JP2002178533A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a bubble is generated through temperature regulation by means of a subheater under low temperature waiting state and a long time is required for recovering ink circulation every time when printing is performed, and to ensure stabilized ejection by enhancing the throughput of recovery before starting print operation. SOLUTION: Thermal energy corresponding to a drive pulse is supplied to ink and a bubble is formed through film boiling, and image recording is performed by ejecting ink from a recording head 107 onto a recording medium based on formation of a bubble. In such an ink jet recorder, preliminary ejection is conducted at the time of waiting. On the other hand, environmental temperature is monitored by a temperature sensor built in the recorder so that the recovery timing and the number of times of preliminary ejection can be varied based on the reading of temperature such that preliminary ejection is conducted only a required number of times.

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 suitable for monochrome printing and color printing.

[0002]

2. Description of the Related Art An ink jet recording apparatus for recording an image by supplying thermal energy according to a driving pulse to ink to form bubbles by film boiling and discharging the ink from a recording head onto a recording medium based on the formation of the bubbles. As a recording head, there is a line printer that fixes a multi-nozzle head in which a plurality of ink ejection ports and nozzles are integrated in order to improve the recording speed, and that arranges a large number of line heads perpendicular to the paper feeding direction, and moves and prints a recording medium. well known.

FIG. 1 schematically shows an example of the ink path of a conventional ink jet recording apparatus together with a recovery processing system.

The recovery processing system includes a recording head 107 for ejecting and recording ink, an ink tank 106 such as an ink cartridge for storing a large amount of ink, an ink tank 106 for temporarily storing ink, and an air communication port 103. A sub-tank 102 having a sensor 115 for detecting the remaining amount of ink and the ink, a recovery tub 104 for receiving and recovering ink ejected from the recording head 107, a pump 101 for supplying ink to the recording head 107, Tank 106
The ink formed from a pump 105 that supplies ink to the sub-tank 102 from the recovery tank 104, collects ink from the recovery tub 104, and returns the ink to the sub-tank 102, and filters 111, 112, 113, and 114 that remove foreign substances contained in the ink. Have a route.

However, the ink path is arranged inside the ink jet recording apparatus main body, and corresponds to a cleaning mechanism inside the ink jet recording apparatus main body, which is not shown.

At the time of recovery of the ejection of the recording head 107, ink circulation is performed by the pumps 101 and 105.
A recording head recovery process is performed. At this time, the pump 10
1 operates to forcibly supply ink from the sub tank 102 to the print head 107 through the filter 113. The ink ejected from the nozzles of the recording head 107 is received by the recovery tub 104, and is supplied to the sub-tank 102 via the filter 111 together with the air by the suction of the pump 105.

After the ink remaining on the recording head is wiped off the nozzle portion by an elastic member disposed in the recovery tub, preliminary ejection is performed into the recovery tub to be in a printable state.

At the time of printing, the ink is ejected from the recording head 107 to the recording medium, recording is performed, and the ink in the sub tank 102 is consumed.

Since the printer is mainly used for business use, it may be used in a low or high temperature external environment. Particularly at low temperatures, the viscosity of the ink increases, which reduces the amount of ink ejected and degrades the print quality of the recorded matter.Therefore, the temperature of the ink in the recording head is increased to a certain temperature, and the amount of ink ejected is increased. Temperature is adjusted to stabilize the temperature.

However, when the low-temperature ink inside the recording head is heated, the gas dissolved in the ink is deposited, which often causes a printing failure.

On the other hand, in the prior art, the ink flow is recovered by removing bubbles which have been deposited by ink circulation in advance, such as when the ink is not used for a long period of time, so that printing can be performed normally immediately after the recovery.

