Patent Application
20200122467
This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2018-197560 filed on Oct. 19, 2018, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a cap unit which is attached to an inkjet recording apparatus which performs recording by ejecting ink onto a recording medium, and which protects an ink ejection surface of a recording head, and in particular, the present disclosure relates to a cap unit that is attached to an inkjet recording apparatus when the inkjet recording apparatus is transported.
Inkjet recording apparatuses which form an image by ejecting ink onto a recording medium, such as a paper sheet, an OHP sheet, or the like, are capable of forming a high-definition image and thus have been widely used as recording apparatuses such as facsimile machines, copiers, and printers.
In such inkjet recording apparatuses, evaporation of ink solvent in an ink ejection nozzle provided in a recording head increases the concentration of the ink, which sometimes causes clogging of an ink ejection port at a leading end of the ink ejection nozzle. To prevent such clogging, inkjet recording apparatuses are provided with a cap for capping the ink ejection port.
For example, in a widely used configuration, an annular rib projecting from a peripheral portion of a cap main body made of rubber is pressed against an ink ejection surface of a recording head to thereby prevent drying of an ink ejection port located inside the annular rib.
According to an aspect of the present disclosure, a cap unit includes a cap portion, a support plate, a unit frame, and a plate moving mechanism. The cap portion intimately contacts an ink ejection surface of a recording head of an inkjet recording apparatus and protects the ink ejection surface. The support plate has the cap portion fixed thereto, and is supported to be movable in an up-down direction with respect to the unit frame. The unit frame supports the support plate, and has a fixing mechanism with respect to an inkjet recording apparatus. The plate moving mechanism is capable of moving the support plate, with the unit frame fixed to the inkjet recording apparatus, to a first position at which the cap portion is in contact with the ink ejection surface, and to a second position at which the cap portion is apart from the ink ejection surface.
Still other objects of the present disclosure and specific advantages provided by the present disclosure will become further apparent from the following descriptions of embodiments.
With reference to
The printer 100 further includes a first sheet conveyance path 4a arranged inside thereof. The first sheet conveyance path 4a is located, with respect to the sheet feeding cassette 2, on the upper-left side, toward which a paper sheet is fed out from the sheet feeding cassette 2. The paper sheet P fed out from the sheet feeding cassette 2 is conveyed vertically upward along a side surface of the printer main body 1 via the first sheet conveyance path 4a.
At a downstream end of the first sheet conveyance path 4a with respect to the sheet conveyance direction, a registration roller pair 13 is provided. Furthermore, a first belt conveyance portion 5 and a recording portion 9 are arranged immediately close to the registration roller pair 13 on a downstream side of the registration roller pair 13 in the sheet conveyance direction. The paper sheet P fed out from the sheet feeding cassette 2 passes through the first sheet conveyance path 4a and reaches the registration roller pair 13. The registration roller pair 13 on one hand temporarily stops the paper sheet P to correct skewed feeding of the paper sheet P, and on the other hand restarts conveying the paper sheet P toward the first belt conveyance portion 5 with timing coordinated with an ink ejection operation performed by the recording portion 9.
On a downstream side (right side in
On a downstream side of the second belt conveyance portion 12 with respect to the sheet conveyance direction, near a right side face of the printer main body 1, a decurler portion 14 is provided. The paper sheet P having had the ink dried at the second belt conveyance portion 12 is sent to the decurler portion 14, where curl in the paper sheet P is corrected by using a plurality of rollers arranged in a sheet width direction.
On the downstream side of (in
Further, a maintenance unit 19 and a cap unit 30 are arranged below the second belt conveyance portion 12. When a later-described purge is performed, the maintenance unit 19 horizontally moves to below the recording portion 9 to wipe away ink having been pushed out from ink ejection nozzles 18 of recording heads 17a to 7c, which will be described later, and collects the ink having been wiped away. At a time of capping an ink ejection surface F (see
As shown in
As shown in
The recording heads 17a to 17c constituting each of the line heads 110 to 11K are supplied with ink of one of four colors (cyan, magenta, yellow, and black) stored in ink tanks (not shown), respectively, which corresponds to a color of each of the line heads 110 to 11K.
