JPH08142321A - Ink jet printing device - Google Patents

Abstract

PURPOSE: To restrain quantity of ink to be consumed by discharge recovery processing in consideration of the influence of heating, in an ink jet printing device having a structure to heat and dry a print medium. CONSTITUTION: When a type of a print medium 10 is detected by a detecting circuit 16 and a heating temperature of a heat generating body 6 for heating and drying is set in accordance with the detection, the higher the set temperature is, the larger the number of discharge liquid drops in preliminary discharge operations of ink jet heads 21Y, 21M, 21C, and 21Bk is set. When the set temperature is low, the number of discharge liquid drops is set to be smaller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing apparatus, and more particularly to an ink jet printing apparatus having a structure for heating and drying a printed matter printed with ink.

[0002]

2. Description of the Related Art Ink jet printers of this kind having a structure for heating and drying a print medium on which ink has been ejected have hitherto been known, for example, in Japanese Patent Publication No. 54-1565.
No. 36 and Japanese Examined Patent Publication No. 55-84670, in which unnecessary bleeding or cockling of the ink is effectively prevented and the fixing of the ink to the print medium is promoted by the heating and drying. ing.

Further, in such a structure for heating and drying, as described in Japanese Patent Publication No. 62-173259, the heating temperature may be changed according to the type of print medium such as OHP paper. Are known. Further, as described in Japanese Patent Publication No. 62-135372, there is also known a structure for preventing clogging of the ejection port of the inkjet head under the influence of the above heating and drying. When the state of not ejecting for a certain time or more continues, the ejection port surface of the inkjet head is covered with the head cap to prevent evaporation of ink moisture and the like due to heating and drying to prevent clogging.

[0004]

However, the above-described conventional clogging prevention technique prevents the heating element for heating and drying from being dried by the residual heat only to the inkjet head in the discharge standby state or the discharge stopped state. To the contrary. That is, in a color inkjet printing apparatus that performs full-color printing, inkjet heads have, for example, four types of C, M, Y, and Bk, and all four types of inkjet heads constantly eject depending on the image to be printed. It doesn't mean that. In this case, even when a certain inkjet head is in the ejection state, the ink is dried by the residual heat from the heating element in the unused inkjet head, and the ejection failure due to clogging easily occurs.

Further, in the above-mentioned conventional example in which the heating temperature is changed according to the type of print medium used, a drying prevention process or an ejection recovery process is performed so that the ink in the ejection port can be well prevented from drying even at the maximum heating temperature. A large amount of so-called preliminary ejection ink, which is performed as part of the above, is set. In this case, even when the print medium used changes and the heating temperature accordingly decreases, the same amount of preliminary ejection as the ejection amount set under the above conditions is performed, resulting in a large amount of wasteful ink consumption. Cause

The present invention has been made in view of the above problems, and an object thereof is to prevent clogging of an ink jet head in a structure in which the temperature of a heating element for heating and drying a print medium changes. At the same time, it is another object of the present invention to provide an inkjet printing apparatus that prevents unnecessary ink consumption in the ejection recovery process.

[0007]

Therefore, according to the present invention,
In an inkjet printing apparatus that uses an inkjet head and discharges ink from the inkjet head onto a print medium to perform printing, a discharge recovery unit that performs a discharge recovery process of the inkjet head, and a heating unit that heats and dries the print medium. A means for obtaining information on the type of print medium, a temperature setting means for setting the heating temperature of the heating means according to the type of print medium obtained by the means, and a heating temperature set by the temperature setting means An ink amount setting unit that sets the amount of ink consumed by the ejection recovery unit for the ejection recovery process.

More preferably, the discharge recovery means is
It is characterized in that the inkjet head is means for performing preliminary ejection for performing ejection not related to printing.

[0009]

According to the above construction, when the temperature for heating and drying is set according to the type of print medium, the amount of discharged ink required for the ejection recovery process is set according to this set temperature. When the temperature is high, the ejected ink amount for ejection recovery can be increased according to the degree of the influence of the set temperature, and when the set temperature is low, the influence is small and the ejected ink amount can be reduced.

When the discharge recovery process is performed by preliminary discharge or the like, this process can be performed during the printing operation, and clogging due to heat drying can be prevented more effectively.

[0011]

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

FIG. 1 is an explanatory view showing the construction of an ink jet printing apparatus according to an embodiment of the present invention.

In the figure, the print medium 10 is conveyed by guide rollers 11 and 12 each consisting of a pair of large and small rollers, and during this conveyance, the print area of the print medium 10 located between these rollers. Inkjet heads 21Y, 21M, 21C, 21Bk
Is printed by. Then, the print medium 10
Are conveyed by a pair of sheet feed rollers 13 which are also driven by a motor 14, and are discharged in the direction of the arrow in the figure. A platen 4 is provided corresponding to the print area of the print medium 10, thereby flattening the print area, which is a portion facing the inkjet head,
The distance between the inkjet head and the print medium can be kept constant. The print medium 10 used in this embodiment is plain paper used in a normal printer,
Coated paper, OHP paper, etc. can be mentioned, and in addition to these, cloth, or a paper obtained by sticking this to a certain mount or the like can be used.

