The present invention contains subject matter related to Japanese Patent Application JP 2007-095320 filed in the Japanese Patent Office on Mar. 30, 2007, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a liquid discharging device having a head cap for closing and protecting discharge ports of a line head in which the discharge ports for discharging liquid are arranged substantially in lines.
2. Description of the Related Art
Ink jet printers (hereinafter, referred to as printers) print images and characters by discharging ink from ink discharge heads onto recording sheets. The ink jet printers have advantages of low operating cost, small device size, and easy color image printing.
In such a printer, ink is supplied from an ink tank to an ink chamber of an ink discharge head. The ink chamber contains a pressure generating element, such as a heating resistor or a piezoelectric element. Pressure is applied to the ink in the ink chamber by the pressure generating element, and the ink is discharged from fine discharge ports, that is, nozzles, in droplet form. The discharged ink droplets land on a recording sheet or the like. Hence, the printer prints an image or a character on the recording sheet.
In such a printer, the ink discharge head is finely manufactured, and thus the ink discharge head should be protected. In particular, the nozzles for discharging ink and the vicinity thereof are protected with an openable/closable head cap. In the printer, the head cap is arranged at a position facing a discharge surface having the nozzles. When printing is not performed (standby state), the head cap closes the nozzles, and when printing is performed, the head cap comes away from the discharge surface to open the nozzles and discharge ink. Accordingly, the nozzles can be prevented from being dried, and dusts, paper dusts, and the like, can be prevented from adhering to the nozzles when printing is not performed (standby state). Thus, problems such as clogging can be prevented from occurring.
Printers include a serial head printer and a line head printer. In the serial head printer, an ink discharge head discharges ink while being mainly moved in a width direction of a recording sheet to perform printing for a line, and the ink discharge head and the recording sheet are relatively scanned to perform printing for a sheet. The line head printer includes a long ink discharge head having a width substantially similar to a width of a recording sheet. The ink discharge head discharges ink for a line at a time, and only the recording sheet is moved to perform printing for a sheet.
In particular, in the line head printer having a wide discharge surface as compared with the serial head printer, a plurality of nozzles are provided substantially in lines along the width direction of the recording sheet. Hence, a head cap for protecting the nozzles, and a capping mechanism for driving the head cap may become large. In the line head printer, for example, the ink discharge head and/or the head cap may be movably arranged, so that the ink discharge head and/or the head cap may be moved between a capping position and a retraction position, to perform capping or uncapping.
Since such a printer moves the ink discharge head and/or the head cap for capping or uncapping, the movement may take an extra time. The nozzles and the discharge surface may not be reliably protected, and drying of the nozzles and adhesion of foreign substances such as dusts to the nozzles may be increased. Also, such a printer has to have a carriage path, a carriage mechanism, and the like, for moving the ink discharge head and/or the head cap. The size and cost of the device may be increased.
For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2004-262020, a line head printer includes a carrying belt having an opening, for carrying a sheet, and a maintenance unit provided at a surface facing an ink discharge surface and having a cap member for closing the ink discharge surface. The cap member is vertically moved to the discharge surface through the opening of the carrying belt, so as to cap the nozzles.
With this printer, discharge ports may be capped merely by vertically moving the cap member to the discharge ports through the opening of the carrying belt. The extra time for capping or uncapping is not necessary at completion or start of printing.
However, with the printer, the opening of the carrying belt has to be moved to a position corresponding to the maintenance unit at every capping, which takes an extra time. The nozzles may be dried and foreign substances such as dusts may adhere to the nozzles during that time.
In light of the above situation, it is desirable to provide a liquid discharging device capable of reducing a time for opening or closing discharge ports, so as to prevent the discharge ports from being dried, and to prevent dusts, paper dusts, and the like, from adhering to the discharge ports.
A liquid discharging device according to an embodiment of the present invention includes a line head, a head cap, and a lift mechanism. The line head has a plurality of discharge ports for discharging liquid. The discharge ports are arranged substantially in lines in a discharge surface. The head cap faces the line head, and closes the discharge ports. The lift mechanism lifts or lowers the head cap. The head cap closes the discharge ports by being lifted with the lift mechanism substantially perpendicularly to the discharge surface. Also, the head cap comes away from the discharge surface by being lowered with the lift mechanism substantially perpendicularly to the discharge surface to allow a recording medium to be carried between the head cap and the discharge surface.
