JP3234906B2 - Inkjet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line type ink jet printer.

[0002]

2. Description of the Related Art At present, an ink jet printer which discharges ink droplets from an orifice and fixes it on a printing paper has been put into practical use as a printer device capable of performing high density printing with low noise. For example, in a line type ink jet printer, a line head having a number of orifices connected in the main scanning direction is provided, and an image forming unit that passes through a recording medium that is held by a platen or the like and moves in the sub scanning direction is provided. It has a structure in which the ink ejection surfaces of the line head are fixedly opposed to each other. Further, in a serial type ink jet printer, a serial head having a plurality of orifices connected to each other is movably supported in a main scanning direction, and is supported by a platen or the like in an image forming section made of a recording medium which moves in a sub scanning direction. It has a structure in which the ink ejection surfaces of the movable serial head are arranged to face each other. In such an ink-jet printer, an image is printed on a recording medium by ejecting ink droplets from a line head or a serial head orifice with driving power corresponding to a print image.

In such an ink jet printer,
If the resting state is extended, the ink in the orifice dries and ink components may precipitate, which may cause clogging. Therefore, in order to prevent the orifice from being clogged, a countermeasure for attaching a cover to the head in the rest state has been conventionally proposed. An outline of such a conventional ink jet printer will be described with reference to FIGS. In FIG. 9, reference numeral 51 denotes a paper feed tray; 52, a platen composed of a pair of plastic templates 52a disposed at the end of the paper feed tray 51; 53, a line head disposed opposite to and above the platen 52; Tray 51
It is a printing sheet that is placed on top and conveyed in a direction perpendicular to the line head 53 and the platen 52. The upper surfaces of the pair of plastic templates 52a are flush with the paper feed tray 51 and form a transport path for the printing paper 54. FIG.
In the figure, reference numeral 55 denotes a bell crank held by a rotating shaft 56 below each plastic template 52a, and an upper end of each bell crank 55 is connected to a lower end of each plastic template 52a via a pin 57. In a space surrounded by the pair of plastic templates 52a and the pair of bell cranks 55, an absorber holder 58 and a porous ink absorber 59 held by the absorber holder 58 are provided at positions corresponding directly below the line head 53. It is arranged to be able to move up and down freely. The horizontal free end on the lower end side of each bell crank 55 serves as a push-up portion 55 a for the absorption pair holder 58.

In a normal state, as shown in FIG. 10A, a pair of plate templates 52a are in a closed state to form a platen 52, and a printing paper 54 (shown in FIG. Line head 53
Printing is performed by ejecting ink droplets from an orifice (not shown). At this time, the ink absorber 59 is covered by a pair of closed plastic templates 52a.

In a discharge recovery process for preventing orifice clogging, as shown in FIG. 10B, when a rotating shaft 56 is driven to swing a bell crank 55, a pair of plastic templates 52a are opened. When the bell crank 55 is subsequently rocked as shown in FIG. 10C, the push-up portion 55a at the end pushes up the absorber holder 58, and the ink absorber 59 is brought into close contact with the orifice of the line head 53. Stop at Then, since the ink absorber 59 closes the orifice and absorbs the remaining ink, clogging of the orifice due to drying and fixing of the ink or adhesion of dust is prevented, and the ejection recovery processing is performed.

For the above prior art, reference was made to, for example, JP-A-63-160849.

[0007]

In the above prior art, since the ink absorber 59, which is the capping means of the line head 53, covers the entire orifice of the line head 53, the line head 53 has When printing is performed on the printing paper 54 corresponding to a part of the width, it is necessary to remove the entirety of the ink absorber 59 from the line head 53. Clogging due to the In order to prevent this problem, it is necessary to perform maintenance operations such as suction and purging even in the printing process, and there is a problem that a large amount of ink is consumed, so that the running cost is high.

The present invention has been made in view of such circumstances, and has as its object to reduce the running cost by minimizing the amount of ink consumed for the maintenance operation of the line head. It is another object of the present invention to make the capping means compact.

[0009]

According to a first aspect of the present invention, there is provided an ink jet printer , wherein capping means is disposed in front of an ink droplet ejection surface of a line head disposed opposite to a platen, and the capping means is provided with the line head.
Belt-shaped member interposed between the platen and the platen.
At the same time, the capping means has a portion that covers the entire orifice in the non-printing area of the orifice group of the line head and a part that exposes the orifice in the printing area. It is characterized by having been done. According to this, the capping means
May be formed in a belt shape, with a complicated configuration and
And the configuration is simplified.

