JP3205592B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet recording apparatus for controlling the temperature of a recording head using a heater.

[0002]

2. Description of the Related Art In an ink jet recording system, the temperature of a recording head, that is, the temperature of ink to be ejected, is a major factor affecting image quality. For example, in a method in which ink is ejected using thermal energy generated by an electrothermal transducer, even if the electric pulse applied to the electrothermal transducer is constant, the higher the ink temperature, the greater the amount of ink ejected. Tend to increase. Therefore, for example, when the environmental temperature is low and the ink temperature of the recording head is low, the amount of ejected ink may be small and the density of the recorded image may be low. Also, the ink temperature of the print head changes during printing,
The density of the image may change during the recording.

As one configuration for preventing image quality deterioration due to the ink temperature of the recording head (hereinafter, simply referred to as head temperature), a heater is provided in the recording head.
A configuration is known in which the driving of the heater is controlled to keep the head temperature constant.

[0004]

However, the above-described conventional head temperature control configuration has the following problems.

[0005] Taking one of the conventional print heads by the present applicant as an example, the power consumption of a heater provided in one print head is 2.4 [W]. The power consumed by the electrothermal transducer for ink ejection is 6 W on average for a recording head having 128 electrothermal transducers. Further, in this case,
For a recording device that performs color recording, black, cyan,
Four recording heads are used for each of the magenta and yellow inks, and the power consumed by the heater is at most 2.
4 [W] x 4 = 9.6 [W], and the power required for ink ejection is a maximum of 6 [W] x 4 = 24 [W].

Here, there are various timings at which the head temperature control using the heater is performed, such as during printing in which ink is being ejected from each print head or during printing standby. Even during the printing standby, there is a case where the printing head performs so-called idle discharge which is not involved in the printing, and in such a case, the ink discharging and the head temperature control are simultaneously performed as in the printing. .

In the case where the ink ejection and the head temperature control using the heater are performed at the same time, the above-described color printing apparatus uses a maximum of 9.6 [W] +24 [W] = 33.6.
[W] of power is required. Further, in the case of the drive mode in which the so-called idle ejection is performed to perform the ejection recovery processing of the recording head, the power required for driving the recording head is larger than 6 [W], and the entire apparatus further has a power of more than 33.6 [W]. It will be big. For this reason, the power supply device becomes relatively large, and its cost also increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to compare the power consumption of the entire apparatus in an ink jet recording apparatus in which a head temperature is controlled using a heater. An object of the present invention is to provide an ink jet recording apparatus that can be made smaller in size.

[0009]

According to the present invention, there is provided:
In an ink jet recording apparatus that has a plurality of operation modes with different power consumptions and performs recording by discharging ink on a recording medium, a recording head for discharging ink and an ink temperature for adjusting the ink temperature of the recording head A plurality of heaters for heating, and a period during which the heaters for heating can be driven and a heat source according to power consumption in the operation mode.
And a control means for limiting an upper limit value simultaneously drivable number of over data,
It is characterized by having.

[0010]

[0011]

According to the above arrangement, the period during which the heater for heating is driven in accordance with the power consumption in the operation mode and the upper limit of the number of simultaneous driving of the heater are respectively limited. When the mode is a mode in which power consumption is high, the number of heaters provided for heating can be reduced. This makes it possible to reduce the total power required for driving the recording head and heating by the heater.

[0012]

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

FIG. 1 is a block diagram showing a control configuration of an ink jet recording apparatus according to one embodiment of the present invention. As shown in the figure, a four-color device for performing color printing
Two recording heads 1C, 1M, 1Y and 1K are provided. Each of these print heads is provided with a temperature sensor, a heater, and an electrothermal transducer, and a circuit for driving them is provided corresponding to each print head.

