JP7052402B2 - Liquid discharge head, liquid discharge unit, liquid discharge device and image forming device - Google Patents

Description

The present invention relates to a liquid discharge head, a liquid discharge unit, a liquid discharge device, and an image forming device.

In an inkjet recording device including a recording head, a pressure generating means such as a plurality of piezoelectric elements (for example, a piezo element) corresponding to each of the plurality of nozzle openings pressurizes ink in a pressure generating chamber communicating with the nozzle to open the nozzles. Ink droplets are ejected from.

In such an inkjet recording device, when the ink is repeatedly ejected, the temperature of the recording head rises and the viscosity of the ink changes. As a result, the amount of ink ejected fluctuates and the density of the image changes to obtain the desired image quality. You will not be able to get it. Therefore, a technique is known in which a temperature detecting means for detecting the temperature of the recording head is arranged near the common liquid chamber, and the amount of ink ejected is controlled by changing the drive waveform and the drive voltage based on the temperature detection result. (For example, Patent Document 1).

However, in the conventional temperature detection near the common liquid chamber including Patent Document 1, there is a difference between the ink temperature near the nozzle (the ink temperature actually ejected) and the ink temperature near the common liquid chamber, so that the ink temperature. There was a problem that the detection accuracy was insufficient.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the temperature detection accuracy of ink.

In order to achieve the above object, the present invention generates pressure in a plurality of nozzles for discharging a liquid, a plurality of pressure chambers communicating with each nozzle and supplying the liquid to the nozzle, and each pressure chamber. A pressure generating means for discharging the liquid from each of the nozzles, a support member for supporting the pressure generating means, a first temperature detecting means provided on the support member, and an adjacent to the pressure chamber are provided. The second temperature detecting means is provided , and a plurality of the first temperature detecting means are provided, and the first temperature detecting means sandwiches the center of the support member in the longitudinal direction of the support member. It is a liquid discharge head characterized in that it is provided on both sides of the head.

According to the present invention, the temperature detection accuracy of ink can be improved.

It is sectional drawing which follows the liquid chamber longitudinal direction of the liquid discharge head which concerns on embodiment of this invention. It is sectional drawing which follows the liquid chamber short side direction of the liquid discharge head of FIG. It is a figure explaining an example of a head driver. (A) is a cross-sectional view of Sa—Sa in (b) of a conventional liquid discharge head, and (b) is a cross-sectional view of a main part of (a) viewed from the lower surface. (A) is a cross-sectional view of Sb-Sb in (c) of the liquid discharge head of the present embodiment, (b) is a cross-sectional view of Sc-Sc in (c), and (c) is a key point of (a) and (b). It is sectional drawing which looked at the part from the lower surface. It is a graph explaining that the temperature distribution for each nozzle row is predicted by temperature detection by a plurality of temperature detection elements. It is a schematic block diagram explaining the whole structure of the mechanism part of the serial type image forming apparatus. FIG. 7 is a plan view of the main part of the mechanism portion of FIG. 7 as viewed from above. It is a schematic block diagram explaining the whole structure of the mechanism part of the line type image forming apparatus. 9 is a plan view of the main part of the mechanism portion of FIG. 9 as viewed from above.

Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) including examples will be described in detail with reference to the drawings. As long as there is no risk of confusion, the components (members and components) and the like having the same function and shape, etc., are described once in each embodiment, and then the same reference numerals are given to the components (members and components), and the description thereof will be omitted.

Before explaining the liquid discharge head according to the embodiment of the present invention, the concept of the "liquid discharge head" and the like will be described.
The "liquid discharge head" is a functional component that discharges and ejects liquid from a nozzle.
The liquid to be discharged may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. Is preferable. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions, etc. containing edible materials such as natural pigments, such as inks for inkjets, surface treatment liquids, components of electronic and light emitting elements, and formation of electronic circuit resist patterns. It can be used in applications such as liquids and material liquids for three-dimensional modeling.

Piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electric heat conversion elements such as heat-generating resistors, and electrostatic actuators that consist of a vibrating plate and counter electrodes are used as energy sources for discharging liquid. Includes what to do.

The basic configuration of the liquid discharge head according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the liquid discharge head according to the embodiment along the longitudinal direction of the liquid chamber, and FIG. 2 is a cross-sectional view of the liquid discharge head of FIG. 1 along the short side of the liquid chamber.
As shown in FIGS. 1 and 2, the liquid ejection head 20 according to the embodiment of the present invention includes a frame 1 having an engraving formed into an ink supply port 1a and a common liquid chamber 1b, a fluid resistance portion 2a, and a pressurized liquid. It is provided with an engraving that serves as a chamber 2b and a flow path plate 2 that forms a communication port 2d that communicates with the nozzle 3a.

A heat-conducting resin is used in the frame 1 to form an engraving that becomes an ink supply port 1a and a common liquid chamber 1b by resin molding. The common liquid chamber 1b has a function of supplying ink as an example of liquid to the pressurized liquid chamber 2b which functions as a pressure chamber described later. The frame 1 in which the common liquid chamber 1b is formed is a housing member.

