head. A cleaning operation for sucking and discharging is performed. Further, a wiping member 12 made of an elastic material such as rubber is disposed on the print area side adjacent to the capping means 11 so that the nozzle forming surface of the recording head can be wiped and cleaned as necessary. It is configured.
[0032]
Next, FIG. 2 schematically shows a configuration of an ink supply system mounted on the recording apparatus shown in FIG. 1, and this ink supply system will be described with reference to FIG. In FIG. 1 and FIG. 2, reference numeral 21 denotes an air pressurization pump, and the air pressurized by the air pressurization pump 21 is supplied to the pressure adjustment valve 22, and further a pressure detector from the pressure adjustment valve 22. The compressed air is supplied to each of the main tanks 9a to 9d (shown as a representative symbol 9 in FIG. 2 and may be described as a representative symbol 9 in the following). It is configured to be.
[0033]
The pressure regulating valve 22 has a function of releasing the pressure and maintaining the air pressure applied to the main tanks 9a to 9d within a predetermined range when the air pressure pressurized by the air pressurizing pump 21 reaches an excessive state. Have. This is because some trouble occurs in a control system by a pressure detector 23 and an air pressurizing pump 21 which will be described later, the pressurizing pump 21 continues to be driven, and an excessive air pressure is applied to the main tank 9 and will be described later. This works to avoid problems such as damage to the ink pack 24.
[0034]
Further, the pressure detector 23 functions to detect the air pressure pressurized by the air pressurizing pump 21 and to control the driving of the air pressurizing pump 21. That is, when it is detected that the air pressure pressurized by the air pressurizing pump 21 has reached a predetermined pressure, the driving of the air pressurizing pump 21 is stopped and the air pressure is determined by the pressure detector 23. When it is detected that the pressure has become lower than the pressure, the air pressurizing pump 21 is controlled to be driven, and the air pressure applied to each of the main tanks 9a to 9d is maintained within a predetermined range by repeating this operation. Function.
[0035]
As shown in FIG. 2, the outline of the main tank 9 is formed in an airtight state, and an ink pack 24 formed of a flexible material encapsulating ink is contained therein. It is stored. A space formed by the main tank 9 and the ink pack 24 constitutes a pressure chamber 25, and pressurized air is supplied into the pressure chamber 25 via the pressure detector 23. ing. With this configuration, the ink packs 24 stored in the main tanks 9a to 9d receive pressure from the pressurized air, and ink flows are generated from the main tanks 9a to 9d to the sub tanks 7a to 7d. It is configured as follows.
[0036]
The ink pressurized in the main tanks 9a to 9d passes through the ink supply valves 26, 26... And the ink supply tubes 10, 10,. The sub-tanks 7a to 7d mounted on the carriage 1 (represented by the reference numeral 7 in FIG. 2 as a representative and may be simply described as the reference numeral 7 in the following) may be supplied. Has been.
[0037]
As shown in FIG. 2, the sub tank 7 has a float member 31 disposed therein, and a permanent magnet 32 is attached to a part of the float member 31. Magnetoelectric conversion elements 33 a and 33 b typified by Hall elements are attached to the substrate 34 and attached to the side wall of the sub tank 7. With this configuration, the permanent magnet 32 disposed on the float member 31 and the ink that generates an electrical output by the Hall elements 33a and 33b according to the magnetic force dose by the permanent magnet 32 according to the floating position of the float member. It constitutes a quantity detection means.
[0038]
Therefore, for example, when the amount of ink in the sub tank 7 decreases, the position of the float member 31 accommodated in the sub tank moves in the direction of gravity, and accordingly, the position of the permanent magnet 32 also moves in the direction of gravity. . Therefore, the electrical output of the Hall elements 33a and 33b due to the movement of the permanent magnet can be sensed as the amount of ink in the sub-tank 7, and the ink supply valve is determined by the electrical output obtained by the Hall elements 33a and 33b. 26 is opened. Thereby, the ink pressurized in the main tank 9 is individually sent out to each sub tank 7 in which the ink amount is reduced.
[0039]
When the ink amount in the sub tank 7 reaches a predetermined capacity, the ink supply valve 26 is closed based on the electrical outputs of the Hall elements 33a and 33b. By repeating such operation, the ink is intermittently replenished from the main tank to the sub-tanks, so that a substantially constant range of ink is always stored in each sub-tank.