Hereinafter, only the recording head 1C for cyan ink will be described. The cyan ink recording head is provided with a plurality of (for example, 128) ejection ports, and the electrothermal conversion element 5 is provided in an ink path communicating with each of the ejection ports. Further, the recording head 1C includes, on both sides of the arrangement of the electrothermal transducers 5,
A temperature sensor 61 and a heater 71 and a temperature sensor 62 and a heater 72 are provided. Temperature sensors 61 and 6
2 detects the temperature of the recording head related to the ink temperature, and this detection signal is sent to the CPU 9 via the level shift & amplifier circuit 8.

The CPU 9 performs head temperature control as described with reference to FIGS. 3 to 5 according to the temperatures detected by the temperature sensors 61 and 62. That is, during this control, ON / OFF of the heaters 71 and 72 via the driver 10 is controlled. Further, the CPU 9 selectively drives the electrothermal transducer 5 via the head driver 2 based on the recording data,
Thus, ink is ejected from each ejection port.
Further, the electrothermal conversion element 5 can be driven to such an extent that ink is not ejected. The ROM 9A stores the processing procedure of the head temperature control and the like, and the RAM 9B is used as a work area in these control processes.

The above-mentioned temperature sensors 61 and 62, heater 7
1, 72 and the electrothermal transducer 5, each recording head 1
Power is supplied from a power supply 11 common to C, 1M, 1Y, and 1K.

The amount of ink ejected from each recording head changes as shown in FIG. 2 depending on, for example, the environmental temperature of the ink jet recording apparatus. That is, as described above, as the environmental temperature increases, the ink temperature of the recording head also increases, and the amount of ejected ink increases. As described above, factors that influence the head temperature include a change in the environmental temperature and a change in the heat generated by the electrothermal conversion element due to the ejection of ink. The head temperature, which changes due to these factors, is detected by the above-described temperature sensors 61, 62, and the on / off of the heaters 71, 72 is controlled based on this detection to control the head temperature to a predetermined temperature. The three straight lines a, b, and c shown in FIG. 2 relate to different recording heads.

Hereinafter, the head temperature control of this embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart of FIG.

[0019] manner that electric power to the electrothermal transducer element is supplied in this example, three modes of operation are roughly the Ru Oh <br/>. The first is a recording mode in which ink is ejected for recording. In this case, as described above, an average power of 24 [W] is required for the four recording heads. Secondly, a recovery operation mode in which ink is ejected for idle ejection as an ejection recovery operation of the recording head. Third, in order to quickly raise the head temperature to a predetermined temperature at the beginning of a recording operation, etc. This is a head heating mode in which an electric pulse having a relatively short pulse width is applied to the electrothermal transducer. In this case, four recording heads require 14.4 [W] of power. Further, in this example, the recovery operation mode by the idle discharge is two modes, and the recovery operation 1 is one in 1 msec.
The ink is ejected at a rate of 9.6 [W] in this case.
In the recovery operation 2, ink is ejected once every 0.25 msec, and 43.2 [W] of power is consumed. The temperature control of this embodiment controls on / off of the heaters 71 and 72 according to each of the above five modes.

The temperature control of this embodiment controls on / off of the heaters 71 and 72 according to each of the above five modes.

FIG. 3 is a flowchart showing the outline of this control. First, it is determined in step S301 whether or not recording is in progress. If recording is in progress, in step S309,
Temperature control A described later with reference to FIG. 4 is performed. If the recording is not being performed, it is determined in step S303 whether or not the recovery operation 1 is being performed. If the recovery operation is being performed, the process proceeds to step S311 in FIG. The temperature control B described later is performed. If a negative determination is made in step S303, it is determined in step S305 whether or not the head is being heated. If the head is being heated, the temperature control B is performed in step S313. If the head is not being heated, it is determined in step S307 whether or not the recovery operation 2 is being performed. If the recovery operation 2 is being performed, the heaters 71 and 72 are turned off in step S315. If it is determined in step S307 that the period is not the period during which the recovery operation 2 is being performed, the temperature control B is performed.

