EP1612052B1

EP1612052B1 - Image recording apparatus

Info

Publication number: EP1612052B1
Application number: EP20050253946
Authority: EP
Inventors: Yukio c/o Brother Kogyo Kabushiki K. Shiohara; Yusaku c/o Brother Kogyo Kabushiki K. Watanabe; Kosuke c/o Brother Kogyo Kabushiki K. Nukui
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2004-06-25
Filing date: 2005-06-24
Publication date: 2009-07-15
Anticipated expiration: 2025-06-24
Also published as: JP4206976B2; JP2006008328A; CN100379661C; CN1712341A; EP1612052A1; DE602005015391D1

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The invention is relates to a configuration of an image recording apparatus having a U-turn path, which separates recording media (cut sheets or sheets of paper) stacked substantially horizontally in a paper feed cassette one by one, to feed a separated recording medium to a recording unit of inkjet type located above the paper feed cassette.

2. Description of the Related Art

There are various conventional image recording apparatuses such as printers or facsimiles. For example, JP 2002-249248 A (see Fig. 1) discloses the following image recording apparatus. A number of sheets of paper (recording media or cut sheets) are substantially horizontally stacked and accommodated in a paper feed cassette, which is arranged in a lower portion of a main body (housing) thereof to be movable (capable of being pulled out) forward and rearward. A feeding roller is disposed in the vicinity of an inclined separating-portion at a leading end of the paper feed cassette and on an upper face of the paper feed cassette. In this image recording apparatus, after the inclined separating-portion guides a sheet of paper fed by the paper feeding roller upward, the sheet of paper is conveyed to a position below a recording head through a conveyance path including a reverse roller and a conveying guide plate (conveying-path plate) disposed to face an outer periphery of the reverse roller. The conveying guide plate has a substantially U-shaped section in side view. Then, the recording head forms an image on the sheet of paper. Thereafter, the sheet of paper is discharged to a front side of the main body of the image recording apparatus.
However, in order to drive the reverse roller as in the configuration of JP 2002-249248 A , a power transmission system including a group of gears is required for power transmission from a driving motor to the reverse roller. Also, the reverse roller should have a large diameter so as to follow a curved inner face of the conveying guide-plate. Thus, there arise problems in that a structure of the image recording apparatus becomes complicated and that a total height of the image forming apparatus becomes high.
Moreover, there arises a problem in that performance of separating recording media one by one at the inclined separating-plate at the leading end of the paper feed cassette varies (is not stable) between a case where a large amount of recording media are stacked in the paper feed cassette and a case where a stacked height of the recording media decreases with progress of an image recording task, or due to degree of rigidity of recording media.
The invention provides an image recording apparatus, which employs a relatively simple configuration to be able to reliably and stably feed even the last sheet of recording media to a recording unit.
EP 1 132 215 A describes a paper feeder for a recording apparatus having a feed roller of relatively large diameter about which a U-shaped conveying path is defined for feeding paper from a hopper to a printing carriage. A plurality of freely rotatable guide rollers are provided facing the outer surface of the feed roller, the conveying path being defined between the feed roller and the guide rollers.
According to one aspect of the invention, there is provided an image recording apparatus as defined in appended claim 1.
According to this structure, since the plurality of freely rotatable small-diameter rollers are provided at the central portion of the conveying-path member having the U-shape in a side view in the widthwise direction of the recording medium, the configuration is compact and the recording medium can be conveyed to the recording unit smoothly and reliably.
In addition to the aforementioned advantages, the following advantages can be achieved. The diameter of one roller located upstream in the conveyance direction is made large and the diameters of rollers located downstream in the conveyance direction are made gradually small, so that the height of the peripheral surfaces of the rollers protruding from the conveying-path member along the surface thereof can be decreased. Also, the resistance caused when the leading edge of the recording medium, which transfers upward from the separating unit, abuts against the peripheral surfaces of the rollers can be extremely decreased. As a result, the recording medium can be conveyed to the downstream side in the conveying-path member, which is curved in the U shape, smoothly and lightly, which is effective for preventing occurrence of paper jamming.
