Recording apparatus

Abstract

To appropriately detect a temperature of a recording head in a recording apparatus having a heating mechanism.SOLUTION: A recording apparatus includes: a recording head that discharges liquid onto a recording medium to form an image; heating means for heating the recording medium; a first temperature sensor provided on the recording head to detect the temperature of the recording head; and a second temperature sensor for detecting the temperature around the recording head. After the power of the recording apparatus is turned on and before the heating means is driven, a correction value for correcting the temperature of the recording head is calculated on the basis of detection results of the first temperature sensor and the second temperature sensor.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a recording apparatus.

Background Art

[0002] Conventionally, there has been known a recording apparatus that records an image by discharging a liquid onto a recording medium by driving a recording element provided in a recording head. In such a recording apparatus, it is known to execute various controls based on the temperature detected by a temperature sensor provided in the recording head. As the temperature sensor provided in the recording head, a diode sensor having excellent thermal responsiveness is generally used. Here, since there are variations in characteristics due to manufacturing errors in the diode sensor, and a temperature different from the actual temperature may be detected due to an error from the reference characteristics, measures for correcting the detection value have been taken. Patent Document 1 discloses a configuration in which a thermistor is provided on a substrate of a control unit of a recording apparatus main body to detect the ambient temperature, and the detection value of a diode sensor provided in the recording head is corrected based on the detected value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the configuration of Patent Document 1, in order to accurately calibrate the temperature of the recording head, it is premised that the temperature of the recording head is substantially the same as the ambient temperature. Therefore, for example, in a recording apparatus equipped with a heating mechanism, it is difficult to accurately obtain a calibration value because the temperature inside the recording apparatus becomes higher than the ambient temperature.

[0005] The present invention has been made in view of the above problems, and in a recording apparatus having a heating mechanism, an object thereof is to appropriately detect the temperature of a recording head.

Means for Solving the Problems

[0006] A recording apparatus according to the present invention includes a recording head that discharges a liquid onto a recording medium to form an image, a heating unit that heats the recording medium, a first temperature sensor provided in the recording head that detects the temperature of the recording head, and a second temperature sensor that detects the temperature around the recording head. The recording apparatus is characterized in that a correction value for correcting the temperature of the recording head is calculated based on detection results of the first temperature sensor and the second temperature sensor between when the power of the recording apparatus is turned on and when the heating unit is driven.

Effects of the Invention

[0007] According to the present invention, in a recording apparatus having a heating mechanism, the temperature of the recording head can be appropriately detected.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] Hereinafter, a recording apparatus using an inkjet recording method as an example of a recording apparatus will be described. The recording apparatus may be, for example, a single-function printer having only a recording function, or a multi-function printer having a plurality of functions such as a recording function, a FAX function, and a scanner function. Further, it may be a manufacturing apparatus for manufacturing a color filter, an electronic device, an optical device, a micro-structure, etc. by a predetermined recording method.

[0011] In the following description, "recording" not only refers to the case of forming significant information such as characters and figures, but also regardless of whether it is significant or not. Further, it also represents the case of forming an image, a pattern, a pattern, a structure, etc. on a recording medium widely, or performing processing on the medium, regardless of whether it is manifested so that a human can perceive it visually.

[0012] In addition, the "recording medium" refers not only to paper used in general recording devices, but also to materials such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, etc. that can receive ink. In particular, the "non-permeable recording medium / low-permeability recording medium" refers to a non-absorbent recording medium / low-absorbent recording medium. Examples of non-permeable recording media include those not manufactured as recording media for aqueous inkjet inks such as glass, plastic, film, and Yupo. Also, for example, those that have not been surface-treated for inkjet printing (i.e., do not have an ink absorption layer), such as those with plastic coated on a substrate such as plastic film or paper, can be mentioned. Examples of plastics include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc. Specific examples of low-permeability recording media include recording media such as printing paper used in offset printing, etc., such as art paper and coated paper.

[0013] A printing paper (difficult-to-absorb recording medium) with extremely low permeability of aqueous ink compared to inkjet special paper will be described. Printing paper refers to the official (real) printing paper used for actual book printing in offset printing to make products (commodities). The paper is made from pulp. Uncoated paper is used as it is, and coated paper has its surface smoothly coated with a white pigment or the like. In inkjet recording, image defects and drying defects due to ink overflow are more prominent in this coated paper. The coating layer is coated with a mixed coating of a sizing agent (such as synthetic resin) that limits the liquid absorbency between pulp gaps and prevents bleeding of aqueous pens, a filler (such as kaolin) that improves opacity, whiteness, smoothness, etc., and a paper strength enhancer (such as starch), etc., at about several to 40 g / m2. The average radius of the capillary pores of the coated paper is normally distributed around about 0.06 μm, and moisture is permeated by a large number of capillaries (capillary action). However, since its pore volume is extremely small compared to inkjet special paper, the permeability of aqueous ink is low, and ink overflows on the paper surface, resulting in prominent image defects and drying defects.

[0014] This paper describes a PVC sheet that has no permeability to aqueous ink compared to dedicated inkjet paper. A PVC sheet is a soft sheet made mainly from vinyl chloride resin with a plasticizer added, and it is excellent in printability and embossability (creating uneven patterns by die stamping) in gravure printing, screen printing, etc. Because of these combinations, various expressions are possible, so it is used in many products such as tarps, canvas, and wallpaper. Since vinyl chloride resin is the main raw material, there is no permeability to aqueous ink, and ink overflows on the paper surface, significantly showing image defects and drying defects.

