Image recording apparatus that supplies solid ink to a recording device

An image recording apparatus allows a single drive device to drive an ink cartridge conveying unit and ink hammers, thereby reducing the production cost. A drive motor supplies a drive force to rollers that convey ink cartridges and link mechanisms that push solid ink pieces out of ink cartridges. A planetary gear is provided to make it possible to select whether to transmit a drive force from the drive motor to the conveying rollers. Therefore, the apparatus is able to transmit a drive force to the conveying rollers only during conveyance of an ink cartridge, and to prevent transmission of drive force to the conveying rollers when the drive motor drives the link mechanisms, while employing the single drive motor to drive the conveying rollers and the link mechanisms.

BACKGROUND OF THE INVENTION
 1. Field of the invention
 The invention relates to an image recording apparatus that uses hot melt
 ink for recording and, more particularly, to a technology for supplying a
 solid piece of ink from an ink cartridge, which houses a plurality of
 solid ink pieces, to a recording device.
 2. Description of the Related Art
 In a conventional image recording apparatus, ink that assumes a solid state
 at normal temperatures is heated and melted by a recording device, and ink
 melt is ejected to a recording medium by the recording device. Such an
 image recording apparatus is mainly used for recording on a large-size
 recording medium.
 When the remaining amount of solid ink becomes short, the aforementioned
 conventional image recording apparatus produces an alarm, to indicate to
 an operator that the ink supply is dwindling. Thus, the conventional image
 recording apparatus is subject to a problem regarding ease of operation.
 SUMMARY OF THE INVENTION
 The invention is intended to solve the aforementioned problem in
 operability. It is an object of the invention to provide an image
 recording apparatus having a single drive device that drives both an ink
 cartridge conveyance unit and an ink hammer, thereby simplifying the
 structure of the apparatus, and reducing the number of component parts and
 the production cost.
 According to the invention, an image recording apparatus is provided that
 includes at least one ink cartridge which houses a plurality of solid ink
 pieces, a recording device that receives one of the plurality solid ink
 pieces from the ink cartridge and uses the one solid ink piece for
 recording by melting the one solid ink piece. The apparatus of the
 invention includes additional devices. Specifically, at least one ink
 supply device supplies a solid ink piece from the ink cartridge to the
 recording device by forcing the solid ink piece out of the ink cartridge.
 A conveyance device either conveys the ink cartridge toward the ink supply
 device, or conveys the solid ink pieces toward the ink supply device. A
 drive device drives the conveyance device and the ink supply device.
 In the image recording apparatus of the invention, the ink supply device
 and conveyance device are driven by the single drive device in order to
 supply a solid ink piece from the ink cartridge to the recording device.
 That is, the ink supply device and the drive device do not require
 separate drive devices. Therefore, the number of required component parts
 is reduced, and the structure is simplified. Furthermore, since the ink
 supply device and the conveyance device can be operated in concert by
 controlling the operation of the single drive device, the control of the
 ink supply device and the conveyance device is simplified.
 In the image recording apparatus of the invention, transmission of drive
 force from the drive device may be changeable between transmission to the
 conveyance device and transmission to the ink supply device, by a
 planetary gear.
 When the planetary gear is in a state that the planetary gear does not
 transmit drive force to the conveyance device, but transmits drive force
 to the ink supply device, an ink supplying operation is performed. When
 the planetary gear is in an opposite state, that is, a state where the
 planetary gear does not transmit drive force to the ink supply device, but
 transmits drive force to the conveyance device, an ink conveying operation
 is performed.
 The image recording apparatus of the invention may also have a structure as
 described below. That is, the conveyance device conveys a plurality of ink
 cartridges of ink colors that are arranged side by side, and an ink supply
 device is provided separately for each of the ink colors of the ink
 cartridges. One of the ink supply devices provided separately for the ink
 colors of the ink cartridges is driven in association with, and in
 correspondence to, an operation of the recording device, so that a solid
 ink piece of a corresponding ink color is supplied to an ink tank of the
 recording device.