[0040]
As described above, each ink pressurized by the air pressure in the sub tank is supplied with ink to each sub tank based on the electrical output based on the position of each float member arranged in the sub tank. Therefore, the ink replenishment response can be improved, and the amount of ink stored in the sub tank is appropriately managed.
[0041]
Each sub tank 7 is configured to supply ink to the recording head 6 through a valve 35 and a tube 36 connected thereto, and is supplied to an actuator (not shown) of the recording head 6. Based on the print data, the ink droplets are ejected from the nozzle openings 6 a formed on the nozzle formation surface of the recording head 6. In FIG. 2, reference numeral 11 denotes the capping means described above, and the tube connected to the capping means 11 is connected to a suction pump (tube pump) (not shown).
[0042]
FIG. 3 is a cross-sectional view of the first embodiment of the pressure detector 23 described above. The pressure detector 23 includes an upper case 41 whose outer shape is formed in a cylindrical shape, and a lower case 42 whose outer shape is also formed in a cylindrical shape, and between the upper case 41 and the lower case 42. The diaphragm 43 formed in a disk shape by a flexible elastic member is arranged in a form in which the peripheral edge is sandwiched.
[0043]
As shown in FIG. 3, the diaphragm 43 has a thick portion 43a formed at the center thereof, and a thin wall having a semicircular cross section between the thick portion 43a and the peripheral portion. A portion 43b is formed. The diaphragm 43 is preferably made of a rubber material. The rubber material is preferably NBR and has a rubber hardness of 40 to 60 degrees. Moreover, the diaphragm 43 may be formed in a state in which a cloth is filled with a rubber material, and in this case, durability as a diaphragm can be enhanced.
[0044]
On the other hand, a cylindrical body 41a is formed integrally with the upper portion of the upper case 41, and an inner cylindrical body 41b is formed integrally with the cylindrical body 41a on the further inner upper portion of the cylindrical body 41a. . In the cross-sectional state shown in FIG. 3, the inner cylinder 41b is drawn in a floating state, but the inner cylinder 41b is orthogonal to the circumferential direction with respect to the state shown in the figure. In position, it is coupled to the cylinder 41a. In other words, as shown in the figure, a pair of openings 41c are formed between the cylindrical body 41a and the inner cylindrical body 41b so as to face each other.
[0045]
A movable member 44 is accommodated inside the cylindrical body 41a so as to be slidable in the axial direction (vertical direction in FIG. 3). The movable member 44 is formed in a bifurcated shape, and a claw-like stopper member 44a is formed at each tip portion. The stopper member 44a enters the opening 41c, and an upper end portion of the cylindrical body 41a. It is comprised so that it may engage with.
[0046]
The movable member 44 is formed with an upright portion 44b that is integrally raised from the inner bottom thereof. In the embodiment shown in FIG. 3, the lower end portion of the inner cylindrical body 41b and the inner portion of the movable member 44 are formed. Between the bottom portion, a coiled spring member 45 is disposed so as to equip the standing portion 44b. With this configuration, the movable member 44 is configured to be urged downward in the figure by the spring member 45, and therefore the lower bottom portion of the movable member 44 is the upper surface of the thick portion 43 a at the center of the diaphragm 43. It is comprised so that it may contact | abut.
[0047]
On the other hand, the lower case 42 has a connection for introducing pressurized air from the air pressurizing pump 21 to the space 42a between the lower case 42 and the diaphragm 43 at the lower bottom thereof. A pipe 42b and a plurality of pressurized air distribution connecting pipes 42c for distributing pressurized air from the space 42a to the main tanks 9 are formed. In this embodiment, the four main tanks 9 are provided as described above. In this case, four connection pipes 42c for distributing pressurized air are provided according to the number of the connection tanks 42c. FIG. 4 shows two connection pipes 42c for distributing pressurized air because this is shown in a sectional view.
