JPH11291511A - Ink-jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet printer which is made compact and low-cost and realizes good print quality. SOLUTION: A maintenance member is arranged to face a discharge part of a line head 30 via a platen 22. At the time of maintenance, the maintenance member is taken out of an opening part 23 formed at the platen 22 to conduct various operations. The platen 22 is moved to retreat from a part where the maintenance member is taken out and therefore can move without interfering with the maintenance member.

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 type printer which discharges ink toward printing paper, and more particularly to an ink jet printer which can be suitably used for a line printer.

[0002]

2. Description of the Related Art In recent years, an ink jet printer using an ink ejection device has a tendency toward high resolution and high speed, and a line printer capable of realizing high resolution and high speed has attracted attention.

FIG. 8 is a schematic view of a line head of a conventional ink jet printer. FIG. 8A is a top view and FIG. 8B is a side sectional view.

In FIG. 8, an ink tank 3 is connected via an ink tube 2 to a line head 1 provided with ink discharging means. An ink flow path 4 communicating with the ink tube 2 is provided inside the line head 1, and a selection electrode 5 is arranged along the ink flow path 4.
A platen 6 made of a conductive metal is disposed at a position facing the line head 1, and the recording paper 7 passes while contacting the peripheral surface of the platen 6. The ink droplets 8 ejected from the printer adhere to the recording paper 7 and are printed. The platen 6 is electrically grounded and serves also as a counter electrode for the line head 1.

In such an ink jet printer,
Ink is supplied from an ink tank 3 through an ink tube 2 to an ink flow path 4 in the line head 1. And
A voltage of about 2 kV is applied to the selection electrode 5 from the voltage application device 9 corresponding to the recording signal, and forms an electric field between the selection electrode 5 and the platen 6. On the other hand, since the electric charge is injected into the ink near the selection electrode 5, the ink receives Coulomb force from the platen 6 to form an ink droplet 8 and lands on the recording paper 7 for printing.

When printing of one line of the recording paper 7 is completed, the platen is moved by a pitch corresponding to the resolution to feed a new line, and printing of the next line is performed. By repeating line feed and printing in this manner, characters and graphics are created on the recording paper 7.

FIG. 9 is a side sectional view showing the line head 1 during a maintenance operation. In FIG. 9, a cap 10 that covers the line head 1 is disposed above the line head 1, and a tube 11 that sends waste ink to a waste ink tank (not shown).
Are connected to the cap 10. A pump (not shown) for sucking waste ink from the line head 1 is incorporated in the flow path from the cap 10 to the tubing 11.

At the time of maintenance of the line head 1, as shown in FIG. 1A, the line head 1 is counterclockwise moved to a position facing the cap 10 by a rotary drive mechanism (not shown) connected thereto. Rotate in the direction. Next, the cap 1 including the purge mechanism for sucking ink moves to the front of the line head 1 as shown in FIG.
The dust and paper dust adhering to the line head 1 together with the ink and the air bubbles inside the ink are suctioned to eliminate the cause of clogging.

During the non-printing period after the maintenance is completed, the ejection surface of the line head 1 is capped and closed by the cap 10 in order to prevent clogging due to evaporation of the ink and entry of dust and dirt from the outside.
Then, when there is a print timing command, the line head 1 returns to the posture shown in FIG. 8A and is ready to perform a printing operation.

[0010]

However, in the conventional structure, since the maintenance space for the line head 1 is provided at a place different from the printing section, the size of the apparatus tends to increase. Further, since the position and posture of the line head are moved for maintenance, for example, the gap between the platen and the line head becomes non-uniform, and the print quality is degraded. Furthermore, since the mechanism is such that the line head can be moved for maintenance, the structure becomes complicated and there is a problem in terms of cost.

An object of the present invention is to provide an ink jet printer which can be reduced in size and cost and realizes good printing quality.

[0012]

According to an ink jet printer of the present invention, a line head in which a plurality of ejection portions are arranged substantially horizontally in a line direction of a recording paper to be printed, and a surface opposite to a printing surface of the recording paper is provided. A hollow cylindrical platen that can be driven in contact with and is rotatable, a maintenance member for various maintenance including capping of the discharge unit incorporated with the inside of the platen as a standby position, and opened on the peripheral wall of the platen. An opening having a size that allows the maintenance member to be led out to the line head side; and a drive unit that movably extends the maintenance member in and out of the opening.

A line head in which a plurality of discharge portions are arranged substantially horizontally in a line direction of the recording paper to be printed; a plate-shaped platen in which the surface on the same side as the printing surface of the recording paper contacts and supports; A maintenance member for various maintenance including capping of the ejection unit, which is disposed facing a surface of the platen opposite to the support surface of the recording paper, and the maintenance member can be led to the platen to the line head side. And a driving unit for moving the maintenance member movably in and out of the opening from the opening.