[0015] In addition, for example, those not made as recording media for aqueous inkjet ink such as glass, plastic, film, and Yupo can be cited. Also, for example, those not surface-treated (i.e., not forming an ink absorption layer) for inkjet printing, such as those with plastic coated on a substrate such as plastic film or paper, can be cited. Examples of plastics include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc.

[0016] Furthermore, "ink" should be interpreted as broadly as the above definition of "recording". Therefore, it represents a liquid that can be used for forming images, patterns, etc., processing the recording medium, or treating the ink (e.g., coagulating or insolubilizing the colorant in the ink applied to the recording medium) by being applied on the recording medium.

[0017] (Overall Configuration) The configuration of the recording apparatus 1 and the outline of the operation during recording will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing the appearance of an inkjet recording apparatus (hereinafter also simply referred to as a recording apparatus) according to the present embodiment, FIG. 2(a) is a schematic cross-sectional view of the recording apparatus seen from the X direction, and FIG. 2(b) is a perspective view of the housing of the recording apparatus and the fixing unit.

[0018] From the spool 101 holding the recording medium 2, the recording medium 2 is conveyed in the Y direction by a conveyance roller driven via a gear by a conveyance motor (not shown). The fed recording medium 2 is nipped and conveyed between a paper feed roller and a pinch roller, and is guided to a recording position (scanning area of the recording head 4) on the platen 6. In order to suppress the recording medium 2 from lifting up, the platen 6 sucks air from a suction port (not shown), and the recording medium 2 guided onto the platen 6 is conveyed in the Y direction while being adsorbed to the platen 6. In this specification, the side in the positive direction with respect to the direction in which the recording medium 2 is conveyed, that is, the side facing from the platen 6 to the paper discharge guide 207 described later, may be referred to as the "downstream in the conveyance direction". Also, the side in the direction opposite to the conveyance direction, that is, the side facing from the paper discharge guide 207 to the platen 6, may be referred to as the "upstream in the conveyance direction".

[0019] The carriage unit 5 reciprocates (moves back and forth) in the X direction along a guide shaft 104 extending in the X direction orthogonal to the Y direction by a carriage motor (not shown). The carriage unit 5 is mounted with the recording head 4. The recording head 4 is connected to an ink tank (not shown) and discharges ink supplied from the ink tank from a plurality of nozzles (discharge ports) provided on the bottom surface of the recording head 4. During the scanning process of the carriage unit 5, the ink discharge operation from the nozzles of the recording head 4 is performed at a timing based on the position signal obtained by the encoder 103, and recording with a constant bandwidth corresponding to the arrangement range of the discharge ports is performed. Thereafter, the recording medium 2 is conveyed, and recording of the next bandwidth is further performed. In this way, by alternately performing the conveyance of the recording medium 2 and the recording scan by the recording head 4, the desired image is configured to be recorded on the recording medium 2.

[0020] The recording device 1 is provided with a platen air supply unit 100 that blows air to the scanning area of the recording head 4. The platen air supply unit 100 includes a platen air supply fan 100a and a heater 100b. The air sent into the platen air supply unit 100 by the fan 100a is heated to a predetermined temperature by the heater 100b and then blown onto the platen 6. When the recording medium 2 is on the platen 6, the air blown from the platen air supply unit 100 is blown onto the recording medium 2. The blowing from the platen air supply unit 100 promotes the evaporation of the moisture of the ink applied onto the recording medium by the recording head 4. Also, the blowing by the platen air supply unit 100 can remove the ink mist generated near the recording head 4 during the recording operation by the recording head 4 from the vicinity of the recording head 4. Note that the platen air supply unit 100 may not include the heater 100b, and the air sucked into the platen air supply unit 100 by the platen air supply fan 100a may be directly blown onto the recording medium 2 without being heated.

[0021] The recording head 4, the carriage unit 5, the platen air supply unit 100, and the platen 6 are provided inside the housing 701, and an access cover 702 is provided on the +Y direction side surface (front side of the recording device 1) of the housing 701. The access cover 702 is rotatable between an open position where the inside of the housing 701 is exposed and a closed position where the inside of the housing 701 is not exposed.

[0022] The recording medium on which recording has been performed by the recording head 4 is conveyed downstream in the conveyance direction and reaches the fixing unit 200 disposed downstream in the conveyance direction from the scanning area of the recording head 4. The recording apparatus 1 includes a paper discharge guide 207 downstream in the conveyance direction of the platen 6, and the paper discharge guide 207 supports the back surface of the recording medium 2 until the recording medium 2 that has passed through the platen 6 passes through the fixing unit 200. The fixing unit 200 is disposed on the downstream side in the conveyance direction of the housing 701, and the fixing unit 200 and the housing 701 are separated from each other in the conveyance direction. The fixing unit 200 includes a fan 201, a heater 202, a chamber 203, and a heat insulating material 204. The fixing unit 200 heats the air blown into the chamber 203 by the fan 201 with the heater 202, and blows the heated air onto the recording medium 2 from a plurality of air blowing holes or slits provided in the chamber bottom 203a. Thereby, water and solvents contained in the ink on the recording medium 2 are evaporated. The width of the fixing unit 200 in the X direction is configured to be larger than the maximum value of the width in the X direction of the recording medium 2 on which recording can be performed by the recording head 4 in the recording apparatus 1. Thereby, the uniformity of the temperature and the wind speed of the warm air blown onto the recording medium 2 is improved.

[0023] The ink used in this embodiment contains water-soluble resin fine particles for bringing the coloring material into close contact with the recording medium 2 and improving the rubbing resistance (fixing property) of the recorded image. The resin fine particles are melted by heat, and the fixing unit 200 forms a film of the resin fine particles and dries the solvent contained in the ink. In this embodiment, the "resin fine particles" means polymer fine particles existing in a state of being dispersed in water.