In accordance with image data received from an external computer or the like, the recording heads 17a to 17c eject ink from the ink ejection nozzles 18 toward the paper sheet P conveyed by being attracted onto a conveyance surface of the first conveyance belt 8. Thereby, on the paper sheet P held on the first conveyance belt 8, ink images of the four colors of cyan, magenta, yellow, and black are superimposed on each other to form a color image.
Further, to prevent defective ejection of ink due to drying up or clogging of the recording heads 17a to 17c, a purge is performed in preparation for a subsequent printing operation in the following fashion. When printing is started after a long period of non-operation state, ink with increased viscosity is expelled from the ink ejection nozzles 18 of all the recording heads 17a to 17c, or, during intermissions in printing, ink with increased viscosity is expelled from such one or ones of the ink ejection nozzles 18 of the recording heads 17a to 17c as have ejected less than a reference amount of ink.
As shown in
The cap unit 30 is capable of reciprocating between a first position (position in
Specifically, as shown in
The cap portions 30b are arranged at positions corresponding to the recording heads 17a to 17c. With this arrangement, as a result of upward movement of the cap unit 30 located at the first position, the cap portions 30b cap the ink ejection surfaces F of the recording heads 17a to 17c. The height-direction positioning protrusions 30c come into contact with the head housing 10 of the recording portion 9 when the cap unit 30 is raised toward the recording portion 9 to cap the recording heads 17a to 17c, and thereby a constant contact state is maintained between the cap portions 30b and the ink ejection surfaces F.
The maintenance unit 19 is capable of reciprocating between a first position (the position in
Specifically, to an external side of the guide rail 60b, there are attached a drive motor 72 for moving the carriage 71 in an arrow-AA′ direction, a gear train (not shown) which engages with the drive motor 72 and with rack teeth 71a of the carriage 71, and a cover member 73 which covers these. Forward rotation of the drive motor 72 makes the gear train rotate to make the carriage 71 and the maintenance unit 19 move from the second position to the first position. Here, the drive motor 72, the gear train, and other components constitute a unit moving mechanism that makes the maintenance unit 19 move in the horizontal direction.
Furthermore, in four corners of the carriage 71, as shown in
As shown in
To the support frame 40, there are attached a wiper drive motor 45 for making the wiper carriage 33 move in the horizontal direction (the arrow-CC′ direction) and a rack drive gear 47 which engages with a rack 32 of the wiper carriage 33. Forward or reverse rotation of the wiper drive motor 45 makes, via the gear train, the rack drive gear 47 rotate forward or reversely to make the wiper carriage 33 reciprocate in the horizontal direction (the arrow-CC′ direction). Here, the wiper drive motor 45, the rack drive gear 47, etc., constitute a wiper moving mechanism which makes the wipers 35 move along the ink ejection surfaces F of the recording heads 17a to 17c.
On the upper surface of the support frame 40, an ink collection tray 44 is arranged for collecting waste ink wiped away from the ink ejection surfaces F by the wipers 35. At a substantially central portion of the ink collection tray 44, an ink discharge hole (not shown) is formed, and tray surfaces on opposite sides with respect to the ink discharge hole are each inclined downward toward the ink discharge hole. Waste ink having been wiped away from the ink ejection surfaces F by the wipers 35 to fall onto the tray surfaces flows toward the ink discharge hole (not shown). Then, the waste ink flows through a waste ink collection passage (not shown) coupled to the ink discharge hole, to be collected in a waste ink collection tank (not shown).
The wipers 35 are each a rubber member made of EPDM, for example, for wiping away ink expelled from the ink ejection nozzles 18 of the recording heads 17a to 17c. The wipers 35 are substantially vertically pressed against wiping starting positions which are outside the nozzle regions R (see
As shown in
As shown in
The positioning pulley 46 is provided at each of four positions on an upper surface of the carriage main body 33a. When the support frame 40 is raised toward the recording portion-9 side for performing the wiping operation with respect to the ink ejection surfaces F of the recording heads 17a to 17c, the positioning pulley 46 contacts the head housing 10 of the recording portion 9, and thereby a constant contact state is maintained between the wipers 35 and the ink ejection surfaces F.