 In this structure, when the recording device is moved to a position
 corresponding to one of the ink supply devices provided for a solid ink
 piece of a desired or needed color, that ink supply device is driven in
 cooperation with a movement of the recording device so that the solid ink
 piece of the desired color is supplied to the recording device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
 A preferred embodiment of the invention will be described in detail
 hereinafter with reference to the accompanying drawings. FIG. 1 is a
 perspective view of a preferred embodiment of the image recording
 apparatus of the invention, and FIG. 2 is a side sectional view of an
 apparatus body of the embodiment shown in FIG. 1.
 An image recording apparatus 1 is a large-size printer capable of recording
 an image on a large-size recording sheet, for example, a recording sheet P
 fed from a roll having a width of the A0 size, wherein the length of the
 recording sheet P can be set to a desired length. To record an image on a
 recording sheet, the image recording apparatus 1 employs an ink jet-type
 recording head that uses hot melt ink. The image recording apparatus 1
 includes an apparatus body 2, and support legs 3 supporting the apparatus
 body 2. Each support leg 3 has casters 4, so that the image recording
 apparatus 1 is movable.
 The apparatus body 2 has, at its upper face portion, a main cover 5 that
 can be opened to provide maintenance of a recording mechanism disposed
 inside the apparatus body 2, and an operating panel 6 provided with
 various operating switches. Formed in a front lower portion of the
 apparatus body 2 is a discharge opening 8 that discharges the recording
 sheet P. Connected to the apparatus body 2 below the discharge opening 8
 is a sheet table 9 that temporarily supports the recording sheet P
 discharged from the discharge opening 8. A housing case 12 that houses a
 plurality of ink cartridges 11 is provided on the upper face of the
 apparatus body 2. A recovery case 13 that receives ink cartridges 11
 discharged from the housing case 12 is provided on the front face of the
 apparatus body 2. Each cartridge 11 contains a plurality of solid ink
 pieces that are used for recording by a recording head portion.
 Disposed in the image recording apparatus 1 are sheet conveying rollers 14
 that convey the recording sheet P. A recording unit (recording device) 15
 that performs recording by ejecting ink from a nozzle portion 15a to the
 recording sheet P is provided at a position that faces the recording sheet
 P that is being conveyed by the conveying rollers 14. The recording unit
 15 is disposed on a guide member 16 extending parallel to the sheet
 conveying rollers 14, in such a manner that the recording unit 15 is
 movable in horizontal lateral directions. The recording unit 15 is moved
 by a drive force that is transmitted to a portion 17 thereof from a drive
 device (not shown) via a timing belt. The recording unit 15 has ink tanks
 18a-18d (only the ink tank 18a is shown in FIG. 2) that receive solid ink
 pieces. Corresponding to the ink tanks 18a-18d, protrusions 19a-19d (only
 the protrusion 19a is shown in FIG. 2) are protruded from a tail end
 portion of the recording unit 15, the tail end portion being opposite from
 the nozzle portion 15a. The protrusions 19a-19d are provided to facilitate
 cooperation between the recording unit 15 and an ink supply mechanism 20
 described below.
 The ink supply mechanism 20 that supplies solid ink pieces 23 from the ink
 cartridges 11 is provided above the recording unit 15. The ink supply
 mechanism 20 includes ink hammers (ink supply devices) 21, each of which
 drops the solid ink pieces 23 that are housed in an ink cartridge 11, one
 at a time, from the ink cartridge 11 into the corresponding one of the ink
 tanks 18a-18d of the recording unit 15, and cartridge conveying rollers
 (conveyance device) 22 that convey ink cartridges 11 toward the ink
 hammers 21. The color (cyan, magenta, yellow and black) ink cartridges 11
 that provide color recording are disposed in the housing case 12 in such a
 manner that the ink cartridges 11 of each color are stacked in vertical
 directions, and ink cartridges 11 of the different colors are arranged
 side by side in lateral directions relative to the apparatus body 2. The
 ink hammers 21 and the conveying rollers 22 are provided individually for
 each of the four ink colors, although only one ink hammer 21 and only
 three conveying rollers 22 are shown in FIG. 2.
 The supply of solid ink pieces to the recording unit 15 performed by the
 ink supply mechanism will be described with reference to FIGS. 3 and 4.