[0048]
With this configuration, the pressurized air from the air pressurizing pump 21 is introduced into the space portion 42a of the pressure detector 23 via the connecting pipe 42b for introducing pressurized air, and the connecting pipe for distributing each pressurized air. It acts so that pressurized air is applied to the pressure chamber 25 in each main tank 9 via 42c. In response to the action of the pressurized air introduced into the space portion 42a, the diaphragm 43 is displaced upward in the figure and acts to push up the movable member 44 upward. A space formed between the diaphragm 43 and the upper case 41 is communicated with the atmosphere through a gap between the cylindrical body 41 a and the movable member 44.
[0049]
In this embodiment, as described above, the movable member 44 is configured to be urged downward in the figure by the spring member 45, and therefore, the air pressure received by the diaphragm 43 and the elasticity of the diaphragm. The movable member 44 is moved up and down based on the displacement of the diaphragm due to the balance between the return force due to the force and the biasing force of the spring member 45.
[0050]
On the other hand, a photosensor 46 that constitutes a signal generating means is disposed in the movement region of the tip of the upright portion 44b formed on the movable member 44. The light source 46a and the light receiving element 46b are arranged so as to face the photo sensor 46. Therefore, when the diaphragm 43 is displaced more than a predetermined value by receiving the pressurized air introduced into the space portion 42a, The tip of the upright portion 44b formed on the movable member 44 acts so as to block the optical axes of the light source 46a and the light receiving element 46b constituting the photosensor 46.
[0051]
Therefore, when the air pressurizing pump 21 is driven and the pressurized air reaches a predetermined pressure or more, the upright portion 44b is pushed up by the displacement of the diaphragm, and the optical axis by the photosensor 46 is cut off. The driving of the air pressurization pump 21 is stopped based on the output of the light receiving element 46b. Further, when the air pressure decreases due to ink consumption or the like, the distal end portion of the standing portion 44b formed on the movable member 44 is caused by the return force due to the elasticity of the diaphragm and the urging force of the spring member 45, so that the light source 46a. And the light receiving element 46b. As a result, an output is generated in the light receiving element 46b, and a pressure detection signal for driving the air pressurizing pump 21 is generated based on the output.
[0052]
In this case, the pressure detection signal based on the output of the light receiving element 46b constituting the photosensor may be used to drive or stop a motor (not shown) directly connected to the air pressurization pump 21, for example, or When a motor for driving another mechanism unit is also used, it can be used to control the engagement of a clutch mechanism (not shown) arranged in the drive system.
[0053]
3, the movable member 44 is formed with a stepped portion 44d for preventing the diaphragm 43 from excessively preventing displacement when pressurized air is received. . In order to explain this configuration and operation, the portion A in FIG. 3 is shown in an enlarged manner in FIG. That is, the diagram shown in the upper half of FIG. 4 shows a state in which the diaphragm receives normal or lower air pressure, and the diagram shown in the lower half of FIG. 4 shows that the diaphragm has an air pressure exceeding a predetermined level. The received state is shown.
[0054]
As shown in FIG. 4, when the diaphragm changes from the normal or lower air pressure state to the predetermined air pressure state or more, the movable member 44 moves upward in the figure, A stepped portion 44d formed on an upright portion 44b erected integrally from the inner bottom portion of the movable member 44 abuts against the abutting portion 41d constituting the lower end portion of the inner cylindrical body 41b, thereby preventing further elevation of the movable member 44. Is configured to do. Thereby, it is possible to avoid the diaphragm 43 from being excessively displaced, and a normal function as the pressure detector 23 is ensured.
[0055]
Further, in the embodiment shown in FIG. 3, the movable member 44 is formed in a bifurcated shape, and a claw-like stopper member 44a is disposed at each tip, so that the stopper member 44a is a cylindrical body 41a. The diaphragm 43 is configured not to be excessively displaced by the spring member 45 by engaging with the upper end portion of the spring member 45. However, when the claw-shaped stopper member 44a as described above is not formed, a cylindrical stopper member 42d is integrally formed at the center of the lower bottom portion of the lower case 42 as indicated by an imaginary line, thereby It is desirable to act to prevent excessive displacement.