According to one aspect of the invention, a diameter of each roller may gradually increase from an end portion of each roller to a central portion of each roller.
Also, according to one aspect of the invention, a corner of an intersecting portion between a peripheral surface of each roller and an end surface of each roller may be removed.
According to those structures, stripes are not created in the surface (recording surface) of the recording medium conveyed while abutting against the peripheral surface of each roller, so that quality of a recorded image in the recording unit is hardly deteriorated.
According to one aspect of the invention, the conveying-path member may further include an accommodating portion that accommodates therein the rollers and shafts of the rollers while exposing the rollers and the shafts to a surface of the conveying-path member along which the recording medium passes. A cover member may be detachably disposed on the surface of the conveying-path member along which the recording medium passes to expose at least a part of each roller and cover the shafts of the rollers.
According to this structure, a troublesome work, which includes placing and mounting a plurality of rollers, for preventing the shafts from falling off can be simply performed by only mounting a cover.
According to one aspect of the invention, a surface of the conveying-path member on which the recording medium slides may be formed into a convex curved surface, on an upstream side in the conveyance direction of the recording medium. The convex curved surface may protrude at the central portion of the conveying-path member in the widthwise direction and retreats gradually as approaching end portions of the conveying-path member in the widthwise direction.
According to this structure, since both end portions of the recording medium in the widthwise direction, which is conveyed along the conveying path curved in the U-shape in a side view, do not come into sliding contact with the conveying-path member or the ribs, so that conveying resistance decreases and thus the recording medium can be conveyed smoothly and lightly.
According to one aspect of the invention, the conveying-path member may further include a plurality of ribs protruding from a surface along which the recording medium passes. The ribs elongate in the conveyance direction of the recording medium and are arranged at predetermined intervals at positions outer than the rollers. Each rib has a cross section in the widthwise direction of the recording medium in which each rib inclines outward at an obtuse angle toward an outside in the widthwise direction.
Also, according to one aspect of the invention, a surface defined by the conveying-path member and the ribs on which the recording medium slides may be formed into a convex curved surface, on an upstream side in the conveyance direction of the recording medium. The convex curved surface may protrude at the central portion of the conveying-path member in the widthwise direction and retreats gradually as approaching end portions of the conveying-path member in the widthwise direction.
According to the former structure, the plurality of ribs, which are arranged at the predetermined intervals at the positions outer than the rollers, have a cross section in the widthwise direction of the recording medium in which the ribs incline outward at the obtuse angle in the widthwise direction. Therefore, the recording medium is conveyed while side edges of the recording medium in the widthwise direction are placed on gentle slopes of the ribs. As a result, meandering of the recording medium can be prevented, and thus occurrence of paper jamming can also be prevented.
According to one aspect of the invention, the separating unit may include a separating member that abuts against leading edges of the plurality of recording media, at the central portion in the widthwise direction to separate the recording media one by one. The separating unit may further include a plate member having a convex curved surface that protrudes to the leading edges of the recording media in a vicinity of the separating member. The inclined separating-plate may retreat from the leading edges of the recording media as approaching end portions of the recording media in the widthwise direction.
According to this structure, the separating member provided in the separating unit at the central portion thereof in the widthwise direction can reliably perform an operation of separating recording media one by one by when the leading edges of the recording media in the widthwise direction firstly abut against the separating member.
According to one aspect of the invention, a rib may be integrally formed with a base portion of the separating unitto close a gap formed between a bottom plate of the feed cassette and the base portion of the separating unithaving the convex curved surface.
According to this structure, when a small amount of stacked recording media is fed in proximity with a bottomplate, the existence of the rib permits a leading edge of the recording medium to be reliably guided to the upper side of the separating unit without the leading edge of the recording medium being fitted into the gap.
According to one aspect of the invention, a friction member may be disposed at a bottom plate of the feed cassette to face the feeding unit. An upward guiding portion may be disposed on the bottom plate on a downstream side from the friction member in the conveyance direction of the recording medium and between a base portion of the separating unit and the friction member. The upward guiding portion is low on a friction-member side and is gradually high toward a base-portion side.