 FIG. 3 is a side view of the ink supply mechanism. FIG. 4 is a front view
 of an ink cartridge 11 provided in the ink supply mechanism.
 The lowermost ink cartridge 11 of the ink cartridges 11 of each color
 stacked in the housing case 12 is conveyed toward the corresponding one of
 the ink hammers 21 by the corresponding conveying rollers 22. Provided
 below each ink hammer 21 is an ink stopper 25 protruding from an upper
 face of the apparatus body 2.
 The front-side wall of each ink cartridge 11 has a cutout 11d (described in
 detail below). Therefore, when an ink cartridge 11 is conveyed toward the
 corresponding ink hammer 21, the corresponding ink stopper 25 extends into
 the ink cartridge 11 via the cutout 11d. As the ink cartridge 11 is
 further conveyed, the ink stopper 25 contacts the foremost one of the
 solid ink pieces 23 held in the ink cartridge 11, so that the foremost
 solid ink piece 23 is appropriately positioned under the ink hammer 21.
 Each ink hammer 21 is movable up and down by a link mechanism (described
 below) in cooperation with the recording unit 15.
 The recording unit 15 will be described with reference to FIG. 5, which is
 a perspective view of the recording unit 15. The recording unit 15 is
 provided with ink tanks 18a-18d disposed side by side, at such positions
 that each ink tank 18a-18d can receive a solid ink piece 23 of the
 corresponding color which is supplied by the ink supply mechanism 20. When
 a solid ink piece 23 is supplied into the recording unit 15, the solid ink
 piece 23 is heated to melt, so that liquefied ink is ejected to the
 recording sheet P. The four protrusions 19a-19d, corresponding to the ink
 tanks 18a-18d, are provided in the tail end portion of the recording unit
 15 opposite from the nozzle portion 15a. The protrusions 19a-19d are used
 to facilitate ink supplying operations performed by the link mechanisms,
 which are provided corresponding to the ink cartridges 11 of the four ink
 colors. The cooperation between the protrusions 19a-19d and the link
 mechanism will be described below.
 The ink cartridges 11 will be described with reference to FIGS. 6A through
 6D. FIG. 6A is a perspective view of an ink cartridge 11, and FIGS. 6B, 6C
 and 6D are a side view, a bottom plan view and a sectional view thereof,
 respectively. The ink cartridge 11 has openings 11a in its top face and
 openings 11b in its bottom face, so that each solid ink piece 23 housed in
 the ink cartridge 11 can be pushed from above by the corresponding one of
 the ink hammers 21 and can be dropped from the ink cartridge 11. An
 end-side wall 11c of the ink cartridge 11 defines the cutout lid, which
 allows an ink stopper 25 to enter the ink cartridge 11.
 When housed in the ink cartridge 11, the solid ink pieces 23 are
 individually separated by partitions 11e. Each of the solid ink piece
 housing cells partially formed by the partitions lie is provided with
 stopper portions 11f that are formed on the inner surfaces of both side
 walls, that hold a solid ink piece 23. Each solid ink piece 23 is shaped
 so as to engage with the stopper portions 11f, as shown in FIG. 6D. Due to
 the engagement with the stopper portions 11f, solid ink pieces 23 are
 retained in the ink cartridge 11. When a solid ink piece 23 housed in the
 ink cartridge 11 in the above-described manner is pushed from above by the
 ink hammer 21, the solid ink piece 23 is forced down to become released
 from the engagement with the stopper portions 11f, so that the solid ink
 piece 23 falls into the corresponding one of the ink tanks 18a-18d of the
 recording unit 15.
 The ink supply mechanism 20 will be described with reference to FIGS. 7A
 and 7B. FIG. 7A is a side view of the ink supply mechanism 20, where an
 ink cartridge is being conveyed. FIG. 7B is a view of a link mechanism
 portion of the ink supply mechanism 20 as viewed from a direction
 indicated by arrow A in FIG. 7A.
