JP2721352B2 - Ink jet recording device - Google Patents

Description

Description: 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 having a heater for promoting fixing of ink adhered to a recording medium.

[Conventional technology]

The ink jet recording apparatus has many advantages such as extremely low noise at the time of recording and high-density recording, and has been increasingly attracting attention in recent years.

Further, the ink jet recording apparatus has a great advantage that plain paper can be selected as a recording medium.
Depending on the type, a problem may occur in the fixing property.
That is, since the ink jet recording apparatus uses liquid ink as the recording material, when the ink absorbency of the recording medium is poor, the ink does not immediately penetrate into the recording medium, and the ink that cannot be absorbed remains in the liquid state. This is because it remains on the recording medium.

When such a state occurs, the conveying member such as a roller is contaminated, and the ink contaminating the conveying member is transferred to the surface of a subsequent recording medium, thereby significantly deteriorating the recording quality. Furthermore, when the operator handles the recorded recording medium,
Not only can they contaminate their hands, but this can also drain the ink and disrupt the quality of the image. Alternatively, when a recorded recording medium is stacked on a tray or the like,
Such a problem may also occur due to rubbing between recording media.

As one method of preventing such a problem and improving the fixability of the ink to the recording medium, the recording medium is heated using a heater, and the evaporation of the water contained in the ink is promoted so that the ink on the recording medium can be quickly discharged. Some of them are dried and solidified. In response to demands for shortening the length of the recording medium conveyance path and speeding up fixing to prevent contamination of the conveyance member, the fixing heater is positioned near the recording position of the recording head, for example, facing the recording head. Is disposed on a platen for restricting the flatness. Further, paying attention to the fact that the ink absorbency increases when the recording medium is dried, a heater may be provided upstream of the recording position on the conveyance path in advance to heat and dry the recording medium.

At this time, the recording medium is not warped, and good and quick fixing is performed when the temperature of the recording medium is 80 ° C to 60 ° C.
It has been confirmed by the applicant's experiment that it should be just about the same.

[Problems to be solved by the invention]

However, when heating is performed by disposing a heater as described above, dew condensation may occur on the surface of a recording head provided with ink discharge ports (hereinafter referred to as a discharge surface). This is because, due to evaporation of moisture from the recording medium due to heating or evaporation of ink moisture, the vicinity of the ejection surface of the recording head becomes a high-humidity atmosphere, while the recording head takes 20 to 20 in consideration of ejection conditions such as ink viscosity. This is probably because the temperature was kept at about 40 ° C., that is, the temperature was lower than the ambient temperature due to heating for fixing.

In general, in the ink jet recording method, ink droplets adhere to a desired position on a recording surface in order to improve recording quality, that is, the ejection direction of flying ink droplets to be recorded is constant and the ejection speed is constant. Further, it is required that the particle diameter of the flying ink droplet is uniform.

However, the ejection of the ink from the recording medium often causes the ink ejection surface to become wet.Therefore, when dew condensation or wetting occurs on the ejection surface, water droplets and the like adhere to the ejection surface unevenly, and the ink Is unevenly pulled when the ink is ejected from the ink ejection port and separates, the ejection direction, the ejection speed, and the particle size of the ink droplets vary, thereby deteriorating the recording quality. Also, paper dust, dust and the like tend to adhere due to the wetting of the ejection surface, which may cause a decrease in recording quality.

On the other hand, the ejection surface has been wiped at a certain timing to eliminate the wetting. However, there has been a problem that the wiping damages the coating of the ejection surface and shortens the life of the recording head. .

The present invention solves such a problem, detects dew condensation on the ejection surface, and implements a wiping operation based on the dew condensation, thereby efficiently removing the wetting of the recording head ejection surface, and improving the ink ejection direction and ejection. An object of the present invention is to provide an ink jet recording apparatus in which the recording quality is prevented from deteriorating by stabilizing the speed and the ink particle diameter.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a recording head for recording an image by ejecting ink on a recording medium, and a recording head provided near the recording head, based on a change in humidity near the recording head. A dew condensation detecting means for detecting dew condensation occurring near the recording head; a blade for wiping an ink ejection surface of the recording head; and a blade for moving the recording head and the blade relative to each other. A wiping drive means for wiping the ink discharge surface, and a control means for driving the wiping drive means to perform wiping based on a detection result by the dew condensation detection means. A recording device is provided.