In the embodiment of the present invention, the head cap for closing the discharge ports is provided to face the plurality of discharge ports arranged in substantially parallel lines of the line head. The head cap opens or closes the discharge ports by being lifted or lowered with the lift mechanism substantially perpendicularly to the discharge surface. With the embodiment of the present invention, since the head cap opens or closes the discharge ports merely by being lifted or lowered substantially perpendicularly to the discharge surface, the discharge ports can be opened or closed in a short time. Also, the discharge ports can be prevented from being dried, and foreign substances, such as dusts and paper dusts, can be prevented from adhering to the discharge ports.
An ink jet printer (hereinafter, referred to as a printer) 1, to which the present invention is applied, is described below in details with reference to the drawings.
As shown in
The head cartridge 3 of the printer 1 is attached and fixed to the device body 4. The head cartridge 3 has a heating resistor, which heats ink supplied from the attached color ink tanks to cause air bubbles to be generated, and ink is discharged by the pressure of the air bubbles. As shown in
The head cartridge 3 discharges ink from the nozzle arrays 9Y, 9M, 9C, and 9K without moving in the width direction of the recording sheet 5. The head cartridge 3 does not have to move the printer head unlike a serial printer that performs printing while moving a printer head in a width direction of a recording sheet 5. Also, the head cartridge 3 allows the recording sheet 5 to be continuously carried, thereby markedly reducing a printing time.
As shown in
The head cap 10 closes the nozzles 7 of the head cartridge 3, so as to prevent the nozzles 7 from being dried, and to prevent foreign substances such as dusts from adhering to the nozzles 7. As shown in
As shown in
As shown in
The support pieces 24 protrude on the upper surface of the reservoir 20 in regions not occupied by the insertion holes 25. The support pieces 24 are provided in the width direction (W direction) of the recording sheet 5 in a substantially staggered manner, in regions not overlapping the nozzle units 8, that is, regions not facing the nozzle units 8. As shown in
The above-described reservoir 20 is a member serves as a platen. The reservoir 20 is apart from the discharge surface 6 of the head cartridge 3 by a space for carrying the recording sheet 5, and fixed to the device body 4.
As shown in
Each of the cap portions 21 attached to the cap base 22 has a substantially long ring shape surrounding the nozzle unit 8 to close the nozzle unit 8 in the discharge surface 6. As shown in
To enhance the sealing between the cap portion 21 and the discharge surface 6, a flexible rubber lip 31 is attached to an upper end of each cap portion 21, the upper end coming into contact with the discharge surface 6.
Also, the cap portion 21 has a recess at an end portion thereof near the discharge surface 6, the recess serving as a groove 32. An ink absorbing body 33 capable of absorbing ink is provided in the groove 32. Since the cap portion 21 has the ink absorbing body 33 in the groove 32, the cap portion 21 can absorb idly discharged ink during the closed state. Also, a through hole 34 is formed in a bottom surface of the groove 32. The through hole 34 allows ink, which was not absorbed with the ink absorbing body 33 and remained at the bottom surface, to be removed.
As shown in
In the head cap 10, while the cap portions 21 are attached to the cap base 22 with the coil springs 29 interposed therebetween, it is not limited thereto. The coil springs 29 may be omitted, the cap base 22 and the cap portions 21 may be integrally formed, and the rubber lips 31 attached to the openings of the cap portions 21 may be replaced with ones having higher elasticity, to enhance the sealing between the head cap 10 and the discharge surface 6.
In the head cap 10, as shown in
The sliders 40 are provided at both ends of the cap base 22 in the width direction of the recording sheet 5. Each slider 40 has, at its upper end, an attachment portion 46 attached to the cap base 22. The cap base 22 is attached to the attachment portions 46 of the sliders 40, for example, by screwing. The sliders 40 also have racks 47 vertically extending along ends near the third gears 45 to mesh with the third gears 45.
In the lift mechanism 11, the driving motor 41 rotates normally or reversely to rotate the first gear 42 normally or reversely. The driving force is transmitted from the first gear 42 to the second gear 43. The shaft 44 with the second gear 43 attached is rotated normally or reversely. Accordingly, the third gears 45 are rotated normally or reversely, and hence, the sliders 40 are vertically moved. In the lift mechanism 11, with the vertical movement of the sliders 40, the cap base 22 attached to the sliders 40 can be vertically moved.
A method of opening or closing the nozzle units 8 by lifting or lowering the cap base 22 is described below.
