JPH06255208A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a recording grade due to continuous recording at low temp. by providing a fan, a means detecting the temp. of a recording head and a means controlling the wind quantity of a fan for controlling the temp. of the recording head part to desired temp. in a recording apparatus. CONSTITUTION:An ink jet recording apparatus is constituted so as to emit the ink in an ink tank 002 to a recording medium using a recording head 001 having an energy generating element for emitting ink to perform recording. A fan 006, a thermistor 007 detecting the temp. of a recording head part 000 and a control panel 005 controlling the wind quantity of the fan 006 as a means for controlling the temp. of the recording head part 000 detected by the thermistor 007 to desired temp. are provided in the recording apparatus. By this constitution, when the temp. of the recording head part 000 detected by the thermistor 007 is not desired temp., the recording head part 000 is controlled to the desired temp. by controlling the wind quantity of the fan 006.

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.

[0002]

2. Description of the Related Art A recording device such as a printer or a facsimile forms dot patterns corresponding to recording information on a recording medium (normal storage sheet) by driving dot forming means of a recording head based on recording. It is configured to go. The ink jet recording apparatus is configured as one type thereof, and is a type in which an ink droplet is ejected from a recording head and the ink droplet is attached to a recording medium of a recording apparatus or a plastic thin plate to form an image. .

In the case of this ink jet recording apparatus, if the temperature inside the apparatus is low, the recording quality deteriorates. The cause is that the viscosity of the ink is large at low temperature, so if the recording operation is performed at low temperature, the amount of ink supplied from the ink tank through a large number of liquid passages decreases, and the recording speed, that is, the consumption of ink. Because it will not be able to keep up with the amount. This phenomenon is remarkable in a recording method that consumes a large amount of ink, such as continuous recording and recording with a large duty.

On the other hand, when the temperature inside the ink jet recording apparatus is high, the viscosity of the ink is small on the contrary, so that the amount of ink supplied from the ink tank through a large number of liquid paths is increased, and the ink is The discharge rate increases. Therefore, the recording quality deteriorates.

In order to prevent the above-mentioned deterioration of recording quality, the following method has hitherto been adopted.

(1) When the temperature is low, the temperature inside the machine is increased by the temperature correction control. That is, a temperature detecting device (usually a thermistor) and a heat-retaining heater for supplying thermal energy to the recording head are provided inside the recording device, and first, the temperature detecting device is used to detect the temperature inside the device, and then the recording head Calculate the temperature. Then, in accordance with the calculated temperature, the ON time of the heat retention heater is determined from the table value in the recording device control ROM, and by driving this, heat energy is given to the recording head, the temperature of the recording head,
As a result, the internal temperature of the ink tank was raised.

The timing for executing this temperature correction control includes a method of heating for a time excluding recording during power-on, a method of heating at the beginning of each recording item, a method of heating at the beginning of each recording item, and the start of the next recording. It is generally known that a method of heating during the heating, a method of heating immediately after cleaning at a low temperature, or a method of combining a plurality of the above methods.

(2) On the other hand, when the temperature is high, a fan is provided inside the machine and driven to lower the temperature inside the machine to improve the recording quality. By the way, as factors that increase the temperature inside the machine, heat dissipation of the control driver of each part on the electric control board at the time of recording etc. can be considered, but these are taken into consideration at the design stage in advance, so serious control is required. Is hard to be the target of.

[0009]

However, after the temperature correction control is performed under the condition that the print head temperature calculated from the temperature inside the printing apparatus is low,
When performing continuous printing, when recording an image with a large recording duty, or when recording with a large number of accumulated recordings, "vertical deviation" is added to the recorded dot pattern.
Phenomena called "lateral skew", "blurring", "thickness", etc. are observed, and these phenomena significantly deteriorate the recording quality.

The cause is considered as follows.

In a low temperature environment, the ink jet recording apparatus supplies heat energy to the recording head by driving the heat retaining heater as described above to perform temperature correction control. It is not the same as the internal temperature of an ink tank that stores a large amount of ink and is sufficiently larger than the print head. Therefore,
When the amount of ink consumption is large, such as when performing continuous printing as described above at low temperatures, when recording an image with a large recording duty, or when recording with a large number of accumulated recordings, the ink supply amount increases. I can't keep up with the recording speed. As a result, the recording quality is deteriorated. In order to solve this problem, it seems that it is better to increase the drive time of the heat retention heater, but if this is done, the difference between the temperature of the print head and the internal temperature of the ink tank will further widen, and the print quality will deteriorate. The result will be encouragement.