[0056]
Next, FIG. 5 shows a second embodiment of the pressure detector by a cross-sectional view. Note that the pressure detector 23 shown in FIG. 5 has the same configuration as that shown in FIGS. 3 and 4 except for the portion of the photosensor 46. Therefore, parts corresponding to the representative parts shown in FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0057]
In the form shown in FIG. 5, the photosensor 46 has a light source 46 a that projects light on a moving path of the upright portion 44 b in the movable member and a light receiving element 46 b that receives the reflected light of the light source based on the movement of the upright portion 44 b. It is comprised by. Therefore, in this configuration, a white synthetic resin material having good reflection characteristics is used as the upright portion 44b, or the upright portion 44b corresponding to the path of the projection light in the light source 46a is made of, for example, aluminum foil. It is desirable to arrange the reflecting member 44c.
[0058]
According to the configuration shown in FIG. 5, when the air pressurizing pump 21 is driven and the pressurized air reaches a predetermined pressure or more, the upright portion 44b of the movable member is pushed up by the displacement of the diaphragm 43, and the upright portion 44b The front end portion or the reflection member 44c disposed on the front end receives the projection light from the light source 46a and reflects it toward the light receiving element 46b. Based on the output of the light receiving element 46b, a pressure detection signal for stopping the driving of the air pressurizing pump 21 is generated.
[0059]
Further, when the air pressure decreases due to ink consumption or the like, the distal end portion of the upright portion 44b formed on the movable member 44 is caused by the return force due to the elasticity of the diaphragm and the urging force of the spring member 45 to generate the light source 46a. Away from the optical axis. As a result, the projection of the reflected light on the light receiving element 46b is blocked, and a pressure detection signal for driving the air pressurizing pump 21 is generated.
[0060]
In the embodiment of the pressure detector 23 shown in FIG. 3 to FIG. 5 described above, between the lower end of the inner cylinder 41b formed on the upper case 41 and the inner bottom portion of the movable member 44, A coiled spring member 45 is arranged so as to equip the upright portion 44b. However, even in the configuration excluding the spring member 45, the pressure detector 23 having the same function can be configured.
[0061]
In this case, the movable member is configured to move forward and backward based on the displacement of the diaphragm due to the balance between the restoring force of the diaphragm 43 made of an elastic material and the air pressure received by the diaphragm. Therefore, when such a configuration is employed, the lower bottom portion of the movable member 44 is bonded to the upper surface of the thick portion 43a of the diaphragm 43, or the thick portion 43a of the diaphragm 43 is the movable member. It is necessary to be formed integrally with the lower bottom portion of 44 and mechanically connected to each other.
[0062]
By the way, it is desirable that the diaphragm 43 used in the pressure detector 23 is made of a material that changes in hardness so that the hardness is high in a low temperature state and the hardness is low in a high temperature state. As described above, a rubber material is used for the diaphragm 43 as a material having such an action. FIG. 6 shows the relationship between the environmental temperature and the ink replenishment flow rate when the material having the temperature characteristics as described above is used for the diaphragm.
[0063]
As described above, the ink replenished from the main tank to the sub tank has a temperature-dependent characteristic in which the viscosity changes depending on the environmental temperature. When the environmental temperature is low, the viscosity of the ink is high and the environmental temperature is As the temperature increases, the viscosity decreases. An area indicated by A0 in FIG. 6 indicates a replenishment flow rate of ink replenished from the main tank to the sub tank at normal temperature (25 ° C.). Note that the flow velocity having a width of A0 indicates a diaphragm that forms the pressure detector 23 and a range of variation that occurs due to the assembly thereof.
[0064]
When the environmental temperature decreases, the ink replenishment flow rate becomes slower as indicated by A1. Here, by using a material that has a high hardness in a low temperature state for the diaphragm constituting the pressure detector 23, the driving of the movable member 44 due to the displacement of the diaphragm is suppressed in the low temperature state. The pressure value when the moving state is detected by the photosensor 46 increases. Therefore, the air pressurization pump 21 continues to be driven, and thus the flow rate of the ink replenished from the main tank 9 to the sub tank 7 is increased. That is, the ink replenishment flow rate in this case is shifted to a range from A1 to B1.
[0065]
On the other hand, when the environmental temperature rises, the ink replenishment flow rate increases as indicated by A2. Here, by using a material that changes the hardness of the diaphragm constituting the pressure detector 23 so as to be low in a high temperature state, the driving action of the movable member 44 due to the displacement of the diaphragm is promoted in a high temperature state. The pressure value when detecting the movement state of the member by the photosensor 46 becomes low. Accordingly, since the driving of the air pressurizing pump 21 is stopped early, this acts to reduce the flow rate of the ink replenished from the main tank 9 to the sub tank 7. That is, the ink replenishment flow rate in this case is shifted to a range from A2 to B2.