[0012]

As described above, conventionally, the dissolved gas continues to be deposited if left unattended, so that it is necessary to perform the ink circulation recovery before printing every time printing is performed. Therefore, it takes time to perform the pre-printing recovery process every time, and the printing throughput is significantly slowed down.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and ink is preliminarily ejected into the recovery tub at intervals determined by the temperature detected by the temperature detecting means, so that recovery is performed during standby. It is an object of the present invention to provide an ink jet recording apparatus capable of performing printing at a high speed.

[0014]

Therefore, in the present invention, an object of the present invention is to provide an ink jet recording apparatus described in any one of the following items (1) to (3) to achieve the above object. is there.

(1) A recording head for performing recording by discharging ink, a sub-heater for changing the temperature of the ink in the recording head, a control means for controlling the sub-heater, and a variable discharge driving condition for the recording head Control means, an ink tank for supplying ink to the printhead, a recovery tub for capping when the printhead is not printing and receiving ink ejected during recovery, and a temperature detecting means for detecting an in-machine temperature. And a preliminary ejection of ink to the recovery tub at intervals determined by the temperature detected by the temperature detecting means.

(2) The ink jet recording apparatus according to the above (1), further comprising a control for preliminarily discharging ink from the recording head into the recovery tub at a predetermined interval when the recording head is in a non-recording state where the power is on. .

(3) In the preliminary ejection into the recovery tub, it is possible to set the ejection drive condition, ejection interval, and number of ejections of the recording head according to a change in environmental temperature.
The inkjet recording apparatus according to the above (2).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail based on embodiments with reference to the drawings.

[0019]

(Embodiment 1) The ink path of an ink jet recording apparatus according to Embodiment 1 of the present invention is substantially the same as the ink path of a conventional ink jet recording apparatus.
This will be described with reference to FIG.

The recovery processing system includes a recording head 107 that discharges and records ink, an ink tank 106 such as an ink cartridge that stores a large amount of ink, an ink tank 106 that temporarily stores ink, and an air communication port 103. A sub-tank 102 having a sensor 115 for detecting the remaining amount of ink and the ink, a recovery tub 104 for receiving and recovering ink ejected from the recording head 107, a pump 101 for supplying ink to the recording head 107, Tank 106
The ink formed from a pump 105 that supplies ink to the sub-tank 102 from the recovery tank 104, collects ink from the recovery tub 104, and returns the ink to the sub-tank 102, and filters 111, 112, 113, and 114 that remove foreign substances contained in the ink. Have a route.

However, the ink path is disposed inside the ink jet recording apparatus main body, and corresponds to a cleaning mechanism inside the ink jet recording apparatus main body, not shown.

FIGS. 2 and 3 are enlarged views of the configuration of a recording head and an ink ejection portion in the ink jet recording apparatus of the first embodiment.

As shown in FIG. 2, the flow of the ink in the ink path during the recovery process is such that the ink is supplied from the pump 101, and the incoming ink passes through the filter 113 from the ink suction port 201, and then passes through the supply path. The liquid flows into the common liquid chamber 204 in the recording head 107 through the 203. At this time,
A part of the ink in the common liquid chamber 204 is discharged from the nozzle 205 and received by the recovery tub 104, and another part passes through the filter 114 via the return supply path 206 and passes from the ink suction port 208 to the sub tank. Return to 102.

Printing is performed by ink ejected from the recording head 107, and new ink is
Through the suction port 201 and the suction port 208, the sub tank 10
Refilled from 2. At this time, the orifice surface 209 is located at a higher position between the liquid surface of the sub-tank 102 and the orifice surface 209 of the recording head 107, and the orifice surface 209 always has a uniform head difference, thereby enabling stable ejection. ing.

As shown in FIG. 3, this recording head 107
Are an element substrate 301 provided with a heating element 302 for applying thermal energy for generating bubbles to the ink, a top plate 303 bonded on the element substrate 301, and front end surfaces of the element substrate 301 and the top plate 303. And an orifice plate 304 joined to the nozzle.