[Action]

With the above configuration, it is possible to detect the state where dew condensation has occurred in the vicinity of the print head, perform the wiping operation efficiently, and remove the wetness of the ink ejection surface of the print head at an appropriate timing.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is an external perspective view of an ink jet recording apparatus (hereinafter, referred to as an ink jet printer or simply a printer) according to an embodiment of the present invention. In the figure, reference numeral 100 denotes an ink jet printer main body. 15 is printer 100
A paper discharge guide 101 which forms a part of a paper discharge port provided in the central part of the upper lid, 101 is a paper discharge tray which is provided continuously to the paper discharge guide 15 and forms a part of the upper lid of the printer 100, The recording medium, such as recording paper, on which printing has been completed is discharged out of the ink jet printer main body 100 while its discharge path is regulated by the discharge guide 15, and is stacked on the discharge tray 101.

Reference numeral 102 denotes an operation panel provided on a part of the top cover of the printer 100, and keys for various operation inputs described later,
The printer is provided with a display lamp for notifying an operation state or the like of each unit in the printer. A paper set lever 103 protrudes through an opening provided at one end of the upper cover of the printer 100. When the paper set lever 103 is operated, the second
A mechanism described later in FIG. 3 or FIG. 3 operates to facilitate supply of recording paper.

FIG. 2 is a perspective view showing a state where the exterior of the printer shown in FIG. 1 is removed.

FIG. 3 is a sectional view taken along line XX in FIG.

2 and 3, reference numerals 1 and 1 'denote sliders which form a part of the recording medium accommodating portion and are slidably provided on a slider shaft 7, and these sliders 1 and 1' are provided.
Can be made to correspond to the width of the recording medium 33 by sliding each of them along the slider shaft 7. Reference numerals 2 and 2 'denote separation tabs provided on the slider 1, respectively.
Separately supply each sheet. Reference numerals 3 and 3 'denote pressure plates forming the bottom plate of the recording medium storage section. Each of the pressure plates 3 and 3' is rotatably supported at one end on a shaft 1A provided on each of the sliders 1 and 1 '. . The pressure plates 3 and 3 'are also urged upward by being pivoted about axes 1A and 1A' by push-up springs 3A and 3A ', respectively, so that the number of sheets 33 of stored recording paper 33 is Regardless, the recording medium 33 can be appropriately engaged with a separation roller shaft described later.

5 and 5 'are slidable along the separation roller shaft 6,
It is a connecting member which holds the separating rollers 4 and 4 'and has connecting members 5A, 5B and 5A', 5B 'for connecting the sliders 1 and 1', respectively.

That is, the separation roller 4, the connecting member 5, the connecting member 5A and
5B are combined together and can move along the slider shaft 7 and the separation roller shaft 6. Further, the separation roller 4 ', the connecting member 5', and the connecting members 5A 'and 5B' are also integrally combined.

When the sliders 1 and 1 'are slid according to the width of the recording medium 33 according to the above configuration, the separation rollers 4 and 4' are respectively displaced on the separation roller shaft 6 with the slide. Further, the pressure plates 3 and 3 'and the separation claws 2 and 2' are respectively provided with the sliders 1 and 1 '.
Are similarly displaced with the sliding of the sliders 1 and 1 '.

Reference numeral 8 denotes a lever provided at one end of the slider shaft 7 for rotating the slider shaft 7. Reference numerals 9 and 9 'denote pressure plate pressing arms fixed to the slider shaft 7 and provided so as to be engageable with the pressure plates 3 and 3', respectively.
With the rotation in the direction A ', the pressure plates 3 and 3' are rotated around the shaft 1A in the counterclockwise direction in the figure. That is, the lever 8 is rotated in the direction of arrow A 'in the figure by the operation of the above-mentioned paper set lever 103, whereby the pressing plate pressing arms 9 and 9' oppose the urging forces of the lifting springs 3A and 3A '. Press down the pressure plates 3 and 3 '. As a result, the engagement between the pressure plate 3 and the separation plate 2 and the engagement between the pressure plate 3 'and the separation plate 2' are released, and the supply of the recording medium 33 becomes easy.