[0024] The heater 202 uses a heater that holds an open coil type nichrome wire with mica or ceramic (not shown) or a sheathed heater. The heater 202 is separated from the surface constituting the chamber 203, and one heater 202 is provided for each fan 201 to form a pair. The air blown by the fan 201 is heated by the heater 202 to become warm air. A plurality of pairs of the fan 201 and the heater 202 are provided in the width direction of the recording apparatus 1, that is, in the X direction. A heat insulating material 204 is provided between the exterior 205 covering the outer periphery of the chamber 203 and the chamber 203, suppressing the exterior 205 from becoming hot even when the inside of the chamber 203 becomes hot.

[0025] (Control unit) FIG. 3 is a block diagram showing the configuration of a control system mounted on the recording apparatus main body of the inkjet recording apparatus according to the present embodiment. The main control unit 300 includes a CPU 101 that executes processing operations such as calculation, control, determination, and setting. And, a ROM 302 that stores control programs and the like to be executed by the CPU 301, a buffer that stores binary recording data representing ink ejection / non-ejection, a RAM 303 used as a work area for processing by the CPU 301, an input / output port 304, and the like are provided. Further, the RAM 303 can also be used as storage means for storing the ink amount in the main tank and the empty capacity of the sub-tank before and after the recording operation. Connected to the input / output port 304 are a conveyance motor (LF motor) 313 that drives the conveyance roller, a carriage motor 314, a recording head 102, heaters 100b and 202, and drive circuits 305 to 310 that drive the fans 100a and 201. These drive circuits 305, 306, 307, 308, 309, and 310 are controlled by the main control unit 300. Connected to the input / output port 304 are various sensors such as diode sensors S1 to S9 that detect the temperature of the recording head 102, an encoder sensor 312 fixed to the carriage 5, and a thermistor 321 that detects the ambient temperature (environmental temperature) inside the recording apparatus 1. Further, the main control unit 300 is connected to a host computer 315 via an interface circuit 311.

[0026] 318 is a borderless ink counter that counts ink recorded outside the recording medium area when performing borderless recording, and 319 is a discharge dot counter that counts ink discharged during recording.

[0027] (Recording head) FIG. 4 is a perspective view schematically showing the recording head 4. On the discharge port forming surface, which is the surface of the recording head 4 facing the recording medium P, two recording element substrates 10a and 10b formed of semiconductor or the like are attached. On the recording element substrates 10a and 10b, discharge port arrays in which discharge ports are arranged along the Y direction orthogonal to the X direction are formed. Specifically, on the recording element substrate 10a, a discharge port array 11 for discharging black ink, a discharge port array 12 for discharging gray ink, a discharge port array 13 for discharging light gray ink, and a discharge port array 14 for discharging light cyan ink are arranged side by side in the X direction. Also, on the recording element substrate 10b, a discharge port array 15 for discharging cyan ink, a discharge port array 16 for discharging light magenta ink, a discharge port array 17 for discharging magenta ink, and a discharge port array 18 for discharging yellow ink are arranged side by side in the X direction.

[0028] In addition, recording element arrays are formed at positions in the recording element substrates 10a and 10b facing the respective discharge port arrays 11 to 18, as will be described later. In the following description, for simplicity, the recording element arrays at positions facing the discharge port arrays 11 to 18 are referred to as recording element arrays 11' to 18'.

[0029] A flexible wiring board (not shown) for supplying signal pulses for driving the recording elements provided in the discharge ports, signals for head temperature control, etc. is attached to the recording head 4. One end of the flexible board is connected to the recording head 4, and the other end is connected to the main control unit 300 described above. Near the main control unit 300, a thermistor 321, which is a temperature sensor for detecting the ambient temperature in the recording apparatus 1, is provided. In the present embodiment, by providing the thermistor 321 near the main control unit 300, a temperature close to the temperature outside the recording apparatus 1 can be detected.

[0030] The recording head 4 is provided with a joint portion 25 for connecting a plurality of ink supply tubes (not shown) for supplying ink to each of the ejection port rows 11 to 18. The ink supply tubes connected to each of the joint portions 25 are connected to a plurality of independent main tanks corresponding to the colors of the ink and supply the ink from the main tanks (not shown) to the recording head 4.

[0031] FIG. 5(a) is a perspective view when the recording element substrate 10b is viewed from a direction perpendicular to the XY plane. Further, FIG. 5(b) is a cross-sectional view when the recording element substrate 10b is cut perpendicularly to the recording element substrate 10b through the line segment AB shown in FIG. 5(a) and viewed from the downstream side in the Y direction of the vicinity of the ejection port row 15 of the cut surface. Since the configuration of the recording element substrate 10a is the same as that of the recording element substrate 10b, the recording element substrate 10b will be described here. Note that specific numerical values such as dimensions and distances shown below may be appropriately set according to the dimensions of the recording element substrate.

[0032] A total of nine diode sensors S1 to S9 are formed on the recording element substrate 10b as temperature sensors for detecting the temperature of the ink in the vicinity of the recording element 34. The diode sensors S1 and S6 are arranged near one end in the Y direction of the ejection port rows 15 to 18. Specifically, the diode sensors S1 and S6 are arranged at positions 0.2 mm away from the ejection ports at one end in the Y direction. Here, the diode sensor S1 is arranged in the middle of the ejection port row 15 and the ejection port row 16 in the X direction, and the diode sensor S6 is arranged in the middle of the ejection port row 17 and the ejection port row 18 in the X direction.

