JPH06286254A - Inkjet recording apparatus - Google Patents

Abstract

PURPOSE:To print elaborately at high speeds by providing a plurality of inkjet recording heads each having a plurality of discharge ports and making at least one of the inkjet recording heads movable in a direction orthogonal to the scanning direction. CONSTITUTION:Two inkjet recording heads 1, 2 each having a plurality of discharge ports 15 are arranged at a carriage 18 in parallel to each other in a scanning direction A which is different from the arranging direction of the discharge ports 15. At this time, the first recording head 1 is fixed detachable to the carriage 18, while the second recording head 2 is set to be movable in a direction orthogonal to the scanning direction A (direction of the arrow B). In other words, a head driving motor 19 is mounted at the lower face of the carriage 18, and gears 20, 21 are rotated by the rotation of the output shaft of the motor 19. A driving shaft 22 meshed with the gear 21 and to which the second recording head 2 is secured is moved in the axial direction. Accordingly, elaborate printing is realized by performing printing at different positions through the movement of the second recording head 2.

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 having an ink jet recording head having a plurality of ejection openings arranged therein.

[0002]

2. Description of the Related Art As shown in FIG. 7, in an ink jet recording apparatus of this type, a carriage 10 in which an ink jet recording head 100 having a plurality of ejection ports 103 is scanned.
It is installed in 4. While scanning the carriage 104 in the scanning direction indicated by the arrow, ink is ejected from the ejection port 103 based on the ejection signal 102 applied at the time interval T to form dots 101 on the recording medium (not shown). Form an image. In addition, in FIG. 7, L indicates a predetermined width of the recording medium (not shown).

By the way, in the conventional ink jet recording apparatus, when printing at high speed, the print density is reduced and the ink jet recording head is scanned at high speed for printing. Further, in the case of high-density printing, the vicinity of the same printing area is divided into a plurality of times and the ink jet recording head is scanned for printing.

[0004]

In the above-mentioned prior art, when high-speed printing is performed, it takes time to eject the ink from the ejection port even if the scanning speed of the ink jet recording head is increased, so that the ink ejection is not possible. There is a problem that the scanning speed of the inkjet recording head cannot be followed and the printing speed cannot be increased so much. Further, in the case of high-definition (high-density) printing, it takes time because the inkjet recording head is scanned a plurality of times in the vicinity of the same print area of the recording medium to be printed, and the fineness determined by the distance between the ejection openings of the inkjet recording head. There is a problem that it is difficult to make the printing speed higher than the resolution and the printing speed faster.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an ink jet recording apparatus capable of high-speed printing and high-definition printing.

[0006]

In order to achieve the above object, the present invention is an ink jet recording apparatus for ejecting ink toward a recording medium to form an image, in which a plurality of ejection ports are arranged. A plurality of ink jet recording heads arranged on the carriage in a scanning direction different from the direction of arrangement of the ejection ports, and at least one of the plurality of ink jet recording heads is movable in a direction orthogonal to the scanning direction. For moving ink and ink ejection control means for ejecting ink from the ejection ports of each inkjet recording head at different timings.

Further, there is provided means for detecting and displaying whether or not the movable ink jet recording head is moving in a direction orthogonal to the scanning direction.

Further, the ink jet recording head is for ejecting ink by utilizing heat energy, and is provided with an electrothermal converter for generating the heat energy.

[0009]

According to the present invention constructed as described above, first, when the movable ink jet recording head is not moving in the direction orthogonal to the scanning direction, when the carriage is scanned, a plurality of ink jet recording means are operated by the ink ejection control means. Ejection signals are alternately supplied to the head at different timings, so that double speed printing can be performed as compared with the case of using one ink jet recording head. That is, by printing a plurality of inkjet recording heads at different positions in the scanning direction while scanning, the scanning speed of the carriage is not limited by the time for ejecting ink from the ejection port, and therefore the printing speed can be increased. it can.

Further, when the carriage is scanned while the ink jet recording head movable by the moving means is moved by a predetermined distance in the direction orthogonal to the scanning direction, the ink ejection control means causes a plurality of ink jet recording heads to move to the plurality of ink jet recording heads. The ejection signals are alternately supplied at different timings. In this case, high-density printing can be performed by one head operation. In other words, by moving the ink jet recording head in a direction perpendicular to the scanning direction and performing scanning, printing is performed at different positions so that the printing speed is higher than that determined by the distance between the ejection ports of the head and the printing speed is faster. it can.