The heating element 302 is obtained by patterning an electric resistance layer and a wiring. A voltage is applied from the wiring to the electric resistance layer, and a current is caused to flow through the electric resistance layer.
2 generates heat, generates bubbles, and discharges ink from the discharge ports 305. Although not shown in FIG. 3, a Di sensor for detecting the heat storage temperature of the element substrate 301 and the heating element 302 is disposed on the element substrate 301.
Means (not shown) for variably controlling the ejection driving conditions of the recording head according to the temperature detected by the Di sensor
Operates to determine the ejection driving conditions.

The top plate 303 constitutes a common liquid chamber 204 for supplying ink to the nozzles 205 connected to the heating elements 302, and a flow path wall 309 extending from the ceiling to between the heating elements 302 is integrally formed. Is provided. The orifice plate 304 corresponds to each nozzle 205,
A plurality of discharge ports 305 communicating with the common liquid chamber 204 via the respective nozzles 205 are formed. Sub heater 31
Numeral 0 is provided in the common liquid chamber 204 on the element substrate 301, and aims at printing within a stable ejection range by keeping the temperature of the ink in the recording head 107 constant and stabilizing the viscosity. The sub heater 310
Are controlled by control means (not shown) for controlling the sub-heater.

In the temperature adjustment by the sub-heater 310, the nozzle 2 when the temperature of the ink is adjusted from a low temperature.
FIG. 4 shows changes over time in the common liquid chamber 05 and the common liquid chamber 204. When the sub-heater 310 in the common liquid chamber 204 starts temperature adjustment (FIG. 4A), the temperature in the common liquid chamber 204 gradually rises, and a state in which gas dissolved in the ink is deposited. (FIG. 4 (b)). In this state, ink can be ejected, but stable ejection cannot be obtained. If this state is left as it is, the gas further accumulates in the common liquid chamber 204, and finally, it becomes in a state where discharge is impossible (FIG. 4).
(C)).

As shown in FIG. 5, the amount of gas to be deposited tends to increase as the temperature is lower, because of the relationship between the temperature and the amount of gas that can be dissolved. This curve changes depending on the type of gas and the type of solvent in which the gas is dissolved. Temperature is T1
When the temperature increases from to T2, the amount of gas that can be dissolved changes from Q1 to Q2. Therefore, gas of Q1-Q2 is deposited.

Therefore, during the temperature control by the sub-heater 310, it is possible to effectively remove accumulated gas by performing preliminary ejection. FIG. 6 shows a method of removing gas in the common liquid chamber 204 of the recording head 107 in the preliminary ejection. Gas 6a is generated in the common liquid chamber 204 of the recording head 107 by the temperature adjustment by the sub-heater 310 (FIG. 6A). Before the gas is accumulated and cannot be ejected, it is applied to the heating element 302 (FIG. 6 (b)) to perform preliminary ejection (FIG. 6 (c)), and eject ink together with the deposited gas 6a to form a common liquid chamber. Reduce the amount of gas deposited in 204 (FIG. 6)
(D)).

Here, the interval (S) for performing the preliminary ejection and the number of preliminary ejections (N) are uniquely determined by the temperature (T) as shown in FIG. A temperature sensor, which is a temperature detecting means, is installed beforehand in the vicinity of the recording head in the ink jet recording apparatus, and thereby detects the temperature inside the apparatus. Then, preliminary ejection is performed according to a predetermined temperature table. Here, A indicates the number of preliminary ejections, and B indicates the interval between preliminary ejections.

Next, the operation in the case of performing the standby preliminary ejection recovery using the recording apparatus having the above configuration will be described with reference to the flowchart of FIG. When the power is turned on in step S100, the previous number of preliminary ejections (N) and the preliminary ejection interval (S) are reset (S101), and the temperature of a temperature sensor, which is a temperature detecting unit in the printing apparatus, is read to read the ambient environment. Is detected (S102), and the preliminary ejection number (N) and the preliminary ejection interval (S) are set (S103). After this,
If the temperature has dropped before the preliminary ejection (S104), the process returns to S101 and resets from the reading of the temperature sensor. Otherwise, it waits for a print signal (S105).

