JPH0929986A - Method and apparatus for cleaning and head of ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for cleaning the head of an ink jet printer capable of preventing a medium to be printed from being stained by ink, miniaturizing the apparatus, and the like. SOLUTION: When the moving direction of a printing head 4 is in the direction of ink adhered to a wiper blade 10 being splashed to a medium 9 to be printed at the time of the wiper blade 10 moving apart from the nozzle surface 4a after the completion of wiping off of the nozzle surface 4a, a mechanism is provided controlling the wiper blade 10 not to wipe off the nozzle surface 4a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head cleaning device and method for wiping ink adhered to a nozzle surface of a print head of an ink jet printer with a wiper blade.

[0002]

2. Description of the Related Art FIG. 8 shows a main structure of a conventional ink jet printer. In FIG. 8, reference numeral 51 is a frame of the printer main body, 52 is a carriage shaft having both ends fixed to the frame 51,
The carriage shaft 52 is provided in a state of being laid on the left and right. Reference numeral 53 denotes a carriage which is guided by the carriage shaft 52 to reciprocate left and right, and a print head 54 is integrally movably attached to the carriage 53. A nozzle surface 54a for ejecting ink is arranged on the lower surface of the print head 54. 5
5 is a spacing belt, and this spacing belt 5
The reference numeral 5 is laid over a pair of pulleys 56 and arranged in parallel with the carriage shaft 52, and a part of the reference numeral 5 is connected to the carriage 53. 57 is the pulley 5 on one side
6 is a spacing motor for driving 6 such as a stepping motor. Then, when the spacing motor 57 is driven, the pulley 56 on one side rotates in a direction corresponding to this rotation direction, the spacing belt 55 is driven via this pulley 56, and the spacing belt 55 The carriage 53 and the print head 54 are integrally guided by the carriage shaft 52 and moved in the left-right direction. Reference numeral 58 is a feed roller for carrying the print medium 59. A wiper blade 60 is provided below the movable area in which the print head 54 reciprocates, and at a position outside the transport path of the print medium 59.

Next, the operation of the ink jet printer thus constructed will be described. The print-receiving medium 59 is
The sheet is fed by the feed roller 58 and set at a predetermined position. On the other hand, when the carriage 53 is moved in the left and right directions by the rotation of the spacing motor 57, the print head 54, which prints on the print medium 59, does not move over the print medium 59 together with the carriage 53. It moves in a contact state, and at this time, the print medium 59 is ejected from a nozzle (not shown).
Ink is ejected toward the printing surface of the to print.

In this structure, since a part of the ink ejected during printing adheres to the nozzle surface, the amount of ink adhering to the nozzle surface 54a increases as the printing continues, and the ink becomes normal. , Which hinders effective jetting and prevents printing. So, with this kind of inkjet printer,
In the middle of printing, according to the operator's instructions, or periodically,
Alternatively, when the power is turned on, the print head 54 is passed over the wiper blade 60 once or a plurality of times, and at this time, the wiper blade 60 is brought into contact with the nozzle surface 54a and rubbed to wipe the ink adhering to the nozzle surface 54a. And doing cleaning. Further, the wiper blade 60 here has a blade-like wiping tip and is made of an elastic material. Then, when wiping the nozzle surface 54a, the wiper blade 60 moves the tip of the nozzle surface 54a.
It is pressed against a and is in a distorted state, and the nozzle surface 5
When 4a has completely passed over the wiper blade 60, the wiper blade 60 returns to its original shape by elasticity, and at that time, the ink adhering to the wiper blade 60 itself is repelled and removed. . As a result, the ink wiped from the nozzle surface 54a during cleaning remains attached to the wiper blade 60, and when the nozzle surface 54a is wiped again, the ink on the wiper blade 60 reversely adheres to the nozzle surface 54a. In order to prevent the ink wiping efficiency from decreasing, the ink remaining on the wiper blade 60 is reduced to prevent the ink wiping efficiency from decreasing. Then, in the cleaning operation in this inkjet printer, when the nozzle surface 54a first passes over the wiper blade 60 after the printing operation, it is from the direction in which the print medium 59 is present.