[0012]

In order to solve the above problems, the present invention employs the following means.

(1) The fan in the recording apparatus is used.

(2) A detecting means such as a thermistor is provided inside or near the recording head so that the temperature of the recording head can be directly detected.

(3) If the temperature of the recording head portion detected by the detecting means such as a thermistor is not the desired temperature,
As thermal energy for increasing the temperature of the recording head,
By utilizing the heat retention heater of the recording head and the heat radiation of various drivers on the electric control board, and combining the thermal energy and the air volume control of the fan, the recording head temperature is controlled to a desired temperature.

[0016]

In the present invention, since the temperature of the recording head portion is controlled by the above-mentioned means, it is possible to prevent the deterioration of recording quality and to improve it.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the low temperature is 20 ° C. or lower and the high temperature is 30 ° C. or higher. Further, the target temperature value of the recording head section is set to 25 ° C. ± 5 ° C. It is assumed that the fan inside the recording apparatus is constantly rotating to keep the temperature inside the apparatus constant.

FIG. 1 is an external perspective view of the ink jet recording apparatus of the embodiment. In FIG. 1, reference numeral 1 is a head cartridge having an ink jet recording head, and 2 is a carriage on which the head cartridge is mounted and which enables scanning in the arrow S direction. Reference numeral 3 is a hook for attaching the head cartridge 1 to the carriage 2, and 4 is an operation lever for operating the hook 3. Reference numeral 5 is a support plate that supports an electrical connection portion for the head cartridge 1, and 6 is an FPC (flexible printed circuit) for connecting the electrical connection portion and the main body connection portion.

Reference numeral 7 is a guide shaft for guiding the carriage 2 in the direction of arrow S, and is inserted into a bearing 8 of the carriage 2. Reference numeral 9 denotes a timing belt to which the carriage 2 is fixed and which transmits power for moving the carriage 2 in the direction of arrow S, and is stretched around pulleys 10A and 10B arranged on both sides of the device. The driving force is transmitted from the carriage motor 11 to one pulley 10B via a transmission mechanism such as a gear. Reference numeral 12 denotes a conveyance roller that regulates the recording surface of a recording medium such as paper and conveys the recording surface during recording, and is driven by a paper feed motor 13.

Reference numeral 14 is a paper pan for guiding the recording medium to the recording position, and 15 is provided in the middle of the feeding path of the recording medium to press the recording medium toward the conveying roller 12 and a pinch for conveying the recording medium. It's Laura. Reference numeral 16 denotes a platen that faces the ejection port of the head cartridge 1 and regulates the recording surface of the recording medium. Reference numeral 17 denotes a recording medium conveyance direction, which is arranged on the downstream side of the recording position. It is a paper ejection roller for ejecting the paper toward the user. Denoted at 18 is a spur provided corresponding to the paper discharge roller 17, and presses the paper discharge roller 17 via the recording medium.
Is for generating a recording medium conveyance force. 19 is a pinch roller 1 for setting a recording medium
5 is a release lever for releasing the urging of the spur 18 and the spur 5.

Both ends of the platen 16 are rotatably supported by the shafts of the paper discharge rollers 17, and are urged from the stop position of the left and right plates 20 toward the front surface portion 21 of the paper pan 14, so that a plurality of thin conveying rollers 12 are provided. A plurality of tongue pieces 16A provided at positions corresponding to the portion 12A are in contact with the inside of the front surface portion 21 of the paper pan 14. Reference numeral 22 denotes a cap made of an elastic material such as rubber that faces the ink ejection port forming surface of the recording head at the home position, and is supported so as to be able to come into contact with and separate from the recording head. The cap 22 is used for protection of the recording head at the time of recording, and for ejection recovery processing of the recording head.

The ejection recovery process is performed by causing the cap 22 to face the ejection port forming surface and driving an energy generating element provided inside the ink ejection and used for ejecting the ink so that the ink is ejected from all the ejection ports. (Preliminary ejection) for removing air bubbles and dust, or ink that has increased in viscosity and is no longer suitable for recording (preliminary ejection), or the ejection port forming surface is covered with the cap 22. In this state, the ejection failure factor is removed by forcibly ejecting the ink from the ejection port.