According to this structure, when a small amount of stacked recording media is fed in proximity with a bottom plate, a leading edge of the recording medium is guided upward reliably along the upward guiding portion. As a result, the recording medium can be reliably guided to the upper side of the separating unit without the leading edge of the recording medium being fitted into the gap.
According to one aspect of the invention, the separating unit may include an inclined plate member. An upper edge of the inclined plate member may extend to a position higher than a lower edge of the conveyance-path member on a recording medium-receiving surface of the conveying-path member so that the inclined plate member partially overlaps the conveyance-path member.
According to this structure, even when the recording media are stacked to approximately maximum amount, a recording medium can be smoothly transferred from the separating unit to a lower end of the conveying-path member:
According to one aspect of the invention, the feed cassette may include an engaging claw on a lower surface of a front end portion. The engaging claw engages with an engaged portion provided in the main body when the feed cassette is completely pushed into the main body of the image recording apparatus. A cam member may be provided between a lower surface side of a bottom plate of the feed cassette and the main body. The cam member guides and elevates the feed cassette while the feed cassette is being pulled out from the main body, to facilitate the engaging claw to be released from the engaged portion.
According to this structure, as the feed cassette is pushed into the main body of the image recording apparatus, the cam member elevates the feed cassette. In this state, the engaging claw is also pushed in while the engaging claw lightly comes into sliding-contact with an upper face of the engaged portion. The engaging claw can engage with the engaged portion at almost the same timing as when pushing-in of the feed cassette is completed. Therefore, the feed cassette descends in a substantially horizontal state, so that a set state of the feed cassette with respect to the main body can be held.
When the feed cassette is pulled out, the cam member elevates the front edge of the feed cassette by an appropriate distance. Therefore, at this timing, the engaging claw lightly comes into sliding contact with the upper face of the engaged portion. Accordingly, the disengagement of the engaging claw from the engaged portion can be facilitated. Further, it is possible to lessen deformation, wear or whitening of resin, which may be caused by violent collision of a lower edge of the engaging claw with the engaged portion due to the repeated advancing and retreating (attaching or detaching) operation of the feed cassette. Also, it is possible to provide a user with click feeling when the feed cassette is pushed in or pulled out.
According to one aspect of the invention, the conveying-path member may be detachably attached to the main body of the image recording apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of an image recording apparatus according to an embodiment of the invention, including an inkjet type recording head.
Fig. 2 is a side sectional view of the image recording apparatus.
Fig. 3 is a perspective view showing a state where an outer cover of a main body of the image recording apparatus and a lid cover member of an image reading device are detached.
Fig. 4 is a perspective view of the image recording apparatus in a state where the image reading device is removed.
Fig. 5 is an enlarged side sectional view taken along a line IV-IV in Fig. 3.
Fig. 6 is an enlarged side sectional view taken along a line VI-VI in Fig. 4.
Fig. 7 is a perspective view of a paper feed cassette and a feeding unit.
Fig. 8 is a perspective view of the paper feed cassette only.
Fig. 9 is a plan view of the paper feed cassette.
Fig. 10 is a perspective view of a state where a conveying-path member for U-turn path is disposed at a leading end of the paper feed cassette.
Fig. 11 is an enlarged sectional view taken along a line XI-XI in Fig. 9.
Fig. 12 is an enlarged side sectional view for explaining operation.
Fig. 13 is a sectional view taken along a line XIII-XIII in Fig. 12.
Fig. 14 is a perspective view showing an inner face (surface) of the conveying-path member for U-turn path as viewed from a lower side thereof.
Fig. 15 is a perspective view showing an outer face of the conveying-path member.
Fig. 16 is an enlarged side sectional view taken along a line XVI-XVI in Figs. 14 and 15.
Fig. 17A is a sectional view taken along a line XVIIa-XVIIa in Fig. 10, and Fig. 17B is a sectional view taken along a line XVIIb-XVIIb in Fig. 10.