[0005]

In the cleaning operation of the above-described conventional inkjet printer,
After the printing operation, when the nozzle surface 54a first passes over the wiper blade 60, it is from the direction in which the print medium 59 is present. Even when the cleaning operation is started, since the ink is most adhered to the nozzle surface immediately after printing, a large amount of ink is wiped and ejected by the wiper blade 60, and the ink ejection direction is also covered. It is the direction in which the print medium is located. Therefore, when there is a large amount of ink adhering to the nozzle surface, such as after performing high-density printing such as graphics or high-quality printing, a large amount of ink is scattered up to the printing medium 59, and the printing medium is There was a problem that it would stain 59.

Therefore, in order to avoid the above problems, the following methods (1) to (4) can be considered, but each of them has the following problems. (1) A wiper blade whose elasticity is weakened is used. When this avoidance method is used, the amount of ink that scatters can be reduced by weakening the elasticity, but the ink wiping effect will be reduced. (2) Reduce the carriage speed when wiping with the wiper blade 60. When this avoidance method is used, the behavior of the wiper blade 60 becomes gradual and the amount of ink that scatters decreases, but the wiping effect of ink also deteriorates. Further, the time required to clean the nozzle surface 54a increases as the carriage speed decreases, and throughput decreases when the cleaning frequency is high. (3) Increase the distance between the wiper blade 60 and the print medium 59. When this avoidance method is used, the lateral width of the device increases as the distance between the wiper blade 60 and the print medium 59 increases, and it is difficult to realize a downsized device. (4) Instead of the wiper blade, a material such as felt that absorbs ink is used to wipe the nozzle surface 54a. When this avoidance method is used, when wiping, the ink in the nozzle is absorbed in addition to the ink attached to the nozzle surface 54a, and waste ink is consumed each time wiping is performed. While repeating, the large amount of ink is absorbed in the felt, the ink absorption rate deteriorates, and the wiping effect decreases. There is also a method of regularly replacing the felt, but the replacement of the felt increases the cost and requires maintenance.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent a stain on a print medium due to ink and to reduce the size of the apparatus. To provide.

[0008]

In order to achieve the above object, in a head cleaning device for an ink jet printer according to the present invention, it is detected which direction the print head moves relative to a print medium. In the case where the moving direction is a direction in which the ink attached to the wiper blade is repelled to the print medium when the wiper blade is separated from the nozzle surface of the print head after the wiping of the nozzle surface is finished, The wiper blade is provided with a means for controlling so as not to wipe the nozzle surface.

In order to achieve the above object, in the ink jet head cleaning method according to the present invention, it is detected which direction the print head is moving with respect to the print medium, and the moving direction is detected. When the wiper blade after the wiping of the nozzle surface is separated from the nozzle surface of the print head, the ink attached to the wiper blade is in the direction of being repelled to the print medium, the wiper blade is The nozzle surface is not wiped.

According to this, when the wiper blade wipes the nozzle surface of the print head, the wiper blade wipes the nozzle surface only when the ink is not ejected to the print medium. become. That is, after the wiping operation of the wiper blade, the direction of the ink that is ejected by the return operation due to the elasticity of the wiper blade is only the direction opposite to the print medium, so that the stain on the print medium is prevented by this ink. be able to.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a main structure of a serial inkjet printer according to the present invention. In FIG. 1, reference numeral 1 is a frame of the printer main body, 2 is a carriage shaft whose both ends are fixed to the frame 1 of the printer main body, and the carriage shaft 2 is provided in a state of being laid on the left and right (paper width direction). Has been. 3 is a carriage that is guided by the carriage shaft 2 and reciprocates left and right.
A print head 4 is attached to the printer so as to be movable integrally. A nozzle surface 4a for ejecting ink is arranged on the lower surface of the print head 4. Reference numeral 5 denotes a spacing belt. The spacing belt 5 is stretched over a pair of pulleys 6 and arranged in parallel with the carriage shaft 2, and a part of the spacing belt 5 is connected to the carriage 3. Reference numeral 7 is a spacing motor for driving the pulley 6 on one side, which is, for example, a stepping motor. Then, when the spacing motor 7 is driven, the pulley 6 on one side rotates in a direction corresponding to this rotation direction, the spacing belt 5 is driven via this pulley 6, and the spacing belt 5 and The carriage 3 and the print head 4 are integrally guided by the carriage shaft 2 and moved in the left-right direction. Reference numeral 8 denotes a feed roller for conveying the print medium 9 to the print position. Reference numeral 10 denotes a wiper blade provided below the movable area in which the print head 4 reciprocates and at a position outside the transport path of the print medium 9. The wiper blade 10 has a blade-shaped wiping tip, and includes, for example, NBR (acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), and the like.
It is made by molding an elastic rubber material.