[0033] Further, the diode sensors S2 and S7 are arranged near the other end in the Y direction across the ejection port rows 15 to 18 with respect to the diode sensors S1 and S6. Here, the diode sensor S2 is arranged in the middle of the ejection port row 15 and the ejection port row 16 in the X direction, and the diode sensor S7 is arranged in the middle of the ejection port row 17 and the ejection port row 18 in the X direction. Specifically, the diode sensors S2 and S7 are arranged at positions 0.2 mm away from the ejection ports at the other end in the Y direction.

[0034] The diode sensors S3, S4, S5, S8, and S9 are respectively arranged at the central portions in the Y direction of the ejection port rows 15 to 18. Here, the diode sensor S4 is located in the middle between the ejection port rows 15 and 16 in the X direction, the diode sensor S5 is located in the middle between the ejection port rows 16 and 17 in the X direction, and the diode sensor S8 is located in the middle between the ejection port rows 17 and 18 in the X direction. Also, the diode sensor S3 is arranged outside the ejection port row 15 in the X direction, and the diode sensor S9 is arranged outside the ejection port row 18 in the X direction.

[0035] Note that the number of diode sensors arranged on the recording element substrate 10b is not limited to nine. For example, when more diode sensors are provided with respect to the recording element substrate, since the number of points for detecting the temperature increases, the temperature of the recording head can be grasped more accurately. Also, generally, the central portion of the nozzle row is more difficult to dissipate heat than the end portion of the nozzle row, so it is easier to increase the temperature. Therefore, a configuration in which more diodes are arranged in the central portion where the temperature is likely to rise and the temperature can be grasped more precisely may be adopted. Furthermore, when precise temperature control is desired, it is preferable to densely arrange more diodes for one nozzle row. From the above viewpoints and the cost viewpoint, the number and arrangement of the diodes of the product may be determined.

[0036] The recording element substrate 10b is provided with heating elements (hereinafter also referred to as sub-heaters) 19a and 19b for heating the temperature of the ink in the ejection port. Here, the heating element 19a is formed as a continuous member so as to surround the side where the diode sensor S3 in the X direction of the ejection port row 15 is provided. Similarly, the heating element 19b is formed as a continuous member so as to cover the side where the diode sensor S9 in the X direction of the ejection port row 18 is provided. Note that the heating elements 19a and 19b are respectively located 1.2 mm outside the ejection port rows 13 in the X direction and 0.2 mm outside the diode sensors S1, S2, S6, and S7 in the Y direction.

[0037] The recording element substrate 10b is composed of a substrate 31 on which various circuits are formed, in addition to diodes sensors S1 to S9 and sub-heaters 19a and 19b, and a discharge port member 35 formed of resin. A common ink chamber 33 is formed between the substrate 31 and the discharge port member 35, and an ink supply port 32 communicates with the common ink chamber 33. An ink flow path 36 extends from the common ink chamber 33, and the ink flow path 36 communicates with a discharge port 30 formed in the discharge port member 35. A foaming chamber 38 is formed at an end of the ink flow path 36 on the discharge port 30 side, and a recording element (main heater) 34 is disposed at a position facing the discharge port 30 in the foaming chamber 38. The recording element 34 does not necessarily have to be an electrothermal conversion element, and a piezoelectric element may be used. Further, a nozzle filter 37 is formed between the ink flow path 36 and the common ink chamber.

[0038] In this embodiment, a representative temperature is calculated based on the temperatures detected from each of the diode sensors S1 to S9, and various temperature controls are executed based on the representative temperature. Here, for simplicity in the following description, the temperature detected from the diode sensor S5 is described as the representative temperature in various temperature controls. However, this embodiment is not limited to a form in which the detected temperature from such a single diode sensor is always commonly used in all temperature controls. For example, a form in which the combination of temperature sensors used to calculate the representative temperature is changed for each type of temperature control may be adopted. As an example, when performing drive pulse control for controlling the drive pulse applied to the recording element according to the temperature in the recording element row 15', the average value of the temperatures detected from the four diode sensors S1, S2, S3, and S4 surrounding the periphery may be used as the representative temperature. Further, when performing the above-described drive pulse control in the recording element row 17x, the four diode sensors S6, S7, S8, and S9 surrounding the periphery may be used. Further, in order to keep the ink warm during recording, when the temperature of the ink is below a predetermined threshold value, the sub-heater 19a may be driven, and when the temperature becomes higher than the predetermined threshold value, the drive of the sub-heater may be stopped. In such a case, a form in which the minimum value of the temperatures detected from the three diode sensors S1, S2, and S3 near the sub-heater 19a is used as the representative temperature may be adopted. Further, this embodiment does not need to have a plurality of diode sensors in the recording head as shown in FIG. 5(a), and it is sufficient to have at least one diode sensor.

[0039] (Data processing process) In this embodiment, the recording data generation processing process executed by the CPU 101 according to the control program will be described.

[0040] First, image data (luminance data) represented by information (0 to 255) of 8 bits and 256 values for each of the red (R), green (G), and blue (B) colors input from the host computer to the recording apparatus is acquired.

[0041] Next, the image data represented by R, G, and B is converted into multi-valued data represented by a plurality of types of inks used for recording. By this color conversion process, multi-valued data represented by 8-bit 256-value information (0 to 255) that determines the gradation in each ink of each pixel group composed of a plurality of pixels is generated.

[0042] Next, quantization of the above-described multi-valued data is performed to generate quantization data (binary data) represented by 1-bit binary information (0, 1) that determines ejection or non-ejection of each ink for each pixel. Here, as the quantization process, processing can be performed according to various quantization methods such as the error diffusion method, the dither method, and the index method.