A cap 23 generates a suction force for forcibly discharging the ink, and at the time of the discharge recovery process by the forced discharge or the discharge recovery process by the preliminary discharge, the cap 22 is provided.
It is a pump used for sucking the ink received in. Reference numeral 24 is a waste ink tank for storing the waste ink sucked by the pump 23. The waste ink tank 24 is connected to the pump 23 by a tube 28.

Reference numeral 25 denotes a blade for wiping the ejection port forming surface of the recording head, and a position for ejecting to the recording head side for wiping in the process of carriage movement and a retracted position not engaging with the ejection port forming surface. It is movably supported by. Reference numeral 26 is a recovery system motor, and 27 is a cam device for receiving power transmitted from the recovery system motor 26 to drive the pump 23 and move the cap 22 and the blade 25, respectively. Reference numeral 29 denotes a fan provided inside the recording apparatus to prevent excessive temperature rise of the recording apparatus.

Next, the control mechanism of the recording apparatus of the embodiment is shown in FIG.
Will be explained. In FIG. 2, the MPU 1000 transmits the recording information 1005 to the printer unit 200 via the interface unit 1004 by a program stored in the ROM 1001. This information is received by the recording device control MPU 800 in the printer control unit 80
It is stored in the AM 802. The MPU 800 controls each driver via the interface unit 803 by a program stored in the ROM 801. The drivers include a head driver 1A for controlling the recording head 1, a motor driver 11A for controlling the carrier motor 11, a motor driver 13A for controlling the carry motor 13, and a motor driver 28A for controlling the recovery system motor 28. Further, information in the printer unit 200 is stored in the interface unit 1
It is stored in the RAM 1002 of the control unit 100 via 004. The fan 804 controls the air volume with the MPU 800.

FIG. 3 is a block diagram showing the flow of thermal energy in the recording apparatus of the embodiment. In FIG. 3, 0
Reference numeral 01 is a recording head, and 002 is an ink tank.
1,002 are connected through a passage 003. In addition, the recording head unit 000 is composed of the above three components 001 to 003.
Is configured. Numeral 004 is a heat retaining heater for warming the recording head 001, numeral 005 is an electric control board of the recording apparatus, and parts such as a driver of each motor and a driver of a heater are mounted. Reference numeral 006 is a fan provided in the recording apparatus, and 007 is a temperature detecting thermistor mounted in the ink tank, which detects the temperature of the recording head portion. In the figure, I to III indicate the flow of heat energy by each part, I is heat energy generated by driving the heat retention heater 004, II is heat energy by heat radiation from the electric control board 005, and III is heat by fan air volume control. Energy.

FIG. 4 is a flow chart showing the flow of operation of the recording apparatus in the embodiment. Now the target temperature is 25 ℃
When ± 5 ° C. is T ° C., T ° C. can be expressed as T = recording head temperature T _a0 + temperature rise (fall) T _b (1.1). The recording head temperature T _a0 is directly detected by the thermistor 007 provided in the ink tank (B
001), (B003). Further, T _b is I to I in FIG.
Letting T _A , T _B , and T _C be the temperature rises (falls) of the recording head unit 000 caused by III, respectively, it can be expressed as T _b = T _A + T _B + T _C (1.2).

When it is detected that the temperature is low during the recording operation (B003), the electric control board 005 and the recording head unit 00
The head drive unit is provided with thermal energy due to the heat radiation energy of the components on the electric control board 005 by means such as connecting 0 with a member having good thermal conductivity (B004). As a result, the recording head portion temperature T _a can be expressed as T _aN = T _a0 + T _B (1.3). Here, T _aN is the current _print head temperature, and T _a0 is the print head temperature before the control.

If the target print head portion temperature T and the actual print head portion temperature T _aN are equal, the control ends (B005),
If they are different, the temperature inside the recording apparatus is increased by lowering the air volume of the fan (B006). Assuming that the temperature rise at this time is T _C , the temperature T _aN ′ of the recording head portion at this time is T _aN ′ = T _aN + T _C (1.4) (B007).