 Each ink hammer 21 receives a drive force transmitted from a drive motor
 (drive device) 31. Link mechanisms (ink supply devices) 30a-30d that
 facilitate cooperation between the recording unit 15 and the ink hammers
 21 are provided separately for the different ink colors. In this
 embodiment, the link mechanisms 30a-30d correspond to yellow (Y), magenta
 (M), cyan (C) and black (K) inks, respectively.
 The drive motor 31 supplies a drive force to the conveying rollers 22 and
 the ink supply mechanism 20 including the link mechanisms 30a-30d (only
 the link mechanism 30a is representatively shown in FIG. 7A). The drive
 force transmission from the drive motor 31 to the link mechanisms 30a-30d
 is accomplished by a plurality of gears 32, 33, 34, 35 and a cam 35a that
 is firmly connected to, or formed together with, the gear 35. The drive
 force transmission from the drive motor 31 to the conveying rollers 22 is
 accomplished by a plurality of gears 32, 37, 38, 39 and a change-over gear
 set 40 including a sun gear 40a and a planetary gear 40b.
 The link mechanisms 30a-30d will be described below. For example, a link
 mechanism 30a corresponding to ink cartridges 11 of one ink color includes
 a link rod 41a connected to the corresponding one of the ink hammers 21, a
 pull link 43a engageable with an engaging protrusion 42a formed in an end
 portion of the link rod 41a spaced from the ink hammer 21. The other link
 mechanisms 30b-30d corresponding to ink cartridges 11 of the other three
 colors each include counterparts of the ink hammer 21, the link rod 41a,
 the engaging protrusion 42aand the pull link 43aof the link mechanism 30a,
 that is, ink hammers 21, link rods 41b-41d, engaging protrusions 42b-42d,
 and pull link 43b-43d, respectively, although only one ink hammer 21 is
 shown in the drawings.
 The link mechanisms 30a-30d further include a link rod 44 pivotably
 connected to the pull link 43a-43d by a pull link shaft 46, and a link rod
 45 pivotably connected to the link rod 44 and pivoted to the apparatus
 body 2. The pull links 43a-43d are parallelly and pivotably connected to
 the single pull link shaft 46, which is pivotably connected to the link
 rod 44. Therefore, the link rod 44 and the pull links 43a-43d are
 pivotably connected via the pull link shaft 46.
 The pull links 43a-43d are hook shaped, as shown in FIG. 7A, so as to
 readily engage with the protrusions 42a-42d, respectively. A lower portion
 of each pull link 43a-43d is shaped so as to appropriately contact the
 corresponding one of the protrusions 19a-19d. The link rod 45 is
 constantly urged upward to contact the cam 35a integrated with the gear
 35. The cam 35a has such a shape that rotation of the cam 35a causes
 up-down movements of the link mechanisms 30a-30d. The cam 35a is connected
 to a switch 50 that detects the orientation of the cam 35a.
 The drive force transmission from the drive motor 31 to the conveying
 rollers 22 will be described with reference to FIGS. 7A and 7B. As
 mentioned above, drive force is transmitted from the drive motor 31 to the
 conveying rollers 22 via the gears 32, 37, 38, 39 and the change-over gear
 set 40 of the sun gear 40a and the planetary gear 40b. The change-over
 gear set 40 is designed to change the state of the planetary gear 40b
 between a state where the planetary gear 40b is meshed with the conveying
 roller-side gear 39 and a state where the planetary gear 40b is unmeshed
 from the conveying roller-side gear 39 in accordance with the operating
 direction of the drive motor 31. That is, when an ink cartridge 11 is to
 be conveyed by the conveying rollers 22, the planetary gear 40b is meshed
 with the conveying roller-side gear 39 to transmit drive force from the
 drive motor 31 to the conveying rollers 22. On the other hand, when a
 solid ink piece 23 is to be pushed out of the ink cartridge 11 by the
 corresponding ink hammer 21 (when ink is supplied), the planetary gear 40b
 is unmeshed from the conveying roller-side gear 39 to discontinue the
 drive force transmission from the drive motor 31 to the conveying rollers
 22, that is, to stop the ink cartridge 11 at a predetermined position.
