JP2003182094A - Double-sided printing inkjet recording device and recovery device - Google Patents

Abstract

(57) [PROBLEMS] To reduce the size of a double-sided printing apparatus having one or more recording heads on both sides of a recording medium. SOLUTION: A recording head provided for double-sided printing is scanned by one drive belt to perform printing. The plurality of recording heads have a mechanism detachable from the belt. During capping, the recording head is released from the drive belt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink jet recording apparatus for obtaining a full color image on a recording medium, and a recording apparatus capable of performing printing on the recording surfaces on both sides of the recording medium substantially simultaneously by a series of operations. Is a proposal of.

The present invention relates to a recovery means for improving the trouble of the recording head in this recording apparatus. There is a capping device that matches the recording head at both ends of the print, and is a proposal for a means for performing a suction operation of ink from the head via the capping device to improve the trouble in the head.

[0003]

2. Description of the Related Art In general, an ink jet recording apparatus supplies ink to a recording head and ejects ink from a fine nozzle by using an ink droplet ejecting means such as a piezoelectric element or an electrothermal converter provided in the recording head. It ejects ink.

On the basis of desired image data, each nozzle is ejected on demand to record and attach patterns of ink dots to a recording medium such as paper to form an image.

A head for obtaining a color image generally ejects a color ink from a head having a yellow ink, a magenta ink, a cyan ink, and a black ink, respectively.

Conventionally, when double-sided printing is performed, a means for printing the recording medium is devised so that the first surface is printed first and the second back surface is printed. At this time, after the printing on the first front surface is completed, the second mechanical conveyance is performed by the mechanical mechanism to start printing on the second rear surface in order to print on the second rear surface.

At this time, there is a step of setting the time when the fixing of the ink printed on the first surface is almost completed, and then printing on the second surface.

Therefore, even if double-sided printing is performed, the printing time requires a waiting time corresponding to two sheets. In addition, there is a problem in that once printing is performed on the surface, the ink permeates the recording medium and the surface condition becomes unstable or wavy.

As a conventional example, Japanese Patent Laid-Open No. 07-276716
(NEC) has inkjet nozzles on the front and back sides so that printing can be performed on both sides of the printing paper. First, after the printing is completed by the head, the printing paper is carried by the carrying roller and fed by a predetermined amount, and then the second head prints on the back surface.

Japanese Patent Laid-Open No. 10-171202 (Hitachi Koki Co., Ltd.) proposes a two-color double-sided printing system using a laser printer and a solid ink jet printer.

The toner image and the ink image are formed on the first surface, and after the step of fixing the toner image, the paper is reversed to print on the second surface, and the second surface is printed. .

In Maikihei 11-221944 (Canon Inc.), there is a printing unit including two printer engines that face each other with a sheet sandwiched between them, and there is a structure capable of double-sided printing, but a drive source for moving the head. It takes more than one.

In Japanese Patent Laid-Open No. 05-261979 (Seiko Epson Co., Ltd.), printing is performed once on a transfer medium by an ink jet, and then the print information of the approximate transfer medium is brought into contact with the recording medium to perform printing. There are two units, and it has been proposed that the first recording unit is used for the first surface and the second second recording unit is used for the print transfer on the back second surface.

As described above, there is a means for reversing and printing on the second printing surface after the first printing surface is discriminated, which requires a long printing time. Further, in the means in which two recording heads are provided at the facing positions, there are a plurality of driving means for moving each recording head, and there is a problem in terms of cost.

[0015]

The advantage of double-sided printing is that the printing time can be speeded up, and by executing double-sided printing, the right effect of the paper can be utilized and consideration for ecology can be made.

In the conventional proposal of the screen printing function, for example, in order to perform double-sided printing, the first recording head first prints the front surface, then the printing paper is conveyed by a predetermined amount, and then the second printing is performed on the back surface. Means for printing with a recording head have been proposed. This has a drawback that an extra base has to be secured in order to perform double-sided printing.

Next, in the method of performing double-sided printing on the front surface and the back surface substantially at the same time, each drive source is required to drive the first recording head and the second recording head, and they are independently controlled. Having a plurality of drive sources has the drawbacks of high cost and the need to secure space.

Here, it is good when two recording heads are simultaneously performing double-sided printing. For example, when the two recording heads are fixed to one-sided printing, it is not necessary to operate the two recording heads simultaneously. There are drawbacks such as a large load to be applied and the nozzles of unused recording heads being dried.

[0019]

According to the present invention, the size of the recording apparatus can be minimized, and the recording head can be driven without having a plurality of drive sources to reduce the cost and save the space. The configuration can be effectively utilized.