A carriage 1 equipped with four ink jet heads 21Y, 21M, 21C and 21Bk corresponding to each ink and yellow (Y), magenta (M), cyan (C) and black (B) supplied to the heads.
The carriage 30 carrying the cartridge type ink tanks 31Y, 31M, 31C and 31Bk for storing the respective inks of k) is slidably engaged with the guide shaft 7 arranged in parallel with the guide rollers 11 and 12, and respectively. The carriages 1 and 30 can be reciprocated along the guide shafts by the driving forces of the carriage motors 8 and 32 transmitted via the belts 9 and 33, respectively.

The cleaning unit 2 includes a carriage 1
The cap is provided in the vicinity of the end of the moving area of the ink jet printer, and the cap can cover the ink ejection port surface of each inkjet head during printing standby, etc. The ejection recovery process of the inkjet head can be performed by sucking the thickened ink or the like. A preliminary ejection box 3 that receives ink ejected by preliminary ejection performed as one of similar ejection recovery processes is arranged near one of the reversal positions in the reciprocating movement of the carriage 1. As a result, it is possible to perform ejection toward the preliminary ejection box 3 when the carriage 1 is reversed during the printing operation. A fixed blade (may be a movable blade) 5 is arranged in the vicinity of the other reversal position of the carriage 1, so that each ink jet head on the carriage moves while moving relative to the blade 5. The bread that comes into contact with the ejection port surface can scrape off the adhered ink and the like on the ejection port surface.

The heating element 6 is arranged behind the platen 4 so as to be along the platen 4, whereby the portion of the print medium 10 in the print area and its vicinity immediately after the ink is ejected or immediately before the ejection is heated and dried. can do.

The operation of the above-described ink jet printing apparatus is controlled by the control circuit 15, as will be described later. Further, in the printing apparatus of this example, the type detection circuit 16 for determining the type of the print medium 10 is used.
Is provided in a paper feeding unit (not shown). This detection circuit 16
Has a light emitting element and a light receiving element, and discriminates its type according to the difference in the level of the reflected light amount of the print medium 10, and a known one can be used.

The configuration for determining the type of the detection circuit 16 is not limited to that using the above-mentioned reflected light, but a transmission type or a type that determines by the thickness, friction coefficient, resistance, etc. of the print medium can be used. Is clear.
Also, the type of print medium can be determined by the operator's setting input. Further, the installation location of the detection circuit 16 is not limited to the above-mentioned paper feeding section, and may be in the transportation path to the print area.

FIG. 2 is a block diagram showing the control arrangement of the ink jet printing apparatus of this embodiment.

The control circuit 15 is configured in the form of a microprocessor, and controls each unit shown in FIG. 1 to execute a printing operation based on print data sent from the host device. The RAM 50 is used as a work area or the like in this control execution. Further, the ROM 51 stores the processing procedure of the above execution and the table described below.

In this table, the set temperature of the heating element 6 and the preliminary ejection amount corresponding thereto, that is, the number of droplets ejected in one preliminary ejection operation, are set according to the type of print medium used. Thus, for example, when the number of droplets ejected in the standard (20 ° C.) mode of preliminary ejection is 100 according to the type of print medium discriminated by the detection circuit 16, the discriminated print medium is plain paper. Has
The temperature of the heating element 6 is set to 130 ° C., and the number of discharged droplets is set to 300.
In the case of starting and OHP paper, the temperature should be set to 70
C., and the number of ejected droplets is 150.

Based on the above settings, the control circuit 15 sends the set temperature information to the heat generating driver 6D, so that the driver 6D controls the amount of heat generated by the heating element 6 and maintains the set temperature. For this control, known control such as feedback control using a temperature sensor can be used. Further, the control circuit can control the amount of preliminary ejection performed for each print of a predetermined amount based on the setting of the preliminary ejection amount.

By the control described above, the amount of preliminary ejection can be determined according to the heating and drying temperature which changes depending on the type of print medium, so that the influence of heating and drying can be prevented and the ejection state can be maintained in good condition. In addition to this, it is possible to perform an optimum amount of preliminary ejection.

FIG. 3 is an explanatory view of an ink jet printing apparatus according to another embodiment of the present invention.

The apparatus configuration shown in the figure is almost the same as that shown in FIG. 1, and the same elements are denoted by the same reference numerals and the description thereof is omitted. The apparatus of this embodiment is different from the configuration shown in FIG. 1 in that the platen 4 of the transport path for the print medium 10 is
The pre-heater 17 is provided in the middle of the path leading to, and the pre-heat of the print medium 10 is performed by this. Here, the temperature of the heating element 6 is controlled according to the type of the print medium 10, and the temperature of the preheater 17 is also controlled according to the type of the print medium 10, as in the above-described embodiment. Therefore, in this embodiment, the discharge amount of the preliminary discharge is set according to the temperatures of these two heat sources.

The preheater 17 raises the temperature of the print medium 10 to some extent by the preheat until it reaches the platen 4, whereby the print medium with the ink adhered by the print can be heated and dried together with the heating element 6. it can. However, in this case as well, the heat of the preheater 17 also accelerates the drying of the ink in the ejection openings of the inkjet head, so the heating temperature of the preheater 17 is also taken into consideration when setting the preliminary ejection amount.