The flow path plate 2 uses a silicon single crystal substrate, and is engraved to be a fluid resistance portion 2a, a pressurized liquid chamber 2b, a liquid introduction portion 2c, and a through port to be a communication port 2d at a position with respect to the nozzle 3a by an etching method. Patterned. The portion left by etching becomes the partition wall 2e (see FIG. 2) of the pressurized liquid chamber 2b.
The fluid resistance portion 2a includes a common liquid chamber 1b that supplies ink to the pressurized liquid chamber 2b, which is a pressure chamber, and a pressurized liquid in the ink flow direction (direction from the left to the right in the figure) in FIG. It is provided between the room 2b and the room 2b.
The pressurized liquid chamber 2b is also called an individual liquid chamber, and functions as a pressure chamber of the present invention that communicates with each nozzle 3a and supplies ink to each nozzle 3a. A plurality of pressurized liquid chambers 2b, which are pressure chambers, are provided.

The liquid ejection head 20 also has a nozzle plate 3 having a plurality of nozzles 3a for ejecting ink, a diaphragm 6 having a convex portion 6a, a diaphragm portion 6b, and an ink inlet 6c, and a diaphragm 6 via an adhesive layer. It includes a bonded laminated piezoelectric element 5 and a base 4 to which the laminated piezoelectric element 5 is fixed.

The nozzle plate 3 is made of a metal material, for example, a nickel (Ni) plating film formed by an electroforming method, and forms a large number of nozzles 3a which are fine ejection ports for flying ink droplets. .. The internal shape (inner shape) of the nozzle 3a is formed in a horn shape in the present embodiment, but may be a substantially cylindrical shape or a substantially circular pyramidal shape.

The ink ejection surface (nozzle surface side) of the nozzle plate 3 is provided with a water-repellent treatment layer that has been subjected to a water-repellent surface treatment. Ink such as PTFE-Ni eutectoid plating, electrodeposition coating of fluororesin, vapor deposition coating of evaporable fluororesin (for example, fluororesin pitch), or baking after solvent application of silicon-based resin / fluororesin. A water-repellent treated film selected according to the physical properties is provided. As a result, the drop shape and flight characteristics of the ink are stabilized, and high-quality image quality can be obtained.

The diaphragm 6 has a thin film diaphragm portion 6b and an island-shaped convex portion 6a also called an island portion that is joined to a laminated piezoelectric element 5 that is a drive portion 5e (described later) formed in the central portion of the diaphragm portion 6b. A thick film portion including a beam to be joined to the support portion 5f (see FIG. 2) and an opening serving as an ink inlet 6c are formed by stacking two layers of nickel (Ni) plating film by electroforming method.

The laminated piezoelectric element 5 is divided onto the comb teeth by a half-cut dicing process, and each of them is used as a drive portion 5e and a non-drive portion 5f. The laminated piezoelectric element 5 includes an internal electrode layer 5b composed of a piezoelectric layer 5a of lead zirconate titanate (PZT) having a thickness of 10 to 50 μm / layer and silver / palladium (AgPd) having a thickness of several μm / layer. The internal electrode layers 5b are alternately laminated, and the internal electrode layers 5b are alternately electrically connected to the individual electrodes 5c and the common electrodes 5d, which are the end face electrodes (external electrodes) of the end faces.

The liquid discharge head 20 is configured to use the laminated piezoelectric element 5 in the d33 method, which is a displacement in the thickness direction, and the pressurized liquid chamber 2b, which is an individual liquid chamber, is contracted and expanded by the expansion and contraction of the laminated piezoelectric element 5. It has become like. When a drive signal is applied to the laminated piezoelectric element 5 and charging is performed, it expands, and when the charge charged in the laminated piezoelectric element 5 is discharged, it contracts in the opposite direction.
The laminated piezoelectric element 5 functions as a pressure generating means of the present invention in which pressure is generated in each pressurized liquid chamber 2b which is a pressure chamber and ink is discharged from each nozzle 3a.

A flexible printed substrate 7 (hereinafter, abbreviated as “FPC7”) is solder-bonded to the individual electrodes 5c of the drive unit 5e. Further, the common electrode 5d is joined to the ground (Gnd) electrode of the FPC 7 by providing an electrode layer at the end of the laminated piezoelectric element 5 and turning it. A head driver composed of an integrated circuit (IC) or the like shown in FIG. 3 to be described later is mounted on the FPC 7, thereby controlling the application of a drive voltage to the drive unit 5e.

In FIG. 1, 7a is a wiring member made of an electric conductor of FPC7, 7b is a base material made of an electric insulating material of FPC7, and 7c is a drive IC equipped with a drive circuit 26 of a head driver 21 shown in FIG. 3 to be described later. Are represented respectively.

The base 4 is made of barium titanate-based ceramic, and two rows of laminated piezoelectric elements 5 are arranged and joined. The base 4 functions as a support member that supports and fixes the laminated piezoelectric element 5 as a pressure generating means. The base 4 has thermal conductivity.

The operation of the liquid discharge head 20 will be described. In the liquid discharge head 20 configured as described above, by applying a drive waveform (pulse voltage of 10 to 50 V) to the drive unit 5e according to the recording signal, displacement in the stacking direction occurs in the drive unit 5e. The pressurized liquid chamber 2b is pressurized through the vibrating plate 6, the pressure of the ink in the pressurized liquid chamber 2b rises, and ink droplets are ejected from the nozzle 3a.