Two recording heads for double-sided printing have a positional relationship in which their nozzles face each other. The first recording head on the front surface side and the second recording head on the back surface side are fixed by one endless belt.

The first recording head and the second recording head are configured to perform printing while moving in the opposite directions by driving the belt. The recording medium is configured to be conveyed in the air at a substantially intermediate position between the first recording head and the second recording head.

The first recording head and the second recording head are
The configuration may be such that they are located directly in front of each other or that they are offset from each other, and the present invention is not limited as long as two recording heads can be driven by a single drive source. Printing with the offset recording head can also be performed on the back surface after a predetermined scan has elapsed after the first recording head has printed.

In such a recording system, there is no problem if the screen printing is always performed, but if the printing of only one side is to be carried out in a large amount, the nozzles of the unused recording head are dried or the motor driving load is reduced. This is very important. Therefore, the recording head on the side not used for printing is detachable from the carriage station joined to the drive belt.
It is desirable to hold the recording head, which is unnecessary for printing, by holding it in the cap unit.

By doing so, the above problem can be solved. When the next printing operation is required, a recovery operation that involves suction is performed by the capping time, and when the time is relatively short, a recovery operation that is not related to printing is executed to stabilize the status. You can do it.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a schematic perspective view showing the entire color ink jet recording apparatus embodying the present invention.

Reference numerals 1a and 1b in the figure denote color ink jet heads of the recording apparatus. Reference numeral 7 denotes a nozzle group for ejecting ink, and a plurality of heads of four colors are arranged for each color. Specifically, 1a and 1b are each black (hereinafter B
K), cyan (hereinafter C), magenta (hereinafter M), and yellow (hereinafter Y) nozzle groups, and a BK nozzle group and C,
M and Y nozzle groups are arranged on a substantially straight line.

Regarding the arrangement of the nozzles, it is not specified that the nozzles are arranged on a straight line, and a nozzle group of each ink may be arranged in parallel in the main scanning direction, or a combination of a straight line and a parallel line may be used. I do not care.

Ink tanks are mounted on the recording heads 1a and 1b as an ink holding mechanism. Some of the ink tanks have a structure capable of generating a predetermined negative pressure, and there is also one that applies a predetermined negative pressure to the recording head to prevent ink dripping during printing. Specifically, the head pressure is -5 Aq-
A raw ink tank structure having an initial negative pressure means of 100 mmAq or a structure using a porous urethane sponge is used.

The ink tank may be replaceable,
In this case, the three colors of BK alone and color CMY may be integrated. Furthermore, BK, C, instead of three color integrated type
It is also possible to use an ink tank structure in which M and Y are independent. As an example of the recording head described above, a recording head having a shape as shown in FIGS. 2 and 3 was used.

In FIG. 2, nozzle groups of a plurality of colors are arranged in a substantially straight line, and yellow (Y), cyan (C) and magenta (M) are arranged.
And black (BK) nozzle groups 7Y to 7BK are arranged. Since YMC has a relatively small ejection amount, the nozzle is small, and BK has a large ejection amount.

In FIG. 3, a group of four color nozzles are arranged side by side, and the ink tank is replaceable. The nozzle size may be uniform, or BK may be set large.

7Y to 7BK represent nozzle groups, and 9Y to 9BK.
BK is an ink tank for each color of the recording head.

In the present invention shown in FIG. 1, a recording head constructed so that the printing surface and the address surface can be printed at the same time using the recording head described above is mounted, and a color head is provided on the printing surface side. It may be mounted and a monochrome / head may be mounted on the address side, and it is not awaited.

It is also possible to combine the recording heads shown in FIGS. 2 and 3. The printing operation will be described with reference to FIG. The recording head 1a is mounted on the carriage station 2a.

The carriage station 2a is provided with an electrical connection (not shown), a print signal input means for printing, and a print board.

Reference numeral 3a is a shaft for scanning the head so that printing can be performed along the recording medium. The carriage station 2a is connected to be able to scan via a transmission belt 4 from a drive motor. The drive transmission belt 4 has a mechanism capable of simultaneously driving the second recording head 1b provided at a position facing the recording head 1a.

Reference numeral 6a is a cap unit (also called a recovery unit) of the recording head. A cap unit (not shown in the drawing) corresponding to the recording head 1b is provided on the opposite side of the recording device.
b) is installed.

The cap unit 6a is arranged at a position where it can be joined to the recording head 1a, and a porous body is inserted in the cap unit below the cap so that ink does not drop when the suction recovery operation is executed. The material is not specified, but it is sufficient if it has no reactivity with ink and the ability to absorb ink instantly.