An automatic sheet feed (ASF) motor 22 is coupled to one end of the separation roller shaft 6 via a transmission mechanism 23. The rotational driving force of the ASF motor 22 is transmitted to the separation roller shaft 6 via the transmission mechanism 23, whereby the separation rollers 4 and 4 'rotate clockwise in the drawing, and cooperate with the separation claws 2 and 2'. The recording media 33 are separated one by one and sent out to the paper feed path.

Reference numeral 24 denotes a paper feed roller, which is disposed at an appropriate location where the recording medium 33 is supplied by the separation rollers 4 and 4 '. 10A and 10B are substantially paper feed rollers from the portion where the recording medium is introduced from the slider 7 to the platen 12.
The paper guide is provided with an appropriate gap along the circumference of 24, and the gap formed by the paper guides 10A and 10B forms a paper feed path for the recording paper 33. Reference numeral 10C denotes a paper press for regulating the behavior of the recording medium 33 and bringing the recording medium 33 into close contact with the platen 12. 25A and 25B are 2 near the circumference of the paper feed roller 24.
A pinch roller which is disposed at a point and abuts on the paper feed roller 24 through a hole provided in the paper guides 10A and 10B.
Is pressed against the paper feed roller 24.

Reference numeral 11 denotes a paper feed motor coupled to one end of the paper feed roller 24 via a transmission mechanism 27. That is, the paper feed motor 11
Is transmitted to the paper feed roller 24 via the transmission mechanism 27, whereby the paper feed roller 24 rotates and the recording medium 33 is conveyed.

A platen 12 is disposed above the paper feed roller 24 and extends over the entire width of the recording medium 33. The platen 13 regulates the recording surface of the recording head to be flat, and 13 and 13 'are located downstream of the platen 12 along the transport path. Is a paper discharge roller disposed in the printer. Reference numerals 14 and 14 'denote paper sensors provided corresponding to the paper discharge rollers 13 and 13', respectively.
The setting or conveyance, and the discharge of paper are detected. With the arrangement of the platen 12 and the discharge rollers 13 and 13 'described above, the recording medium 33 on which recording has been completed is
The paper is ejected to the upper side of the
Guided above.

Reference numeral 50 denotes a fixing heater mounted on the surface of the platen 12 opposite to the surface in contact with the recording paper 33. The platen 12 is heated by the fixing heater 50, and the heat of the platen 12 is transmitted to the recording medium 33, whereby the ink can be dried on the recording medium 33 itself or on the recording medium 33 on which recording has been completed.

Reference numeral 20 denotes a recording head provided with a nozzle group for discharging ink while facing the recording surface of the recording medium 33 regulated by the platen 12. An electrothermal conversion element or an electromechanical conversion element or the like is arranged at an appropriate position in the ink flow path such as the nozzle, and the ejection energy is applied to the ink in response to the supply of the drive signal. More ink is ejected. Reference numeral 16 denotes a carriage for holding a recording head 20, which is fixed to a drive belt 18 and a platen 12
Is slidable with the two guide shafts 19A and 19B disposed in parallel with the direction in which the recording head 33 extends, the recording head 33 can reciprocate over the entire width of the recording paper 33.

Reference numeral 17 denotes a head drive motor disposed near one end of a reciprocating movement path of the recording head 20, and a pulley 17A is attached to a rotating shaft of the head drive motor. Also, head 2
A pulley 17B is disposed at the other end of the zero reciprocating path, and a belt 18 is stretched between the pulleys 17A and 17B. That is, the rotational driving force of the head drive motor 17 is converted into a linear driving force by the belt 18 and transmitted to the carriage 16 coupled to the belt 18. This allows the recording head
20 is reciprocated in the width direction of the recording medium 33.