After that, with the end of ink droplet ejection, the ink pressure in the pressurized liquid chamber 2b decreases, and negative pressure is generated in the pressurized liquid chamber 2b due to the inertia of the ink flow and the discharge process of the drive pulse to fill the ink. Move to the process. At this time, the ink supplied from the ink tank flows into the common liquid chamber 1b, passes through the liquid introduction portion 2c and the fluid resistance portion 2a from the common liquid chamber 1b through the ink inlet 6c, and fills the pressurized liquid chamber 2b. Will be done.

The fluid resistance portion 2a has an effect on damping the residual pressure vibration after discharge, but on the other hand, it becomes a resistance against refilling due to surface tension. By appropriately selecting the fluid resistance unit, the residual pressure attenuation and the refill time can be balanced, and the time (drive cycle) until the next ink droplet ejection operation can be performed can be shortened.

A head driver for controlling the laminated piezoelectric element of the liquid discharge head 20 will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a head driver that controls a laminated piezoelectric element of the liquid discharge head 20.
As shown in FIG. 3, the head driver 21 has a drive waveform generation unit 25 that generates and outputs a drive waveform composed of a plurality of drive pulses (drive signals) within one print cycle at the time of image formation, and a printed image. It is provided with corresponding 3-bit image data (gradation signals 0, 1, 2), a clock signal, a circuit described later for processing a latch signal (LAT), and the like.
The drop control signal is a 3-bit signal that indicates the drive waveform stored in the head driver 21.

The head driver 21 includes a shift register 22 for inputting image data and waveform data using a transfer clock and serial communication data from a data transfer unit, a latch circuit 23 for latching each register value of the shift register 22 with a latch signal, and a latch circuit 23. The drive waveform data signal line 24 represented by D1 to D320 and the drive waveform generation unit 25 described above are provided. The head driver 21 also includes a drive circuit 26 represented by Drv, a drive waveform amplifier line 27 represented by VDO1 to VDO320, and a laminated piezoelectric element 5 composed of piezo elements represented by PZT-1 to PZT-320. A drive signal is selected from the gradation data and applied to the laminated piezoelectric element 5.
The laminated piezoelectric element 5 composed of the drive waveform data signal line 24 represented by D1 to D320, the drive waveform amplifier line 27 represented by VDO1 to VDO320, and the piezo element represented by PZT-1 to PZT-320 is the liquid discharge head 20. It is set corresponding to each nozzle (1 to 320 channels (ch)).

With reference to FIG. 4, the detection of the mounting position of the temperature detection element and the ink temperature in the vicinity of the common liquid chamber in the liquid discharge head 20X having the conventional configuration will be described. 4 (a) is a cross-sectional view of Sa-Sa in FIG. 4 (b) of the conventional liquid discharge head, and FIG. 4 (b) is a cross-sectional view of the main part of FIG. 4 (a) as viewed from the lower surface.
Compared with the liquid discharge head 20 of the present embodiment shown in FIGS. 1 to 3 and FIG. 5 described later, the liquid discharge head 20X shown in FIG. 4 uses a thermistor as the temperature detecting element 9X in the vicinity of the common liquid chamber 1b. The difference is that it is arranged and mounted in the frame 1 and detects the ink temperature in the vicinity of the common liquid chamber 1b.

As a temperature detecting means for detecting the temperature of the ink filled in the liquid chamber of the liquid ejection head, there is a temperature detecting element using a thermistor. As shown in FIG. 4, the temperature detecting element 9X is arranged at the bottom of the temperature detecting element arranging hole 1Xc formed substantially in the center of the frame 1 and is fixed by a heat conductive adhesive or the like. In FIG. 4, 9Xa represents an electrode wire connected to the temperature detecting element 9X.

In the conventional liquid ejection head 20X, a temperature detecting element 9X made of a thermistor is mounted on a frame 1 having a common liquid chamber 1b for supplying ink to the pressurized liquid chamber 2b (individual liquid chamber), and a single temperature detection is performed. The element 9X detects the temperature of the ink for a plurality of nozzle rows in the head.
However, in temperature detection in the vicinity of the common liquid chamber 1b as in the temperature detection element 9X in the liquid ejection head 20X, there is a difference between the ink temperature in the vicinity of the nozzle 3a (the ink temperature actually ejected) and the ink temperature in the vicinity of the common liquid chamber 1b. Therefore, there is a problem that the temperature detection accuracy of the ink is insufficient.

With reference to FIGS. 5 and 6, the detection of the unique arrangement position of the temperature detecting element and the ink temperature in the liquid ejection head 20 of the present embodiment will be described. 5 (a) is a cross-sectional view of Sb-Sb in FIG. 5 (c) of the liquid discharge head of the present embodiment, FIG. 5 (b) is a cross-sectional view of Sc-Sc in FIG. 5 (c), and FIG. 5 (c). 5 (a) and 5 (b) are cross-sectional views of the main parts of FIGS. 5 (a) and 5 (b) as viewed from the lower surface. FIG. 6 is a graph illustrating that the temperature distribution for each nozzle row is predicted by temperature detection by a plurality of temperature detection elements.
The liquid discharge head 20 shown in FIG. 5 has a plurality of temperature detection elements 9-1, 9-3 instead of the single temperature detection element 9X as compared with the liquid discharge head 20X having the conventional configuration shown in FIG. Is provided on the base 4 which is a support member, and a plurality of temperature detecting elements 9-2-1 and 9-2-2 are provided adjacent to the pressurized liquid chamber 2b which is a pressure chamber.
The plurality of temperature detecting elements 9-1 and 9-3 function as the first temperature detecting means according to the present invention. The plurality of temperature detecting elements 9-2-1 and 9-2-2 function as the second temperature detecting means according to the present invention.