The recording head 1a has a mechanism 10 for attaching and detaching the recording head and a guide portion 11. At the home position, there is a mechanism for fitting with the cap unit side 10, 11, and there is a hole 12 for fitting with the attaching / detaching mechanism 10.
There is a groove 13 for receiving the guide.

When it is set not to print,
The corresponding recording head 1a (if the side 1a is not used) moves the carriage station to the home position, fits the recording head with the cap unit, and opens the recording head from the carriage station for capping operation.

FIG. 4 is a schematic view showing a state when the recording head 1a is opened at the home position. At the home position, the recording head 1a is held in a state in which it is electrically disconnected from the main body and is capable of capping operation. The carriage station 2a is provided with an electrical connecting means 20 so that it can be joined when the recording head 1a is mounted.

The recovery operation of the recording head is performed by a suction means (not shown) after capping. When the printing operation is started, the capping time is measured, and when a predetermined time or more elapses, the suction recovery operation is performed and then the carriage station is joined.

If a print operation start command is issued within a predetermined time, the recording head is moved from the cap unit to the carriage station and joined. At that time, since the recording head is electrically connected, it is desirable to execute a recovery process related to ink ejection.

Here, the recovery operation related to suction can be performed without electrical connection as described above. However, during the printing operation, the recovery operation can be performed even if the recording head is not electrically disconnected from the carriage station. It is configured to be able to.

FIG. 5 is a side view as seen in the direction AA of FIG. The assigned symbols indicate the same. When a print signal is input from a print signal input means (not shown), the recording medium is fed from the upper part of the recording device via the paper feed mechanism of the main body. The recording medium 8 is guided to the place to be printed 41
Paper is fed while passing through a and b, and pinch rollers 42a and 42b
And is conveyed to the spurs 43a and 43b.

Further, the recording medium is conveyed, enters the spurs 44a and 44b, and the recording medium is set. It is desirable that the spur can be transmitted from a drive (not shown) and can rotate. The rotation speeds of 43a and 43b and the rotation speeds of 44a and 44b are devised so that the recording medium can be conveyed smoothly.

In an apparatus having a mechanism capable of simultaneous double-sided printing with such a configuration, it is easy to handle a recording medium that is slightly thick and has rigidity. This embodiment is suitable for printing postcards, cards, glossy paper or glossy film as special paper.

For example, when simultaneously printing on postcards, the first recording head may be set on the address side and the color head may be installed on the printing side. It is also possible to use pigment ink or special ink to print on the black side of the address surface alone.

When printing with two recording heads with one drive belt, as is clear from the figure, when the first head performs printing in the right direction, secondly, the recording head moves to the left side in the opposite direction. Printing can be performed while moving. After the printing is completed, the first and second heads are moved to the home position apart from the printing area, and then the paper discharge operation is performed.

It is desirable that the first and second recording heads perform a preliminary ejection operation and a recovery operation that are not related to printing, if necessary. In this case, a recovery device or a recovery unit portion provided at a home position (not shown) is used.

The ink ejected from the recording head of the present invention is not specified, but it is preferable to use one that has a property of being fixed and absorbed on the recording medium in a short time immediately after printing. Specifically, when considering plain paper as a target, the ink has a low surface tension as a physical property, and a physical property value in the vicinity of about 30 dyne / cm is good. In the ink of this embodiment, it is generally desirable to use a surfactant or the like as a substance for lowering the surface tension, and about 1% of acetylenol is used.
The added one was used.

By lowering the surface tension, the wettability to paper can be improved and the wettability to paper can be penetrated in a short time, and as a result, the fixability is improved. Even if an ink having a high surface tension is used, there is no particular problem as long as the ink absorption of the recording medium is high in combination with the recording medium. The ink viscosity is 2 CP (centipoise).
A material having a characteristic of ˜3 CP is preferable, and 2 CP is also used in the present application.

FIG. 6 is a side view showing the positional relationship with the cap unit which is the recovery device. 6a
Is a cap unit having an opening for receiving regular preliminary ejection during printing. Preliminary ejection is not limited to the cap, and may be provided adjacent to the cap unit and may be an opening.

While printing with the recording head 1a,
As a means for preventing drying of unused nozzles, well-known preliminary ejection is performed in inkjet. Preliminary ejection has a great influence on the nozzle configuration of the recording head and the physical properties of the ink, and differs depending on the recording apparatus system. In this embodiment, a means for detecting the head temperature and the environmental temperature during printing is provided, and the preliminary ejection during printing is set at a predetermined time according to the information.