Reference numeral 26 denotes a head recovery device disposed at one end of the movement path of the recording head 20 outside the recording range, for example, at the home position, and by appropriately configuring the above-described transmission mechanism 23, according to the driving of the ASF motor 22. The recording head 20 to the cap section 26A
Thus, the capping operation and the operation of retreating from the moving path of the recording head 20 can be performed. In connection with the capping of the head recovery device 26 to the recording head 20, the ink is suctioned by an appropriate suction device provided in the head recovery device 26 or by an appropriate pressurizing device provided in an ink supply path to the recording head 20. Perform ink pressure feed,
By forcibly discharging the ink from the discharge port, discharge recovery processing such as removing the thickened ink in the nozzle can be performed. Further, by performing capping at the end of recording or the like, the head is protected when not in use.

31 is provided on the side of the head recovery device 26 and has a recording head.
A blade as a wiper member engageable with the ejection surface of the recording head 20. Like the head recovery unit 26, the blade is engaged / disengaged with the recording head 20 according to the driving of the ASF motor 22 by an appropriate configuration of the transmission mechanism 23. You can do so. That is,
At an appropriate timing at the time of dew condensation detection described later in the reciprocating operation of the recording head 20, or after an ejection recovery process using the head recovery device 6, the blade 31 is protruded into the moving path of the recording head 20, and the reciprocating operation of the head 20 is performed. In this case, the ink and dew that have overflowed near the nozzle tip of the head 20 are wiped off. In the case of a configuration of the transmission mechanism 23 for performing the separation supply and the capping and wiping of the recording medium 33 by the single motor 22, or when a pump is provided as a suction unit in the head recovery device 26, the drive and separation of the pump are performed. A configuration in which paper feeding is performed by a single motor is described in, for example, Japanese Patent Application No. 61-81637 or Japanese Patent Application No. 61-197201 by the present applicant.
Can be used.

FIG. 4 is a view showing the mounting state of the recording head and the dew condensation sensor. In this drawing, the dew condensation sensor 30 for detecting dew condensation is attached to the recording head radiator plate Al near the ink droplet ejection portion H48 of the recording head 20 with a depth. The lead wire R1 (shown by a dotted line) is connected to the printed circuit board PB through the rear surface of the heat sink. This printed circuit board PB is wired with a signal for ink discharge and a signal of a positive temperature-dependent resistor PST for heating the head radiating plate in reverse when the external temperature is low to maintain a constant temperature. Each terminal of the PB is pressed into contact with a terminal of the flexible cable FC to be connected to an electric control circuit unit described later.

Further, the heat radiating plate Al is in close contact with the ink droplet discharging portion H48, and the condensation sensor 30 attached to the heat radiating plate Al is provided.
Has substantially the same temperature via the ink droplet discharge unit H48 and the heat radiating plate Al, and can detect a dew state similar to the dew state of the ink droplet discharge unit.

5 (A) to 5 (C) are top views showing the positional relationship between the head recovery device and the blade and the recording head shown in FIG.

FIG. 5A shows an arrow A in the figure after the recording head 20 has finished recording.
, And returns to the home position. At this time, the head recovery device 26 and the blade 31 are moved.
Is located at a position retracted from the movement path of the recording head 20.

In FIG. 5B, the recording head 20 stops at the home position, and the cap section 26A of the head recovery device 26 moves the recording head 2 to the home position.
This is the case where the capping is performed while abutting the ejection surface of No. 0, and at this time, the head recovery device 26 moves in the arrow B direction in the figure. On the other hand, the blade 31 also moves together with the head recovery device 26, but does not move relative to the head recovery device 26.

FIG. 5C shows the case where the recording head 20 moves in the direction indicated by the arrow D in the figure, that is, from the home position to the recording start position. At this time, the head recovering device 26 moves from the moving path of the recording head 20 to the recording head. Have been evacuated. In contrast,
The blade 31 is moved in the direction indicated by arrow C
And protrudes into the movement path of the recording head 20. As a result, the ejection surface of the recording head 20 is wiped by the blade 31.

The wiping by the blade 31 makes it possible to remove dew condensation and wetness of the ejection surface due to splashing of ink from the recording medium.

FIG. 6 is a block diagram showing a control system of the printer shown in FIG. 1 to FIG. 3 and FIG.