[0011]

An embodiment of the present invention will be described with reference to the drawings.

First, the overall structure of the ink jet recording apparatus will be described with reference to FIG.

In the ink jet recording apparatus of this embodiment, the carriage 18 on which two first and second ink jet recording heads 1 and 2 to be described later are mounted is driven by a drive motor 10.
Connected to a part of the drive belt 9 that transmits the driving force of
Two guide shafts 11a arranged parallel to each other,
It is slidably attached to 11b. A platen in which the first and second inkjet recording heads 1 and 2 are arranged so as to face the ejection port forming surfaces of the first and second inkjet recording heads 1 and 2 by the driving force of the drive motor 10. A recording medium (recording medium) fed from a medium feeding device (not shown) is reciprocated over the entire width of the recording medium 12 to perform recording on the recording medium.

Further, in the ink jet recording apparatus of this embodiment, the first and second ink jet recording heads 1 and 2 are out of the range of reciprocating movement in the recording operation, and the first and second ink jet recording heads are in the head recovering operation. Recording heads 1 and 2
Is moved to a position (the left end of the guide shaft 11a in the figure,
Hereinafter, it is referred to as a recovery position. ), The first and second ink jet recording heads 1 and 2 are driven by the driving force of the cleaning motor 7 via the transmission mechanism 4 so as to face the ejection port forming surfaces of the first and second ink jet recording heads 1 and 2. A head recovery device 6 having a cap 3 for sequentially capping the ejection port forming surfaces of the recording heads 1 and 2 is provided.

The head recovery device 6 has a recovery system pump (not shown) in connection with capping of the ejection port forming surfaces of the first and second ink jet recording heads 1 and 2 by the cap 3 during the head recovery operation. Ink is sucked or ink is pressure-fed by an appropriate pressure means provided in the ink supply paths to the first and second inkjet recording heads 1 and 2, and the ink is forcibly discharged from the ejection port.
A head recovery operation such as removing the thickened ink in the ejection port is performed. By this head recovery processing, the waste ink discharged from each of the ejection ports of the first and second inkjet recording heads 1 and 2 is discharged and stored in the waste ink tank 13 serving as a storage member.

Further, on the side surface of the head recovery device 6, a blade 5 made of silicon rubber as a wiping member is held in a cantilever form by a blade holding member 8, and like the head recovery device 6, a cleaning motor 7 and a cleaning motor 7 are provided. It operates by the transmission mechanism and can be engaged with the ejection port forming surfaces of the first and second inkjet recording heads 1 and 2. As a result, after the head recovery operation using the head recovery device 6, the blade 5 is projected into the moving path of the first and second inkjet recording heads 1 and 2, and the first and second inkjet recording heads 1 and 2 are ejected. Two
Condensation, wetting, dust, or the like on the ejection port forming surfaces of the first and second inkjet recording heads 1 and 2 is wiped with the scanning operation.

The ink jet recording head will be described below.

As shown in FIG. 2, the first and second ink jet recording heads 1 and 2 are arranged in rows (in this embodiment, 1
In order to eject the recording liquid from a plurality of ejection ports 15 provided in a row, an electrothermal converter 14 that generates thermal energy supplied with an applied voltage is provided in each liquid passage. Then, by applying a drive signal, thermal energy is generated in the electrothermal converter 14 to cause film boiling and form bubbles in the ink liquid path. Then, ink droplets are ejected from the ejection port 15 by the growth of the bubbles. The plurality of discharge ports 15 are formed in the orifice plate 16, and the plurality of electrothermal converters 14 are provided on the heater board.

Next, the head moving means, which is a feature of this embodiment, will be described. FIG. 3 is a diagram showing moving means of the second inkjet recording head shown in FIG.
Is a front view, FIG. 4B is a bottom view, and FIG. 4 is a control block diagram of the moving means and the ink ejection timing shown in FIG.

As shown in FIG. 3, the carriage 18 is provided with two first and second ink jet recording heads 1 and 2 arranged in the scanning direction (direction of arrow A). In this embodiment, the first and second ink jet recording heads are provided. The distance between the inkjet recording heads 1 and 2 is 12.7 mm. The first inkjet recording head 1 is detachably fixed to the carriage 18, while the second inkjet recording head 2 is moved in a direction (arrow B direction) orthogonal to the scanning direction A by a moving unit described later.
Can be moved to.