2 and 3 are views showing a detailed structure of the head cleaning mechanism portion, FIG. 2 is a side view of the mechanism portion, and FIG. 3 is a front view of the mechanism portion. Therefore, FIGS. 2 and 3
In addition, the structure of the head cleaning mechanism in the serial inkjet printer shown in FIG. 1 will be further described. The wiper blade 10 is provided on the L-shaped arm 11 which is arranged so as to intersect the moving direction of the carriage 3 and project in the vertical direction. Similarly, the blade surface of the wiper blade 10 is fixed in a state of being perpendicular to the moving direction of the carriage 3. In addition, the L-shaped arm 11 here is the horizontal portion 11
It is integrally formed with a and a vertical portion 11b and is formed in an L shape. A state in which the vertical portion 11b is fitted in the groove of the U-shaped slit 12 attached to the print main body so as to be movable in the vertical direction, and the wiper blade 10 is attached on the horizontal portion 11a. It has become. On the other hand, the vertical portion 1 of the L-shaped arm 11
A horizontal plate 13 having approximately the same size as the lateral width of the print head 4 is obliquely attached to the front end (upper end) of 1b so that the end closer to the print medium 9 is lowered.

On the other hand, in the print head 4, a slide bar 14 is horizontally projected so as to be in contact with the upper surface or the lower surface of the horizontal plate 13 of the L-shaped arm 11. The slide bar 14 has a vertical portion 14a at one end, and the vertical portion 14a is engaged with a guide groove 15 formed on the print head 4 side, and a part of the vertical portion 14a is passed through a slide slit 16 so that the L-shaped arm 11 is horizontal. It is attached to the side of the plate 13 so as to project to a position where it does not come into contact with the vertical portion 11b and is movable in the vertical direction by the guide groove 15 and the slide slit 16. In addition, in the guide groove 15 of the print head 4, a spring 17 is provided above the slide bar 14.
Is attached, and with this spring 17, the slide bar 1
4 is held in a suspended state. Further, the position of the slide bar 14 suspended by the spring 17 is a position approximately in the middle of the slide slit 16 as shown in FIG.
Further, the L-shaped arm 11 is adjusted to stop at a position slightly lower than the right end of the horizontal plate 13 (the end farther from the print medium 9).

4 and 5 show the operating state of the wiper blade 10, that is, the slide bar 14 and the L-shaped arm 11.
FIG. 6 is a diagram for explaining an operating state of and. Therefore, FIG.
The operation of the wiper blade 10 will be described with reference to FIGS. First, when the carriage 3 is moved together with the print head 4 from the left end to the right end, the L-shaped arm 11 is moved by its own weight to the lowermost end of the vertical movable range. Then, when the carriage 3 substantially reaches the position out of the conveyance path of the print medium 9, the slide bar 14 contacts the upper surface of the horizontal plate 13. When the carriage 3 is further moved toward the right end, the slide bar 13 bends the spring 17 and moves upward to slide on the upper surface of the horizontal plate 13 to pass therethrough. Therefore, as shown in FIG. 4, when the carriage 3 moves together with the print head 4 from the left end to the right end,
The L-shaped arm 11 is held at the lowermost end of the vertically movable region, and the wiper blade 10 fixed to the L-shaped arm 11 does not contact the nozzle surface 4 a of the print head 4.
Further, when the carriage 3 reaches the rightmost end, the slide bar 14 is arranged at a position where it has completely passed over the horizontal plate 13. Then, the slide bar 14 has the spring 17
It is returned to the lower side of the horizontal plate 13 by the urging force of.

Next, when the carriage 3 is moved from the right end to the left end together with the print head 4, the slide bar 14 comes into contact with the lower surface of the horizontal plate 13 in the middle thereof. When the carriage 3 is further moved toward the left end, the slide bar 14 passes the lower surface of the horizontal plate 13 while applying a force to push the L-shaped arm 11 upward. Therefore, as shown in FIG. 5, when the carriage 3 moves from the right end to the left end together with the print head 4, the L-shaped arm 11 is moved to the uppermost end of the vertical movable region, and at this time, the L-shaped arm 11 is moved.
The wiper blade 10 fixed to the print head 4
Contact the nozzle surface 4a. As a result, the wiper blade 10 wipes the nozzle surface 4a.