In FIG. 6, reference numeral 61 denotes a microprocessor unit (MPU), which controls the entire printer. Reference numeral 62 denotes a read-only memory (ROM) which stores processing means for controlling the printer, such as processing procedures described later with reference to FIGS. 9 to 12, and a table showing the relationship between humidity and the number of dots. I have. A random access memory (RAM) 63 has an area (buffer) for temporarily storing image information to be recorded, a work area for control, and an area for a counter to be described later. Reference numeral 64 denotes a character generator (CG), which stores characters corresponding to character information in the image information. 65 is an input / output interface (I / O) for exchanging data with the host computer, and 66 is an input / output interface (I / O) for exchanging data with various sensors and motors in the printer, and further with the operation panel. It is. Reference numeral 69 denotes a timer for generating operation timing in the printer, such as the drive timing of a motor provided in each section of the printer, and reference numeral 20C denotes a head control circuit for controlling the driving of the recording head 20. 62 described above
The parts indicated by .about.66, 69 and 20C are connected to the MPU 61 by an address bus 67, and the parts are mutually connected by a data bus 68.

105 is a sensor for detecting the absence of paper, the presence or absence of ink, the width of the recording paper, whether or not the recording head 20 is at the home position, etc., 50A is a fixing heater thermistor for detecting the temperature of the fixing heater 50, and 20A is A head thermistor for detecting the temperature of the recording head 20; 70 is thermistors 50A and 20A
From the temperature information, with a predetermined temperature as a threshold for each
This is a comparator that converts the value into a value signal.

Reference numeral 30A denotes a dew condensation detection circuit described later with reference to FIG. 7, which is connected to a dew condensation sensor 30 for detecting dew condensation in the recording area.
From dew sensor 30A, the signal line l ₂ is output to the I / O 66.

20B is a positive thermistor, Tr ₁ is a transistor,
Transistor Tr ₁ is "ON" next by a logic "1" of the signal line l ₄ connected to the I / O 66, raising the temperature of the recording head 20 by applying a current to the PTC thermistor 20B.

50B is a fixing heater control circuit to be described later in FIG. 8, is controlled by a logic signal of the signal line l ₁ to be connected to I / O 66. As a result, the temperature of the fixing heater 50 is controlled by receiving the power supply from the AC power supply 106.

The I / O 66 is a signal line other than the signal line l ₁ to l ₄ described above, ASF motor 22, the operation panel 102, head drive motor 17,
It is connected to the paper feed motor 11, the sensor 105 for detecting the presence or absence of the paperless ink, and the comparator 70, respectively.

FIG. 7 shows details of the dew condensation detection circuit shown in FIG.
In the figure, the voltage divided by the condensation sensor 30 and the resistor R1 is amplified by the amplifier H3 and input to one of the comparators H4, and the other is input by dividing the reference voltage by the resistors R2 and R3. . The dew condensation sensor 30 has a resistance value of 200 KΩ or more at 100% and 75%,
Since the voltage greatly changes to 0 KΩ or less, the voltage input to the comparator via the amplifier H3 changes extremely. That is, the input voltage greatly changes depending on the presence or absence of dew condensation. This was compared with a reference voltage (R2 and partial pressure value by R3) by a comparator, to change the logic signal of the signal line l _2. That is, by determining the value of the resistor connected to the circuit appropriately, if the at logic l ₂ not so and if the dew condensation dew sensor 30 caused to be "1" or "0".

Thus, when the logic of l ₂ is “1”, it indicates that condensation has occurred, and when l ₂ is 0, it indicates that no condensation has occurred.

FIG. 8 shows details of the fixing heater control circuit shown in FIG. In FIG., Tr ₂ are transistors, T1 is Fuotokapura, T3 is bidirectional triode thyristor, 50 denotes a fixing heater as described above. When the logic of the signal line l ₁ is set to “1” via the I / O 66 under the control of the MPU 61, the transistor Tr ₂
N ", a current flows through the light emitting element of the photocoupler T1 to emit light. With this light emission, a current flows through the light receiving element of the photocoupler T1, and this current is input to the gate electrode of the bidirectional three-terminal thyristor T3.

As long as there is an input to the gate electrode, the bidirectional three-terminal thyristor T3 transmits AC power to the fixing heater 50 regardless of its sign, thereby increasing the temperature of the heater.