According to a second aspect of the present invention, there is provided an ink jet printer, comprising: a line head provided opposite to a platen;
The capping means is placed in front of the ink drop ejection surface,
The capping means includes the orifices of the line head.
Of the orifice in the non-printing area
The part to be coated is removed from the orifice in the printing area.
A portion for exposing it is formed, and
Moving means along the longitudinal direction of the line head.
It is characterized by the fact that it is currently configured. This
The capping means moves in the longitudinal direction of the line head
The area covering the orifice (exposed
Area) can be changed continuously to meet various paper sizes.
As well as the entire ink drop ejection surface of the line head.
It is also possible to coat the surface.

According to a third aspect of the present invention, there is provided an ink jet printer according to the first or second aspect, further comprising a paper size detecting means for detecting a size of the printing paper, and exposing the capping means based on the detected paper size. The length of the area is automatically adjusted. Irrespective of the change in the paper size, the length of the exposed area of the orifice by the capping means is automatically adjusted to match the paper size, and the effect of covering all the orifices other than the print area is maintained. This also maintains the effect of reducing the running cost by minimizing the amount of ink consumed during the maintenance operation according to the paper size.

According to a fourth aspect of the present invention, there is provided an ink jet printer according to any one of the first to third aspects, wherein the capping means is configured in a belt shape capable of being wound up. . The entire capping means can be made compact.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the ink jet printer according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a schematic configuration of a main part of an ink jet printer according to an embodiment. In FIG. 1, 1 is a paper feed tray, 2 is a platen disposed at an end of the paper feed tray 1, 3 is a line head disposed above the platen 2, and 4 is placed on the paper feed tray 1. One of the printing papers 5a and 5b conveyed in a direction perpendicular to the line head 3 and the platen 2 moves laterally with respect to the paper feed tray 1 in accordance with the size of the printing paper 4, and sandwiches the printing paper 4, The electrodes 6a, 6b, 6c, and 6d provided on the paper feed tray 1 according to the paper size (currently, the electrode 6d is a paper size detecting means) 5b (which is in contact with 5b and is not shown) to detect the paper size by being electrically conducted. The paper size detecting means 5a has a fixed position, and the paper size detecting means 5b detects the paper size by moving it by hand and bringing it into contact with any of the electrodes 6a, 6b, 6c and 6d. Reference numeral 7 denotes a paper feed roller which feeds the print paper 4 toward the line head 3 on the paper feed tray 1, and reference numerals 8a and 8b denote the printed print paper 4 which are arranged vertically above and below the platen 2 on the discharge side.
And a capping belt 10 that covers the ink droplet ejection surface on the orifice side of the line head 3 and is arranged so as to reciprocate along the longitudinal direction of the line head 3. Reference numerals 10a and 10b denote line heads. 3
A winding device that winds and holds both end portions of the capping belt 9 on both outer sides of the capping belt 9; tension rollers 12a, 12b for the capping belt 9;
b is a positioning roller for determining the height position of the capping belt 9. Each of the winding devices 10a and 10b is connected to a forward / reverse switching type motor (not shown), and by supplying a control signal to the motor, the motor is driven to rotate the winding devices 10a and 10b, and the capping belt 9 is moved. The line head 3 is moved along the longitudinal direction.

FIG. 2 is a front view showing the means for changing the position of the capping belt 9. 13a and 13b are spring guides for urging the positioning rollers 12a and 12b upward, and 14a and 14b are positioning rollers 12a and 12b.
, The cams which hold the cams downward, 15 are two cams 14a, 1
4b is a camshaft for connecting and rotating. Cam 1
4a and 14b are positioning rollers 12a and 1
In the state shown in FIG. 2A in contact with the positioning guides 2b, the positioning rollers 12a and 12b are connected to the spring guides 13a and 13b.
b by the urging force of the positioning roller 12
A capping belt 9 stretched between a and 12b is in close contact with the ink droplet ejection surface 3a of the line head 3. In this state, the capping belt 9 covers all or a part of the orifices 3b formed in the line head 3 in large numbers. In the state of FIG. 2B where the large diameter portions of the cams 14a and 14b are in contact with the positioning rollers 12a and 12b, the positioning rollers 12a and 12b are lowered against the urging force of the spring guides 13a and 13b. , The capping belt 9 is the ink droplet ejection surface 3 of the line head 3.
a. In this state, the winding device 10a,
The capping belt 9 can be moved along the longitudinal direction of the line head 3 without rubbing the line head 3 by driving the head 10b.