If there is a print signal, S1 after printing is completed
Return to 01 and reset from reading the temperature sensor.

If there is no print input signal, preliminary ejection is performed in step S106, and the process returns to step S101 and repeats from reading of the temperature sensor.

By performing the preliminary ejection during standby as described above, it is possible to stabilize ejection of the recording head, reduce printing defects at low temperatures, and perform printing at high speed. .

(Embodiment 2) In the first embodiment, when temperature is detected by a temperature sensor, if a temperature sensor is disposed on the element substrate 301 in the printing apparatus or the inside of the printing apparatus is closed, the temperature on the PCB may be reduced. In some cases, the temperature near the recording head 107 cannot be accurately detected due to the influence of heat generated by a driver or the like.

On the other hand, in the second embodiment, in addition to the configuration of the first embodiment, means for correcting the detected temperature detected by the temperature sensor provided near the recording head 107 based on the elapsed time from when the main body power is turned on. And the recording head 10
The temperature near 7 can be obtained. Therefore, an accurate temperature can be detected by correcting the value of the temperature sensor by integrating the elapsed time from when the main body power is turned on.

[0038]

As is apparent from the above description, according to the present invention, ink is recovered during standby by preliminary discharging ink into the recovery tub at intervals determined by the temperature detected by the temperature detecting means. In addition, it is possible to provide an ink jet recording apparatus capable of performing high-speed printing throughput. Further, bubbles accumulated in the recording head can be efficiently removed, and good printing can be obtained regardless of changes in the environment.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of an ink path of a conventional inkjet recording apparatus.

FIG. 2 is a configuration diagram of a recording head in the inkjet recording apparatus according to the first embodiment.

FIG. 3 is an enlarged view of an ink ejection portion of a recording head in the inkjet recording apparatus according to the first embodiment.

FIG. 4 Changes with time in the nozzle and the common liquid chamber when the temperature of the ink is adjusted from a low temperature.

FIG. 5 is a relationship between the amount of gas dissolved in a generally known liquid and temperature.

FIG. 6 is a schematic view showing a method of removing gas in a common liquid chamber of a print head in preliminary ejection.

FIG. 7 shows the relationship between the number of preliminary ejections, the interval between preliminary ejections, and the temperature.

FIG. 8 is a flowchart of a recovery sequence.

[Explanation of symbols]

 6a Gas 101 Pump 102 Subtank 103 Atmospheric communication port 104 Recovery tub 105 Pump 106 Ink tank 107 Recording head 111, 112, 113, 114 Filter 115 Electrode ink remaining amount detection sensor 201 Suction port 203 Supply path 204 Common liquid chamber 205 Nozzle 206 Return Supply path 208 Suction port 209 Orifice surface 301 Element substrate 302 Heating element 303 Top plate 304 Orifice plate 305 Discharge port 309 Flow path wall 310 Sub heater

Claims (3)

[Claims] A recording head that discharges ink to perform recording, a sub-heater that changes the temperature of the ink in the recording head, and control means that controls the sub-heater.
Means for variably controlling the ejection driving conditions of the recording head, an ink tank for supplying ink to the recording head, and a recovery tub for capping when the recording head is not recording and receiving ink ejected during recovery. An ink jet recording apparatus comprising: a temperature detecting unit for detecting an in-machine temperature; and preliminary discharging ink into the recovery tub at intervals determined by the temperature detected by the temperature detecting unit. 2. The ink jet recording apparatus according to claim 1, further comprising a control for preliminarily discharging ink from the recording head into a recovery tub at predetermined intervals in a non-recording state where the recording head is powered on. 3. The pre-discharge into the recovery tub, wherein the discharge drive condition, discharge interval and discharge number of the print head can be set according to a change in the temperature of the environment.
3. The ink jet recording apparatus according to claim 1.