Next, a description will be given of a recovery operation performed with respect to the recording heads 17a to 17c in the printer 100. When processing to recover the recording heads 17a to 17c is to be performed by the maintenance unit 19, as shown in
Then, before the wiping operation is performed, ink 22 is supplied to the recording heads 17a to 17c. The thus supplied ink 22 is forcibly expelled (purged) from the ink ejection nozzles 18. By this purge operation, thickened ink, foreign matters, and bubbles are discharged from inside the ink ejection nozzles 18, whereby the recording heads 17a to 17c can be recovered.
Next, the wiping operation is performed to wipe away the ink 22 having been discharged onto the ink ejection surfaces F. Specifically, as shown in
Then, the wiper carriage 33 is horizontally moved in the arrow-C direction by means of the wiper drive motor 45 (see
After the wipers 35 moves to downstream-side end portions of the ink ejection surfaces F of the recording heads 17a to 17c, the wiper carriage 33 is lowered by means of the unit lift mechanism. Thereby, the wipers 35 is retracted downward from the ink ejection surfaces F of the recording heads 17a to 17c.
Then, the maintenance unit 19 is moved in the arrow-A direction from the first position by means of the unit moving mechanism. Thereby, as shown in
Next, a description will be given of an operation of attaching the cap unit 30 to the recording heads 17a to 17c in the printer 100 of the present embodiment. When capping is performed with respect to the recording heads 17a to 17c by means of the cap unit 30, as shown in
Then, as shown in
The unit frame 51 is a rectangular, metal sheet member, and supports the four support plates 53a to 53d on its upper surface. Fixing pins 51a are provided one at each of two positions on a rear-side (in
The support plates 53a to 53d are arranged parallel to each other in a width direction of the unit frame 51 (an up-down direction in
The cap portions 55 intimately contact the ink ejection surfaces F of the recording heads 17a to 17c and protect the ink ejection surfaces F, and they also prevent leakage and evaporation of ink from the ink ejection nozzles 18 (see
The plate fixing screws 57 fix the support plates 53a to 53d, with the cap portions 55 in intimate contact with the recording heads 17a to 18c of the line heads 110 to 11K. The plate fixing screws 57 are arranged one on each of front and rear sides of each of the four support plates 53a to 53d, and thus a total of eight plate fixing screws 57 are provided.
Each of the plate fixing screws 57 has a spacer 80 around its shaft portion. When the plate fixing screws 57 are fastened, the spacer 80 prevents the support plates 53a to 53d from rising above a predetermined position, and maintains the pressure-contact state between the recording heads 17a to 17c and the cap portions 55 constant. Note that, on the rear side of the transport cap unit 50 as well, four plate fixing screws 57 having the above configuration are arranged one at each of four positions.
Next, a description will be given of how to attach the transport cap unit 50 to the recording heads 17a to 17c of the printer 100.
First, as shown in
Next, as shown in
Next, a second stage of the attachment procedure is executed, in which the cap portions 55 are brought into pressure contact with the ink ejection surfaces F of the recording heads 17a to 17c. Specifically, by holding and pushing up the knob portions 57a of the plate fixing screws 57, as shown in
Then, as shown in
To detach the transport cap unit 50 from the printer 100, the above procedure is performed in a reverse order. First, the plate fixing screws 57 is unfastened from the state shown in
Next, the screws 90 having been fastened via the screw fastening portions 51b into the screw fixing holes 83 are unfastened to release the front side of the transport cap unit 50 from the fixed state. Lastly, the fixing pins 51a are pulled out of the pin fixing holes 81, and the transport cap unit 50 is removed.
According to the transport cap unit 50 having the above configuration, the cap portions 55, which are made of an elastic material, intimately contact the ink ejection surfaces F of the recording heads 17a to 17c, and this makes it possible to securely protect the ink ejection surfaces F from an external force caused by vibration, shock, or the like during transport.