Further, in this structure, the photo sensor 18 is attached to the rear surface of the carriage 3, and further the horizontal plate 13 is provided.
A reflecting plate 19 having the same horizontal dimension as or slightly longer than the horizontal dimension is attached in parallel with the carriage shaft 2 at a position where the horizontal plate 13 is provided on the frame 1 of the printer body. Then, the photo sensor 18 becomes the reflection plate 1.
By detecting 9, the structure is such that it can be determined whether the slide bar 14 has passed the horizontal plate 13.

FIG. 6 is a block diagram showing the structure of a control unit for operating the main structure of the ink jet printer of the present invention. In FIG. 6, reference numeral 21 is a CPU (central processing unit)
Reference numeral 22 is a program ROM, and 23 is a motor control circuit for controlling the driving of the spacing motor (SP motor) 7. Then, in this control unit, the CPU
21 is operated according to a microprogram stored in advance in the program ROM 22, and the CPU 21 outputs a motor drive signal (b), a drive direction selection signal (c), and a drive speed selection signal (d) to the motor control circuit 23. There is. Further, the motor control circuit 23
When the motor drive signal (b) is "H" (high), the drive current is supplied to the spacing motor 7 to rotate the spacing motor 7, and the drive direction selection signal (c) is "H". The direction of the current polarity supplied to the spacing motor 7 is switched between the case of "" and the case of "L" (low),
The rotation direction (right rotation / left rotation) of the spacing motor 7 is switched depending on the direction of this polarity. In addition, when the drive speed selection signal (d) is "H", compared with the case where the drive speed selection signal (d) is "L",
The current value passed through the spacing motor 7 is increased so that the spacing motor 7 rotates at high speed.
As a result, the CPU 21 causes the spaceing motor 7
The rotation / stop, rotation direction, and rotation speed of can be switched. Further, the signal (a) of the photo sensor 18 attached to the carriage 3 is input to the CPU 21, and the carriage 3 is currently passing the portion of the wiper blade 10 by detecting this signal (a). It is configured to be able to determine whether or not there is.

FIG. 7 shows an example of a time chart when the nozzle surface 4a is cleaned after the printing operation is completed. Therefore, the head cleaning operation in the printer according to this embodiment will be described below with reference to the time chart of FIG. First, when the printing operation is completed,
The CPU 21 moves the carriage 3 toward the right end position outside the conveyance path of the print medium 9 to perform cleaning, and sets the drive direction selection signal (c) to "H" and the drive speed selection signal (d) to "H". ", And the motor drive signal (b) is set to" H "to rotate the spacing motor 7 in the forward (right) direction to move the carriage 3 to the right.

Next, the CPU 21 monitors the signal (a) from the photo sensor 18, and when the signal (a) changes from "L" to "H", the carriage 3 reaches the position of the wiper blade 10. I judge that I did. After that, the signal (a) from the photo sensor 18 is monitored, and when the signal (a) becomes “L”, the carriage 3 passes the position of the wiper blade 10, that is, the slide bar 14 moves the horizontal plate 13. It is judged that it was placed in a position where you completely got over,
The motor drive signal (b) is set to "L" to stop the rotation of the spacing motor 7. In addition, the operation until the print medium 9 is moved to the right end after being stopped from the conveying path,
Hereinafter referred to as "operation A".

Then, the drive direction selection signal (c) is set to "L".
At the same time, the motor drive signal (b) is set to “H” again, the spacing motor 7 is rotated in the negative (left) direction, and the carriage 3 is moved leftward. Then, the slide bar 14 passes while contacting the lower surface of the horizontal plate 13, and at this time, the wiper blade 10 fixed to the L-shaped arm 11 contacts the nozzle surface 4a of the print head 4 and wipes the nozzle surface 4a. I do. Also, the CPU 21
Monitors the signal (a) of the photo sensor 18, and when the signal (a) changes from “L” to “H” and from “H” to “L”, the carriage 3 moves on the wiper blade 10. It is determined that the passing has been completed, the motor drive signal (b) is set to "L", and the rotation of the spacing motor 7 is stopped. In addition, the operation from the right end of the print medium 9 which is out of the conveyance path to the end of the carriage 3 passing over the wiper blade 10 is referred to as “operation B”. Then, the “motion A” and the “motion B” are the wiper blade 10
Is the control required to wipe the nozzle surface 4a of the print head 4 once, and when repeating the wiping, by repeating the operation consisting of "operation A" and "operation B" by the number of times of wiping. realizable.