[0043] Then, a distribution process is performed to distribute the quantization data to multiple scans of the recording head for each unit area. By this distribution process, recording data represented by 1-bit binary information (0, 1) that determines ejection or non-ejection of each ink for each pixel in each of the multiple scans of the recording medium for each unit area is generated. This distribution process corresponds to multiple scans and is executed using a mask pattern that determines allowable or non-allowable ejection of ink for each pixel.

[0044] Ink ejection from the recording head is performed according to the recording data generated as described above.

[0045] Here, although the form in which the CPU 101 in the recording apparatus 1 executes all of the above processes has been described, implementation according to other forms is also possible. For example, a form in which all of the above processes are executed by a host computer may be used. Further, for example, a form in which a part is executed by a host computer and the remainder is executed by the recording apparatus 1 may be used. (Ink Composition) The composition of the colored ink and the water-soluble resin fine particle ink used in this embodiment will be described. Hereinafter, "parts" and "%" are based on mass unless otherwise specified.

[0046] The colored ink containing the pigment and the water-soluble resin fine particle ink containing no pigment or only a trace amount thereof used in this embodiment both contain a water-soluble organic solvent. For reasons of wettability and moisture retention of the head face, the water-soluble organic solvent preferably has a boiling point of 150°C or higher and 300°C or lower. Also, from the viewpoints of the function of the film-forming aid for the resin fine particles and the swelling solubility in the recording medium on which the resin layer is formed, ketone compounds such as acetone and cyclohexanone; propylene glycol derivatives such as tetraethylene glycol dimethyl ether; and heterocyclic compounds having a lactam structure typified by N-methyl-pyrrolidone and 2-pyrrolidone are particularly preferred. From the viewpoint of ejection performance, the content of the water-soluble organic solvent is preferably 3 wt% or more and 30 wt% or less. Specifically, the water-soluble organic solvent includes, for example, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol; or alkylene glycols having 2 to 6 carbon atoms in the alkylene group such as propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate; glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether; polyhydric alcohols such as trimethylolpropane and trimethylolethane; and N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like. The water-soluble organic solvent as described above can be used alone or as a mixture.Also, it is desirable to use deionized water as the water. For the colored ink and the water-soluble resin fine particle ink used in this embodiment, in order to give desired physical property values as necessary, surfactants, defoaming agents, preservatives, fungicides, etc. can be appropriately added in addition to the above components.

[0047] · Preparation of resin fine particle dispersion The colored ink of this embodiment contains water-soluble resin fine particles for improving the rubbing resistance (fixing property) of the recorded image by bringing the recording medium and the coloring material into close contact. The resin fine particles melt by heat, and the film formation of the resin fine particles and the drying of the solvent contained in the ink are performed by a heater. In this embodiment, the "resin fine particles" means polymer fine particles existing in a state of being dispersed in water. Specifically, acrylic resin fine particles synthesized by emulsion polymerization of monomers such as (meth) acrylic acid alkyl ester and (meth) acrylic acid alkylamide. Styrene-acrylic resin fine particles synthesized by emulsion polymerization of monomers such as (meth) acrylic acid alkyl ester and (meth) acrylic acid alkylamide and styrene. Examples include polyethylene resin fine particles, polypropylene resin fine particles, polyurethane resin fine particles, and styrene-butadiene resin fine particles. Also, core-shell type resin fine particles in which the polymer composition is different between the core part and the shell part constituting the resin fine particles, or resin fine particles obtained by using acrylic fine particles synthesized in advance as seed particles and performing emulsion polymerization around them may be used. Furthermore, hybrid type resin fine particles in which different resin fine particles such as acrylic resin fine particles and urethane resin fine particles are chemically bonded may be used.

[0048] Furthermore, the "polymer microparticles dispersed in water" may be in the form of resin microparticles obtained by homopolymerizing or copolymerizing multiple types of monomers having a dissociable group, that is, a so-called self-dispersing resin microparticle dispersion. Examples of the dissociable group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and examples of the monomer having the dissociable group include acrylic acid and methacrylic acid. Furthermore, the polymer may be a so-called emulsion dispersion type resin microparticle dispersion in which resin microparticles are dispersed by an emulsifier. As the emulsifier, a material having an anionic charge can be used regardless of whether it is a low molecular weight or a high molecular weight.

[0049] Processing fluid In addition, in this embodiment, a treatment liquid (RCT) is used for the purpose of forming an image on a poorly absorbing or non-absorbing medium. The treatment liquid used in this embodiment contains a reactive component that reacts with a pigment contained in the ink and causes the pigment to aggregate or gel. Specifically, this reactive component is a component that can destroy the dispersion stability of an ink when mixed on a recording medium or the like with an ink having a pigment that is stably dispersed or dissolved in an aqueous medium by the action of an ionic group. In this embodiment, an anionic coloring material is used, so the reactants can be roughly classified into acid-based reactants, polyvalent metal-based reactants, and cationic polymer-based reactants.

[0050] As acid-based reactants, they can be broadly classified into inorganic acids and organic acids. In this embodiment, organic acids will be described, but it is not limited to organic acids. Specific examples of water-soluble organic acids include oxalic acid, polyacrylic acid, formic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, levulinic acid, succinic acid, glutaric acid, glutamic acid, fumaric acid, citric acid, tartaric acid, lactic acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, oxysuccinic acid, and dioxysuccinic acid. The content of the organic acid is preferably 3.0% by mass or more and 90.0% by mass or less, more preferably 5.0% by mass or more and 70.0% by mass or less, based on the total mass of the composition contained in the treatment liquid.