[0066]
As a result, even if the environmental temperature changes from a low temperature state to a high temperature state or vice versa, as a result, the ink replenishment flow rate is shifted from A3 to B3. In other words, the diaphragm constituting the pressure detector 23 and the range of variation generated with the assembly thereof are reduced.
[0067]
In the embodiment described above, the air pressure applied to the pressure chamber 25 in the main tank is such that the lower limit of the ink replenishment flow rate is equal to or faster than the amount of ink ejected by the recording head 6. Must be set to Therefore, as shown in FIG. 6, as a result, the ink replenishment flow rate is shifted to the range of B3 and the lower limit value is increased. Therefore, even if the set pressure of the air pressure applied to the pressure chamber 25 is lowered, the operation is continued. There will be room.
[0068]
Therefore, the set value of the air pressure applied to the pressure chamber 25 of the main tank can be further lowered, and the function of the pressurizing pump 21 and the reliability of each component constituting the air flow path from the pressurizing pump to the main tank. It can contribute to improving.
[0069]
In addition, although the above-mentioned description is made based on the case where the material which changes so that hardness is high as a diaphragm 43 at a low-temperature state and hardness becomes low at a high-temperature state, the volume shrinks as a diaphragm 43 at a low-temperature state. And even if it is comprised with the raw material which changes so that volume may expand in a high temperature state, the same effect can be acquired. In other words, in this case, the diaphragm 43 contracts in a low temperature state, and the upright portion 44b of the movable member 44 is substantially shifted away from the detection area of the photosensor 46. The pressure value when the state is detected by the photosensor 46 increases. Therefore, the air pressurization pump continues to be driven, and thereby the flow rate of ink replenished from the main tank to the sub tank is increased.
[0070]
On the other hand, in a high temperature state, the diaphragm expands, and the upright portion 44b of the movable member 44 is substantially shifted so as to approach the detection region of the photosensor. The pressure value when detecting is lowered. Accordingly, since the driving of the air pressurization pump is stopped early, this acts to reduce the flow rate of the ink replenished from the main tank to the sub tank. Therefore, the ink replenishment flow rate is shifted from the range of A3 shown in FIG. 6 to the range of B3, and as a result, the same effect can be obtained.
[0071]
Further, the movable member 44 that mechanically couples the diaphragm 43 and the photosensor 46 as the signal generating means uses a material whose dimension in the movable direction changes so that it contracts in a low temperature state and expands in a high temperature state. Even if configured, the same effect can be obtained. That is, in this case, in the low temperature state, the dimension in the movable direction of the upright portion 44b of the movable member 44 contracts, and the leading end portion of the movable member is substantially shifted away from the detection area of the photosensor. Therefore, the pressure value when the moving state of the movable member is detected by the photosensor becomes high. Therefore, the air pressurization pump continues to be driven, and thereby the flow rate of ink replenished from the main tank to the sub tank is increased.
[0072]
On the other hand, in the high temperature state, the dimension of the movable member 44 in the movable direction of the upright portion 44b expands and is shifted so that the tip of the movable member substantially approaches the detection area of the photosensor. The value of the pressure when the moving state is detected by the photosensor becomes low. Accordingly, since the driving of the air pressurization pump is stopped early, this acts to reduce the flow rate of the ink replenished from the main tank to the sub tank. Therefore, the ink replenishment flow rate is shifted from the range of A3 shown in FIG. 6 to the range of B3, and as a result, the same effect can be obtained.
[0073]
Even if any one of the above-described means or a combination thereof is adopted, the temperature-dependent characteristic of the pressure value at which the pressure detection signal is generated by the pressure detector is the temperature at the viscosity of the ink replenished from the main tank. It is desirable to configure so as to be approximately equal to the dependence characteristic. Further, it is desirable that the temperature dependence characteristic of the pressure value at which the pressure detection signal is generated by the pressure detector is substantially equal to the temperature dependence characteristic of the pressure loss in the ink replenishment path replenished from the main tank. . As a result, the amount of change in the ink flow rate replenished from the main tank can be maintained within a predetermined range even when the change in environmental temperature is received.