As an example, in the environment of 20 ° C., it is carried out about every 10 seconds, and when the environment temperature is lower than room temperature, a short setting is good and the preliminary discharge is executed every 5 seconds. The setting of the time may be changed according to the nozzle diameter and the physical properties of the ink as in the previous period.

During recording, the recording head 1a carries out preliminary ejection unrelated to printing to the opening portion (in the cap in this example) of the cap unit 6a at regular intervals. Ink accumulated in the cap is calculated according to the volume in the cap and empty suction is performed. The size of the flying ink drop,
It is calculated according to the number of shots and the physical properties of the ink.

Next, when the recording head is ejecting ink for the printing operation, unnecessary bubble accumulation in the head and ink wetting on the head face surface occur, which deteriorates the printing quality. ing. Therefore, a recovery operation involving suction is set after the predetermined print quantity is performed.

The cap unit and the recording head shown in FIG. 6 can be joined to the cap units on both sides of the recording heads 1a and 1b substantially at the same time. The cap unit can be moved back and forth via a driving means (not shown). The recovery operation can be individually performed and is executed when necessary. The recovery means includes a suction pump and a wiper means (not shown) for removing ink on the head face surface.

The recovery means are installed at both ends of the main body and are connected to negative pressure generating means (not shown). However, in some cases, two capping units are connected to one negative pressure means, and The recovery operation may be performed simultaneously, or the left and right may be separately controlled by means such as a switching valve.

The cap unit 6a is capable of capping the head while rotating, and when the cap unit 6a is in close contact with the head, the cap unit 6a is placed substantially parallel to the face surface of the head. The advantage of the rotary cap unit is that it reduces the ink drop when the cap is opened after the ink is sucked from the head. When the cap is opened, the ink held in the cap flows downward because the ink is released from the top.

Thus, the cap structure in which the ink flow is taken into consideration is still preferable.

(Second Embodiment) FIG. 7 shows a second embodiment. Two recording heads are mounted on one side. One is a recording head 71a for black ink, and the other is a recording head 71c for color ink. Respective cap units 76a and 76c are prepared for the recording head.

The reason why the recording heads are separated is that black ink and color ink have reactive physical properties.
A system using a reaction between anions and cations or a divalent metal ionic ink is adopted to improve the bleeding of the ink on the recording medium, particularly the bleeding at the boundary between black and color inks. With such an ink system, a color image can be printed with high quality.

The cap units 76a and 76c include a negative pressure generating means for performing a suction operation (not shown) and the suction tube 7.
It is connected via 7a and 77b. In this embodiment, a tube pump, which is one negative pressure generating means, is used to
The ink suction operation from the individual caps is such that the black head and the color head can be sucked simultaneously.

Further, the cap units 77a, 77
b is also capable of individual suction operation, and there is a mechanism for crushing valves and tubes in the paths of the suction tubes 77a and 77b, so that individual suction operation can be selectively executed. Therefore, it is not necessary to waste ink consumption.

Regarding the joining of the cap units 76a, 76b and the recording heads 71a, 71c, it is desirable to devise such that the ink does not drop from the caps after the recovery operation is executed as described in FIG. Further, when they are joined in a horizontal state, it is possible to avoid ink dripping by means of opening the cap while performing minute suction.

The carriage station 72a, on which the recording heads 71a and 71c are mounted, is detachable. When the carriage station moves to the home position while moving via the drive belt 74, the attachment / detachment mechanism 80 and the guide portion 81 can be fitted with the fitting portions 82 and 83 of the head holding unit at the home position to open the recording head. Has become. The fitting portion 82 can be moved up and down by an electromagnetic valve mechanism such as a plunger or a mechanical structure so that the recording heads 71a and 71c can be held simultaneously.

The capping operation is performed by the cap units 76a and 76c facing the recording heads 71a and 71c.
When performing the suction recovery operation, it is possible to perform the suction recovery operation regardless of the electrical connection with the carriage station as described above.

(Third Embodiment) FIG. 8 is a schematic view of a third embodiment of the present invention, which is a modification of the capping means of the recording head and is seen from above the recording apparatus. In order to prevent the nozzles from drying during printing, the recording head 1a is provided with an opening (not shown) in which preliminary ejection is lined up in the cap unit of the main body.
To do. When performing capping, the recording head 1a
Is configured to fit with the cap unit 87 while moving in the main running direction.

The cap unit 86 is a guide rail 88.
It is possible to move back and forth toward the recording head along.

The capping unit is connected to a suction means (not shown) and a suction tube 87. The waste ink sucked from the recording head flows from the cap unit 86 through the suction tube 87 to the pump means.