However, since the fan controls the temperature inside the recording apparatus, it is problematic to reduce the air flow for a long time. Therefore, the temperature of the recording head unit 000 may not be raised to a desired temperature. This shortage T _A is compensated by driving the heat retention heater. This process is B0
It is 08. By using the above three thermal energies, the temperature of the recording head portion can be controlled to the desired temperature T.

Similarly, when it is detected that the temperature is high, the driving of the heat retention heater is first confirmed (B009). If it is driving, the driving is stopped and T _A = 0 (B01
0). As a result, the target recording head temperature T
Is not the actual _print head temperature T _aN ′ (B01
1) The temperature of the recording head unit 000 is lowered by increasing the air volume of the fan so that T = T _aN ′ (B012). By performing the control as described above, the temperature of the _print head portion is constantly controlled so that T = T _aN .

By the way, the timing of this control is
Similar to the general temperature correction control timing, the time excluding recording from power ON, the first time of one item, the first time of each recording line, the time until the start of the next recording, cleaning at low temperature The time immediately after, or the time when a plurality of the above methods are combined can be considered.

(Other Embodiments) (1) In the above control, the temperature of the recording head portion was controlled to a desired temperature by using three thermal energies, but the heat radiation from the electric control board was almost equal to the temperature of the recording head portion in advance. If it is designed and constructed so as not to affect,
And the temperature increase T _b the recording device internal temperature rise caused by the control of the fan energy, there is no problem be configured to compensate a thermal energy of thermal insulation heater.

(2) In a recording apparatus which does not have a built-in heat-retaining heater, an electric control board and a fan are installed near the recording head section in order to sufficiently utilize the heat radiation of the electric control board to raise the temperature of the recording head section. The heat radiation may be sufficiently conducted to the recording head portion.

(3) In the case of detecting the temperature, in the above-described embodiment, the thermistor is directly provided in the ink tank and the thermistor is directly detected. However, the temperature may be calculated according to the recording mode. For example, as shown in the flowchart of FIG. 5, the recording number counter CA, the cumulative recording counter CB, and the extended area recording flag FA are stored in the control ROM 801 shown in FIG.
To prepare. The ink tank temperature is detected immediately before the start of recording (BC001), and the recording sheet number counter CA, cumulative recording counter CB, and extended area recording flag FA are cleared (BC
002). Simultaneously with the start of recording, the recording number counter CA for counting the number of recordings and the cumulative recording counter CB for counting the cumulative number of recordings are respectively counted (B
C003). Also, an illustration record at the beginning of each record,
Processing of an extended area recording flag FA, which is a flag indicating whether or not there is recording of an extended area such as outline recording, is performed (B
C004). Based on the above states of CA, CB and FA, how much the temperature of the recording head is increased due to heat radiation of the electric control board is stored in the control ROM in advance, and the corresponding recording is performed at the time of recording. The head temperature can be detected (BC005 to BC007). The temperature may be controlled using the above detection method.

(4) Recorded-sheet counter C in (3) above
A, the cumulative recording counter CB, and the extended area recording flag FA are used to directly detect the recording head temperature and the CA and C.
Control can also be performed depending on the states of B and FA. That is, as shown in the flowchart of FIG. 6, when the low temperature or the high temperature is detected after the temperature of the recording head unit is detected (BD001), the above control is not performed immediately, but the recording sheet counter CA becomes 2 or more, That is, in continuous recording, when the cumulative recording counter CB is 3000 or more, the extended area recording flag FA is set to a flag, and the like, no control to control 7 (BD010 to BD01)
The method of performing 7) may be used.

(5) The above method is a control for varying the recording head temperature so as to match the desired temperature. The desired temperature is always constant, but conversely, the desired temperature is changed to the recording state. There is also a method of changing it depending on the situation. FIG. 7 shows a graph showing the relationship between recording quality and recording time (number of sheets). As shown in the figure, up to the recording quality a is set as an allowable range, and the current state is set as (a). Recording time (number of sheets)
6 is a graph showing the relationship between the recording head temperature and the recording head temperature. Is a case like the embodiment in which some kind of control is performed to maintain the temperature of the recording head portion at a constant temperature. Is the case where the above control is not performed at all. As shown in (1), the longer the recording time (the number of sheets), the higher the temperature of the recording head portion. Therefore, in such a case, the target temperature may be raised accordingly. By doing so, the relationship as shown in FIG. 7B is established, and the recording quality can be improved. Specifically, it is possible to prevent deterioration of recording quality by changing desired temperatures in the controls 1 to 7 of FIG. 6 and controlling to new target values. Further, in this way, the difference between the target value and the current value is smaller and the power consumption is smaller than in the above method.