Further, the platen may be configured so that the maintenance member can be set to a retracted position or a retracted position in which the maintenance member can be led out to the line head side.

[0015]

According to the first aspect of the present invention, there is provided a line head in which a plurality of ejection portions are arranged substantially horizontally in a line direction of a recording paper to be printed, and a surface opposite to a printing surface of the recording paper is provided. A hollow cylindrical platen that can be driven in contact with and is rotatable, a maintenance member for various maintenance including capping of the discharge unit incorporated with the inside of the platen as a standby position, and opened on the peripheral wall of the platen. The maintenance member comprises an opening having a size capable of being led out to the line head side, and driving means for moving the maintenance member movably in and out of the opening, and the maintenance member is placed in the platen. Since it is housed, it has the effect that the device capacity occupied by the maintenance member can be reduced.

According to a second aspect of the present invention, there is provided a detection system for detecting that the platen has rotated to a rotation position where the opening faces the line head, and the maintenance means is provided by the driving means based on a signal of the detection system. 2. The ink jet printer according to claim 1, further comprising a drive system for feeding a member out of the opening, and has an effect that the maintenance member can be driven in conjunction with the rotation of the platen.

According to a third aspect of the present invention, there is provided a line head in which a plurality of ejection portions are arranged substantially horizontally in a line direction of a recording paper to be printed, and a surface on the same side as a printing surface of the recording paper is in contact with and supported. A plate-shaped platen, a maintenance member for various maintenance including capping of the ejection unit disposed facing a surface of the platen opposite to a support surface of the recording paper, and the maintenance member on the platen. An opening of a size that can be led out to the line head side, and a driving unit that movably extends the maintenance member from the opening to the inside and outside, and the maintenance member is located at a position sandwiching a flat platen. Since it is located, the device capacity occupied by the maintenance member can be reduced.

The invention according to claim 4 is the ink jet printer according to claim 3, wherein the platen is provided with a shutter for opening and closing the opening along a surface opposite to a support surface of the recording paper. Since the recording paper is backed by the shutter, there is an effect that good printing can be obtained.

According to a fifth aspect of the present invention, the discharge unit includes a selection electrode for recording a print signal, and applies an electric field between the selection electrode and a counter electrode disposed in front of the selection electrode to apply an electrostatic force to the ink. The ink jet printer according to claim 4, wherein the ejection force can be urged by causing the shutter to be disposed as the counter electrode, and the shutter can be used as the counter electrode during a printing period, so that the ink can be reliably discharged. It has the effect that good printing can be obtained.

According to a sixth aspect of the present invention, there is provided a line head in which a plurality of ejection portions are arranged substantially horizontally in a line direction of a recording paper to be printed, and a surface on the same side as a printing surface of the recording paper is in contact with and supported. A flat platen to be provided, and a maintenance member for various maintenance including capping of the ejection unit disposed facing the surface of the platen opposite to the support surface of the recording paper, and the platen includes: The maintenance member can be set to a retracted position or a retracted position that can be led out to the line head side, and the space required to change the position and the position of the platen itself is sufficient, so that the device capacity can be reduced.

According to a seventh aspect of the present invention, the platen is movable between a printing position facing an ink ejection area from the ejection portion and a retracted position which does not interfere with the movement of the maintenance member. Item 6 is an ink jet printer, which has an effect that the capacity of the device is sufficient to secure a space for the flat platen to move.

According to the present invention, the whole or a part of the platen can be turned from a position facing the ink discharge region from the discharge portion to a tilt position not interfering with the movement of the maintenance member. 7. An ink jet printer according to claim 6, wherein the simple device for changing the position of the platen has an effect that the capacity of the apparatus can be reduced.

According to a ninth aspect of the present invention, the discharge section is
A selection electrode for recording a print signal is provided, and an ejection force can be urged by applying an electric field between the counter electrode disposed in front of the selection electrode and applying an electrostatic force to the ink,
9. The ink jet printer according to claim 6, wherein the platen is disposed as the counter electrode, and a platen can be used as the counter electrode during a printing period, so that reliable ejection of ink and good printing can be obtained. Has the effect of being

Hereinafter, embodiments of the present invention will be described. FIGS. 1A and 1B are schematic side views showing a main part of a line head and a maintenance peripheral portion thereof according to an embodiment of the present invention, wherein FIG. 1A shows a printing operation, and FIG. (C) of FIG. 6 shows the end of maintenance.