[0051] As polyvalent metal-based reactants, the following are preferred. For example, divalent metal ions such as Ca2+, Cu2+, Ni2+, Mg2+, Zn2+, Sr2+ and Ba2+ can be mentioned. Furthermore, trivalent metal ions such as Al3+, Fe3+, Cr3+ and Y3+ can also be mentioned, but it is not limited to these. In order to contain these polyvalent metal ions in the treatment liquid, it is advisable to use salts of polyvalent metals. A salt is a metal salt composed of polyvalent metal ions as mentioned above and anions that bind to these ions, and it is required to be soluble in water. Preferred anions for forming salts include, for example, Cl―, NO3―, I―, Br―, ClO3―, SO42―, CO32―, CH3COO― and HCOO―, etc., but it is not limited to this.

[0052] In the present invention, from the viewpoints of reactivity, coloring property, and ease of handling, etc., as polyvalent metal ions, Ca2+, Mg2+, Sr2+, Al3+ and Y3+ are particularly preferred, and among them, Ca2+ is particularly preferred. Also, as an anion for forming a salt with polyvalent metal ions, methanesulfonic acid is particularly preferred from the viewpoints of safety, etc.

[0053] As the cationic polymer-based reactant, those soluble in water are preferred. Specific examples of the cationic polymer include polyallylamine hydrochloride, polyamine sulfonate, polyvinylamine hydrochloride, chitosan acetate, etc. In addition, other examples include copolymers of vinylpyrrolidone obtained by cationizing a part of a nonionic polymer substance and a quaternary salt of aminoalkyl acrylate, copolymers of acrylamide and a quaternary salt of aminomethylacrylamide, etc. The treatment liquid containing a cationic polymer as a reactive component is preferably colorless, but does not necessarily have to show no absorption in the visible region. That is, even if it shows absorption in the visible region, as long as it does not affect the image substantially when the image is formed, it may be a light-colored one showing absorption in the visible region. Note that the treatment liquid does not necessarily have to be used in all recording modes, and is applied only in an amount necessary for forming a printed image in view of the ink application amount.

[0054] (First Embodiment) Hereinafter, the head temperature correction flow in this embodiment will be described with reference to FIG. 6. The head temperature correction flow in this embodiment is executed when the recording apparatus 1 is powered on, that is, when the power is turned on, and calculates a correction value of the recording head temperature (hereinafter referred to as the Di correction value).

[0055] First, in step 601 shown in FIG. 6, the detected temperature Tdi from the diode sensor S5 provided in the recording head 4 is acquired. Here, the temperature acquired simply from the diode sensor S5 arranged at the center of the recording element substrate 10b is defined as Tdi, but as described above, the value obtained by averaging the detected temperatures of a plurality of diode sensors may be defined as Tdi. The information indicating the acquired detected temperature Tdi is stored in the RAM 303. In step 602, the detected temperature Tenv from the thermistor 321 is acquired. The information indicating the acquired detected temperature Tenv is stored in the RAM 303. Here, the detected temperature Tenv indicates the ambient temperature inside the recording apparatus 1 as described above.

[0056] In step 603, the difference between the detected temperature Tdi from the diode sensor S5 and the detected temperature Tenv from the thermistor 321, which are obtained in steps 601 and 602, is calculated and used as the Di correction value Tadj. The calculated Di correction value Tadj is stored in the ROM 302 in step 604. After the end of step 604, in step 605, the power of the platen air supply unit 100 and the fixing unit 200 is turned on to start the printing preparation.

[0057] Next, a method of applying the Di correction value calculated in the head temperature correction flow will be described. FIG. 10 is a flowchart showing the process of obtaining the correction temperature when controlling the temperature of the recording head 4. For simplicity in the following description, the temperature obtained from the diode sensor during temperature control is denoted as Tdic, and the corrected temperature after correction is denoted as Th. In step S1001 of FIG. 10, the temperature Tdic detected by the diode sensor S5 is obtained immediately before executing the temperature control. In step S1002, the correction value Tadj stored in the RAM 303 is read out.

[0058] In step S1003, the corrected temperature Th is calculated according to the calculation formula for correcting the temperature detected by the diode sensor shown in the following (Equation 1). Th = Tdic + Tadj ··· (Equation 1)

[0059] When calculating the correction value in the head temperature correction flow of FIG. 6, if the detected temperature of the thermistor 321 is higher than the detected temperature of the diode sensor S5, the corrected temperature Th calculated in S1003 will be higher than the temperature Tdic before correction (Th > Tdic). Conversely, when calculating the correction value in the head temperature correction flow of FIG. 6, if the detected temperature of the thermistor 321 is lower than the detected temperature of the diode sensor S5, the corrected temperature Th calculated in S1003 will be lower than the temperature Tdic before correction (Th < Tdic).

[0060] Then, the temperature control of the recording head 4 is executed using the corrected temperature Th calculated in step S1004. Here, as the temperature control, for example, drive pulse control, sub-heater heating control, short pulse heating control, etc. can be executed.

[0061] With the above configuration, before the start of heating by the heating mechanism, appropriate correction processing can be executed based on the detection results of the diode sensor S5 and the thermistor 321. When the power is turned on, the heating mechanism that needs to warm up from the state adapted to the outside air temperature to the target temperature is desired to start heating promptly after the power of the recording device is turned on. However, if heating is started prior to the correction of the head temperature, the temperature of the recording head and the ambient temperature inside the machine will rise due to the influence of the temperature increase by the heating mechanism, and as a result, the correction of the head temperature will not be performed correctly.

[0062] In the present embodiment, since the Di correction is performed prior to the start of heating of the drying mechanism having the heating mechanism, and the Di correction is performed in a state where the recording head and the ambient temperature inside the machine are not affected by the temperature increase by the heating mechanism, the temperature of the recording head can be calibrated accurately.