The plurality of temperature detecting elements 9-2-1 and 9-2-2 are provided adjacent to the diaphragm 6 forming a part of the wall surface of the pressurized liquid chamber 2b, which is a pressure chamber, and have fluid resistance. It is provided near the upper part of the portion 2a.

As shown in FIG. 5C, the plurality of temperature detecting elements 9-1 and 9-3 are located on both sides (of FIG. 5C) with the center of the base 4 interposed therebetween in the longitudinal direction of the base 4 which is a support member. It is provided on each of the left and right sides).

As shown in FIGS. 5 (b) and 5 (c), a plurality of nozzle rows in which a plurality of nozzles 3a are arranged are provided, and the plurality of temperature detecting elements 9-2-1 and 9-2-2 are provided. It is arranged so as to correspond to each nozzle row.

Since the temperature detection elements 9-1, 9-3, 9-2-1, and 9-2-2 have different arrangement positions, the reference numerals are changed to clarify the arrangement positions, but they are common thermistors. Is used. The temperature detection elements 9-1, 9-3, 9-2-1 and 9-2-2 are connected to the electrode wire 9a. The temperature detection elements 9-1 and 9-3 are arranged at the bottom of the temperature detection element arrangement hole 4c formed substantially in the center of the base 4, and are fixed with a heat conductive adhesive or the like. The temperature detecting elements 9-2-1 and 9-2-2 are fixed in the vicinity of the nozzles of each nozzle row in the frame 1 with a heat conductive adhesive or the like.

In the graph shown in FIG. 6, the channel (ch) positions (n1, n2 ... 320) corresponding to the individual nozzles are taken on the horizontal axis, and the temperature detection elements 9-1, 9-3, 9-2-1. The temperature [° C.] detected by 9-2-2 is shown on the vertical axis.
With this configuration, as shown in the graph shown in FIG. 6, a plurality of temperature detecting elements 9-1 and 9-3 are used in the nozzle row (longitudinal direction of the liquid chamber in FIG. 5 (c): FIGS. 7 and 8 described later, etc.). By detecting (T1, T2) and sampling the temperature (corresponding to the sub-scanning direction F), it is possible to predict the temperature distribution in the nozzle row.

Further, the temperature of one point (in the short side of the liquid chamber in FIG. 5C) for each nozzle row is provided by a plurality of temperature detecting elements 9-2-1 and 9-2-2 arranged in the vicinity of the nozzle for each nozzle. By detecting (T0), it becomes possible to predict the temperature distribution for each nozzle row.
As described above, the plurality of temperature detecting elements 9-1 and 9-3 which are the first temperature detecting means and the plurality of temperature detecting elements 9-2-1 and 9-2-2 which are the second temperature detecting means. By using in combination with, it is possible to predict the temperature distribution for each nozzle row and to predict the temperature distribution of the entire nozzle in the liquid discharge head together with the predicted value in the nozzle row described above.

Therefore, according to the present embodiment, it is possible to detect the temperature distribution of the liquid in the vicinity of each individual nozzle by a plurality of temperature detecting elements arranged at unique arrangement positions, and detect the temperature distribution of the entire nozzle in the head. can. This makes it possible to improve the temperature detection accuracy of the ink. In other words, it is possible to provide a liquid ejection head capable of predicting the temperature distribution of the liquid for each individual nozzle, predicting the temperature distribution of the entire nozzle in the head, and improving the temperature detection accuracy of the ink.

Further, since the density correction can be performed by an image based on the temperature distribution in the nozzle row and for each nozzle row detected by the plurality of temperature detecting elements, it is possible to suppress the density fluctuation due to the fluctuation of the temperature distribution.

Further, since it is possible to correct the amount of droplets ejected for each individual nozzle based on the temperature distribution detected by the plurality of temperature detecting elements, it is possible to suppress the concentration fluctuation due to the fluctuation of the temperature distribution. ..

Further, by arranging a plurality of temperature detecting elements in the vicinity of all the nozzles, the temperature of the liquid in the vicinity of the nozzles can be detected with higher accuracy.

In addition, if the nozzles can be driven individually, voltage correction is performed on each nozzle to correct the discharge speed and landing position, so that correction can be performed with higher accuracy, and high-quality image quality can be obtained. Can be done.

In this embodiment, two temperature detection elements are used to detect the temperature distribution in the nozzle row, but three or more temperature detection elements are used to predict the temperature distribution with higher accuracy. You may.
Further, in an actual liquid ejection head such as an inkjet head, the temperature distribution changes according to the number and location of drive nozzles, so information that predicts the number and location of drive channels (ch) from images is used as a recording medium at the time of shipment. It is also possible to record and make corrections according to the image at the time of printing.