The present invention brings excellent effects particularly in a recording head and a recording apparatus of a system which utilizes thermal energy among ink jet recording systems.

Regarding the typical structure and principle thereof, see, for example, US Pat. Nos. 4,723,129 and 4740.
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 recorded 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. As a result, bubbles can be formed in the liquid (ink) in a one-to-one correspondence with this drive signal, which is effective. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening,
At least one droplet is formed. It is more preferable to make the driving signal in a pulse shape because bubbles can be grown and contracted immediately and appropriately, and thus liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, U.S. Pat. Nos. 4,463,359 and 4,434 are used.
Those as described in 5262 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 configuration disclosed in the specification of 459600 can also be adopted 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 present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to the ejection portion.

[0041]

As described above, according to the present invention,
With the configuration as described above, it is possible to improve the deterioration of the recording quality due to continuous recording at a low temperature, reduce the load on the heat retention heater, and efficiently use the heat dissipation of the electric control board.

[Brief description of drawings]

FIG. 1 is an external perspective view of an inkjet recording apparatus according to an embodiment.

FIG. 2 is a block diagram showing a control mechanism of the inkjet recording apparatus of the embodiment.

FIG. 3 is a block diagram showing a flow of thermal energy according to an embodiment.

FIG. 4 is a flowchart showing a flow of operations of the embodiment.

FIG. 5 is a flowchart showing a flow of operations of another embodiment.

FIG. 6 is a flowchart showing the flow of operation of another embodiment.

FIG. 7 is a graph showing a correlation between recording time (number of sheets) and recording quality in another example.

FIG. 8 is a graph showing a correlation between recording time (number of sheets) and recording head temperature in another example.

[Explanation of symbols]

 1 Head Cartridge 2 Carriage 11 Carriage Motor 12 Conveying Roller 15 Pinch Roller 16 Platen 17 Paper Ejection Roller 23 Pump 24 Waste Ink Tank 29 Fan

Claims (9)

[Claims] 1. An inkjet recording apparatus for performing recording by ejecting ink onto a recording medium using a recording head having an energy generating element for ejecting ink, wherein a fan and a recording head are provided in the recording apparatus. An ink jet recording apparatus comprising: a unit temperature detecting unit; and a unit for controlling the air volume of the fan, which is a unit for controlling the recording head unit temperature detected by the unit to a desired temperature. 2. A heat-retaining heater for warming the print-head part, a heat-energy of the heat-retaining heater, and heat energy due to heat dissipation from parts on an electric control board for controlling the recording device and a fan-air volume control to control the print-head temperature The ink jet recording apparatus according to claim 1, further comprising a means for controlling the temperature to be controlled. 3. An ink jet recording apparatus according to claim 1, further comprising: a heat retaining heater for warming the recording head portion, and means for controlling the temperature of the recording head portion to a desired temperature by controlling thermal energy of the heat retaining heater and air volume of a fan. . 4. The ink jet recording according to claim 1, further comprising means for controlling the temperature of the recording head portion to a desired temperature by controlling the thermal energy by the heat radiation of the components on the electric control board for controlling the recording device and the air volume of the fan. apparatus. 5. The ink jet recording apparatus according to claim 1, further comprising means for directly detecting the temperature of the recording head section. 6. The ink jet recording apparatus according to claim 1, further comprising means for calculating the temperature of a recording head portion based on recording information. 7. A means for directly detecting the temperature of the recording head portion, and means for controlling the temperature of the recording head portion to a desired temperature according to the temperature detected by the means and the state of the recording information. The recording apparatus according to any one of 1 and 4. 8. A unit for detecting or calculating the temperature of the recording head section, and a unit for variably controlling the temperature detected or calculated by the unit to an appropriate temperature for each recording information in accordance with the detected recording information. The inkjet recording apparatus according to claim 1. 9. The recording head is provided for each of a plurality of ejecting sections for ejecting ink and corresponding ejecting sections, causes a state change in the ink due to heat, and ejects the ink based on the state change. The inkjet recording apparatus according to claim 1, further comprising: a thermal energy generating unit that discharges the droplets to form flying droplets.