FIG. 3 is a bottom view of the line head 3 and the capping belt 9 as viewed from below. FIG. 3A shows the line head 3, 3a is an ink droplet ejection surface, and 3b are a number of orifices formed along the longitudinal direction of the line head 3. As shown in FIG. 3B, the capping belt 9 has orifices 3b.
And a slit portion 9 for exposing the orifices 3b... Corresponding to the printing area.
b. The full width covering portions 9a and the slit portions 9b are provided alternately in the longitudinal direction of the capping belt 9. In the line head 3, a region covered by the full width covering portion 9a of the capping belt 9 becomes a capping region 3A as a non-printing region, and a region corresponding to the slit portion 9b becomes a non-capping region 3B as a printing region. FIG. 3B shows a state in which the slit portion 9b is wound on the left winder 10b side, and the entire surface of the ink droplet ejection surface 3a of the line head 3 is covered with the full width covering portion 9a.

FIG. 4 shows a sectional structure of the capping belt 9. The capping belt 9 has a two-layer structure of a base film 9c made of stainless steel or plastic, and a capping film 9d made of a flexible material such as rubber pasted on the base film 9c. The thickness of the base film 9c is 0.05-0.
About 3 mm, the thickness of the capping film 9 d is 0.0
About 3 to 0.05 mm is suitable.

FIG. 5 shows an example of a control mechanism of the movement of the capping belt 9. In FIG. 5, 16 is the winding device 1
A motor 18a is interlocked with a drive shaft 17 via a drive shaft 17, and 18 is a rotary encoder attached to the drive shaft 17 for detecting the amount of rotation. The rotary encoder 18 has a large number of slits. Rotating disk 18
a, and a photo interrupter 18b that projects and receives light through the slit, and detects the moving amount and the moving direction of the capping belt 9 based on the detection of the rotation amount and the rotation direction of the drive shaft 17. I have. Each electrode 6 of the paper size detecting means 5a, 5b
The data of the paper size detected by a, 6b, 6c, 6d is input to a motor control circuit (not shown), and the rotary encoder is adjusted so that the slit portion 9b corresponds to the position of the line head 3 by a length corresponding to the detected paper size. The motor 16 is controlled via 18.

FIG. 6 is a vertical sectional front view showing an ink suction means as a maintenance device, FIG. 7 is a plan view thereof, and FIG. 8 is a side view thereof. In these figures, 19 is a space formed so as to penetrate vertically in the central portion of the platen 2 corresponding to the position of the line head 3, and 20 is a U-shaped cross-section mounted on the upper part of the space 19 so as to be slidable up and down. The ink suction device is slightly longer than the line head 3, 21 is a porous ink absorber housed inside the ink suction device 20, and 22 is communicated with the longitudinal end of the ink suction device 20 and is not shown. A suction pipe connected to a vacuum suction pump, a long cam 23 slightly shorter than the ink suction device 20 horizontally arranged in the space 19 in a state of contacting the lower surface of the ink suction device 20, and a long cam 23 Is a cam drive shaft for driving and rotating. Long cam 23 when printing
FIG. 8 in which the small diameter portion of FIG.
In the state (a), the upper surface of the ink suction device 20 is flush with or lower than the upper surface of the platen 2. In the state shown in FIGS. 8B and 8C in which the large-diameter portion of the long cam 23 contacts the lower surface of the ink suction device 20 during maintenance, the ink suction device 20 is guided up by the space 19 and rises. Are in contact with the capping belt 9 which is in close contact with the ink droplet ejection surface 3a of the line head 3. The upper surface of the ink suction device 20 is made of a flexible material such as rubber, so that the ink droplet ejection surface 3a can be hermetically sealed in close contact with the capping belt 9.