A serial image forming apparatus including a liquid ejection unit including a liquid ejection head and a liquid ejection device according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic configuration diagram illustrating the overall configuration of the mechanism portion of the device, and FIG. 8 is a plan view of the main part of the mechanism unit as viewed from above.
The image forming apparatus shown in FIGS. 7 and 8 is a serial type image forming apparatus, and the main mechanical parts include an image forming unit 293 including a carriage 233 and the like, a paper feed cassette 290, a feeding means, and the like. There is a paper unit 294, a transport unit 295 including a transport belt 251 and various transport members, and a paper discharge section 296 including a paper discharge roller 262 and a paper discharge tray 291.

Side plates 237A and 237B are fixed and arranged on the left and right sides of the main body of the apparatus shown in FIG. A master-slave guide rod 231 and 232, which are guide members, are laid across the side plates 237A and 237B so as to lie down. The guide rods 231 and 232 slidably hold the carriage 233 in the main scanning direction S. The carriage 233 is moved and scanned in the arrow direction (main scanning direction S of the carriage 233) via a timing belt to which the carriage 233 is fixed by a main scanning motor (not shown).

The carriage 233 is referred to as a recording head 234a or 234b for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K) (when not distinguished, it is referred to as "recording head 234". .) Is installed. A row of nozzles composed of a plurality of nozzles is arranged in the sub-scanning direction F orthogonal to the main scanning direction S in the recording head 234, and the carriage 233 is a recording head so that the ink droplet ejection direction from the nozzles is downward. I am wearing 234.

The recording head 234 includes a plurality of temperature detection elements 9-1, 9-3 and a plurality of temperature detection elements 9-2-1, 9-2-, which are arranged at unique arrangement positions in the liquid discharge head 20 of FIG. It has the same configuration as No. 2 and has the above-mentioned basic effect.

The recording head 234 has two nozzle rows each, one nozzle row of the recording head 234a is a black (K) droplet, the other nozzle row is a cyan (C) droplet, and the recording head 234b. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets.

Further, the carriage 233 is equipped with sub tanks 235a and 235b (referred to as "sub tank 235" when not distinguished) for supplying ink of each color corresponding to the nozzle row of the recording head 234. The sub tank 235 is replenished with ink of each color from the ink cartridges 265y, 265m, 265c, and 265k of each color that are detachably attached to the cartridge loading unit 292 via the supply tubes 236 of each color. The ink cartridges 265y, 265m, 265c, and 265k of each color are referred to as "ink cartridges 265" when they are not distinguished. The supply tube 236 of each color serves as an ink supply path for each color.

On the other hand, the paper cassette 290 is lowered from the feeding position (position state shown in FIG. 7) in which the paper P is placed and the paper P is brought into contact with the paper feeding roller 243 provided on the main body side of the apparatus and the feeding position. It has a bottom plate 241 that can swing with and from the lowered position. In order to feed the paper P loaded on the bottom plate 241 of the paper feed cassette 290, the paper P on the bottom plate 241 is separated and fed one by one, facing the paper feed roller 243 and the paper feed roller 243, and facing the paper P. A separation pad 244 is provided as a separation means made of a material having a large coefficient of friction. The separation pad 244 is urged to the paper feed roller 243 side by an urging means such as a spring.

Then, a transport unit 295 is arranged in order to feed the paper P fed from the paper feed cassette 290 to the lower side of the recording head 234. The transport unit 295 electrostatically attracts and records the guide member 245 for guiding the paper P, the counter roller 246, the transport guide member 247, the holding member 248 having the tip pressure roller 249, and the fed paper P. It is provided with a transport belt 251 which is a transport means for transporting at a position facing the head 234.

The transport belt 251 is an endless belt, and is configured to be hung between the transport roller 252 and the tension roller 253 and to rotate in the belt transport direction (sub-scanning direction F). A charging roller 256, which is a charging means for charging the surface of the transport belt 251 is provided. The charging roller 256 is arranged so as to come into contact with the surface layer of the transport belt 251 and rotate in accordance with the rotation of the transport belt 251. The transport belt 251 orbits in the belt transport direction by rotationally driving the transport roller 252 via the timing belt by a sub-scanning motor (not shown).

As the paper ejection unit 296 for ejecting the paper P recorded by the recording head 234, a separation claw 261 for separating the paper P from the transport belt 251, a paper ejection roller 262, and a spur 263 which is a paper ejection roller 263. , A paper ejection tray 291 arranged below the paper ejection roller 262 is provided.

A double-sided unit 271 shown in FIG. 7 is detachably attached to the back surface of the main body of the apparatus. The double-sided unit 271 takes in the paper P returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. Further, the upper surface of the double-sided unit 271 is a manual feed tray 272.

Further, as shown in FIG. 8, a maintenance / recovery mechanism 281 for maintaining and recovering the state of the nozzle of the recording head 234 is arranged in the non-printing area on one side of the carriage 233 in the scanning direction. The maintenance / recovery mechanism 281 includes cap members 282a and 282b (referred to as “cap member 282” when not distinguished), a wiper member 283, an empty discharge receiver 284, a carriage lock 287, and the like. The cap member 282 is for capping each nozzle surface of the recording head 234, and the wiper member 283 is composed of a wiper blade or the like for wiping the nozzle surface. The empty discharge receiver 284 receives droplets when performing empty discharge to discharge droplets that do not contribute to recording in order to discharge the thickened recording liquid, and the carriage lock 287 is maintained by the maintenance / recovery mechanism 281. It is for locking the carriage 233 so that the recovery operation can be performed.