FIG. 4 is an explanatory view for explaining the constitution of an ink jet printing apparatus according to still another embodiment of the present invention.

This embodiment differs from the embodiment shown in FIG. 1 in that the ink jet heads 21Y, 21M and 21 are different.
The temperature sensor 18 for detecting the temperature is provided in C and 21Bk, and the detected temperature is also involved in the discharge amount setting of the preliminary discharge.

That is, for example, in the embodiment shown in FIG.
When the print medium 10 is plain paper, the heating element 6 has a temperature of 130 ° C.
However, it is unlikely that the head temperature rises rapidly at the beginning of the printing operation, which accelerates ink drying. Therefore, for example, when the detected head temperature exceeds 50 ° C., the ejection amount of the preliminary ejection is set to 300, and when the head temperature is 50 ° C. or less, the normal ejection amount is 1
Set to 00.

As a result, the amount of ink ejected by the preliminary ejection is further optimized, and unnecessary ink consumption can be suppressed.

As still another embodiment, a sensor for detecting the temperature of the platen 4 is provided, the heat generation of the heating element is controlled based on the temperature detected by the sensor, and the discharge amount of the preliminary discharge is determined. You can also

Furthermore, it is also possible to combine the above embodiment with the embodiment shown in FIG. 3 and / or FIG.

In each of the above-described embodiments, the target to be controlled based on the set temperature of the heating element is the number of droplets discharged in one preliminary discharge operation, but the target to be controlled is not limited to this. It may be the number or frequency of the ejection operations, or may be the suction amount in the suction recovery process other than the preliminary ejection.

(Others) The present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention brings about excellent effects in a recording head and a recording apparatus of the type in which the state of ink is changed by the heat energy. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the electrical connection to the main body of the apparatus and the ink from the main body of the apparatus by being mounted on the main body of the apparatus. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means and the like since the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change from the solid state of the ink to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying heat energy such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function. It may be a form or the like.

[0043]

As is apparent from the above description, according to the present invention, when the temperature of heating and drying is set according to the type of print medium, the discharge required for the ejection recovery process is set according to the set temperature. Since the ink amount is set, when the set temperature is high, the discharge ink amount for ejection recovery can be increased according to the degree of the influence of the set temperature, and when the set temperature is low, the influence is small, so the discharge ink amount is small. The amount can be reduced.

When the discharge recovery process is performed by preliminary discharge or the like, this process can be performed during the printing operation, and clogging due to heat drying can be prevented more effectively.

As a result, the amount of ink consumed in the ejection recovery process such as preliminary ejection can be appropriately reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an inkjet printing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control configuration of the device.

FIG. 3 is an explanatory diagram showing a configuration of an inkjet printing apparatus according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of an inkjet printing apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 1 Carriage 2 Cleaning Unit 3 Preliminary Discharge Box 4 Platen 5 Blade 6 Heating Element 7 Guide Axis 8 Carriage Motor 9 Timing Belt 10 Print Medium 11, 12 Guide Roller 13 Sheet Feed Roller 14 Sheet Feed Motor 15 Control Circuit 16 Detecting Type of Print Medium Circuit 17 Preheater 18 Head temperature sensor 50 RAM 51 ROM

Claims (6)

[Claims] 1. An inkjet printing apparatus, which uses an inkjet head and discharges ink from the inkjet head onto a print medium to perform printing, and an ejection recovery unit that performs an ejection recovery process of the inkjet head, and heat-drys the print medium. Heating means, means for obtaining information on the type of print medium, temperature setting means for setting the heating temperature of the heating means according to the type of print medium obtained by the means, and the temperature setting means An ink jet printing apparatus comprising: an ink amount setting unit that sets an amount of ink consumed by the ejection recovery unit for the ejection recovery process according to a heating temperature. 2. The ink jet printing apparatus further comprises head temperature detecting means for detecting the temperature of the ink jet head, and the ink amount setting means further determines the ink amount according to the temperature detected by the head temperature detecting means. 2. The inkjet printing apparatus according to claim 1, wherein: 3. An ink jet printing apparatus, which uses an ink jet head and ejects ink from the ink jet head onto a print medium for printing, and an ejection recovery means for performing an ejection recovery process of the ink jet head, and a print medium is dried by heating. And an ink amount setting unit that sets the amount of ink consumed by the ejection recovery unit for the ejection recovery process according to the heating temperature of the heating unit. apparatus. 4. The inkjet printing apparatus according to claim 1, wherein the ejection recovery unit is a unit that performs preliminary ejection in which the inkjet head performs ejection that is not involved in printing. 5. The ejection recovery unit is a unit that causes a pressure difference in an ink supply system of the inkjet head to eject ink from the ink ejection port. The inkjet printing apparatus described in 1. 6. The ink jet head according to claim 1, wherein heat energy is applied to the ink to generate bubbles in the ink, and the ink is ejected by the generation of the bubbles. The inkjet printing apparatus according to any one of claims.