JPH1086353A - Ink jetrecorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To p rovide an ink jet recorder having a fixing mechanism that can achieve miniaturization and simplification of the device, reduction in cost and in power consumption and quick starting at the same time. SOLUTION: One halogen heater 501 and a reflection plate 503 having a semicylindrical surface that covers the outside of the heater are provided below a platen that opposes a recording head. The halogen heater 501 applies preheating, main heating and after-heating to a recording medium P conveyed on the platen by one heater using radiant heat and convection heat by the reflection plate 503.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink fixing technique in an ink jet recording apparatus which performs recording by discharging ink from a recording head onto a recording material.

[0002]

2. Description of the Related Art Recording devices such as printers, copiers, and facsimile machines are configured to record an image composed of a dot pattern on a recording material such as paper, a plastic thin plate, or cloth based on image information. ing.

[0003] Such a recording apparatus uses a recording method,
It can be divided into ink jet type, wire dot type, thermal type, laser beam type, etc. Among them, the ink jet type recording device discharges ink (recording liquid) droplets from the discharge port of the recording head, and this is used as a recording material. It is configured to record by attaching.

In recent years, a large number of recording apparatuses have been used, and high-speed recording, color recording, conversion to plain paper, high resolution, high image quality, low noise, and the like are required for these recording apparatuses. . The above-mentioned ink jet recording apparatus can be cited as a recording apparatus that meets such demands. In the ink jet recording apparatus, non-contact printing is possible because recording is performed by discharging ink from a recording head, and therefore, a very stable recorded image can be obtained.

[0005]

However, in the ink jet recording system, since printing is performed on ordinary recording paper which is a fluid mainly composed of water, there are problems such as (1) occurrence of feathering and (2) occurrence of bleeding. (3) Decrease in concentration
(4) Deterioration of color development (5) Fixability (drying) (6) Cockling and curling.

Therefore, how to solve the above problems is an important technical point. Specific means for this include (a) elaborate the recording material, (b) elaborate the ink, (c) perform pre- and post-processing, and (d) provide auxiliary means such as fixing means. Can be considered.

The method (a) can solve the above-mentioned problems (1) to (5) by applying a coating to a recording material.
There is no effect on the problem of (6) above, and when coated, the manufacturing cost is increased, and as a result, the running cost is increased, and printing on the back side because it is a single-sided coating adversely affects the printer body. In addition, there is a problem that the obtaining means of the coated paper is troublesome.

In the method (b), the above problems (1) to (5) can be slightly solved by imparting permeability and drying property to the ink, but this method is not sufficient. Has no effect on the problem described above, and also has a problem of adversely affecting the intrinsic ejection characteristics and durability of ink jet recording. More specifically, for example, when a surfactant (such as acetylenol) is added to ink to impart super-permeability, the ink immediately penetrates ordinary recording paper, thereby improving fixability and reducing smear. Although bleeding that occurs at the boundary of ink during multicolor printing is reduced, feathering increases when characters are printed, and the quality of characters is reduced, or it penetrates deeply into the recording part A decrease in density, a decrease in color developability, strikethrough, etc. occur. On the other hand, in the ink in which a large amount of volatile components (such as alcohols) are added to improve the drying property, the fixing property is increased and smear is reduced, but the ink is thickened in the recording head due to the increased evaporation rate. Poorness of ejection (ejecting property of the first droplet) and sticking property are deteriorated, and a decrease in foaming stability due to a change in ink components occurs.

The method (c) is a method in which the processing liquid is applied before and after the ink is applied to the recording medium to solidify the ink. In this method, the method of applying the processing liquid is complicated, If the problem does not occur completely, the problems (1) to (5) above will not be sufficiently solved, and the problem (6) will worsen further. There is also a problem of adversely affecting the durability and durability.

The method (d) can solve all of the above problems (1) to (6) depending on the device of the fixing device or the like. However, there are various problems such as an increase in the cost of the apparatus, an adverse effect due to the generation of water vapor, a rise in the temperature of the entire apparatus, and safety, and the method has not been easily introduced.

As a fixing technique, there is a heating method for a recording material. (I) Contact / contact? (ii) Before printing, during printing,
After printing? (iii) Is it the print surface / print back surface? (iv) What is the required heating temperature? Various heater configurations, fixing configurations, and control methods can be considered depending on items such as. The heating method can be considered as a basic principle. (A) Is it based on heat conduction? (B) Due to radiant heat? (C) Convection? (D) Is the above combination? You need to choose.

In the conventional fixing / heater configuration, heat conduction by platen heating has been mainly used. However, the temperature rise is slow, there is a problem in safety, it is difficult, and there is a problem with the recording material. There has been a problem that the occurrence of a temperature distribution due to poor contact deteriorates an image. In addition, there are some that use radiant heat (including convection heat) using infrared rays or the like, but they consume a lot of power, have problems with safety, have insufficient environmental stability, and have recently used high-speed printing. (E.g., a large amount of ink is ejected in a short time) and high image quality technology (high demand for full-color or dot / image cutting) is insufficient. Had.

On the other hand, a printer for forming a monochrome / color image is required to have various stability such as dot reproducibility and color reproducibility. .

Accordingly, a first object of the present invention is to provide an ink jet recording apparatus capable of achieving miniaturization of the apparatus by making the function of the heating unit hybrid.

A second object of the present invention is to provide an ink jet recording apparatus capable of reducing the cost of the apparatus by making the function of the heating unit hybrid.