Fig. 18 is a sectional view taken along a line XVIII-XVIII in Fig. 10.
Fig. 19 is a partial side view' showing a state where an inclined separating-plate is removed from the leading end portion of the paper feed cassette.
Fig. 20 is a sectional view taken along a line XX-XX with some part omitted in Fig. 14.
Fig. 21 is a perspective view showing an engaging member and a cam member at a lower face of the paper feed cassette.
Fig. 22 is a perspective view showing a part of a reinforcing bar on a bottom portion of an opening of an accommodating portion of the paper feed cassette.
Fig. 23 is a side view for explaining a pulled-out state from an engaging state of the paper feed cassette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, embodiments of the invention will be described.
The image recording apparatus 1 of this embodiment is a multi function device (MFD), to which the invention is applied, having a printer function, a copier function, a scanner function, and a facsimile function. As shown in Figs. 1 and 2, a paper feed cassette 3 is disposed on a bottom portion of a housing 2 composed of an injection-molded article made of a synthetic resin, which serves as a main body of the image recording apparatus 1 made of a synthetic resin. The paper feed cassette 3 is insertable through an opening portion 2a defined at a front side (left side in Fig. 2) of the image recording apparatus 1.
An image reading device 12 for reading a document in the copier function or the facsimile function is disposed in an upper portion of the housing 2. A bottom wall 11 of the image reading device 12 overlaps an upper cover member 30 without substantial gap therebetween from above the upper cover member 30. The image reading device 12 is rotatable up and down so as to be opened and closed, about one end of the housing 2 through a pivot portion, which is not shown. Further, a rear end of a document cover member 13, which covers an upper face of the image reading device 12, is mounted to be rotatable up and down about a pivot 12a with respect to the rear end of the image reading device 12.
On the upper side of the housing 2, -an operating panel 14 having various operation buttons, a liquid crystal display, and the like are disposed at the front of the image reading device 12. The upper face of the image reading device 12 is provided with a glass plate 16 for placement, on which a document can be placed after the document cover member 13 is opened upward. Below the glass plate 16, an image scanner (CIS: Contact Image Sensor) 17 for reading a document is provided so as to be reciprocable along a guide shaft 44 extending in a direction (a main scanning direction or Y-axis direction in Figs. 1, 3 and 4) orthogonal to the surface of paper showing Figs. 2, 5 and 6.
A recording unit 7, a paper discharging unit 10 and an ink storage unit 15 provided on one side of the paper discharging unit 10 are arranged below the image reading device 12 and the operation panel 14 so as to be located within a projection area of the image reading device 12 and the operation panel 14 in plan view.
As shown in Figs. 2 to 6, the recording unit 7 is supported by a box-shaped main frame 21 and a pair of left and right lateral plates, and is formed between a first and second guide members 22 and 23 which have a laterally elongated plate shape and extend in the Y-axis direction (main scanning direction). A carriage 5 on which having a recording head 4 of the recording unit 7 is mounted is slidably supported (mounted) while bridging the first guide member 22 on the upstream side in a paper conveyance direction and the second guide member 23 on the downstream side in the paper conveyance direction, so as to be reciprocable therebetween.
In order to reciprocate the carriage 5, a timing belt 24 is disposed on the upper face of the second guide member 23 disposed on the downstream side in the paper conveyance direction (the direction indicated by an arrow A), to extend in the main scanning direction (Y-axis direction). The timing belt 24 is wound around a pulley. A CR (carriage) motor 25 (shown in Fig. 4), which drives the timing belt 24, is fixed to the lower face of the second guide member 23. In this embodiment, the motor may be any other motor such as a DC motor or a stepping motor. The second guide member 23 is provided with an encoder strip 47 extending along the main scanning direction, for detecting a position of the carriage 5 in the Y-axis direction (main scanning direction). The encoder strip 47 of a stripe shape is disposed such that its detecting surface (a surface where slits are arranged at regular intervals in the Y-axis direction) extends in a vertical direction.