On the lower side of the maintenance / recovery mechanism 281, there is a first non-replaceable waste liquid tank 285 for accommodating the waste liquid generated from the empty discharge receiver 284 due to the empty discharge to the empty discharge receiver 284 in the maintenance / recovery operation and the cleaning of the wiper member 283. I have. Further, on the side side of the maintenance / recovery mechanism 281, a second waste liquid tank 286 that can be replaced from the front side of the main body of the apparatus is provided below the cartridge loading portion 292.

Further, in the non-printing area on the other side of the carriage 233 in the scanning direction, the liquid that receives the droplets when the blank ejection is performed to eject the droplets that do not contribute to recording in order to discharge the thickened recording liquid during recording or the like. An ink recovery unit 288, which is also called an empty ejection receiver, which is a recovery container, is arranged. The ink recovery unit 288 is provided with an opening 289 or the like along the nozzle row direction of the recording head 234.

In this image forming apparatus configured as described above, the paper P is separately fed from the paper feed cassette 290 one by one, and the paper P fed substantially vertically upward is guided by the guide member 245 and is guided by the guide member 245. It is sandwiched between the counter roller 246 and the counter roller 246 and transported. The tip of the paper P thus conveyed is further guided by the transfer guide member 247, pressed against the transfer belt 251 by the tip pressurizing roller 249, and the transfer direction is changed by approximately 90 °.

At this time, positive output and negative output are alternately repeated for the charging roller 256, that is, alternating voltages are applied, and the charging voltage pattern in which the conveyor belt 251 alternates, that is, in the sub-scanning direction which is the circumferential direction. , Plus and minus are alternately charged in a strip shape with a predetermined width. When the paper P is fed onto the transport belt 251 charged alternately with plus and minus, the paper P is electrostatically attracted to the transport belt 251 and the paper P is moved around the transport belt 251 in the sub-scanning direction F. Will be transported to.

Therefore, by driving the recording head 234 in response to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper P to record one line, and after transporting a predetermined amount of the paper P, the paper P is conveyed. Record the next line. When the recording end signal or the signal that the rear end of the paper P reaches the recording area is received, the recording operation is ended and the paper P is discharged to the paper output tray 291.

Then, when the nozzle of the recording head 234 is maintained and recovered, the carriage 233 is moved to a position facing the maintenance and recovery mechanism 281 which is the home position. Then, by performing maintenance and recovery operations such as nozzle suction by capping with the cap member 282 and suction from the nozzle, and empty ejection of droplets that do not contribute to image formation, image formation by stable droplet ejection is performed. It can be performed.

The serial type image forming apparatus of FIGS. 7 and 8 described above includes a recording head 234 having the same configuration as the liquid discharge head 20 according to the embodiment shown in FIG. Therefore, according to the serial type image forming apparatus of FIGS. 7 and 8, the temperature distribution of the liquid in the vicinity of each individual nozzle is detected by a plurality of temperature detecting elements arranged at unique arrangement positions, and the entire nozzle in the head is detected. The temperature distribution of can be detected. This makes it possible to improve the temperature detection accuracy of the ink.
Further, the density can be corrected by an image based on the temperature distribution detected by a plurality of temperature detecting elements. Further, if the nozzles can be individually driven, voltage correction can be performed on each nozzle to make corrections with higher accuracy. With these corrections, high-quality image quality can be obtained.

The carriage 233 having the above configuration constitutes a liquid discharge unit integrated with the liquid discharge head and the head tank according to the present invention.
Further, the pressure generating means used for the "liquid discharge head" is not limited. For example, in addition to the piezoelectric actuator using the laminated piezoelectric element as described in the above embodiment, a thermal actuator using an electric heat conversion element such as a heat generating resistor, an electrostatic actuator composed of a vibrating plate and a counter electrode, and the like are used. It may be something to do.

The "liquid discharge unit" is a liquid discharge head integrated with functional parts and a mechanism, and is a collection of parts related to liquid discharge. For example, the "liquid discharge unit" includes a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, a main scanning movement mechanism in which at least one of the configurations is combined with a liquid discharge head, and the like.

Here, the term "integration" means, for example, a liquid discharge head and a functional component, a mechanism in which the mechanism is fixed to each other by fastening, bonding, engagement, etc., or one in which one is movably held with respect to the other. include. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.

Further, in the terms of the present application, image formation, recording, printing, printing, printing, modeling, etc. are all synonymous.

In the present application, the "device for discharging a liquid" (hereinafter referred to as "liquid discharge device") is a device provided with a liquid discharge head or a liquid discharge unit and driving the liquid discharge head to discharge the liquid. The device includes not only a device capable of discharging a liquid to a device to which the liquid can adhere, but also a device capable of discharging the liquid into the air or into the liquid.

This "liquid discharge device" can also include means related to feeding, transporting, and discharging paper to which a liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "liquid ejection device", an image forming apparatus that ejects ink to form an image on paper, and a powder in which powder is formed in layers in order to form a three-dimensional model (three-dimensional model). There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid to the body layer.

Further, the "liquid discharge device" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "thing to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as a material to which the liquid adheres and adheres, and a material to which the liquid adheres and permeates. Specific examples include sheets, for example, paper, recording paper, recording paper, film, recorded media such as cloth, electronic substrates, other electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and inspections. It is a medium such as a cell, and includes all substances to which a liquid adheres unless otherwise specified.