A third object of the present invention is to provide an ink jet recording apparatus capable of achieving power saving of the apparatus by hybridizing the function of a heating unit.

A fourth object of the present invention is to provide an ink jet recording apparatus capable of realizing a quick start of the apparatus by hybridizing the function of a heating unit.

A fifth object of the present invention is to provide an ink jet recording apparatus capable of improving the safety of the apparatus.

A sixth object of the present invention is to provide an ink jet recording apparatus capable of improving the color developability (including the density), reducing bleeding and reducing feathering by the fixing mechanism and improving the image quality. It is in.

A seventh object of the present invention is to provide an ink jet recording apparatus capable of reducing cockling and curling, reducing smear (high-speed fixing), and improving media handling.

[0021]

According to the present invention, there is provided a recording head having a plurality of nozzles for discharging ink from a discharge port. In an ink jet recording apparatus for forming an image by heating, the heating means for heating the recording medium, and drying the image formed with ink, the heating means,
It is characterized in that the heating of the recording area of the recording medium by the recording head is controlled by one heating means for preheating, heating during recording, and postheating.

Preferably, in the above-mentioned ink jet recording apparatus, preheating (preheating), heating during recording (main heat), and postheating (after heat) of the heating means include heat conduction (contact heating) and radiation (non-contact heating). Among the three heating principles of 1) and convection (non-contact heating 2), the recording medium and the ink are mainly heated using radiation (contact heating).

Preferably, preheating, heating during recording, and postheating of the heating means are based on three heating principles of heat conduction (contact heating), radiation (non-contact heating 1), and convection (non-contact heating 2). Among them, the recording medium and the ink are mainly heated using heat conduction.

Preferably, the preheating, heating during recording, and postheating of the heating means are based on three heating principles: heat conduction (contact heating), radiation (non-contact heating 1), and convection (non-contact heating 2). The recording medium and the ink are heated using the recording medium.

Preferably, the preheating of the heating means is performed by heat conduction (contact heating), and the heating during recording and the post-heating are performed by radiation (non-contact heating 1) and convection (non-contact heating 2). Is used to heat the recording medium and the ink.

Further, in any one of the above-described ink jet recording apparatuses, it is preferable that the heating means is capable of emitting at least infrared rays, specifically, a ceramic heater. The heating means may be directly or indirectly rotatable, or may be capable of changing heat distribution characteristics by a control means.

According to the invention as described above, an ink jet recording apparatus which has a plurality of discharge ports and discharges ink from the discharge ports to form an image by discharging ink on a recording medium is used. And a heating unit for heating the recording medium and drying the image formed by the ink. The heating unit includes a heating unit that preheats (preheats) a recording area on the recording medium by the recording head and heats during recording. (Main heat) and 1 post-heat (after heat)
Heating can be controlled with two heating units. This makes it possible to provide a heating control method required for ink jet recording with a simple unit configuration, and to reduce the size and simplification of the apparatus.
At the same time, cost reduction, power saving, quick start, improvement of device safety, and improvement of image quality can be supported.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] The present embodiment is characterized in that one heater performs preheating and main heating.

(I) Main Body Configuration FIG. 1 shows the main body configuration of a first embodiment of the ink jet recording apparatus of the present invention. The apparatus according to the present embodiment is a full-color serial type printer, and as shown in FIG. 1, four exchanges corresponding to four color inks of black (Bk), cyan (C), magenta (M), and yellow (Y). The recording head cartridge C is provided. The recording head cartridge C is formed by integrally forming a recording head and an ink tank storing ink for supplying ink to the recording head. This recording head has, for example, a resolution of 360 dpi,
The drive frequency was 10.8 (KHz) and the number of discharge ports was 128.

The recording head cartridge C includes the carriage 2
Is detachably attached to the device by a configuration (not shown).
The carriage 2 is slidably engaged with the guide shaft 11 and is connected to a part of a drive belt 52 that is moved by a main scanning motor (not shown). Thus, the recording head cartridge C can be moved for scanning along the guide shaft 11.

Conveying rollers 15 are provided at the far side and near side in the drawing of the recording area by scanning of the recording head cartridge C.
16, 17, 18 extend substantially parallel to the guide shaft 11. The transport rollers 15, 16 and 17, 18 are driven by a control circuit (not shown) and a sub-scanning motor to drive the recording medium P.
Is heated and transported. The conveyed recording medium P faces the surface of the recording head cartridge C on which the ejection port surface is provided, and forms a recording surface.

Next, the recording medium P conveyed is subjected to preheating heating and main heating heating by the infrared heating unit 500 from the lower surface side of the printing at the platen portion, thereby rapidly increasing the temperature of the recording medium P to a desired temperature. The infrared heater unit 500 includes the halogen heater 50
2, a mesh-shaped platen 502 for preventing the recording medium from entering and enabling efficient heating, a reflection plate 503 for condensing infrared rays on the recording medium side, and a temperature sensor such as a thermistor (see FIG. 2). 504) and a heater control circuit (shown by reference numeral 870 in FIG. 2).

A recovery system unit is provided facing a movable area of the cartridge C adjacent to a recording area of the recording head cartridge C. The recovery system unit includes cap units 300 respectively corresponding to a plurality of cartridges C having a recording head. The cap unit 300 is slidable in the left-right direction in the figure with the movement of the carriage 2 and is vertically movable up and down. When the carriage 2 is at the home position, the cap unit 300 rises and joins with the recording head unit, and caps it. The recovery system unit further includes first and second blades 401 and 402 as wiping members, and a blade cleaner 403 made of, for example, an absorber to clean the first blade 401.