In FIG. 1, a line head 30 functioning according to a conventionally well-known ejection principle such as an electrostatic system, an electric-to-heat conversion means, or a piezo is provided with an ink for supplying ink in the same configuration as the conventional example of FIG. A tube 2 and an ink tank 3 for storing ink are arranged, and ink droplets discharged from the ink flow path 4 of the line head 30 can be printed on the recording paper 7 on the platen 12.

The platen 12 is provided with an opening 13 for a maintenance unit to enter and exit from the inside and outside, and a detection hole 14 for detecting a rotational position. A photo interrupter for detecting the cutout 14 is provided inside and outside. 15 are provided.
Further, a detection circuit 16 for receiving a detection signal from the photo interrupter 15 is provided.

Inside the platen 12, the line head 3
A blade 17 made of an elastic member such as rubber for cleaning the ejection surface of the line 0, a cap 18 covering the line head 30,
Waste ink tube 19 for sending waste ink to waste ink tank
Are provided. These blade 17, cap 1
8 and the waste ink tube 19 are the platen 12
All are reciprocally movable in the left-right direction by a moving mechanism (not shown) accommodated in the inside. The waste ink tube 19 is connected to a pump (not shown) for sending waste ink to a waste ink tank.

In the printing period, as shown in FIG.
It is housed inside. During the maintenance operation, when the photo interrupter 15 detects the detection hole 14, the detection circuit 16 instructs the printer control unit (not shown) to stop the rotation of the platen 12, as shown in FIG. I do. When the platen 12 stops, the opening 1
3 is set at a position facing the front of the line head 30.

After the above setting of the position, the blade 17
Moves to a position where it contacts the front surface of the line head 30 by the blade moving mechanism, and further moves the blade 17 downward by the blade moving mechanism. Such operation of the blade 17 removes ink, dust, paper dust, and the like adhering to the ejection portion of the line head 30, and then returns the blade 17 to its original position as shown in FIG.

Next, the cap 18 and the waste ink tube 19 move to the capping position of the line head 30, and the cap 18 closes around the ink discharge port of the line head 30. Thereafter, the suction operation of the waste ink from the line head 30 is started by a purge pump (not shown), and the dirt, paper dust, and air bubbles inside the ink, which adhere to the surface of the line head 30 together with the ink, are suctioned. Eliminate clogging factors.

After the maintenance is completed, during the non-printing period, the cap 18 is held at the position where the discharge port portion of the line head 30 is closed in order to protect the clogging due to the evaporation of the ink and the entry of dust and dust from the outside. You. Then, during the printing period, the cap 18 is retracted into the platen 12 as shown in FIG.

FIG. 2 is a schematic vertical sectional view of a main part showing a second embodiment of the present invention. In addition, about the same member as the example of FIG. 1, it designates with a common code | symbol and the detailed description is abbreviate | omitted.

A platen 22 having a flat plate shape is arranged so as to follow the paper feeding direction of the recording paper 7 fed by the paper feed roller 20 and the idler 21, and an opening 23 for maintenance is opened in the platen 22. It is. At the lower end of the platen 22, a paper pressing plate 24 for applying a pressing force to the recording paper 7 is disposed.

When printing of one line of the recording paper 7 is completed,
The paper feed roller 20 is fed by a pitch corresponding to the resolution by the paper feed driving means (not shown), and prints the next line. On the other hand, as shown in FIG. 2A, the maintenance unit is housed on the opposite side of the line head 30 across the platen 22 during printing. At the time of maintenance, the blade 17 is moved to a position where it comes into contact with the line head 30 by a blade moving mechanism (not shown), and then moved downward by the blade moving mechanism. After cleaning the surface, return to the original position. Note that the blade mechanism may have any configuration as long as the blade 17 can be moved to a position in contact with the front surface of the line head 30 and further moved from above the ink ejection portion of the line head 30 to below.

Next, the cap 18 and the waste ink tube 19 move to the capping position of the line head 30 to suck the waste ink, and the capping state is maintained during the non-printing period as in the example of FIG. It retracts to the position shown in FIG.

In the second embodiment described above, since the position of the opening 23 of the platen 22 is fixed, the position detecting means for detecting the position of the opening 23 becomes unnecessary. The number of parts can be reduced.

FIG. 3 is a schematic longitudinal sectional view of a main part showing a third embodiment of the present invention. In this example, a shutter 25 is added to the configuration of FIG. 2, and other members are indicated by common reference numerals.

As shown in the figure, the shutter 25 is driven by a drive mechanism (not shown) from the position (a) in the figure along the surface of the plate-shaped platen 22 facing the waiting maintenance member. Is arranged so as to be able to reciprocate to the position. The shutter 25 has a size that covers the entire opening 23 of the platen 22 and closes when the shutter 25 is at the position shown in FIG.