[0063] The reason for starting the head temperature correction flow shown in FIG. 6 when the power of the recording device 1 is turned on is that in the power-off state, since neither the recording head nor the drying mechanism is operating, the temperature increase due to printing or drying does not occur, and thus it can start. However, in view of the case where printing or drying has been performed until immediately before and the power is turned on immediately after the power is turned off, it is better to add a determination as to whether or not to perform the correction depending on whether the time when the power was turned off is longer than a predetermined time.

[0064] (Second Embodiment) Hereinafter, the second embodiment will be described, but the description of the same configuration as that of the first embodiment will be omitted. In the first embodiment, by performing the Di correction before the start of heating of the drying mechanism, the temperature correction was performed by eliminating the influence of the temperature increase due to heating. In the present embodiment, further, the temperature sensor mounted on the drying mechanism is also used to determine whether or not to perform the Di correction.

[0065] The platen air supply unit 100 includes a heater 100b and a platen air supply fan 100a, and further includes a sensor (not shown) for detecting the temperature of the air to be supplied. Since the platen air supply unit 100 is located closer to the recording head 4 than the thermistor 321, the temperature obtained from the sensor provided in the platen air supply unit 100 can be used for calculating the Di correction value, thereby more accurately estimating the temperature of the recording head 4.

[0066] FIG. 7 shows the head temperature correction flow in the present embodiment. In steps 701 and 702, similar to the first embodiment, the detected temperature Tdi from the diode sensor S5 and the detected temperature Tenv from the thermistor 321 are acquired and stored in the RAM 303. In step 703, the detected temperature Tdry from the temperature sensor mounted on the platen air supply unit 100 is acquired. It is preferable to use a thermistor as the sensor mounted on the platen air supply unit 100, similar to the sensor for obtaining the ambient temperature.

[0067] Next, in step 704, the difference between the temperature Tdry of the drying mechanism obtained in step 703 and the ambient temperature Tenv obtained in step 702 is calculated. By comparing Tenv, which is close to the air temperature outside the recording device, with Tdry, which is the ambient temperature at a position close to the recording head 4, it is determined whether the temperature inside the recording device has risen compared to the outside air temperature. When the absolute value of the difference between Tenv and Tdry is less than a predetermined temperature Tthr (S704: NO), it is considered that the temperature inside the recording device has not risen compared to the outside air temperature, and Di correction is performed in steps 705 and 706 in the same manner as steps 603 and 604 in FIG. 6. On the other hand, when the difference between Tenv and Tdry is equal to or greater than Tthr (S704: YES), Di correction is not performed, and the process proceeds to step 707 to start heating the drying mechanism. Here, Tthr may be set to a value such that it does not exceed Tthr due to detection errors of Tenv and Tdry and detection variations. For example, if the detection errors and detection variations of Tenv and Tdry are ±0.5 °C, setting Tthr to be greater than 1.0 °C allows for good determination without being affected by noise such as detection variations. The application process of the calculated correction value is the same as in the first embodiment and is therefore omitted.

[0068] According to the above method, since the ambient temperature near the recording head and the temperature of the thermistor installed at a location close to the outside air inside the recording device are compared, it is possible to determine whether the temperature inside the recording device 1 has risen before calculating the Di correction value. Therefore, when it is determined that the absolute value of the difference between the temperature inside the recording device and the ambient temperature is equal to or greater than a predetermined value, Di correction is not performed, and correction is performed at the timing when the power is turned on in subsequent times. Also, when the absolute value of the difference between the temperature inside the recording device and the ambient temperature is less than the predetermined value, Di correction is performed. When the actual temperature is higher than the outside air temperature and the temperature of the recording head is corrected on the premise that it is equal to the outside air temperature, the temperature of the recording head will be recognized as lower than the original temperature. When control is performed to heat the recording head to the target temperature in such a case, the recording head will be heated to a temperature higher than the target temperature.

[0069] If such excessive heating occurs, it may impose a load on the recording head 4 and affect printing. Also, since the pulse for ink ejection is changed according to the temperature of the recording head to control the ejection amount to be constant, the head temperature may be recognized with a large error from the original head temperature, and the ink ejection amount may become inappropriate.

[0070] On the other hand, when it is determined that the temperature inside the recording apparatus is within a predetermined value from the outside air temperature, Di correction is performed, and as a result, Di correction can be performed with high accuracy.

[0071] In the flowchart shown in FIG. 7, it is determined whether to perform Di correction when the power is turned on. However, the applicable range of the flowchart in FIG. 7 is not necessarily limited to when the power is turned on. When it can be determined that the recording head is not warming up, for example, when the elapsed time from the previous printing has exceeded a certain time, it is considered that the recording head 4 has not been warmed up by printing, so the temperature of the recording head 4 can be estimated to be in the same state as when the power was turned on. Therefore, the flowchart in FIG. 7 may be started when a certain time or more has elapsed since the previous printing.

[0072] (Third Embodiment) Hereinafter, the third embodiment will be described, but descriptions of the same configurations as those in the first and second embodiments will be omitted. In this embodiment, using the blower mechanism mounted on the drying mechanism and the temperature sensor of the drying mechanism, it is determined whether the temperature inside the recording apparatus is close to the outside air temperature. If Di correction is performed in a state where the temperature inside the recording apparatus has not adapted to the outside air temperature, although the actual temperature is higher than the outside air temperature, it will be corrected to be equivalent to the outside air temperature, and the temperature of the recording head will be recognized to be lower than the original temperature.