Further, there is provided a pump unit 400 for absorbing ink and the like from the discharge port of the recording head and the vicinity thereof through the cap unit 300.

FIG. 2 is a block diagram showing a configuration example of a control system in the above-described ink jet recording apparatus.

Here, the control system of the above-described recording apparatus has a controller 800 as a main control unit. The controller 800 includes a CPU 801 in the form of, for example, a microcomputer that executes various sequences, a ROM 803 storing programs, tables, and other set values corresponding to the procedures, and a RAM 805. The controller 800 transmits and receives image data and other commands and status signals via an interface (I / F) 812. The supply source of the image data is constituted by the host device 810 (may be a reader unit for image reading).

A power switch 822 and a switch 824 for instructing the start of recording are provided to the controller 800.
Switches 820 for receiving a command input by an operator, such as a recovery switch 826 for instructing activation of recovery and recovery.
Also, a sensor group 830 for detecting the state of the apparatus, such as a sensor 832 for detecting the position of the carriage 2 such as a home position and a start position, and a sensor 834 used for detecting a pump position, is input.

Further, a head driver 840 for driving the electric transducer of the recording head according to the recording data output from the controller 800 is provided.
A part of the head driver 840 is also used to drive the heaters 30A and 30B mounted on the recording head. Further, the temperature sensors 20 of the heaters 30A and 30B
The temperature detection values from A and 20B are input to the controller 800.

A control signal is output from the controller 800 to the motor driver 852 of the main scanning motor 850, and the main scanning motor 850 moves the carriage 2 in the main scanning direction. Similarly, a control signal is output from the controller 800 to the motor driver 854 of the sub-scanning motor 860, and the sub-scanning motor 860 is used to convey the recording medium in the sub-scanning direction.

Further, a heater control circuit 870 for driving the halogen heater 503 of the heater unit 500, which is a fixing unit, is controlled in accordance with print data from the controller 800. Further, the temperature detection value of the halogen heater 503 by the temperature sensor 504 is input to the controller 800 so that the halogen heater 503 achieves a desired stable temperature.

Here, the outline of the effect of the fixing unit will be briefly described. The heating effect of the fixing unit can be roughly divided into the following three positions.

1) Preheat heating effect 2) Main heat heating effect 3) After heat heating effect The concept of the fixing mechanism will be described with reference to FIG. 3 in order to explain the role at each position.

(1) Heating area before printing: Here, the recording medium before printing is heated to improve the printing quality, and only the recording medium containing no ink is heated. At this time, the paper easily rises in temperature due to its small heat capacity, but it is difficult to maintain the temperature and does not have the effect of drying the ink.Therefore, when the environmental temperature is low, the effect in the main heating section is reduced. Serves as an aid. However, there is an effect that the amount of water in the recording medium is reduced to increase the temperature and time required to reach the absolute temperature of the recording medium after printing. It is not directly related to the rate of temperature rise (however, it decreases when the amount of water is reduced).

(2) Heating area during printing: Here, the printing medium is directly heated during printing to improve the printing quality. The improvement effects described below are enormous.

1. 1. Feathering: a form factor for determining character quality, especially Bk ink is important. 2. Bleed: The bleeding of a color boundary for determining the break of a color image, and in particular, a one-color / two-color boundary is important. 3. Density: a factor for determining character quality and image contrast, particularly dot density and line density are important. 4. Chromogenicity: a factor that determines the contrast of a color image, and in particular, the saturation (Lab) is important. 5. Fixing property: a factor that determines the user's handling property, provided that it is dry (no smear) before discharging. 6. Cockling: A factor that determines the paper output quality and landing accuracy, with no uneven head contact. 7. Curl: a factor that determines the quality of discharged paper, and requires that multiple sheets be easily superimposed. White haze: A peculiar phenomenon that occurs with ink with or without surfactant goods, especially at the border between black and color

(3) Heating area after printing: Here, the recording medium after printing is heated to assist the above-mentioned effect which cannot be achieved during printing. It is mainly effective for drying ink (measures against smear).

The above-described relationship with the recording position causes the respective effects to be related to each other to form a fixing mechanism. In order to maximize the fixing effect, (1) to (3)
The required system (recording speed (number of nozzles, resolution, drive frequency, etc.)), type of recording medium (plain paper to special paper),
Appropriate control is performed in combination with the recording method [1 to N pass], the type of ink (super penetrating system to additional system), and the type of image [ink ejection amount, image characteristics (gradation to resolution to color development, etc.)]. It is desirable to use it.

(Ii) Fixing Unit Configuration FIG. 4 shows an outline of the heater unit used in the present embodiment. FIG. 5A is a plan view of a reflection plate 53 on which a halogen heater 501 is arranged, and FIG.
FIG. 2C is a perspective view of a heater unit 500 in which a mesh platen 502 is installed on a reflection plate 503.

FIG. 5 shows the structure of the halogen heater 501. FIG. 3A is a front view of the halogen heater 501, and FIG. 3B is a detailed view of the inside of the halogen heater.