Next, the operation will be described. When the printing paper 4 is set on the paper feed tray 1, when the paper size detecting means 5b, which also serves as a paper transport guide, is moved in the horizontal direction according to the paper size, the paper size among the plurality of electrodes 6a, 6b, 6c, 6d is reduced. The paper size detecting means 5b is electrically connected to the electrode corresponding to the above, and the paper size is detected.
Then, a motor (not shown) is driven to rotate the camshaft 15 by 180 °. As shown in FIG. 2 (b), the two cams 14a and 14b have large-diameter portions connected to the positioning rollers 12a and 12b by the spring guides 13a and 13b. 2A, the capping belt 9 stretched between the positioning rollers 12a and 12b is in contact with the ink droplet ejection surface 3a of the line head 3 in FIG. 2A. From the ink droplet ejection surface 3a as shown in FIG. Further, the data of the detected paper size is input to the control circuit of the motor 16 shown in FIG. 5, and the motor 16 is driven to rotate the winding device 10a, thereby moving the capping belt 9 to the tension roller 11
a while being guided by the positioning roller 12a and wound by the winding device 10a. The winding amount is only the amount corresponding to the detected sheet size, and the motor 16 is stopped via the rotary encoder 18. When the capping belt 9 moves, immediately before the movement, FIG.
As shown in FIG.
Is not separated from the ink droplet ejection surface 3a, so that the capping belt 9 is not rubbed and damaged. Due to such movement of the capping belt 9, the slit portion 9b is fed out from the winding device 10b as shown in FIG. 3B, and reveals a non-capping area 3B having a length corresponding to the sheet size. This non-capping area 3B is a printing area. In the remaining capping region 3A, the full width covering portion 9a corresponds to the position of the ink droplet ejection surface 3a. When the capping belt 9 is moved by an amount corresponding to the sheet size without rubbing, the motor (not shown) is driven again, and the camshaft 15 is moved by one.
The two cams 1 are rotated by 80 °, as shown in FIG.
4a and 14b are positioning rollers 12 whose small diameter portions are
a, 12b, so that the positioning rollers 12a, 12b
b is moved upward by the urging force of the spring guides 13a and 13b, and the capping belt 9 stretched between the positioning rollers 12a and 12b is shown in FIG.
The state of the line head 3 which has been separated from the ink droplet ejection surface 3a returns to the state of being in contact with the ink droplet ejection surface 3a as shown in FIG. As a result, the entire width covering portion 9a of the capping belt 9 in the capping region 3A
Covers the ink droplet ejection surface 3a of the line head 3, and prevents clogging of the orifices 3b. That is, it is not necessary to retract the entire capping belt 9 from the front surface of the ink droplet ejection surface 3a during printing, and the orifices 3b not used for printing can be covered with the capping belt 9 to prevent clogging. In the non-capping area 3B, the slit portion 9b is located in a range corresponding to the paper size,
The orifices 3b are exposed in that range (FIG. 3).
(B)).

When the print button is pressed, a paper feed roller 7 and a paper discharge roller 8a are driven by a motor (not shown).
8b is driven and rotated, and a print signal is supplied to the line head 3. The printing paper 4 is fed between the line head 3 and the platen 2 by the paper feeding roller 7, and ink droplets are ejected from the orifices 3b in the non-capping area 3B in accordance with a printing signal, and printing is performed on the printing paper 4. Then, the printing paper 4 is subsequently discharged by the discharge rollers 8a,
8b.

When the ink jet printer is at rest, the capping belt 9 is once separated from the ink droplet ejection surface 3a of the line head 3 by the same operation as described above (FIG. 2 (b)). The motor is driven to wind the line head 3 around the winding device 10b by a predetermined amount, and the capping belt 9 again covers the entire ink droplet ejection surface 3a of the line head 3 (FIG. 3).
(C)). This prevents clogging of all the orifices 3b... Due to drying of the ink and adhesion of dust in the rest state.

Next, the maintenance operation will be described. When a printing failure occurs during the printing operation, the host computer or the inkjet printer is operated to give a maintenance operation instruction to the printer. The print performance recovery process can be performed by giving an instruction for the maintenance operation periodically or during a fixed amount of printing during the printing operation. A motor (not shown) is driven to rotate the cam drive shaft 24 by 90 °, and at the same time, the long cam 2
3 is also rotated by 90 ° so that the large diameter portion of the long cam 23 comes into contact with the lower surface of the ink suction device 20 (FIG. 8).
(Change from (a) to FIGS. 8 (b) and 8 (c)), the ink suction device 20 ascends while being guided by the space 19 of the platen 2, and the upper surface of the ink suction device 20 passes through the capping belt 9 and the ink droplets of the line head 3. It comes into contact with and comes into close contact with the ejection surface 3a (see FIG. 6). At this time, at a position corresponding to the slit portion 9b, as shown in FIG.
b ... are connected to the ink suction device 20 and can be sucked. At the portion corresponding to the full width covering portion 9a instead of the slit portion 9b, the orifices 3b are covered with the capping belt 9 as shown in FIG. Next, by operating a suction pump (not shown) to reduce the pressure inside the ink suction device 20 through the suction pipe 22, ink is sucked from the orifices 3b... 3b can be prevented from being clogged. The ink dropped by suction can be absorbed by the ink absorber 21. No ink is suctioned from the orifices 3b... Corresponding to the full width covering portion 9a of the line head 3, the amount of ink consumption during the maintenance operation is minimized, and appropriate printing performance recovery processing is performed. Running costs can be reduced. When the suction for a predetermined time is completed, the long cam 23 is again rotated by 90 °, the ink suction device 20 is lowered, separated from the line head 3, and returned to the state of FIG. Instead of applying a negative pressure and sucking, a positive pressure may be applied for purging.