Now, the moving means will be described.
A head moving motor 19 is attached to the lower surface of the carriage 18 via a bracket 23, and a first gear 20 is fixed to the output shaft of the head moving motor 19. The first gear 20 is engaged with a second gear 21 having an internal thread formed on the inner peripheral portion thereof.
Is screwed to a drive shaft 22 to be described later, and the carriage 18
It is located below. The lower half of the drive shaft 22 is a threaded portion 42, and the second gear 21 is screwed into the threaded portion 42. The drive shaft 22 penetrates the carriage 18 slidably in the axial direction, and the second inkjet recording head 2 is fixed to the upper end of the drive shaft 22. The first and second nuts 25 and 26 are screwed onto the drive shaft 22 and have a so-called double nut type structure. First nut 25 and second
A spring 24 is sandwiched between the gear 21 and the gear 21.
This spring 24 connects the second gear 21 to the carriage 1
It is pressed against the lower surface of 8 and held in that position. Non-rotating pin 3
Reference numeral 9 is for preventing the rotation of the second inkjet recording head 2 with respect to the carriage 18. The detent pin 39 has one end fixed to the carriage 18 and the other end slidable with respect to the second inkjet recording head 2. As a result, when the rotational force of the head moving motor 19 is transmitted to the second gear 21, the drive shaft 22 is moved in the vertical direction (arrow B direction) without rotating, and the second inkjet recording head 2 is also moved. Be moved.

Next, with reference to FIGS. 3 and 4, the control of the ink jet recording head moving means and ink ejection timing will be described.

The head movement motor 19 is driven and controlled by the head movement control circuit 27 so that the second ink jet recording head 2 can be moved upward (in the direction of arrow B) by a predetermined distance. It can be held in a state of being moved by half the distance. The amount of movement of the second inkjet recording head 2 may be a distance obtained by adding a half of the pitch to a multiple of the pitch.
When the number of inkjet recording heads and the ejection port pitch are N and P, the moving amount of the inkjet recording head 2 is preferably P / N. On the other hand, the first and second inkjet recording heads 1 and 2 are supplied with an ejection signal (see FIG. 5B and FIG. 6B) alternately by the ink ejection control circuit 28 and for each row of ejection ports. To be done.
The control unit 29 as a CPU has a head movement control circuit 27.
Also, the ink ejection control circuit 28 is controlled at a predetermined timing. The detection unit 41 is for detecting whether or not the second inkjet recording head 2 is moving, and is an encoder for detecting the rotation angle of the leaf switch or the head moving motor 19. The display unit 30 is provided on an operation panel (not shown) that controls the print mode, power on / off, etc. of the recording apparatus, and the second inkjet recording head 2 is located at a predetermined position as shown in FIG. If it is moving, this is displayed. As a result, the user can easily know whether the printing mode is the high-speed printing mode, which will be described later, or the high-definition printing mode, without looking at the printing result of the test printing of the recording apparatus.

Next, the operation of this embodiment will be described.

(In case of high speed printing mode) First, as shown in FIG. 5A, in a state before the second ink jet recording head 2 moves upward (in the direction of arrow B), the carriage 18 moves in the direction of arrow A. When scanning at a speed twice as fast as the conventional scanning speed, the first and second inkjet recording heads 1 and 2 have a time interval T as shown in FIG.
Of the discharge signals 33, 34 of different times (time T / 2
Are alternately supplied at different timings), and rows of dots 31 and 32 are alternately formed on a recording medium (not shown) by the first and second inkjet recording heads 1 and 2, respectively. Similar to FIG. 7, L indicates a predetermined width of the recording medium (not shown). Here, in this embodiment,
The time interval T for applying the ejection signals 33 and 34 is 163.4 μm.
In sec, the relationship between the interval between the first and second inkjet recording heads 1 and 2, the time interval T, and the scanning speed is T ×
180 × scanning speed = 12.7 mm. Also,
The dots 31 indicated by white circles indicate the ink ejected from the ejection ports 15 of the first inkjet recording head 1, and the dots 32 indicated by the black circles indicate the ink ejected from the ejection ports 40 of the second inkjet recording head 2. Shows. In this case, it is possible to perform double speed printing as compared with the case of using one ink jet recording head. That is,
By printing at two different positions in the scanning direction while scanning the two inkjet recording heads 1 and 2, even if the driving frequency of the recording head is the same as the conventional one, the scanning speed of the carriage depends on the time at which ink is ejected from the ejection port. Since there is no limitation, the printing speed can be increased.