FIG. 4 is a flowchart showing the details of the temperature control A. First, in step S401, the head temperature of the recording head 1C is obtained by the temperature sensors 61 and 62, and it is determined whether this temperature is lower than a predetermined temperature T1 (for example, 25 ° C.). If the head temperature is lower than the predetermined temperature T1, the heaters 71 and 72 of the recording head 1C are turned on and the heaters of the other recording heads are turned off in step S403. If the head temperature is higher than the predetermined temperature T1, all the recording heads 1C to 1K are determined in step S417.
Is turned off. The time during which the heaters 71 and 72 are turned on is predetermined in accordance with the specifications of the recording head. Hereinafter, the same processing as described above is sequentially performed on the recording heads 1M, 1Y, and 1K, and the processing ends.

According to the above processing, only the heater of any one of the recording heads is turned on. In other words, the heater
The upper limit of the number of simultaneous drives is limited to one. As a result, the electric power consumed for driving the heater in the temperature control A is 2.4 [W] at the maximum.

FIG. 5 is a flowchart showing the details of the temperature control B. First, in step S501, the recording head 1
It is determined whether the head temperature of C is lower than a predetermined temperature T1. If it is lower, the recording head 1C is determined in step S503.
The heaters 71 and 72 of the recording head 1C are turned on, and if the temperature is higher than the predetermined temperature T1, the heater 7 of the recording head 1C is determined in step S517.
1, 72 are turned off. Hereinafter, the recording heads 1M, 1
Similar processing is performed for Y and 1K.

According to the above temperature control B, the heaters of all the print heads may be simultaneously turned on at the same time, and the power consumption at that time is 2.4 [W] × 4 = 9.6 [W].

The power consumption in each mode of the processing described with reference to FIGS. 3 to 5 is summarized as follows.

Recording: ink discharge 24 [W] + heater 2.4 [W] = 26.4 [W] Recovery operation 1: ink discharge 9.6 [W] + heater 9.6
[W] = 19.2 [W] Recovery operation 2: ink discharge 43.2 [W] + heater 0
[W] = 43.2 [W] Head heating: ink ejection 14.4 [W] + heater 9.6
[W] = 24 [W] As is clear from this, the power supply device 11 and the configuration for power supply in the recording apparatus of the present example have a maximum of 43.2.
What is necessary is just to correspond to [W], and the maximum power consumption in the device is suppressed.

FIG. 6 is a schematic perspective view showing a main part of an ink jet recording apparatus according to one embodiment of the present invention. In FIG. 6, each of the recording heads 1Y, 1M, 1C, and 1K that ejects Y, M, C, and K inks has 62.5
For example, 128 discharge ports are provided at intervals of μm in the transport direction of the recording paper 2 (hereinafter, also referred to as a sub-scanning direction), and ink paths corresponding to the respective discharge ports are provided for ink discharge. And an electrothermal conversion element for generating thermal energy used for the heat treatment. The electrothermal conversion element generates heat in response to an electric pulse applied in accordance with the drive data, thereby causing film boiling in the ink, and generating air bubbles due to the film boiling from each of the discharge ports. Ink droplets are ejected.

The carriage 64 has the recording head 1 mounted thereon.
Two guide shafts 6 slidably engaged at a part thereof
It moves while being guided by 5A and 65B. The carriage 64 is moved by, for example, attaching a wire 68 stretched by a pulley to a part of the carriage 64,
This is performed by the movement of the wire by the rotation of the motor 67 via the pulley. The recording heads 1Y, 1M,
The ink supplied to 1C and 1K is stored in each ink cartridge (not shown) mounted in the carriage 64. Then, this ink is supplied to the recording head via an ink supply path (not shown). The flexible cables 67Y, 67M, 67C, and 67K are the recording heads 1Y,
1M, 1C, and 1K, respectively, thereby transmitting a drive signal and a control signal based on print data from the apparatus control board 615 to a head drive circuit (head driver) provided in a part thereof. be able to.