 The ink supplying operation performed by the ink supply mechanism 20 will
 be described with reference to FIGS. 8A through 9B. FIG. 8A is a side view
 of the ink supply mechanism, showing a link mechanism corresponding to the
 color of a solid ink piece that is about to be supplied. FIG. 8B
 illustrates the operation of the link mechanisms corresponding to the four
 color inks in the situation illustrated in FIG. 8A. FIG. 9A is a side view
 of the ink supply mechanism, showing a link mechanism corresponding to the
 color of a solid ink piece that is not about to be supplied, while a solid
 ink piece of a different color is about to be supplied. FIG. 9B
 illustrates the operation of the link mechanisms corresponding to the four
 color inks in the situation illustrated in FIG. 9A.
 To supply a solid ink piece 23 to the recording unit 15, the drive motor 31
 is operated in a direction indicated by an arrow in FIG. 8A. In this case,
 the gears 32, 37, 38 and the sun gear 40a, which are disposed between the
 drive motor 31 and the conveying rollers 22, are rotated in directions
 indicated by arrows, and the planetary gear 40b is moved away from the
 gear 39 (in a direction indicated by an arrow). Therefore, no drive force
 is transmitted from the drive motor 31 to the gear 39, so that the
 conveying rollers 22 do not convey the ink cartridge 11, that is, the ink
 cartridge 11 remains in position.
 The ink cartridge conveyance performed by the ink supply mechanism 20 will
 be described with reference to FIGS. 7A and 7B. To convey the ink
 cartridge 11 toward the corresponding ink hammer 21, the drive motor 31 is
 operated in a direction indicated by an arrow in FIG. 7A, so that the
 gears 32, 37, 38 and the sun gear 40a, which are disposed between the
 drive motor 31 and the conveying rollers 22, are rotated in directions
 indicated by arrows, and the planetary gear 40b is moved to mesh with the
 gear 39. Therefore, a drive force is transmitted from the drive motor 31
 to the conveying rollers 22 to rotate the conveying rollers 22 in a
 direction indicated by arrows, thereby conveying the ink cartridge 11
 toward the ink hammer 21. During this operation, the cam 35a rotates in a
 direction indicated by an arrow, so that, due to the shape of the cam 35a,
 the ink hammer 21 and the corresponding link mechanism 30a are raised and
 then returned to the lower position. When the switch 50 turns on as the
 cam 35a rotates, the operation of the drive motor 31 is stopped. Through
 this conveying operation, the ink cartridge 11 is conveyed by a
 predetermined amount such that the leading-end solid ink piece 23 in the
 ink cartridge 11 is positioned under the ink hammer 21.
 The link mechanisms 30a-30d operate as follows. When the cam 35a rotates in
 the direction indicated by an arrow in FIG. 8A, the cam 35a pushes the
 link rod 45 down and thereby lowers the pull links 43a-43d. If one of the
 protrusions 19a-19d of the recording unit 15 has been set at such a
 position that it will contact the pull link of the link mechanism
 corresponding to the color of ink that needs to be supplied, for example,
 if the protrusion 19b of the recording unit 15 has been set at a position
 under the pull link 43b of the link mechanism 30b as shown in FIGS. 8A and
 8B, a lower portion of the pull link 43b contacts the protrusion 19b when
 the pull link 43b is lowered, as described above. As the pull link 43b is
 further lowered together with the other pull links, the pull link 43b is
 pushed by the protrusion 19b in a direction indicated by an arrow in FIG.
 8A to engage with the engaging protrusion 42b of the link rod 41b. Due to
 this engagement, the link rod 41b and the corresponding ink hammer 21 are
 pulled down together with the pull link 43b, when the pull link shaft 46
 connected to the pull links 43a-43b is lowered, from a position indicated
 by a broken line in FIG. 8B, to a position indicated by a solid line in
 FIG. 8B. As the ink hammer 21 is moved downward in this manner, the
 leading-end solid ink piece 23 is pushed down from the magenta ink
 cartridge 11 against the retaining force provided by the stopper portions
 11f of the ink cartridge 11, so that the solid ink piece 23 falls into the
 ink tank 19b. Solid ink pieces of the other colors can also be supplied to
 the recording unit 15 by a similar operation.