In this embodiment, the halogen heater 50
In order to make the radiant heat generated in 1 be mutually usable between the preheat and the main heat, use a radiant heat that is designed to have two peaks so that the radiation direction (heat distribution characteristics) of the radiant heat can be used effectively. I have. FIG. 6 shows the heat distribution characteristics of the present embodiment, and FIG. 7 shows an embodiment of a halogen heater for obtaining the heat distribution characteristics of FIG. Here, the heat distribution characteristics will be described. In this embodiment, the radiant heat of the halogen heater is set to a desired value of 2
In order to distribute the light in the direction, ceramic coating was performed in a predetermined range around the heater wire. That is,
As shown in (3) of FIG. 7, the range of 135 degrees to 225 degrees is black, and the range of 225 degrees to 360 degrees (0 degrees) and 45 degrees to 0 degrees are 45 degrees.
Ceramic coating white in the range of degrees, the remaining 4
The body is designed so that the preheating direction is at 90 degrees and the main heat is at 180 degrees with no coating in the range of 5 to 135 degrees, and the heat distribution characteristics of the halogen heater are adjusted to the above positions. The heat distribution characteristics were designed such that the position at 90 degrees was about 70% of the energy of the main heat. The position at 180 degrees in the coating range of 0 to 360 degrees corresponds to the main heat heating position.

Further, as shown in FIG. 7A, when there is no coating, a uniform heat distribution is obtained as shown by a dotted line in FIG. As shown in FIG. 7 (2), when the ceramic coating is performed in black in the range of 90 ° to 270 ° and white in the remaining range, it is biased in the direction of 180 ° as shown by the solid line in FIG. It becomes a heat distribution.

(Iii) Heater configuration As the heater, a halogen heater with a reflector was used. This heater is manufactured by Ushio Corporation, for example, and a temperature sensor is optionally incorporated as a unit by design. In the present embodiment, the surface temperature of the recording medium is 200 ° C.
The unit is devised so that the emission of far-infrared rays near the wavelengths of about 3 (μm) and about 6 (μm) is increased. The reason for selecting this wavelength is to match the absorption wavelength of water, which is the main component of the ink. Power consumption is about 200 (W) on average.

The rise time of the heater is determined by a control means (not shown), and the thermal design and control conditions are determined so as to reach a desired temperature in about several seconds. The efficiency of the heating of the recording medium is improved by using both the radiant heat and the convective heat and the heat conduction from the surrounding metal plate.

(Iv) Sequence (algorithm) Next, a printing method will be described. Printing is performed using the following head.

<Head Configuration> Resolution: 360 dpi Driving frequency: f = 10.0 (KHz) Total number of nozzles: N = 128 Number of divided blocks: Nb = 16 (block) Driving condition: Double pulse driving (P1 / P2 / P3) =
(1/4/3) (μs) <Printing conditions> FAST printing: 1-pass bidirectional NORMAL printing: 2-pass bidirectional & 64 nozzle offset printing HIGH QUALITY printing: 4-pass unidirectional 32 nozzle offset printing <Sequence> FIG. 2 shows a specific sequence of a printing method used in the embodiment. In step S1, a printing condition and a fixing condition are determined by reading, for example, a signal from a host or a setting of a recording device, which is surrounded by a broken line. (1: Hi
gh speed ・ 2 ： Normal speed ・
3: High quality: 4: Others / (recording medium type setting) / image information, etc.) In step S2, according to the printing conditions determined in step S1, drive conditions (drive frequency / drive signal, etc.) and printing method ( Multi-pass number / Print mask / Print data development /
Paper feed conditions, etc., fusing conditions (ambient environment (temperature, humidity)
/ Heating start timing / Heating temperature / Wait time etc.)
Is set, and each part of the recording apparatus is set to the above conditions.

Step S3 is a sequence for performing a recording medium feeding operation.

Step S4 is a process of developing an image into image data most suitable for printing conditions, and is determined by the mask pattern, the number of passes, and the like.

In step S5, the fixing unit including the preheat roller and the halogen heater is driven to set the recording medium to a required temperature before printing.
Further, during printing, feedback control by a sensor is also performed so that the temperature of the recording medium becomes constant. Others
Although not shown in the drawing, conditions for operating the recording apparatus properly are determined, and the information is sent to step S6.

In step S6, steps S3 to S
5. It is determined whether to start printing according to other situations.

In the case of yes, in step S7, the driving of the recording head is started, and the recording operation is started.

If no, at step S8, it is checked whether there is any abnormality in the recording device or the like, and if abnormal, an abnormal display is made at step S9.

If no abnormality is found, the printing operation is repeated by another abnormality canceling determination operation.

Thereafter, continuous printing or the like is performed by repeating the above steps S1 to S7.

(V) Paper Conveyance As in the present invention, when the recording medium is heated by the non-contact type heating unit, it is necessary to devise the paper conveyance. As shown in FIG. 9, when preheating and main heating including before and after the printing area are heated by one heating means (halogen heater), the recording medium is preheated (halogen heater: use of heat distribution characteristics). , It is necessary to increase the heating efficiency of the main heat by the halogen heater.
Since the rising speed of the recording medium by the halogen heater is about 10 to 20 degrees / second, it is necessary to preliminarily heat the recording area before applying the infrared rays by using a mesh structure. Further, the network structure is optimal because it is necessary to increase a substantial projected area in order to efficiently absorb the infrared rays from the halogen heater into the recording medium and to prevent the recording medium from entering the heater unit. In order to prevent the water vapor generated from the ink from adhering to the recording head, it is desirable to provide a mechanism for generating a flow of air and discharging the water vapor out of the apparatus.