The material of the above "material to which liquid can adhere" may be paper, thread, fiber, cloth, leather, metal, plastic (including OHP sheet), glass, wood, ceramics, etc. as long as the liquid can adhere even temporarily. ..

The "liquid" may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. It is preferable to have. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions, etc. containing edible materials such as natural pigments, such as inks for inkjets, surface treatment liquids, components of electronic and light emitting elements, and formation of electronic circuit resist patterns. It can be used in applications such as liquids and material liquids for three-dimensional modeling.

Further, the "liquid discharge device" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include the above-mentioned serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like, which will be described later.

In addition, as a "liquid ejection device", a processing liquid application device that ejects a treatment liquid onto a paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, and a solution of raw materials. There is an injection granulator that granulates fine particles of raw materials by injecting a composition liquid dispersed therein through a nozzle.

An example of a line-type image forming apparatus including a liquid ejection unit including a liquid ejection head and a liquid ejection device according to the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a cross-sectional view showing the configuration of the image forming apparatus according to the present invention, and FIG. 10 is a plan view of the image forming apparatus according to the present invention as viewed from above.
The image forming apparatus shown in FIGS. 9 and 10 is a line-type image forming apparatus, and is an apparatus main body 11, a paper feed tray 12 for loading and feeding paper P, and a discharge for discharging and loading printed paper P. It includes a paper tray 13 and a transport unit 14 for transporting the paper P from the paper feed tray 12 to the paper discharge tray 13.

The image forming apparatus shown in FIGS. 9 and 10 also includes an image forming unit 15 including a head module array 50 constituting a recording head that ejects and prints droplets on the paper P conveyed by the conveying unit 14, and after printing is completed. Alternatively, a head cleaning device 16 which is a maintenance / recovery mechanism for maintaining and recovering a plurality of heads of each head module array 50 of the image forming unit 15 at a required timing, a transport guide unit 17 for opening and closing the head cleaning device 16, and image forming. It includes an ink supply system including a sub tank and a main tank that supply ink to the head module array 50 of the unit 15.

The apparatus main body 11 is composed of front and rear side plates, stays, and the like, and the paper P loaded on the paper feed tray 12 is fed to the transport unit 14 one by one by the paper feed roller 29 and the separation roller 30. ..

The transport unit 14 includes a transport drive roller 41A, a transport driven roller 41B, and an endless transport belt 43 hung between the transport drive roller 41A and the transport driven roller 41B. A plurality of suction holes are formed on the surface of the conveyor belt 43, and a suction fan 44 for sucking the paper P is arranged below the conveyor belt 43. Further, the transfer guide rollers 42A and 42B are held on the upper portions of the transfer drive roller 41A and the transfer driven roller 41B by guide members (not shown), respectively, and are in contact with the transfer belt 43 by their own weight.

The transport belt 43 orbits when the transport drive roller 41A is rotated by a motor, and the paper P is sucked onto the transport belt 43 by the suction fan 44 and is conveyed by the orbital movement of the transport belt 43. The transfer driven roller 41B and the transfer guide rollers 42A and 42B are driven by the transfer belt 43 and rotate.

An image forming unit 15 composed of a head module array 50 for ejecting droplets to be printed on the paper P is arranged on the upper portion of the transport unit 14 so as to be movable in the direction A (and in the opposite direction). The image forming unit 15 is moved to the upper side of the head cleaning device 16 during the maintenance / recovery operation (during cleaning), and is returned to the position shown in FIG. 1 during image forming.

The image forming unit 15 has four colors of ink (yellow (Y), magenta (M), cyan (C), black (K)) for the paper P that is adsorbed and held on the transport belt 43 and transported. It has a head module array 50 that constitutes a line-type recording head that ejects droplets.

In the head module array 50, a branch member 54 that distributes and supplies ink to the recording heads 101 in each row is integrally provided. Ink is supplied to the branch member 54 from a sub tank (not shown). Ink is supplied to this sub tank from the main tank. The ink colors used are not limited to these four colors, and colors such as red, green, blue, and gray may be added in order to expand the range of colors to be reproduced and gradations.

The recording head 101 includes a plurality of temperature detection elements 9-1, 9-3 and a plurality of temperature detection elements 9-2-1, 9-2-, which are arranged at unique arrangement positions in the liquid discharge head 20 of FIG. It has the same configuration as No. 2 and has the above-mentioned basic effect.

Further, the recording head 101 overlaps (overlaps) one or a plurality of nozzles at the ends of two adjacent recording heads 101 in the head arrangement direction (X direction in FIG. 10 and a direction orthogonal to the paper transport direction). Are arranged. As a result, recording can be performed at the same recording position (dot position) by the nozzles of the two recording heads 101.
The nozzle at the end of the recording head 101 capable of recording at the same recording position is called an "overlapping nozzle", and the area of the overlapping nozzles is the "connecting portion", the "nozzle row overlapping portion", and the "overlapping nozzle area (or the overlapping nozzle area"). Part) or "overlap area (or part)".