 During the above-described operation, the link mechanisms 30a, 30c, 30d
 corresponding to the color inks that do not need to be supplied operate as
 shown in FIGS. 9A and 9B. That is, when the pull links 43a, 43c, 43d are
 lowered by the cam 35 pushing the link rod 45 down, the pull links 43a,
 43c, 43d do not contact the protrusions 19a, 19c, 19d of the recording
 unit 15. Therefore, the pull links 43a, 43c, 43d are not moved toward the
 engaging protrusions 42a, 42c, 42d, but simply descend while maintaining
 their orientations. Since the pull links 43a, 43c, 43d do not engage with
 the engaging protrusions 42a, 42c, 42d, the corresponding ink hammers 21
 are not pulled down, so that solid ink pieces 23 are not supplied from the
 corresponding ink cartridges 11 to the recording unit 15. The interval or
 distance between the protrusions 19a-19d of the recording unit 15 is
 different from the interval or distance between the engaging protrusions
 43a-43d of the link mechanisms 30a-30d, so that two or more pull links do
 not simultaneously contact protrusions of the recording unit 15.
 As understood from the above description, in the image recording apparatus
 1 of this embodiment, the planetary gear 40b is meshed with, or unmeshed
 from, the conveying roller-side gear 39 in accordance with the operating
 direction of the drive motor 31. Therefore, by controlling the operating
 direction of the drive motor 31, it can be selected whether to transmit a
 drive force from the drive motor 31 to the conveying rollers 22. That is,
 the image recording apparatus 1 makes it possible to drive the conveying
 rollers 22 and the ink supply mechanism 20 (including the link mechanisms
 30a-30d), by using only one drive motor. Furthermore, the link mechanisms
 30a-30d are provided separately for the ink colors of ink cartridges 11,
 and a link mechanism corresponding to an ink cartridge 11 of a desired ink
 color can be specifically operated by the cooperation between the
 corresponding one of the protrusions 19a-19d of the recording unit 15 and
 the corresponding one of the pull links 43a-43d. That is, a solid ink
 piece 23 of a desired color can be supplied to the corresponding one of
 the ink tanks 18a-18d of the recording unit 15, in association with an
 operation of the recording unit 15.
 It is to be understood that the invention is not restricted to the
 particular forms shown in the foregoing embodiment. Various modifications
 and alternations can be made thereto without departing from the scope of
 the invention.
 For example, although in the foregoing embodiment, the change-over gear set
 40 of the sun gear 40a and the planetary gear 40b is used to switch on and
 off the drive force transmission to the conveying rollers 22 in order to
 drive the conveying rollers 22 and the ink supply mechanism 20 (including
 the link mechanisms 30a-30d) by using the single drive motor 31, this
 structure is merely illustrative. It is also possible to use a different
 change-over mechanism to switch on and off the drive force transmission to
 the conveying rollers 22.
 Furthermore, although in the foregoing embodiment, the ink supply mechanism
 20 includes the link mechanisms 30a-30d in order to enable solid ink
 pieces 23 of the four colors to be supplied for recording, it is also
 possible to construct an ink supply mechanism that supplies solid ink
 pieces of one color for monochrome recording, and therefore includes a
 link mechanism provided only for ink cartridges containing solid ink
 pieces of that color.
 As understood from the foregoing description, the image recording apparatus
 of the invention is able to drive the ink supply device and the conveyance
 device by using a single drive device, so that the structure is simplified
 in comparison with an apparatus in which drive devices are provided
 separately for the ink supply device and the conveyance device. Therefore,
 the production cost can be reduced. Furthermore, since the operation of
 ink supply device and the operation of the conveyance device can be
 controlled by controlling the operation of the single drive device, the
 control of the ink supply device and the conveyance device is simplified.
 Furthermore, the drive force transmission from the drive device is changed
 between the transmission to the ink supply device and the transmission to
 the conveyance device by using the planetary gear. Therefore, the drive
 force transmission can reliably be switched by a simple mechanism.
 Further, a solid ink piece can be supplied by a corresponding ink supply
 device in cooperation with a movement of the recording device. Therefore,
 a solid ink piece of a needed color can be supplied to the recording
 device simply by controlling the movement of the recording device.