[0074]
【The invention's effect】
As is apparent from the above description, according to the ink jet recording apparatus of the present invention, a pressure detector having a signal generating means for generating a pressure detection signal based on the displacement amount of the diaphragm is used to generate a signal from the diaphragm. By using a temperature-dependent material for the constituent members reaching the means, the flow rate of the ink replenished from the main tank can be maintained within a predetermined range even when the environmental temperature changes. In addition, since the above-described function can be obtained with a relatively simple configuration using a diaphragm, this can be realized at a relatively low cost.
[Brief description of the drawings]
FIG. 1 is a plan view showing an overall configuration of an ink jet recording apparatus to which the present invention is applied.
FIG. 2 is a schematic diagram illustrating an ink supply system from a main tank to a recording head.
FIG. 3 is a cross-sectional view showing a first embodiment of a pressure detector used in the ink supply system shown in FIG. 2;
4 is an enlarged cross-sectional view showing a part of the configuration of the pressure detector shown in FIG. 3;
FIG. 5 is a cross-sectional view showing a second embodiment of the pressure detector.
FIG. 6 is a diagram showing a relationship between an environmental temperature and a replenishment flow rate of ink when a material having temperature characteristics is used for a diaphragm.
[Explanation of symbols]
1 Carriage
6 Recording head
7 (7a, 7b, 7c, 7d) Sub tank
8 Cartridge holder
9 (9a, 9b, 9c, 9d) Main tank (ink cartridge)
10 Ink supply tube (ink supply path)
21 Air pressurization pump
22 Pressure regulating valve
23 Pressure detector
24 ink pack
25 Pressure chamber
26 Ink supply valve
31 Float member
32 Permanent magnet
33 (33a, 33b) Hall element
41 Upper case
41a Cylindrical body
41b Inner cylinder
41d contact part
42 Lower case
42a space
42b Connecting pipe for introducing pressurized air
42c Connecting pipe for distributing pressurized air
42d Stopper member
43 Diaphragm
44 Movable members
44a Stopper member
44b Standing part
44c Reflective member
44d Stepped part
45 Spring member
46 Photosensor (Signal generation means)
46a Light source
46b Light receiving element

Claims (15)

Pressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured,
An air flow path between the air pressurization pump and the main tank includes a diaphragm that receives and displaces the pressurized air, and a signal generation unit that generates a pressure detection signal based on the displacement amount of the diaphragm. And the diaphragm is made of a material whose hardness changes according to the environmental temperature, and the air pressurization pump is driven based on a pressure detection signal generated by the signal generation means. while being configured to control,
An ink jet type configured such that a temperature dependent characteristic of a pressure value at which a pressure detection signal is generated by the signal generating means is substantially equal to a temperature dependent characteristic in the viscosity of ink replenished from the main tank to the recording head side. Recording device. Pressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured,
An air flow path between the air pressurization pump and the main tank includes a diaphragm that receives and displaces the pressurized air, and a signal generation unit that generates a pressure detection signal based on the displacement amount of the diaphragm. And the diaphragm is made of a material whose hardness changes according to the environmental temperature, and the air pressurization pump is driven based on a pressure detection signal generated by the signal generation means. Configured to control,
An ink jet type configured so that a temperature dependent characteristic of a pressure value at which a pressure detection signal is generated from the signal generating means is substantially equal to a temperature dependent characteristic of a pressure loss in a replenishment path of ink replenished from the main tank. Recording device. Pressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured,
An air flow path between the air pressurization pump and the main tank includes a diaphragm that receives and displaces the pressurized air, and a signal generation unit that generates a pressure detection signal based on the displacement amount of the diaphragm. The diaphragm is made of a material whose volume changes according to the environmental temperature, and the air pressurization pump is driven based on the pressure detection signal generated by the signal generation means. Configured to control,
An ink jet type configured such that a temperature dependent characteristic of a pressure value at which a pressure detection signal is generated by the signal generating means is substantially equal to a temperature dependent characteristic in the viscosity of ink replenished from the main tank to the recording head side. Recording device. Pressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured,
An air flow path between the air pressurization pump and the main tank includes a diaphragm that receives and displaces the pressurized air, and a signal generation unit that generates a pressure detection signal based on the displacement amount of the diaphragm. The diaphragm is made of a material whose volume changes according to the environmental temperature, and the air pressurization pump is driven based on the pressure detection signal generated by the signal generation means. Configured to control,