FIG. 9 is a flowchart showing the procedure of the operation or processing of each section of the printer described above.

When the power of the printer is turned “ON”, the RAM 63 is set in step S1.
Various initializations and checks in the printer 100 are performed, such as clearing flags and counters in the printer, checking input / output ports, and the like. Next, in step S2, the thermistor 20B of the head 20 and the fixing heater control circuit 50B are turned "ON" to heat the fixing heater 50 and the recording head 20.

In step S3, it is determined whether or not the recording medium 33 is in the recording area. If a negative determination is made here, the process proceeds to step S12, in which the paper lamp of the operation panel 102 is turned on to warn that there is no paper. Next, in step S13, error processing such as replenishing the recording medium 33 or transporting the recording medium 33 to the recording area is performed, and in step S14, it is determined whether or not the paper-out error has been eliminated. When the error is released, the process returns to step S3.

If an affirmative determination is made in step S3, the process proceeds to step S4,
Online with the host computer, and the operation panel
Turn on the 102 online lamp. Next, step S5
, A signal that sets the logic of the Busy signal to “0” is output,
In a state where data from the host computer can be received, an image to be recorded is received in step S6, and a dot image for each scan is developed in the RAM 63.

In step S7, processing relating to "condensation detection, wiping and recording" described later with reference to FIG. 10, FIG. 11, or FIG. 12 is performed. In the recording process, the head drive motor 17 and the nozzle of the recording head 20 are driven so that the carriage 16 rises from the home position and performs recording in a predetermined printing section, and then the carriage 16 returns to the home position in a return operation. Then, the operation of stopping at a predetermined position is started. In the step S8, the paper of the recording medium 33 is fed during the operation of the carriage 16 until the return operation or the stop operation.

In the meantime, in steps S9 and S10, image data may be received from the host computer. In step S11, it is determined whether the head drive motor 17 and the paper feed motor 11 have stopped. The recording of one line is completed by this series of operations.

One scan of printing and processing accompanying it are performed by the processing in each of the above steps, and if an affirmative determination is made in step S11, the process returns to step S5.

FIG. 10 is a flowchart showing details of the processing of “condensation detection, wiping and recording” shown in FIG.

Step S201 is a timer for detecting the dew condensation again after a certain time has elapsed after the dew condensation is detected (FIG. 6).
If the determination is negative, the timer count has ended or the count has not been started, so the flow proceeds to step S202 for detecting dew condensation. In step S202, the signal line l ₂ = 1
Dew condensation is detected depending on whether or not. If l ₂ = 1, an affirmative judgment is made, and dew condensation is detected, and there is a possibility that the head discharge surface is greatly wet. Therefore, before recording in step S203, the wiping operation described above with reference to FIG. To eliminate wetting. Thereafter, in order to efficiently perform the wiping operation, the count of the timer for detecting the dew condensation again after a predetermined time has elapsed as described above is started in step S204. In addition, the affirmative judgment in step S201 and the step
The negative determination in S202 indicates that dew has been detected and the timer is counting and no dew has been detected.
Proceed to the recording routine of step S209 following 04. In step S209, the drive of the carriage drive motor 17 equipped with the recording head is started in step S205, and the process waits for the recording head 20 to move to the recording position in step S206. Head 20
Is moved to the recording position, in step S207, a dot image is output from the print buffer of the RAM 63 and recording is performed. Next, in step S208, the process is terminated by detecting that the head 20 has moved to the recording end position.

FIG. 11 shows another embodiment of the processing shown in FIG. The difference from FIG. 10 is that when condensation is detected in step S202, that is, in the case of an affirmative determination that condensation has been detected, the signal line ₁₁ is logically connected to the fixing heater control circuit 50B for controlling the fixing heater 50 in step S301. 0 "or stop heating of the fixing heater 50 as the l ₁ by the detection of the fixing heater thermistor 50A" 1 "," to low temperature by controlling the 0 ". In the step S302, by driving the transistor Tr ₁ and the temperature of the head by a signal line l _4, it is raised while detecting via the head thermistor 20A by controlling the temperature-dependent resistor (PTC thermistor) 20B.