(Vi) From Ejection to Fixing Phenomenon FIG. 10 schematically shows a recording mechanism on a recording medium during ink recording, which is a feature of the present invention. The recording mechanism from the ejection to the fixing phenomenon in the following order will be described with reference to FIG.

. Ink droplets ejected from the inkjet head land on the recording medium. At this time, the temperature (Th) of the recording head and the environmental temperature (TR) depend on the temperature of the flying ink droplet:
TINK (t) (° C.) is determined, and the actual ink temperature is equal to or lower than the head temperature: Th (° C.). At this time, the ink droplet temperature (TINK) is environmental temperature: TR (° C.), flying distance (head-to-paper distance): G (mm), ejection volume: Vd (pl), ejection speed: v (m / s), etc. Varies by.

[0068] At the same time as the ink droplet lands on the recording medium, the kinetic energy of the ink droplet itself: (Vd · ρ · v ·
v) / 2, a spherical ink droplet (sphere diameter: d1 (μ
m)) is lazy and disc-shaped (diameter of disc: d2 (μ
m)) and spread (see FIG. 10A). The temperature of the ink droplet at this time is defined as TINK (t0).

[0069] The temperature of the recording medium at the time of impact is Tp
(Tp> TINK). For example, as shown in FIG. 10A, when the ink lands on the recording material and is deformed from a sphere into a disk shape, the ink droplet temperature is T2 and the recording material temperature is T1. T1> T2.

. Instantly when the ink droplet lands (depending on the solvent composition of the ink, it takes several hundred (μs) to several (m
s) about the contact angle of the ink droplet with the recording medium and the ink:
θ decreases with time and begins to get wet. For example, as shown in FIG. 10B, when the ink starts to wet the recording material and moves on the recording material, the ink droplet temperature is:
When T3 and recording material temperature: T1, T1> T3. When wet, the temperature of the ink droplet is efficiently heated by heat conduction from the recording medium and radiant heating by infrared absorption of water, and starts to rise rapidly. In the case of a configuration in which color recording is performed with the heads arranged side by side as in the present embodiment, for example, in the case of forming a secondary color such as R / G / B, color formation is performed by subtractive color mixing using C / M / Y. R is (M + Y), G is (C + Y), B is (C + M)
And the ink ejection amount per unit pixel is doubled compared to the primary color. In addition, the secondary colors are ejected one after another with a moving time of the head interval.

[0071] The water in the ink starts to evaporate (depending on the solvent composition of the ink, but about several (ms) to several (s) in time). First, rapid penetration of the solvent component into the recording medium and rapid evaporation of moisture and the like due to heating occur. For example, as shown in FIG. 10C, when the ink starts to penetrate into the recording material and bleeds on the recording material, the ink droplet temperature is T4 and the recording material temperature is T1.
≧ T4. If the heating conditions are controlled so that the evaporation rate is greater than the permeation rate when moisture evaporates in this way, fiber contraction caused by infiltration of moisture etc. into the recording medium does not occur. (Rippling phenomenon) can be reduced.

[0072] In the penetration phenomenon at this time, different penetration behaviors occur in the plane direction and the depth direction of the recording medium. The penetration speed in the plane direction: vp and the penetration speed in the depth direction: vp have a relationship of vp <vd. When a boundary between secondary colors is formed, for example, C / M /
None and none / M / Y successively at approximately the same time as adjacent pixels (time interval depends on the head interval and recording speed, but the time interval at which other colors are ejected is approximately several tens to several hundreds (ms)) Driven. At this time, if the heating is not performed, a different color boundary is formed before the ink absorption is completed, and the ink is mixed due to the various factors described above, and bleeding (ink bleeding phenomenon) occurs. Therefore,
When rapid heating is used as in the present invention, the ink reduces bleeding due to planar permeation on the recording medium and further reduces permeation in the depth direction due to evaporation, so that the entire ink component acts to leave on the top of the recording medium. In addition, the color density and the color development are also improved.

[0073] The solvent component (mainly a volatile component such as water) that has penetrated mainly in the depth direction is also actively evaporating and the recording medium dries. For example, as shown in FIG. 10D, when the ink has completely penetrated the recording material, T1 = T5 when the ink droplet temperature is T5 and the recording material temperature is T1.

[0074] When the printing portion deviates from the heating area, the temperature of the recording medium rapidly decreases. At this time, the dye is securely attached to the fibers of the recording medium, and the fixing is completed (a little water and solvent remain). For example, as shown in FIG.
In a state where the ink is discharged from the heating area and the ink is fixed on the recording liquid material, T5> T6 when the ink droplet temperature is T5 and the recording material temperature is T6.

(Vi) Fixing Effect As described above, at the moment when the ink reaches the recording medium, only the solvent system penetrates the recording medium, the dye component remains on the recording medium, and the complex fiber shape of the recording medium ( From the results of our experiments, it seems that the feathering generated between the fibers of the recording medium is related to the problem that the liquid moves through a gap of about 0.1 to 1 (μm) between the fibers. It is considered that the effect of the surface tension, viscosity, and gravity of the ink is dominant if the moving speed is slow in a large space. Therefore, when the fixing unit of the present invention is used, dot formation is stably performed regardless of the effect of the fiber,
Character formation with less feathering can be performed, and image quality can be improved.