The shutter 25 is at a position where the opening 23 is closed during the printing period as shown in FIG. 3A, and moves downward as shown in FIG. 3B during the non-printing period and the maintenance operation period. The opening 23 is opened, and the cleaning of the discharge port portion of the line head 30 and the suction and discharge of waste ink are performed by the operation of each member similar to the example of FIG.

Since the shutter 25 closes the opening 23 during the printing period, the amount of bending of the recording paper 7 near the opening 23 can be suppressed. That is, if the platen 22 is slightly thicker than the recording paper 7, the shutter 25 will back the recording paper 7, so that even if there is the opening 23, the bending of the recording paper 7 can be suppressed. it can. Therefore, it is possible to prevent the print quality from deteriorating due to the bending of the recording paper 7.

FIG. 4 is a longitudinal sectional view schematically showing the periphery of a line head and a maintenance section according to a fourth embodiment of the present invention.

In this example, the shutter 26 in the configuration shown in FIG. 3 is made of a metal having good conductivity and is electrically grounded, and a counter electrode with respect to the selection electrode 5 provided in the ink flow path 4 of the line head 30. It is intended to also serve as.

A plurality of selection electrodes 5 are arranged under the ink flow path 4 at a width substantially equal to that of the printing paper in accordance with the resolution, and are connected to the voltage application device 9. Then, according to a print record signal from the controller, the voltage application device 9
To about 2 kV is applied to the selection electrode 5, thereby forming an electric field with the shutter 26 which is grounded.

The operation of the shutter 26 and the function of each maintenance member are exactly the same as those shown in the example of FIG.
Since the shutter 26 stops at the position where the opening 23 of the platen 22 is closed during the printing period, the selection electrode 5 can be arranged in front of the field electrode. Therefore, the electric field strength can be increased, and the reliable ejection of the ink droplets 8 and clearer printing on the recording paper 7 can be performed. This is particularly effective when performing electrostatic printing.

The fact that the opening 23 is closed by the shutter 26 during the printing period to prevent the recording paper 7 from being bent is the same as in the example of FIG.

FIG. 5 is a schematic longitudinal sectional view showing a main part of a line head and a maintenance unit at the time of printing according to a fifth embodiment of the present invention. In this example, the same members as those described above are designated by the same reference numerals.

The schematic configuration is the same as that of the example shown in FIG. 2, except that the platen 27 along the paper feeding surface of the recording paper 7 does not have an opening. As shown in b), the platen 27 descends to a position where almost the entire front surface of the line head 30 faces the maintenance member.

As described above, by increasing the stroke of the platen 27, the blade 17 and the like can be exposed to the line head 30 without interference, so that a maintenance operation can be performed. Then, during the printing period, the entire platen 27 lines the recording paper 7, so that good printing is maintained without occurrence of bending.

FIG. 6 is a schematic vertical sectional view showing a main part around a line head and a maintenance unit at the time of printing according to a sixth embodiment of the present invention. This example is a combination of the configurations shown in FIGS. 4 and 5, and the same members are indicated by common reference numerals.

In this configuration, during the printing period, FIG.
Since the platen 28 which is installed on the ground and constitutes the counter electrode with respect to the selection electrode 5 is located in front of the line head 30, the electric field strength is increased and the reliable ejection and printing of the ink droplets 8 are possible. . In addition, since the entire platen 28 lines the recording paper 7, bending deformation of the recording paper 7 is suppressed, and excellent printing is maintained.

At the time of maintenance, FIG.
As shown in FIG. 5, the entire platen 28 can be moved downward to enable cleaning with the blade 17 and the like, as in the example of FIG.

FIG. 7 is a schematic longitudinal sectional view showing a main part of a peripheral portion of a line head and a maintenance section at the time of printing according to a seventh embodiment of the present invention.

This example is substantially the same as, for example, the one provided with the platen 23 in FIG. 5, except that the platen 29 is not movable.

The platen 29 is divided into upper and lower members and connected by a hinge mechanism.
As shown in FIG. 3, the lower member is connected to a drive mechanism (not shown) so as to rotate the lower member away from the line head 30.

With such a platen 29, the recording paper 7 is set in a posture to back the recording paper 7 during the printing period as shown in FIG.
At the maintenance time, the blade 17 is opened by opening a part of the platen 29 as shown in FIG.
And the like can be moved to the line head 30 side.