FIG. 9 is a view showing a state in which the recording head 1a is joined to the cap unit 86. Since the cap unit 86 is pulled by the spring member 89, the cap unit 86 can move back and forth between the guide portions 88. The spring force applied to the cap unit uses a compression spring and may be installed on the side surface of the cap unit and is not specified.

In order to fix the recording head 1a with the cap unit 86, the recording head can be released from the carriage station by the fixing means shown in the first and second embodiments.

As described above, when the recording head is not involved in printing, it is not necessary to reduce the motor load during driving and to prevent the drying of unused nozzles during printing by fitting and holding the cap unit. Therefore, it suffices to periodically execute the recovery process for only the recording head related to printing.

[0075]

As described below, the object of the present invention is to use in a recording apparatus which is capable of simultaneously printing two recording heads with an endless belt using one driving source, and is not used when double-sided printing is not actually performed. Since the recording head can be held by the cap unit, it is possible to reduce the motor load during printing and to eliminate unnecessary maintenance of the unused recording head, thereby preventing wasteful ink consumption and reduction in printing throughput.

[Brief description of drawings]

FIG. 1 is a conceptual perspective view of a double-sided printing mechanism of a first embodiment used in the present invention.

FIG. 2 is a perspective view of a first example of a recording head.

FIG. 3 is a perspective view of a second example of a recording head.

FIG. 4 is a conceptual diagram illustrating a holding mechanism of the recording head according to the first embodiment.

FIG. 5 is a schematic view of the first embodiment taken along the line A-A as seen from the lateral direction.

FIG. 6 is a diagram showing a capping unit of a recording head.

FIG. 7 is a schematic diagram of a double-sided printing device according to a second embodiment.

FIG. 8 is a conceptual diagram seen from above for explaining the means for capping the recording head in the third embodiment.

FIG. 9 is a conceptual diagram showing a state in which a recording head is capped in the third embodiment.

[Explanation of symbols]

1a, 1b Recording heads 2a, 2b Carriage stations 3a, 3b Shaft 4 Endless drive belts 6a, 6b Cap unit 7 Nozzles 7Y to 7BK Y (yellow) nozzles to BK (black) nozzles 8 Recording medium (paper, film, etc.) 9Y 9 BK Y (yellow) ink tank to BK (black) ink tank 10 Recording head attachment / detachment mechanism section 11 Guide section 12 Attachment / detachment mechanism section engagement section 13 Guy section engagement section 20 Electrical connection pads 41a, 41b Media guide section 42a, 42b Pinch rollers 43a, 43b Spurs A 44a, 44b Spurs B 71a BK recording head 71c Color recording head 74 Drive belt 76a BK cap unit 76c Color cap unit 77a BK suction tube 77c Color suction tube 80 Rail 89 spring member for moving the fitment portion 86 cap unit 87 suction tube 88 Cap unit fitting portion 83 guide portion of the detachment mechanism section 81 guide portion 82 detaching mechanism portion of the head

Claims (8)

[Claims] 1. One or a plurality of recording heads are arranged so as to face each other on both sides of a recording medium so that printing can be performed substantially at the same time, and the plurality of recording heads are driven by one drive belt in the main scanning direction. In the recording apparatus capable of performing printing while reciprocating, the recording head has a structure in which a carriage station portion installed on a drive belt is detachable. 2. A plurality of recording heads according to claim 1, wherein when a plurality of recording heads are joined to the cap unit, they move in a main scanning direction to be released from a carriage station on a drive belt and come into close contact with the cap unit. Recording device. 3. The recording apparatus according to claim 1 or 2, wherein the capped recording head is electrically disconnected from the recording main body. 4. A recording head according to claim 1, wherein one recording head sandwiching the recording medium is a color head, the other recording head is a monochrome head, and each recording head includes an ink tank means. Recording device. 5. The method according to any one of claims 1 to 4,
A recovery device, wherein a recovery operation is performed in a state where an electric connection is cut off in a capping state of a recording head. 6. The method according to any one of claims 1 to 5,
A recovery device, which is electrically connected when a recording head is joined to a carriage station and performs a recovery operation using the ejection of ink droplets from a nozzle. 7. One or a plurality of recording heads are arranged so as to face each other on both sides of the recording medium so as to be able to print at substantially the same time, and the plurality of recording heads are driven by one drive belt in the main scanning direction. In a recording device that can print while reciprocating, the recording head can be attached to and detached from the carriage station installed on the drive belt, and the recording head can be attached and detached by controlling the main scanning direction of the carriage station. And recording device. 8. The recording head attaching / detaching means according to claim 7, wherein the recording head is opened when the carriage operation is pushed up to the cap unit by an odd number of times, and is joined when the cap unit is pushed by an even number of operations. Characterized recording device.