Turning off or lowering the fixing heater and increasing the head temperature in steps S301 and S302 are means for eliminating the temperature between the two and making dew condensation difficult. Step S202
If the determination is negative, that is, if condensation has not occurred, the signal lines l ₁ and l ₄ are controlled by the detection temperatures of the thermistors and the thermistors to control the fixing heater and the head temperature to the normal set temperature in step S303.

After the above steps are completed, the recording operation of step S209 is executed, and the process ends.

FIG. 12 shows still another embodiment of the processing shown in FIGS. 10 and 11.

In the above embodiment, the dew condensation was detected before the printing operation.However, in the present embodiment, the dew condensation was detected just before the printing during the printing operation, and when the dew condensation was detected, the head 20 was moved to the home position unit. Forcibly return and execute the wiping operation. Hereinafter, each step will be described.

In step S401, the drive of the carriage drive motor 17 is started in the same manner as described above, and in step S402, the CPU waits for the recording head 20 to move to the recording position.When the position is reached and printing is performed, whether the timer is counting in step S403 as described above. If not, the process proceeds to step S404. Step
S404 affirmative decision is made in l ₂ = 1 performs detection of condensation by the signal line l ₂ in, that for a defective print this remains printing executed if condensation, the carriage by driving the carriage drive motor 17 at step S408 The wiping operation is forcibly moved to the home position, and the wiping operation is executed in step S409.
OFF or lowering control is performed, and in step S411, the head temperature is raised to the set temperature. This eliminates the temperature difference between the two and prevents dew condensation thereafter. Further, the timer count is started in step S412 due to the execution of the wiping operation in the same manner as described above. Then, the recording operation is executed in the same manner as in step S209.

In step S404, when l ₂ = 0, that is, when there is no condensation, a normal printing operation is performed. In step S405, the fixing heater and the head temperature are controlled to the normal set temperatures as described above.
In step S406, a dot image is output from the buffer of the RAM 63 and recorded. Then, in step S407, the process is terminated by detecting that the head 20 has moved to the recording end position. If the determination in step S403 is affirmative during the counting of the timer, the dew condensation was detected during the previous printing, and since the timer is counting and no dew condensation has occurred, the process proceeds to step S406, and printing is executed until the end of the recording.

FIG. 13 shows another embodiment of the mounting position of the dew condensation sensor 30. In FIG. 13, the dew condensation sensor 30 is mounted on the recording head heat radiating plate Al on the rear upper surface of the ink droplet discharge portion H48, and the printed circuit board is Connected to PB. The radiator plate Al with this condensation sensor is integrated with the radiator plate Al of the ink droplet discharge part H48, and is almost the same as the temperature of the ink droplet discharge part, and since it is not on the front of the head, it is suitable for head capping etc. This does not cause an obstacle, and also makes it possible to avoid the fine particles of the ejected ink, the splashing of the ink on the paper at the time of printing, and the scattering of the ink at the time of wiping.

〔The invention's effect〕

As described above, according to the present invention, the dew condensation detector is mounted at a place where the same temperature as that of the ink discharge unit is obtained, thereby eliminating the difference from the dew condensation state with the ink discharge unit, and detecting the dew condensation of the head. Accuracy is improved, and wiping is executed at the time of detecting dew condensation, and the subsequent dew detection is also performed at a fixed time using a timer, so that wiping can be efficiently executed at an appropriate timing.

In addition, the occurrence of defective printing can be prevented before each ejection by detecting dew condensation at each ink droplet ejection during printing.

Further, since the temperature of the fixing heater and the temperature of the head are changed after the detection of the dew condensation, the dew condensation can hardly occur thereafter.

As is clear from the above description, it is possible to efficiently perform wiping by detecting the proper dew condensation by the mounting position and the timer and performing wiping after the detection, it is possible to reduce the number of times of wiping and prevent deterioration of the head discharge surface, The effect of extending the life of the recording head was obtained.