[0056]

According to the present invention, various members for maintenance such as capping and wiping of a line head for performing stable ejection of ink are arranged at a position facing the line head and on the back surface or inside of the platen. Therefore, the capacity of the device around the line head can be reduced, and the size and cost of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a main portion of a line head and a maintenance peripheral portion thereof.

FIG. 2 is a schematic longitudinal sectional view of a main part showing a second embodiment of the present invention.

FIG. 3 is a schematic longitudinal sectional view of a main part showing a third embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view schematically showing a periphery of a line head and a maintenance unit according to a fourth embodiment of the present invention.

FIG. 5 is a schematic longitudinal sectional view showing a main part of a line head and a maintenance unit at the time of printing according to a fifth embodiment of the present invention.

FIG. 6 is a schematic longitudinal sectional view showing a main part around a line head and a maintenance unit at the time of printing according to a sixth embodiment of the present invention.

FIG. 7 is a schematic longitudinal sectional view showing a main part around a line head and a maintenance unit at the time of printing according to a seventh embodiment of the present invention.

FIG. 8 is a schematic view of a line head of a conventional inkjet printer, in which (a) is a top view and (b) is a side sectional view.

FIG. 9 is a side sectional view showing a maintenance operation of the line head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Line head 2 Ink tube 3 Ink tank 4 Ink channel 5 Selection electrode 6 Platen 7 Recording paper 8 Ink drop 9 Voltage application device 10 Cap 11 Waste ink tube 12 Platen 13 Opening 14 Detection hole 15 Photointerrupter 16 Detection circuit 17 Blade 18 Cap 19 Waste Ink Tube 20 Paper Feed Roller 21 Idler 22 Platen 23 Opening 24 Paper Holder 25 Shutter 26 Shutter 27 Platen 28 Platen 29 Platen 30 Line Head

Claims (9)

[Claims] 1. A rotatable and rotatable hollow cylinder in which a line head having a plurality of ejection portions arranged substantially horizontally in a line direction of a recording paper to be printed and a surface opposite to a printing surface of the recording paper contacting and supporting the line head. -Shaped platen, a maintenance member incorporated inside the platen as a standby position for various maintenance including capping of the discharge unit, and a maintenance member opened on the peripheral wall of the platen and led out to the line head side An ink jet printer comprising: an opening having a size as large as possible; and driving means for moving the maintenance member movably in and out of the opening. A detection system for detecting that the platen has rotated to a rotation position where the opening faces the line head, and the maintenance member is moved by the driving means in accordance with a signal of the detection system. 2. An ink jet printer according to claim 1, further comprising a drive system for feeding out of the printer. 3. A line head in which a plurality of ejection portions are arranged substantially horizontally in a line direction of a recording paper to be printed, a plate-shaped platen which is in contact with and supports a surface on the same side as a printing surface of the recording paper; A maintenance member for various maintenance including capping of the ejection unit, which is disposed facing a surface of the platen opposite to the support surface of the recording paper, and the maintenance member can be led to the platen to the line head side. An ink jet printer comprising: an opening having an appropriate size; and driving means for moving the maintenance member movably in and out of the opening. 4. An ink jet printer according to claim 3, wherein said platen includes a shutter for opening and closing said opening along a surface opposite to a support surface of said recording paper. 5. The discharge unit includes a selection electrode for recording a print signal, and applies an electric field between the selection electrode and a counter electrode disposed in front of the selection electrode to cause an electrostatic force to act on the ink to discharge the ink. 5. The ink jet printer according to claim 3, wherein the shutter is arranged as the counter electrode. 6. A line head in which a plurality of ejection portions are arranged substantially horizontally in a line direction of a recording paper to be printed, a plate-shaped platen which is in contact with and supports a surface on the same side as a printing surface of the recording paper; A maintenance member arranged for facing the surface of the platen opposite to the support surface of the recording paper for various maintenance including capping of the ejection unit, wherein the platen includes the maintenance member on the line head side. An ink jet printer characterized in that it can be set to a retreat position or a retreat posture which can be derived to a user. 7. The apparatus according to claim 6, wherein said platen is movable between a printing position facing an ink discharge area from said discharge section and a retracted position which does not interfere with the movement of said maintenance member. Inkjet printer. 8. The apparatus according to claim 1, wherein the whole or a part of the platen is rotatable from a position facing the ink discharge region from the discharge portion to a tilt position not interfering with the movement of the maintenance member. Item 7. An inkjet printer according to Item 6. 9. The discharge unit includes a selection electrode for recording a print signal, and applies an electric field between the selection electrode and a counter electrode disposed in front of the selection electrode to cause an electrostatic force to act on the ink, thereby causing a discharge force. And the platen is arranged as the counter electrode.
The inkjet printer according to any one of the above.