Further, by using a highly efficient fixing unit configuration, it is possible to improve color development and reduce bleeding when forming a color image, and to reduce solvent penetration as much as possible by heating at a high temperature. Therefore, cockling can be reduced even during color recording with a large amount of shots.

(Vii) Ink Composition The ink used in the present embodiment is obtained by dissolving a dye in a solvent containing water as a main component. In the present embodiment, the dye concentration is set to 3 to 5% (differing according to color). Regarding the solvent composition, the composition used for ordinary inkjet recording may be referred to. However, at the time of printing of color and mixed image characters as in the present embodiment, the color ink is of a type that can penetrate the recording material quickly and is used for characters (B).
k) is preferably a composition of a slow permeation type.

[Second Embodiment] In the present embodiment,
It is characterized in that preheat by heat conduction and main heat by radiant / convective heat are performed by two heaters.

(I) Main Body Configuration FIG. 11 is a sectional view of a fixing unit applied to the second embodiment of the ink jet recording apparatus of the present invention. The specific configuration of the main body is substantially the same as that of the first embodiment, and therefore will not be described. However, the paper transport path has been devised, and will be described in detail below. That is, as shown in FIG. 11, a cylindrical aluminum reflector 503a is arranged around a halogen heater 501 located below a mesh-shaped platen 502 so that the platen 502 becomes a part of the aluminum reflector 503a. ing. Also, the pickup roller 511
The recording medium fed in step 1
A paper transport guide plate 5 that guides the upper surface of the platen 502 along the outer surface of the aluminum reflecting plate 503a so as to change by 80 degrees.
12 is provided outside the aluminum reflection plate 503a.
Black alumite 515 is applied to the inside of the portion of the aluminum reflection plate 503a where the paper transport guide plate 512 is installed so that the recording medium is preheated by heat conduction. The recording medium guided onto the platen 502 is discharged by a pair of a roller 513 and a spur 514. Further, in order to prevent the water vapor generated from the ink from adhering to the recording head portion, an exhaust mechanism 516 for generating a flow of air and discharging the water vapor out of the apparatus is provided.

(Ii) Fixing Unit Configuration FIG. 12 schematically shows a halogen heater unit used in the present embodiment. The configuration of the halogen heater is shown in FIG.
Is the same as that shown in FIG.

In the present embodiment, the halogen heater 50
1 so that the radiant heat generated by the heat transfer sheet 1 can be used for preheating by heat conduction and main heat by radiant and convective heat.
Radiation direction (heat distribution characteristic) biased toward the main heat area inside the cylindrical aluminum reflection plate 503a provided with No. 15
The one designed to have is used. In particular,
As shown by the solid line in FIG. 6, the halogen heater 501 is provided with the ceramic coating shown in FIG.

(Iii) Heater configuration As the heater, a halogen heater with a reflector was used. This heater is manufactured by Ushio Corporation, for example, and a temperature sensor is optionally incorporated as a unit by design.
In this embodiment, the recording medium is unitized so that the surface temperature of the recording medium becomes 200 ° C., and the wavelength is about 3 (μm) and about 6 μm.
(Μm) is designed to increase the amount of far infrared radiation emitted. The reason for selecting this wavelength is to match the absorption wavelength of water, which is the main component of the ink. Power consumption is about 200 (W) on average.

The heat rise time of the heater is determined by a control means (not shown), and the thermal design and control conditions are determined so as to reach a desired temperature in about several seconds. The efficiency of the heating of the recording medium is improved by using both the radiant heat and the convective heat and the heat conduction from the surrounding metal plate.

In order to enhance the preheating effect, the aluminum heat absorbing plate in the paper conveyance area effectively receives the radiant heat generated from the halogen heater, and performs a sufficient preheating of the recording medium before reaching the printing area. Have.

The aluminum plate is painted black so as to be able to effectively absorb radiant heat. Therefore, it is possible to sufficiently preheat the recording medium by contact heating with the aluminum plate in the process of being conveyed along the half-moon guide travel path after the recording medium is fed.

(Iv) Sequence (algorithm) Next, a printing method will be described. Printing is performed using the following head.

<Head Configuration> Resolution: 360 dpi Drive frequency: f = 10.0 (KHz) Total number of nozzles: N = 128 Number of divided blocks: Nb = 16 (block) Drive conditions: Double pulse drive (P1 / P2 / P3) =
(1/4/3) (μs) <Printing conditions> FAST printing: 1-pass bidirectional NORMAL printing: 2-pass bidirectional & 64-nozzle offset printing HIGH QUALITY printing: 4-pass unidirectional 32 nozzle offset printing <Sequence> FIG. 2 shows a specific sequence of a printing method used in the embodiment. In step S11, a print signal and a fixing condition are determined by reading a signal or a setting of the recording device from a host, for example, surrounded by a dashed line. (1:
High speed ・ 2 ： Normal speed
* 3: High quality * 4: Others / (setting of recording medium type) / image information, etc.) In step S12, driving conditions (driving frequency / driving signal, etc.) are determined according to the printing conditions determined in step S11.
-Printing method (number of multi-passes / print mask / print data development / paper feed conditions, etc.)-Fixing conditions (ambient environment (temperature, humidity) / heating start timing / heating temperature / wait time, etc.) and set each part of the recording device Is set to the above condition.

Step S13 is a sequence for performing a feeding operation of the recording medium.

In step S14, the process of developing an image into image data most suitable for printing conditions is determined by the mask pattern, the number of passes, and the like.