To lift the cap base 22 and close the nozzle units 8 with the cap portions 21, as shown in
To open the nozzle units 8, as shown in
The device body 4 includes, in addition to the above-described head cap 10 and lift mechanism 11, the carriage mechanism 12 that carries the recording sheet 5. As shown in
With the printer 1 having the above-described arrangement, to close the nozzle units 8 after printing, the driving motor 41 is normally rotated. This rotates the first gear 42 in the direction indicated by arrow B in
With such a printer 1, the head cap 10 having a simple structure is arranged to face the discharge surface 6. The nozzle units 8 can be closed merely by lifting the cap base 22 substantially perpendicularly to the discharge surface 6. The nozzle units 8 can be closed in a short time. Accordingly, with the printer 1, the nozzle units 8 can be closed immediately after printing. The nozzles 7 can be prevented from being dried, and foreign substances, such as dusts and paper dusts, can be prevented from adhering to the nozzles 7.
Also, with the printer 1, since the nozzle units 8 can be closed in a short time, the nozzle units 8 can be closed even when an interval between printing operations is short. The nozzle units 8 can be closed with the cap portions 21 frequently, and hence, drying of the nozzles 7 and adhesion of dusts to the nozzles 7 can be reliably prevented.
In the printer 1, while the nozzle units 8 are closed with the cap portions 21, ink may be idly discharged to the grooves 32 of the cap portions 21, for example, immediately before printing is started, so that thickened ink in the nozzles 7 may be discharged. In the printer 1, after the idle discharging, the ink absorbing bodies 33 in the grooves 32 absorb the ink. Thus, humidity of the grooves 32 can be kept and the nozzles 7 can be prevented from being dried because of the absorbed ink while the discharge surface 6 is closed.
Also, in the printer 1, since the nozzle units 8 are individually closed, the nozzles 7 can be reliably closed.
As shown in
With the printer 1, the nozzle units 8 can be opened immediately after the cap base 22 comes away from the discharge surface 6. Accordingly, if the cap base 22 comes away from the discharge surface 6 when the recording sheet 5 is carried to the position just before the bead cartridge 3, printing can be performed. With the printer 1, the nozzles 7 are closed with the cap portions 21 till a time immediately before the nozzles 7 discharge ink. Thus, the ink can be discharged without the nozzles 7 being dried, and without dusts and the like adhering to the nozzles 7. The printer 1 can print a high quality image without problems such as irregular discharging of the nozzles 7, or without unprinted spots and the like.
Also, with the printer 1, the nozzle units 8 can be closed or opened by the cap base 22 in a short time. For example, to discontinuously print a plurality of images, the nozzle units 8 may be closed, and the nozzles 7 may perform idle discharging to the grooves 32 of the cap portions 21, during an interval between printing operations. Accordingly, foreign substances such as dusts entering the nozzles 7 can be removed, and the nozzles 7 can be moisturized. Thus, problems with the nozzles 7 can be prevented from occurring.
To discontinuously print a plurality of images, if it is determined that a total printing time of images exceeds a predetermined time(=T), the nozzle units 8 may be closed when the predetermined time T has elapsed, and may be controlled to perform idle discharging to the grooves 32 of the cap portions 21, so as to remove foreign substances such as dusts entering the nozzles 7, and to moisturize the nozzles 7. Accordingly, even when the printer 1 performs printing after the predetermined time has elapsed, the nozzle units 8 may be properly closed, so that the nozzles 7 are moisturized and foreign substances are removed. Thus, the problems with the nozzles 7 can be prevented from occurring.
With this printer 1, since the cap base 22 does not move in a wide range, a space and a large drive mechanism for moving the cap base 22 are not necessary. Thus, the space of the device can be saved, and the device can be downsized.
Also, with the printer 1, since only the cap base 22 is moved relative to the discharge surface 6 while the head cartridge 3 is fixed, a given distance between the discharge surface 6 and the recording sheet 5 can be accurately kept. Accordingly, a high quality image can be formed without the position of the head cartridge 3 and the distance between the head cartridge 3 and the recording sheet 5 being adjusted at every printing operation.
Also, in the printer 1, since the head cartridge 3 is continuously fixed, destruction of meniscus of ink in the nozzles 7 can be reduced, ink can be prevented from leaking from the nozzles 7, and air bubbles can be prevented from entering the nozzles 7. Thus, the meniscus of ink in the nozzles 7 can be easily kept.
Also, in the printer 1, even when the line head is employed, and hence, the area of the discharge surface 6 is large, the entire discharge surface 6 can be reliably protected and the nozzles 7 can be easily closed, as described above. The nozzles 7 can be prevented from being dried, and foreign substances such as dusts can be prevented from adhering to the nozzles 7.
In the above-described printer, the head cartridge 3 and the head cap 10 correspond to the width of the recording sheet 5, for example, the widths of A4 and A3 sizes.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
Number | Date | Country | Kind |
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P2007-095320 | Mar 2007 | JP | national |