(In case of high-definition printing mode) (a) of FIG.
As shown in FIG. 3, the carriage 1 is moved in the state in which the second ink jet recording head 2 is moved upward (in the direction of arrow B) by a distance that is half the pitch of the ejection openings by the moving means.
When 8 scans in the direction of arrow A, the first and second inkjet recording heads 1 and 2 have different timings (time intervals) when the ejection signals 37 and 38 having time intervals T are different as shown in FIG. 6B. Are alternately supplied at a timing (shifted by T / 2), and dots 31, are formed on a recording medium (not shown) by the first and second inkjet recording heads 1 and 2, respectively.
32 rows are formed alternately. Similar to FIG. 7, L indicates a predetermined width of the recording medium (not shown). here,
In this embodiment, the time interval T for applying the ejection signals 37 and 38 is T.
Is 163.4 μsec, and the relationship between the interval between the first and second inkjet recording heads 1 and 2, the time interval T, and the scanning speed is T × 180 × scanning speed = 12.7 mm. In this way, high-density printing can be performed with one head operation. That is, printing is performed at different positions while moving and arranging the ink jet recording head in the direction perpendicular to the scanning direction to perform printing with higher definition and higher printing speed than the definition determined by the pitch of the ejection ports.

(Other Embodiments) In the above embodiments, the motor is used as the drive source of the moving means for moving up and down, but a piezoelectric element or the like may be used as this drive source. Further, an example in which the number of ink jet recording heads is two has been shown, but in the case of color printing, it can be carried out if the same form is tripled or quadrupled. The number of systems is not limited to three, and if three or four are used, high-speed printing of 3 times or 4 times or similar high-density printing is possible.

For example, concretely, four ink jet recording heads are used, and two ink jet recording heads among them are shifted in a direction perpendicular to the scanning direction by a distance of a half of an ejection port to perform printing. As a result, the definition and the printing speed can be doubled.

The present invention brings excellent effects particularly in a recording head and a recording apparatus of the type which ejects ink by utilizing thermal energy, which is proposed by Canon Inc. among ink jet recording systems.

With regard to its typical structure and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. This method is applicable to both so-called on-demand type and continuous type, but in particular,
In the case of the on-demand type, the electrothermal converter arranged corresponding to the sheet or liquid path where the liquid (ink) is held corresponds to the recorded information and the temperature rises rapidly beyond the nucleate boiling. By applying at least one drive signal that gives a heat energy to the electrothermal converter, the film is boiled on the heat-acting surface of the recording head, and as a result, the liquid (ink It is effective because bubbles can be formed inside. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make the driving signal into a pulse shape because bubbles can be grown and contracted immediately and appropriately, and thus a liquid (ink) with excellent responsiveness can be ejected. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. In addition,
US Pat. No. 4, of the invention relating to the rate of temperature rise of the heat acting surface,
If the conditions described in the specification of 313,124 are adopted,
Further 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 straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. U.S. Pat.No. 4,558,333, U.S. Pat.
The structure using the specification of No. 9,600 is also included in the present invention. In addition, for a plurality of electrothermal converters, JP-A-123670 discloses a configuration in which a common slit serves as a discharge portion of the electrothermal converters and an opening for absorbing a pressure wave of thermal energy. Japanese Patent Application Laid-Open No. Sho-Ai discloses a structure corresponding to a discharge unit
The present invention is also effective as a configuration based on the '138461 publication.

In addition, by being mounted on the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. The present invention is also effective when a cartridge-type recording head that is specially provided is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. . Specific examples thereof include capping means, cleaning means, pressurization or suction means, an electrothermal converter or a heating element other than this, a preheating means for the recording head, and a recording head for the recording head. It is also effective to perform a preliminary ejection mode in which another ejection is performed for stable recording.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full color by color mixing.