In steps S15 and S16, the fixing unit including the preheat roller and the halogen heater is driven to set the recording medium to a required temperature before printing. Further, during printing, feedback control by a sensor is also performed so that the temperature of the recording medium becomes constant. In addition, although not shown, conditions for properly operating the recording device are determined, and the information is sent to step S17.

In step S17, it is determined whether or not printing is to be started according to steps S13 to S16 and other situations.

In the case of yes, in step S18, the driving of the recording head is started to start the recording operation.

In the case of no, in step S19, it is checked whether or not there is any abnormality in the recording device or the like, and in the case of abnormality, an abnormality is displayed in step S20.

If no abnormality has occurred, the printing operation is repeated again by another abnormality canceling determination operation.

Thereafter, the above steps S11 to S18
Is repeated to repeat continuous printing.

(V) Paper Conveyance As in the present invention, in order to simultaneously perform preheating heating, main heating heating, and after-heating heating with one halogen heater, non-contact heating heat is transferred to an aluminum plate having a high heat capacity. For example, it is necessary to temporarily store the heat in preheating by contact heating using the heat. Therefore, it is necessary to devise both in the case of effectively heating the recording medium and in the paper conveyance. As shown in FIG. 11, when heating the recording medium by indirect heating using radiation of the halogen heater including the front and rear of the printing area and heating the recording medium by direct heating of the halogen heater, the recording medium is transported by paper. It is necessary to increase the efficiency of direct heating by the halogen heater by preheating by some means in the middle of the route. In the present embodiment, the heat distribution characteristics of the halogen heater are designed such that the traveling path in front of the recording area and the direct heating of the recording area can be used mutually. This is effective especially in high-speed recording for the purpose of increasing the temperature rise rate of the recording medium by the halogen heater of the main heat due to the preheating effect which has been described many times earlier and further improving the effect of the main heating. .
Other effects are the same as those of the first embodiment, and a description thereof will be omitted.

(Vi) From Discharge to Fixing Phenomena The description here is the same as in the first embodiment, and will not be repeated.

(Vii) Fixing effect The description here is the same as in the first embodiment, and will not be repeated.

(Viii) Ink Composition The description here is the same as that of the first embodiment, and therefore will be omitted.

[Third Embodiment] In the present embodiment,
It is characterized by devising the wavelength design of the heater, heat distribution characteristics, and rising characteristics.

FIGS. 14A and 14B show the features of various modifications of the heater unit in the third embodiment of the ink jet recording apparatus of the present invention. FIG. 14A shows a type in which the heater is rotated to change and control the heat distribution characteristics. , (B) is a type in which a reflector is rotated to change and control the heat distribution characteristics, (c)
FIG. 3 is a conceptual diagram of a type in which a plurality of filaments (heater wires) are controlled to change and control the heat distribution characteristics.

(1) Implementation of Heat Distribution Characteristics Change Control of Heater (Heater Rotation Type) In the embodiment shown in FIG. 14A, for example, the infrared heater is initially rotated by directly rotating a halogen heater 501 which is an infrared heater. This is a method in which the heat distribution characteristics (heating / heating characteristics depending on the surrounding position due to radiant heat) are changed by rotation. Therefore, a heating unit should be created so that the heating section is directed to the required location when needed, and the heating unit is adjusted according to the recording signal, the type of medium, and the surrounding environment (temperature (inside / outside the machine), humidity), etc. Controls unit orientation and power. For example, when the room temperature is 25 degrees / 60%, the recording medium is plain paper, and the average print data (10%), the recording medium itself does not absorb much moisture and is preheated because it is in a normal room temperature state. The paper drying process and the preheating (preheating) do not require much startup power. That is, although the rotation control of the heater does not need to be performed, the room temperature is 10 degrees / 20%.
When the recording medium is plain paper and average print data (40%), the recording medium itself does not absorb much moisture because the temperature is low, but the temperature is low. The role of the role becomes more important. In particular, when the paper is initially fed, a recording medium having a temperature of 10 ° C. is fed, and thus the paper drying step performed by preheating and the preheating (preheating) require startup power. Therefore, the rotation control of the heater is performed so that the center of the heat distribution characteristic is directed to the preheat side during the preheat heating to assist the initial startup characteristic. Also, at the time when recording actually starts, the preheat side members also reach a certain temperature or higher, so control centering on main heat, which is heating during recording, is performed, and rotation is returned to the heating side during recording. Aims at the center of the heat distribution characteristics.

As described above, quick start can be realized with only one heating member by performing intensive heating control by making good use of the heat distribution characteristics of one heating member.

(2) Implementation of control for changing the heat distribution characteristics of the heater (reflection plate rotation type) The embodiment shown in FIG. 14B is, for example, a cylindrical aluminum heater provided around a halogen heater 501 which is an infrared heater. This is a method in which the initial heat distribution characteristics (heating / heating characteristics depending on the surrounding position by radiant heat) of the infrared heater are changed by rotating the reflector 503a by indirect rotation of the heater. The operation of this method is the same as that of the above-described heater rotating type, and therefore the description thereof is omitted.

(3) Others (switching of heat distribution characteristics: heater control) In the modes shown in FIGS. 14A and 14B, the direction of the entire heater and the use of radiant heat such as a reflector are controlled by rotation control. However, as shown in FIG. 14C, a plurality of heater wires (filaments) in the infrared heater are provided, and by controlling each heater wire, the heat distribution characteristics of the heater itself can be controlled. You may do.