The capping belt 9 is made sufficiently thin and can be wound up, so that the capping means can be made more compact than in the prior art shown in FIG.

In the above-described embodiment, the slit portion 9b is formed to provide a printing area in the capping belt 9. However, instead of this, the shape of the orifice 3b is changed by reducing the width of the capping belt 9, for example. May be exposed.

[0026]

According to the ink jet printer of the first aspect of the present invention, in the non-printing area in the printing process, the orifices can be covered with the capping means to prevent clogging of the orifices. When performing a maintenance operation for preventing clogging of the orifice in the area, since the orifice is covered with the capping means in the non-printing area, ink is discharged only from the orifice in the printing area and consumed by the maintenance operation. Since the amount of ink is kept to a minimum, running costs can be reduced. Also capping
Since the means are belt-shaped, if the structure is complicated
However, the configuration can be simplified.

According to the ink jet printer of claim 2 according to the invention, since the capping means is movable in the longitudinal direction of the line head, Ryo covering the orifice
The area (exposed area) can be changed continuously,
Paper size can be accommodated, and the line head
Cover the entire surface of the ink droplet ejection surface to prevent clogging
Can be opened.

According to the third aspect of the present invention, since the length of the exposed area of the capping means is automatically adjusted based on the detected paper size, the orifice formed by the capping means regardless of the change in the paper size. The length of the exposed area is automatically adjusted to match the paper size, and the effect of reducing the running cost by minimizing the amount of ink consumed during the maintenance operation according to the paper size can be further enhanced.

According to the ink jet printer of the fourth aspect of the present invention, the entire capping means can be made compact by forming the capping means into a belt shape that can be wound up.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic structure of an ink jet printer according to an embodiment of the present invention.

FIG. 2 is a front view showing the structure and operation of a capping belt position changing unit in the inkjet printer according to the embodiment.

FIG. 3 is a bottom view of the line head and the capping belt in the inkjet printer according to the embodiment, as viewed from below.

FIG. 4 is a cross-sectional view showing a cross-sectional structure of the capping belt in the embodiment.

FIG. 5 is a perspective view showing a structure of a control mechanism for moving the capping belt in the embodiment.

FIG. 6 is a vertical sectional front view showing a structure of an ink suction unit as a maintenance device in the inkjet printer according to the embodiment.

FIG. 7 is a plan view illustrating a structure of an ink absorbing unit according to the embodiment.

FIG. 8 is a side view showing the structure and operation of the ink suction means of the embodiment.

FIG. 9 is a perspective view showing a schematic structure of an ink jet printer according to the related art.

FIG. 10 is a side view showing the structure and operation of a mechanism for a print performance recovery process of an ink jet printer according to the related art.

[Explanation of symbols]

 2 ... Platen 3 ... Line head 3A ... Capping area 3B ... Non-capping area 3a ... Ink droplet ejection surface 3b ... Orifice 5b ... Paper size detecting means 6a etc .... Electrode 9 ... Capping belt 9a ... ... Full width covering part 9b ... Slit part 10a, 10b ... Rewinding device 16 ... Motor 18 ... Rotary encoder 20 ... Ink suction device 21 ... Ink absorber 22 ... Suction pipe 23 ... Long cam

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor ▲ Yoshi ▼ Murahisa 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Takahiro Horiuchi 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Norihiro Ochi 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Prefecture Sharp Corporation (56) References JP-A-2-2014 (JP, A) JP-A-63-160849 ( JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B41J 2/165-2/175 B41J 11/42

Claims (4)

(57) [Claims] 1. A capping means is disposed on a front surface of an ink droplet ejection surface of a line head opposed to a platen,
The capping means includes the line head and the platen.
And formed into a belt interposed between the
The capping means has a portion that covers the entire orifice in the non-printing area of the orifice group of the line head and a part that exposes the orifice in the printing area. An ink jet printer, characterized in that: 2. A line head opposed to a platen.
Arrange the capping means in front of the ink droplet ejection surface of
The capping means includes an orifice of the line head.
Orifices in the non-printing area
The part to be covered to the orifice in the printing area
Part is formed to expose it, and
Ping means moves along the longitudinal direction of the line head.
An ink jet apparatus characterized by being configured to be movable.
Printer. 3. The printing apparatus according to claim 1, further comprising a paper size detecting means for detecting a size of the printing paper, wherein the length of the exposed area of the capping means is automatically adjusted based on the detected paper size. The inkjet printer according to claim 2 . 4. A claim, characterized in that are configured to capable winding capping means belt-like 2 or
An inkjet printer according to claim 3 .