In addition, by wiping by dew condensation detection at the time of printing,
Non-uniform wetting on the ejection surface can be removed, the ejection direction and ejection speed of the ink droplet from the ejection port are stabilized, and high-quality image recording has become possible.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an ink jet printer according to one embodiment of the present invention. 2 and 3 are a perspective view and a cross-sectional view, respectively, of the ink jet printer shown in FIG. 1 when the exterior is removed. FIG. 4 is a perspective view of a recording head equipped with a dew condensation sensor. 5 (A) to 5 (C) are top views showing the operation of the head recovery device and the blade shown in FIGS. 2 and 3. FIG. FIG. 6 is a block diagram showing a control system of the ink jet printer according to one embodiment of the present invention. FIG. 7 is a circuit diagram of the condensation detecting circuit shown in FIG. FIG. 8 is a circuit diagram of the fixing heater control circuit shown in FIG. FIG. 9 is a flowchart showing a recording operation of the ink jet printer according to one embodiment of the present invention and a process accompanying the recording operation. FIG. 10 is a flowchart showing details of the dew condensation detection, wiping and recording processes shown in FIG. FIG. 11 is a flow chart showing a fixing heater, a dew condensation detection including a head temperature control, a wiping and a recording process according to another embodiment of the present invention. FIG. 12 is a flowchart showing a process of dew condensation detection, wiping and recording during printing according to another embodiment of the present invention. FIG. 13 is a perspective view of a recording head according to another embodiment equipped with a condensation sensor. 1,1 '... Slider shaft 2,2' ... Separation joint 3,3 '... Press plate 4,4' ... Separation roller 5,5 '... Connection member 5A, 5A', 5B, 5B '... Connection member 6: Separating roller shaft 7: Slider shaft 8: Lever 9, 9 ': Press plate pressing arm 10A, 10B: Paper guide 11: Paper feed motor 12: Platen 13, 13' Discharge rollers 14, 14 '... Discharge sensor 15 ... Guide 16 ... Carriage 17 ... Head drive motor 17A, 17B ... Pulley 18 ... Belt 19A, 19B ... Guide shaft 20 ... Recording head 20C ... ... Head controller circuit 22 ... ASF motor 23,27 ... Transmission mechanism 25A, 25B ... Pinch roller 26 ... Head recovery device 26A ... Cap part 30 ... Condensation sensor 30A ... Condensation detection circuit 31 ... Blade 50 …… Fixing heater 50A …… Fixing heater thermistor 50B …… Fixing heater control circuit 61 …… MPU 62 …… ROM 63 …… RAM 64 …… CG 65,66 …… I / O 67 …… Dress bus 68 Data bus 69 Timer 70 Comparator 100 Inkjet printer 101 Output tray 102 Operation panel 103 Paper set lever 105 Sensor 106 Power supply H3 Amplifier H4 ...... comparator T1 ...... Fuotokapura T3 ...... bidirectional triode thyristor Tr _1, Tr ₂ ...... transistors R1, R2, R3 ...... reference resistor _{l 1, l 2, l 4} ...... signal line

Claims (5)

(57) [Claims] A recording head for ejecting ink onto a recording medium to record an image, and a dew condensation provided near the recording head and generated near the recording head based on a change in humidity near the recording head. A blade for wiping the ink ejection surface of the recording head, and wiping the ink ejection surface by the blade by relatively moving the recording head and the blade. An ink jet recording apparatus comprising: a wiping drive unit for performing wiping; and a control unit for driving the wiping drive unit to perform wiping based on a detection result by the dew condensation detection unit. 2. An ink jet recording apparatus according to claim 1, wherein said condensation detecting means is provided at a position having a temperature substantially equal to a temperature of said recording head. 3. The ink jet recording apparatus according to claim 1, wherein said control means interrupts a printing operation when dew condensation is detected during a recording operation by said recording head, and controls said wiping drive means. An ink jet recording apparatus for continuously performing a recording operation after wiping is performed. 4. The ink jet recording apparatus according to claim 1, wherein when dew is detected by said dew detecting means, a predetermined time interval is set until the presence or absence of the next dew is detected. Ink jet recording apparatus. 5. The ink jet recording apparatus according to claim 1, further comprising a print fixing heater for promoting fixation of the ink ejected on the recording medium by the recording head onto the recording medium, wherein the dew condensation heater is provided. An ink jet recording apparatus, wherein the temperature of the print fixing heater and the temperature of the recording head are managed based on a detection result of a detecting unit.