[0073] FIG. 8 shows the temperature correction flow in the present embodiment. Also in the present embodiment, similar to the first embodiment, Di correction value calculation is performed when the power of the recording apparatus 1 is turned on. When the process starts, the temperature Tdry1 detected by the temperature sensor of the drying mechanism is acquired in step 801 and stored in the RAM 303. Next, in step 802, only the air blowing of the platen air blowing unit 100 is performed. At this time, the platen air blowing unit 100 drives the platen air blowing fan 100a and the heater 100b is not driven.

[0074] Thereafter, in step 803, the temperature Tdry2 of the drying mechanism after performing the air blowing for N seconds is acquired, and the difference from Tdry1 is calculated. If the absolute value of the difference between Tdry1 and Tdry2 is less than the predetermined value Tthr (S803: NO), Di correction is performed in steps 804 to 806. On the other hand, when the difference between Tdry1 and Tdry2 is Tthr or more (S803: YES), without performing Di correction, the process proceeds to step 807, and the heater 100b of the platen air blowing unit 100 is driven to start heating. Since the application process of the calculated correction value is the same as that in the first embodiment, it is omitted.

[0075] In the present embodiment, when the temperature of the outside air taken into the recording apparatus 1 by the air blowing from the platen air blowing unit 100 is greatly different from the temperature inside the recording apparatus, the temperature change from Tdry1 to Tdry2 should be large. Conversely, when the outside air and the temperature inside the recording apparatus are substantially the same, the temperature change from Tdry1 to Tdry2 becomes small. In the present embodiment, the above is utilized to determine whether the ambient temperature inside the recording apparatus is sufficiently adapted to the outside air.

[0076] Therefore, it is desirable that the configuration of the platen air blowing unit 100 in the present embodiment is a configuration for taking in the outside air or a mechanism capable of adjusting the intake amount of the outside air. Also, in order to shorten the time (N seconds) from the start of the air blowing to the determination, when implementing the flow of the present embodiment, it is desirable that the intake amount of the outside air is set as large as possible. Also, the start of the flow of the present embodiment is not limited to when the power is turned on, similar to the second embodiment.

[0077] (Fourth Embodiment) The following describes the third embodiment. However, descriptions of the same configurations as those in the first to third embodiments are omitted. This embodiment combines the flows shown in the second and third embodiments to more accurately determine whether the inside of the recording device has adapted to the outside air.

[0078] FIG. 9 shows the head temperature correction flow in this embodiment. First, in steps 901 to 903, the head temperature Tdi, the ambient temperature Tenv, and the temperature Tdry1 of the drying mechanism are acquired. Next, in step 904, the difference between the temperature Tdry1 of the drying mechanism and the ambient temperature Tenv is calculated. If the absolute value of the difference between the temperature Tdry1 of the drying mechanism and the ambient temperature Tenv is equal to or greater than the threshold temperature Tthr1, Di correction is not performed, and the process proceeds to step 909 to start heating the platen air supply unit 100. If the difference between the temperature Tdry1 of the drying mechanism and the ambient temperature Tenv is less than the threshold temperature Tthr1, the process proceeds to step 905. The flow after step 905 is the same as steps 803, 805 to 807 in FIG. 8, so the description is omitted.

[0079] In this embodiment, in addition to comparing the ambient temperature and the temperature of the drying mechanism shown in the second embodiment, it is also determined whether the head temperature can be corrected based on the temperature change inside the recording device before and after air supply shown in the third embodiment.

[0080] With this configuration, for example, it is possible to prevent the head temperature from being corrected when the ambient temperature and the temperature of the drying mechanism are substantially the same but both are higher than the outside air temperature, and it is possible to more accurately determine whether the temperature inside the recording device has adapted to the outside air temperature. Thereby, the correction accuracy of the head temperature is improved.

[0081] Note that in any of the first to fourth embodiments, the present invention is not limited to the configuration of a recording apparatus including the serial type recording head 4 as shown in FIG. 1. For example, the present invention can also be applied to a so-called full-line type recording apparatus in which the recording position of the recording head 4 is fixed and an image is recorded on a recording medium by continuously conveying the recording medium facing the recording head 4.

Explanation of Signs

[0082] 1 Recording apparatus 4 Recording head 321 Thermistor S1 to S9 Diode sensor

Claims

1. A recording head that discharges liquid onto a recording medium to form an image, heating means for heating the recording medium, a first temperature sensor provided in the recording head for detecting the temperature of the recording head, a second temperature sensor for detecting the temperature around the recording head, and a recording apparatus comprising: A correction value for correcting the temperature of the recording head is calculated based on the detection results of the first temperature sensor and the second temperature sensor between when the power of the recording apparatus is turned on and when the heating means is driven. A recording apparatus characterized by that.

2. The heating means includes a heater for heating air, a fan for blowing air, and a third temperature sensor for detecting the temperature of the air heated by the heater and blown by the fan. The recording apparatus according to claim 1, characterized by that.

3. Between when the power of the recording apparatus is turned on and when the heating means is driven, the second temperature detected by the second temperature sensor and the third temperature detected by the third temperature sensor are compared, and when the difference between the second temperature and the third temperature is less than a first value, the correction value is calculated. The recording apparatus according to claim 2, characterized in that when the difference is greater than or equal to the first value, the correction value is not calculated.

4. Between when the power of the recording apparatus is turned on and when the heating means is driven, and before driving the fan of the heating means, a fourth temperature detected by the third temperature sensor and a fifth temperature detected by the third temperature sensor after driving the fan of the heating means are compared, and when the difference between the fourth temperature and the fifth temperature is less than a second value, the correction value is calculated. The recording apparatus according to claim 2 or 3, characterized in that when the difference is greater than or equal to the second value, the correction value is not calculated.

5. The recording apparatus according to claim 1, characterized in that the driving of the recording head is controlled based on the temperature of the recording head corrected based on the correction value.

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