In the embodiment of the present invention described above, the ink is described as a liquid, but it is an ink that solidifies at room temperature or below, and is softened or liquid at room temperature, or the ink itself is 30 in the above-mentioned ink jet. It is common to adjust the temperature within a range of ℃ to 70 ℃ to control the temperature of the ink so that the viscosity of the ink is within the stable ejection range. Good. In addition, it is possible to prevent the temperature rise due to thermal energy from being positively used as energy for changing the state of the ink from a solid state to a liquid state, or
Whether or not ink that solidifies in a standing state is used for the purpose of preventing evaporation of the ink, and in any case, the ink liquefies by being applied according to the recording signal of thermal energy and is ejected as an ink liquid or reaches a recording medium. The use of inks that have the property of only liquefying by thermal energy, such as those that have already begun to solidify at this point, is also applicable to the present invention. In such a case, the ink, as described in JP-A-54-56847 or JP-A-60-71260, in a state of being held as a liquid or a solid in the recesses or through holes of the porous sheet, It may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

[0036]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, a plurality of ink jet recording heads are arranged in the scanning direction and printing is performed at different positions in the scanning direction while scanning the ink jet recording heads. The printing speed can be increased because it is not limited by the time of ejection from the ejection port, and at the same time, printing is performed at different positions while scanning while moving at least one inkjet recording head in the direction perpendicular to the scanning direction. Thus, it is possible to achieve higher definition and higher printing speed than the definition determined by the distance between the ejection openings of the head.

According to the invention of claim 2, in addition to the above effects,
The user can easily know whether the printing mode is the high-speed printing mode or the high-definition printing mode without looking at the printing result of the test printing of the recording apparatus.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an entire inkjet recording apparatus of the present invention.

2 is a schematic perspective view of the inkjet recording head shown in FIG. 1. FIG.

3A and 3B are diagrams showing moving means of the inkjet recording head shown in FIG. 1, FIG. 3A being a front view and FIG. 3B being a bottom view.

FIG. 4 is a control block diagram of moving means and ink ejection timing shown in FIG.

5A is a front view of each ink jet recording head shown in FIG. 1, showing a state in which a position of a second ink jet recording head is not moved, and FIG. 5B is each ink jet recording head. FIG. 6 is a diagram showing the ink ejection timing in FIG. 4 and dots formed on each recording medium by each inkjet recording head.

6A is a front view of each inkjet recording head shown in FIG. 1, showing a state in which the position of the second inkjet recording head is moving, and FIG. 6B is each inkjet recording head. Ink ejection timing in
It is a figure which shows the dot on a recording medium formed by each inkjet recording head.

FIG. 7 is a diagram showing a conventional technique, (a) is a front view of an inkjet recording head, and (b) is a diagram showing dots and ejection timing by the inkjet recording head.

[Explanation of symbols]

 1 1st inkjet recording head 2 2nd inkjet recording head 3 cap 4 transmission mechanism 5 blade 6 head recovery device 7 cleaning motor 8 blade holding member 9 drive belt 10 drive motors 11a, 11b guide shaft 12 platen 13 waste ink tank 14 Electrothermal Converter 15 Discharge Port 16 Orifice Plate 17 Heater Board 18 Carriage 19 Head Moving Motor 20 First Gear 21 Second Gear 22 Drive Shaft 23 Bracket 24 Spring 25 First Nut 26 Second Nut 27 Head Movement control circuit 28 Ink ejection control circuit 29 Control section (CPU) 30 Display section 31,32 Dot 33,34 Discharge signal 35,36 Dot 37,38 Discharge signal 39 Rotation pin 40 Discharge port 41 Detection section 42 The arrangement direction of the Part A scanning direction B discharge port

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Claims (3)

[Claims] 1. An ink jet recording apparatus for forming an image by ejecting ink toward a recording medium, each of which has a plurality of ejection openings arranged in a scanning direction different from the arrangement direction of the ejection openings. A plurality of ink jet recording heads arranged on the carriage; moving means for moving at least one of the plurality of ink jet recording heads in a direction orthogonal to the scanning direction; Ink ejection control means for ejecting ink at different timings,
An inkjet recording apparatus comprising: 2. Whether or not the movable ink jet recording head is moving in a direction orthogonal to the scanning direction,
The ink jet recording apparatus according to claim 1, further comprising means for detecting and displaying. 3. The ink jet recording head ejects ink by utilizing thermal energy, and is provided with an electrothermal converter for generating the thermal energy. Inkjet recording device.