Therefore, in the ink jet printer having the head cleaning mechanism constructed as described above, the nozzle surface by the wiper blade 10 is provided only in the "operation B" in which the carriage 3 moves from the right end side to the print medium 9 side. The wiping operation of 4a will be performed. Therefore, the direction of the ink that is ejected by the return operation due to the elasticity after the wiping operation of the wiper blade 10 is only in the direction opposite to the print target medium 9, and the stain of the print target medium due to this ink can be prevented. . As a result, it is possible to prevent the print-receiving medium from being contaminated by the ink and to reduce the physical distance between the print-receiving medium 9 and the wiper blade 10 without deteriorating the ink wiping effect and the printing quality. It becomes possible to shorten the width of the device.

In the above structure, the carriage 3 is used as power for moving the wiper blade in the vertical direction.
However, the same effect can be obtained by using a motor or the like for independently moving only the wiper blade in the vertical direction.

[0023]

As described above, according to the present invention,
After the wiping operation of the wiper blade, the direction of the ink ejected by the return operation due to the elasticity of the wiper blade can be suppressed only in the direction opposite to the print medium to prevent the print medium from being contaminated. Therefore, the physical distance between the print medium and the wiper blade can be reduced. Therefore, the lateral width of the device can be shortened by that amount, and the effect that the device can be downsized can be expected.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main structure of a printer shown as an embodiment of the present invention.

FIG. 2 is a side view of a head cleaning mechanism section.

FIG. 3 is a front view of a head cleaning mechanism section.

FIG. 4 is an operation explanatory view of a head cleaning mechanism section.

FIG. 5 is an operation explanatory view of a head cleaning mechanism section.

FIG. 6 is a block diagram of a control unit in the printer shown as an embodiment of the present invention.

FIG. 7 is an operation timing chart of the control unit.

FIG. 8 is a perspective view showing a main structure of a conventional printer.

[Explanation of symbols]

 2 Carriage Shaft 3 Carriage 4 Print Head 4a Nozzle Surface 9 Printed Medium 10 Wiper Blade 11 L-Shaped Frame (First Means) 13 Horizontal Plate 14 Slide Bar

Claims (4)

[Claims] 1. A wiper blade having elasticity,
In an inkjet head cleaning device that wipes by contacting a nozzle surface of a moving print head, it is detected which direction the print head moves with respect to a print medium, and the moving direction is In the case where the ink attached to the wiper blade when the wiper blade is separated from the nozzle surface after the wiping of the nozzle surface is in the direction of being ejected to the print medium,
A head cleaning device for an inkjet printer, comprising means for controlling the wiper blade so as not to wipe the nozzle surface. 2. A wiper blade having elasticity,
In an inkjet head cleaning device that wipes a nozzle surface of a moving print head by contacting the nozzle surface of the print head, the wiper blade is moved together with the wiper blade so that the nozzle surface of the print head can be wiped. A first means that is movable to a position and a non-operating position that is not in contact with the nozzle surface; and in which direction the print head moves relative to the print medium, and the print head detects the print medium. When moving in a direction away from the widthwise end of the
When the means for moving the nozzle surface is moved to a direction approaching the end of the print medium in the width direction without wiping the nozzle surface by the wiper blade, the second means is used. A head cleaning device for an inkjet printer, wherein the head cleaning device is provided in an operating position and provided with a switching means that can be switched so that the nozzle surface can be wiped by the wiper blade. 3. The second means is a slide bar that reciprocates together with the print head, and is arranged in a moving path of the slide bar so as to move together with the first means to the operating position and the non-operating position. And a horizontal plate to be moved, the horizontal plate is tilted in the movement path of the slide bar,
When the print head moves in a direction away from the end of the print medium in the width direction, the slide bar moves while abutting on the upper surface of the horizontal plate to reach the end of the print medium in the width direction. The head cleaning device for an inkjet printer according to claim 2, wherein the slide bar is provided so as to move while coming into contact with the lower surface of the horizontal van when moving in the approaching direction. 4. A wiper blade having elasticity,
In an inkjet head cleaning method of wiping by contacting a nozzle surface of a moving print head, it is detected which direction the print head moves relative to a print medium, and the moving direction is the In the case where the ink attached to the wiper blade when the wiper blade is separated from the nozzle surface after the wiping of the nozzle surface is in the direction of being ejected to the print medium,
A method for cleaning a head of an inkjet printer, wherein the wiper blade does not wipe the nozzle surface.