On the downstream side of the transport unit 14, a transport guide unit 17 for discharging the paper P to the paper ejection tray 13 is provided. The paper P guided and conveyed by the transfer guide unit 17 is discharged to the output tray 13. The paper output tray 13 includes a pair of side fences 31 that regulate the width direction of the paper P and an end fence 32 that regulates the tip of the paper P.

The head cleaning device 16 is a maintenance / recovery mechanism, and the cap member 62 and the wiper member corresponding to each head 101 of each recording head of the image forming unit 15 and the nozzle surface (nozzle is formed) of the recording head 101 by the cap member 62. A suction pump 63 for sucking ink from the nozzle with the surface) capped is arranged.

Further, in this image forming apparatus, after printing is completed, ink is sucked from the nozzles in a state where the nozzle surface of each recording head 101 of the recording head 101 that ejects droplets is capped by the cap member 62 of the head cleaning device 16. Alternatively, when cleaning the ink adhering to the nozzle surface of each head 101 of the recording head with a wiping member, as shown in FIG. 9, after printing is stopped, the entire transfer unit 14 is indicated by an arrow with the transfer driven roller 41B as a fulcrum. Swing in the B direction. As a result, the space between the image forming unit 15 and the image forming unit 15 is made larger than that at the time of image forming, so that the moving space of the image forming unit 15 is secured. At this time, the transport guide plate 71 of the transport guide unit 17 arranged above the head cleaning device 16 is also swung upward in the arrow C direction at the fulcrum 72, and the upper portion of the head cleaning device 16 is opened.

Then, after the transport unit 14 and the transport guide unit 17 are each released (released), the image forming unit 15 moves in the paper passing direction (direction of arrow A), is stopped above the head cleaning device 16, and is a cap member. 62 and the like rise to shift to a cleaning operation (maintenance / recovery operation) of each head 101 of the recording head.

The line-type image forming apparatus of FIGS. 9 and 10 described above includes a recording head 101 having the same configuration as the liquid discharge head 20 according to the embodiment shown in FIG. Therefore, according to the line-type image forming apparatus of FIGS. 9 and 10, the temperature distribution of the liquid in the vicinity of each individual nozzle is detected by a plurality of temperature detecting elements arranged at unique arrangement positions, and the entire nozzle in the head is detected. The temperature distribution of can be detected. This makes it possible to improve the temperature detection accuracy of the ink.
Further, the density can be corrected by an image based on the temperature distribution detected by a plurality of temperature detecting elements. Further, if the nozzles can be individually driven, voltage correction can be performed on each nozzle to make corrections with higher accuracy. With these corrections, high-quality image quality can be obtained.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and unless otherwise specified in the above description, the present invention described in the claims. Various modifications and changes are possible within the scope of the above. For example, the technical items described in the above-described embodiments may be appropriately combined.

The effects appropriately described in the embodiments of the present invention merely list the most suitable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. It's not a thing.

1 frame (housing member)
1b Common liquid chamber 2 Flow path plate 2a Fluid resistance part 2b Pressurized liquid chamber (an example of pressure chamber)
3 Nozzle plate 3a Nozzle 4 Base (example of support member)
5 Laminated piezoelectric element (an example of pressure generating means)
6 diaphragm 7 FPC
9-1, 9-3 Temperature detecting element (an example of the first temperature detecting means)
9-2-1, 9-2-2 Temperature detection element (example of second temperature detection means)
20 Liquid discharge head

Japanese Unexamined Patent Publication No. 2001-054943

Claims (7)

Multiple nozzles that eject liquid and
A plurality of pressure chambers that communicate with each of the nozzles and supply the liquid to the nozzles.
A pressure generating means for generating pressure in each of the pressure chambers and discharging the liquid from each of the nozzles.
A support member that supports the pressure generating means and
The first temperature detecting means provided on the support member and
A second temperature detecting means provided adjacent to the pressure chamber, and
Equipped with
A plurality of the first temperature detecting means are provided, and the first temperature detecting means is provided.
The first temperature detecting means is a liquid discharge head provided on both sides of the support member in the longitudinal direction with the center of the support member interposed therebetween . The liquid discharge head according to claim 1, wherein the second temperature detecting means is provided adjacent to a diaphragm forming a part of a wall surface of the pressure chamber. A fluid resistance unit provided between a common liquid chamber for supplying the liquid to the pressure chamber and the pressure chamber in the flow direction of the liquid is provided.
The liquid discharge head according to claim 2, wherein the second temperature detecting means is provided above the fluid resistance portion. A plurality of nozzle rows in which the plurality of nozzles are arranged are provided.
The liquid discharge head according to any one of claims 1 to 3, wherein the second temperature detecting means is arranged so as to correspond to each of the nozzle rows . The liquid discharge head according to any one of claims 1 to 4,
A head tank for storing the liquid to be supplied to the common liquid chamber of the liquid discharge head, a carriage on which the liquid discharge head is mounted and movable, a liquid supply mechanism, a maintenance / recovery mechanism, and at least one of a main scanning movement mechanism.
A liquid discharge unit characterized by being equipped with. A liquid discharge device comprising the liquid discharge head according to any one of claims 1 to 4 or the liquid discharge unit according to claim 5, and driving the liquid discharge head to discharge a liquid. An image forming apparatus comprising the liquid discharge head according to any one of claims 1 to 4, the liquid discharge unit according to claim 5, or the liquid discharge device according to claim 6.

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