Further, in the transport cap unit 50 according to the embodiment, unlike in the cap unit 30 used when the printer 100 is in operation, there is no space between the cap portions 55 and the ink ejection surfaces F. Thus, it is possible to prevent leakage of preservation liquid having been filled into the recording heads 17a to 17c at the time of shipment from the factory.
Further, with the transport cap unit 50 attached to the printer 100, the support plates 53a to 53d can be moved to the first position and to the second position. Thus, it is possible, after the transport cap unit 50 is attached to the printer 100, to make the support plates 53a to 53d move from the first position to the second position to substantially vertically bring the cap portions 55 into contact with the ink ejection surfaces F. Further, it is possible to make the support plates 53a to 53d move from the second position to the first position before detaching the transport cap unit 50 to separate the cap portions 55 substantially vertically from the ink ejection surfaces F. Accordingly, it is possible to securely prevent friction between the ink ejection surfaces F and the cap portions 55 during attachment and detachment of the transport cap unit 50.
The four support plates 53a to 53d are provided independently one for each of the colors corresponding to the line heads 11C to 11K of the recording portion 9. As a result, in comparison with a configuration where the cap portions 55 for the four colors are all supported by using a single support plate, vibration of the support plates 53a to 53d, which are each light-weight, is reduced. Moreover, the support plates 53a to 53d can be raised or lowered with an easier operation.
For replacement of the recording heads 17a to 17c with new ones, an operation is performed with the power turned off, and thus the transport cap unit 50 is attached in place of the cap unit 30, which is for use when the printer is in operation. At this time, if the cap portions 55 contact the new recording heads 17a to 17c, the ink ejection surfaces F may be damaged. By providing the support plates 53a to 53d independently one for each color as in the embodiment, it becomes possible to have the cap portions 55 pressed against such ones of the recording heads 17a to 17c as are not to be replaced with new ones, while having the cap portions 55 apart from such ones of the recording heads 17a to 17c as are to be replaced with new ones. Thus, it is possible to prevent damage to the recording heads 17a to 17c at the time of attachment, and also to prevent drying of such ones of the recording heads 17a to 17c as are not to be replaced.
Here, in a case where vibration is applied to the printer 100 during transport, there may occur a phase shift between the vibration of the front-side frame 101a and the rear-side frame 101b and the vibration of the recording heads 17a to 17c. At this time, if the cap portions 55 are fixed directly to the front-side frame 101a or the rear-side frame 101b of the printer 100, the ink ejection surfaces F may be rubbed by surfaces of the cap portions 55.
In the transport cap unit 50 of the embodiment, the support plates 53a to 53d which support the cap portions 55 are fixed, by means of the plate fixing screws 57, to the head housing 10 which holds the recording heads 17a to 17c. Thereby, even when vibration is generated during transport, no phase shift occurs between the vibration of the recording heads 17a to 17c and the vibration of the cap portions 55, and thus, it is possible to effectively reduce rubbing between the ink ejection surfaces F and the cap portions 55 during transport.
It should be understood that the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the present disclosure. For example, as the unit moving mechanism constituted by the drive motor 72, the gear train, etc., and the unit lift mechanism constituted by the wipe lift motor 76, the gear train, the rotation shaft 75, etc., conventionally known other drive mechanisms may be used.
The number of the ink ejection nozzles 18 and the intervals between the ink ejection nozzles 18 in the recording heads 17a to 17c, for example, can be appropriately set in accordance with the specifications of the printer 100. Further, the number of the recording heads in each of the line heads 11C to 11K is not limited to three, and, for example, one recording head, two recording heads, or four or more recording heads may be arranged in each of the line heads 11C to 11K.
The present disclosure is usable in a cap unit that protects an ink ejection surface of a recording head. By using the present disclosure, it is possible to provide such a cap unit for a recording head as is capable of reducing leakage of preservation liquid from the recording heads into which the preservation liquid has been filled, and is also capable of reducing rubbing between a recording head and a cap at the time of attaching or detaching the cap or during transport, and an inkjet recording apparatus provided with such a cap unit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-197560 | Oct 2018 | JP | national |