An ink jet type configured so that a temperature dependent characteristic of a pressure value at which a pressure detection signal is generated from the signal generating means is substantially equal to a temperature dependent characteristic of a pressure loss in a replenishment path of ink replenished from the main tank. Recording device. Pressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured,
An air flow path between the air pressurization pump and the main tank includes a diaphragm that receives and displaces the pressurized air, and a signal generation unit that generates a pressure detection signal based on the displacement amount of the diaphragm. A movable member that mechanically couples the diaphragm and the signal generation means is made of a material whose dimension in the movable direction changes according to the environmental temperature, and is generated by the signal generation means. Configured to control the driving of the air pressurization pump based on the detected pressure signal,
An ink jet type configured such that a temperature dependent characteristic of a pressure value at which a pressure detection signal is generated by the signal generating means is substantially equal to a temperature dependent characteristic in the viscosity of ink replenished from the main tank to the recording head side. Recording device. Pressurized air generated by an air pressurization pump is applied to the main tank in which ink is stored, and ink is supplied from the main tank to the recording head mounted on the carriage by the action of the pressurized air. An ink jet recording apparatus configured,
An air flow path between the air pressurization pump and the main tank includes a diaphragm that receives and displaces the pressurized air, and a signal generation unit that generates a pressure detection signal based on the displacement amount of the diaphragm. A movable member that mechanically couples the diaphragm and the signal generation means is made of a material whose dimension in the movable direction changes according to the environmental temperature, and is generated by the signal generation means. Configured to control the driving of the air pressurization pump based on the detected pressure signal,
An ink jet type configured so that a temperature dependent characteristic of a pressure value at which a pressure detection signal is generated from the signal generating means is substantially equal to a temperature dependent characteristic of a pressure loss in a replenishment path of ink replenished from the main tank. Recording device. The ink jet recording apparatus according to claim 1, wherein the diaphragm is made of a material that changes in hardness so that the hardness is high in a low temperature state and low in a high temperature state. 5. The ink jet recording apparatus according to claim 3, wherein the diaphragm is made of a material that changes in volume such that the volume contracts in a low temperature state and expands in a high temperature state. 7. The ink jet recording according to claim 5, wherein the movable member is made of a material whose dimension in a movable direction contracts in a low temperature state and changes so as to expand in a high temperature state. apparatus. The ink is supplied from the main tank to a sub tank mounted on a carriage via an ink supply path, and the ink is supplied from the sub tank to the recording head mounted on the carriage. Item 10. The ink jet recording apparatus according to any one of Items 9 . The ink jet recording apparatus according to claim 10, wherein the ink supply path from the main tank to the sub tank is configured by a flexible ink supply tube . The signal generation means includes a movable member that is advanced and retracted by displacement of the diaphragm, a photosensor that includes a light source and a light receiving element that are arranged so as to cross a movement path of the movable member, and constitutes the photosensor. The ink jet recording apparatus according to claim 1, wherein the pressure detection signal is generated based on an output of a light receiving element . The signal generating means includes a movable member that is advanced and retracted by displacement of the diaphragm, a light source that projects light onto a movement path of the movable member, and a light receiving element that receives reflected light of the light source based on the movement of the movable member. It is composed of a photosensor, an ink jet recording apparatus according to any one of 請 Motomeko 1 to claim 11 adapted to generate the pressure sense signal based on the output of the light receiving elements constituting the photo-sensor. The said diaphragm is comprised with the elastic material, The said movable member is comprised so that the said movable member may be advanced or retracted based on the displacement of the diaphragm by the balance of the air pressure which the said diaphragm receives, and the restoring force of a diaphragm. 2. An ink jet recording apparatus according to 1. A spring member that urges the diaphragm in the return direction is further provided, and the movable member moves forward and backward based on the displacement of the diaphragm due to the balance between the air pressure received by the diaphragm, the return force of the diaphragm, and the urging force of the spring member. The ink jet recording apparatus according to claim 14, which is configured as described above .

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