[0106]

As described above, the present invention uses a recording head having a plurality of discharge ports for discharging ink from the discharge ports, and forming an image by discharging ink onto a recording medium. The recording apparatus has a heating unit (heater unit) for heating a recording medium and drying an image formed with ink, and the heating unit includes:
A simple configuration is achieved by controlling the heating of pre-heating (pre-heating), heating during recording (main heat), and post-heating (after-heating) of the recording area on the recording medium by the recording head with one heating unit mechanism. Thus, a heating control method required for inkjet recording can be provided. Further, by making the function of the heating unit mechanism of the apparatus hybrid as described above, downsizing, cost reduction, power saving, and quick start can be achieved. Furthermore, improvement of image quality which is the fundamental function of the fixing mechanism (improvement of color development including density, reduction of bleed, reduction of feathering by the fixing mechanism)
And media handling improvement (reduction of cockling
(Smear reduction for high-speed fixing) can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main body showing a first embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a control system in the inkjet recording apparatus illustrated in FIG.

FIG. 3 is a view for explaining the concept of a fixing mechanism in the first embodiment of the ink jet recording apparatus of the present invention.

FIG. 4 shows an outline of the heater unit shown in FIG. 1,
(A) is a plan view of a reflector plate on which a halogen heater is arranged, (b) is a plan view of a mesh platen, and (c) is a perspective view of a heater unit having a mesh platen installed on the reflector plate. FIG.

5 shows a configuration of the halogen heater shown in FIG. 4,
(A) is a front view of the halogen heater, and (b) is a detailed view of the inside of the halogen heater.

FIG. 6 is a diagram showing heat distribution characteristics of a halogen heater.

FIG. 7 is a diagram showing an embodiment of a halogen heater for obtaining the heat distribution characteristics of FIG.

FIG. 8 is a flowchart showing a specific sequence of a printing method used in the first embodiment of the ink jet recording apparatus of the present invention.

FIG. 9 is an enlarged view of a heater unit and a recording unit according to the first embodiment of the ink jet recording apparatus of the present invention.

FIG. 10 is an explanatory diagram schematically showing a recording mechanism on a recording medium during ink recording, which is a feature of the present invention.

FIG. 11 is a sectional view showing a fixing unit applied to a second embodiment of the ink jet recording apparatus of the present invention.

FIG. 12 is a schematic configuration diagram illustrating a halogen heater unit that is a fixing unit according to a second embodiment of the present invention.

FIG. 13 is a flowchart showing a specific sequence of a printing method used in the second embodiment of the ink jet recording apparatus of the present invention.

FIG. 14 is a schematic configuration diagram showing characteristic portions of various modifications of the heater unit in the third embodiment of the ink jet recording apparatus of the present invention.

[Explanation of symbols]

 C Recording head cartridge P Recording medium 2 Carriage 11 Guide shaft 15, 16, 17, 18 Transport roller 20A, 20B Temperature sensor 30A, 30B Temperature heater 52 Drive belt 300 Cap unit 401 First blade 402 Second blade 403 Blade cleaner 500 Infrared heater unit 501 Halogen heater 502 Reticulated platen 503 Reflector 503a Aluminum reflector 504 Temperature sensor 511 Pickup roller 512 Paper transport guide plate 513 Roller 514 Spur 515 Black anodized 516 Exhaust mechanism 800 Controller 801 CPU 803 ROM 805 RAM 8 812 I / F 822 Power switch 824 Copy switch 826 Large recovery switch 830 Sensor group 832 Tsu di position sensor 834 pump position sensor 840 the head driver 850 main scanning motor 852, 854 a motor driver 860 sub-scanning motor 870 heater control circuit

Claims (9)

[Claims] 1. An ink jet recording apparatus, comprising: a recording head having a plurality of nozzles for ejecting ink from said ejection ports, forming an image by ejecting ink to the recording medium; Heating means for heating and drying the image formed by the ink, the heating means being one heating means for pre-heating, heating during recording, and post-heating the recording area of the recording medium by the recording head; An ink jet recording apparatus characterized in that the heating is controlled by: 2. The preheating, heating during recording, and postheating of the heating means are performed by heating the recording medium and the ink by mainly using radiation among three heating principles of heat conduction, radiation, and convection. The inkjet recording apparatus according to claim 1, wherein the apparatus is configured. 3. The preheating, heating during recording, and postheating of the heating means are performed by mainly using heat conduction among the three heating principles of heat conduction, radiation, and convection to heat the recording medium and the ink. The ink jet recording apparatus according to claim 1, wherein: 4. The recording medium and the ink are heated by using three heating principles of heat conduction, radiation, and convection for preheating, heating during recording, and postheating of the heating means.
3. The ink jet recording apparatus according to claim 1. 5. The recording medium and the ink are heated using heat conduction for preheating of the heating means, and heating during recording and postheating based on two heating principles of radiation and convection. 3. The ink jet recording apparatus according to claim 1. 6. The ink jet recording apparatus according to claim 1, wherein said heating means is capable of emitting at least infrared light. 7. The ink jet recording apparatus according to claim 1, wherein said heating means is a ceramic heater. 8. The ink jet recording apparatus according to claim 1, wherein said heating means is rotatable directly or indirectly. 9. The ink jet recording apparatus according to claim 1, wherein the heating means can change a heat distribution characteristic by a control means.