The paper feed rollers 63A and 63B extend in the longitudinal direction in parallel with the guide shafts 65A and 65B, rotate according to the driving force of the paper feed motor 64, and convey the recording paper 62 as a recording medium. . Below the paper feed rollers 63A and 63B, similar paper feed rollers 66A and 66B are provided, rotate according to the conveyance of the recording paper 62, and move the recording surface of the recording paper 62 between the paper feed rollers 63A and 63B. Regulate flat. In the above configuration, the recording heads 1Y, 1
M, 1C, and 1K eject ink on the recording surface of the recording paper 62, that is, the portion opposed to the ejection port, to perform recording as the carriage 4 moves.

The present invention also includes a configuration in which a single printhead has a plurality of heaters and controls the number of heaters to be driven in accordance with the power consumption mode for discharging ink in the printhead.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination configuration (a linear liquid flow path or a right-angle liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably 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 on which a recording apparatus can record. 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 integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body or an electric connection with the apparatus main body or ink from the apparatus main body by being attached to the apparatus main body. 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 provided integrally with the recording head itself is used.

It is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the constitution of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

The type and number of recording heads to be mounted are not limited to those provided only for one color ink, and for a plurality of inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiment of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or 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, the form of the ink jet recording apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also for a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0041]

As described above, according to the present invention,
A heater drive that heats according to the power consumption of the operation mode
The upper limit simultaneously driven number of dynamic capable period and the heater it
Since each is limited, when the operation mode is a mode with high power consumption, the number of heaters provided for heating can be reduced. This makes it possible to reduce the total power required for driving the recording head and heating by the heater.

As a result, the power supply device can be made small and simple, and the cost for that can be kept low.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control configuration of an ink jet recording apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between an ambient temperature of a print head and an ink ejection amount.

FIG. 3 is a flowchart illustrating temperature control of a print head according to an embodiment of the present invention.

FIG. 4 is a flowchart showing details of temperature control A shown in FIG.

FIG. 5 is a flowchart showing details of temperature control B shown in FIG. 3;

FIG. 6 is a perspective view schematically showing an ink jet recording apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 1C, 1M, 1Y, 1K Recording head 2 Head driver 5 Electrothermal conversion element 8 Level shift & amplifier circuit 9 CPU 9A ROM 9B RAM 10 Driver 11 Power supply

Claims (7)

(57) [Claims] 1. An ink jet recording apparatus having a plurality of operation modes having different power consumptions and performing recording by discharging ink on a recording medium, a recording head for discharging ink, and an ink temperature of the recording head. a plurality of heaters for heating for adjusting, in response to the power consumption in the operation mode, the heating
An ink-jet recording apparatus comprising: a control unit that limits a period during which the heater can be driven and an upper limit value of the number of heaters that can be simultaneously driven. A plurality of recording heads for detecting a temperature of each of the plurality of heaters and a temperature of the head;
The inkjet recording apparatus according to claim 1, wherein a temperature sensor is provided for each of the plurality of recording heads. 3. The control means according to claim 1 , wherein
Heaters for each printhead in order according to the detected temperature.
Control to perform heating, detected by the temperature sensor
Heaters of all print heads that need to be heated according to temperature
Means for switching between simultaneous driving and restriction.
3. The ink jet recording apparatus according to 2. 4. The control unit according to claim 1, wherein in any one of the plurality of operation modes, the sum of the power required to perform this mode and the power required to heat the heater determines the power supply capability of the power supply device. an ink jet recording apparatus according to claim 2 or 3, characterized in that a means for controlling so as not to exceed. Wherein said plurality of operation modes, according to any one of 4 to claims 1, characterized in that includes mode for ejection recovery by mode and the ink discharge raises the temperature of the recording head Ink jet recording device. Wherein said recording head, the ink causes bubbles in using thermal energy, according to any one of claims 1 to 5, characterized in that for ejecting ink based on the generation of the bubble Ink jet recording device. 7. The ink jet recording apparatus according to claim 6 , wherein the heater is a unit different from an electrothermal converter for generating the thermal energy for discharging ink.