A flat platen 26, which extends in the Y-axis direction so as to face the lower face of the recording head 4 in the carriage 5, is fixed to the upper side of a bottom plate 21b of the main frame 21, between both the guide members 22 and 23.
A partition plate (lower cover) 29 made of a synthetic resin is integrally formed with the housing 2 so as to cover an upper side of the paper discharging unit 10 from the lower face 23 of the guide member 23 on the downstream side in the paper conveyance direction to a paper discharging port 10a at a front end of the housing 2 (see Figs. 2 and 4) at almost the same height position as a bottom plate 21b of the main frame 21.
Further, the upper cover member 30 is disposed above the partition plate (lower cover) 29 with an appropriate space therebetween so as to cover the carriage 5 and the upper side of its reciprocating path. In addition, a rectangular window hole 31, which allows the reciprocating path of the carriage 5 to be seen from the top, is formed in a midway portion of the upper cover member 30 (see Fig. 3). If a sheet of paper P causes paper jamming in the recording unit 7, a user can turn the image reading device 12 from the housing 2 to remove the paper P through the window hole 31.
Next, an arrangement of flexible ink supply tubes 20, which always connects individual ink cartridges 19 housed in the ink storage unit 15 with the recording head 4 in the recording unit 7, will be described.
The ink storage unit 15 is open to the upper side of the housing 2. The substantially rectangular ink cartridges 19 (reference numerals 19a to 19d respectively denote ink cartridges for individual colors, that is, black (BK), cyan (C), magenta (M) and yellow (Y); see Figs. 3 and 4), which respectively contain four kinds of color ink for full color recording, have a small area in plan view and have a large height dimension. The ink storage unit 15 is configured so as to be able to accommodate the ink cartridges 19 with being arranged in a single row along an X-axis direction and to be detachable from above.
Also, ink is supplied from the respective ink cartridges 19 (individually denoted by reference numerals 19a to 19d) to the inkjet-type recording head 4 through a plurality of (four in the embodiment) ink supply tubes (ink tubes) 20 (individually denoted by reference numerals 20a to 20d; see Fig. 5). In addition, when several ink colors (six to eight colors, etc.) more than four colors are used, cartridges corresponding to the number of the ink colors may be housed in ink storage unit 15, and the number of the ink supply tubes 20 may also be increased in accordance with the number of the ink cartridges.
In the embodiment, the respective ink supply tubes 20a to 20d are mutually independent tubes. Further, the ink supply tubes 20a to 20d having the same length are used.
As shown in Figs. 4 and 5, root portions of the plurality of (four in the embodiment) ink supply tubes 20 are bundled by a portion of one end 15a of the ink storage unit 15, and the ink supply tubes 20 extend on the upper face of the lower cover 29 from one end (right end as viewed from the downstream side in the paper conveyance direction, in Fig. 4) thereof toward the other end (left end as viewed from the downstream side in the paper conveyance direction, in Fig. 4) along the Y-axis direction. In this case, the root portions of all the ink supply tubes 20a to 20d are arranged laterally in a row along the upper face of the substantially flat lower cover 29. At least portions (midway portions or the like) of the ink supply tubes 20 are supported by the upper face of the lower cover 29.
Subsequently, all the ink supply tubes 20a to 20d are twisted so that its midway portions extend along a one longitudinal face (an almost vertical plane) of a laterally long longitudinal partitioning plate 32 in the lower cover 29. Also, the midway portions of all the ink supply tubes 20a to 20d are arranged longitudinally in a row and fixed (held or pinched) between the one longitudinal face of the longitudinal partition plate 32 and a longitudinal plate-shaped fixing member 33 made of a synthetic resin, which is fixed with screws or the like while facing the one longitudinal face of the longitudinal partition plate 32. Portions of the fixing member 33 and one longitudinal face of the longitudinal partition plate 32, which fix (hold) all the ink supply tubes 20a to 20d, serve as an intermediate fixing portion.
The carriage 5 is provided with a coupling piece, which extends substantially horizontally toward the downstream side in the paper conveyance direction (a direction indicated by an arrow A). Leading ends of all the ink supply tubes 20a to 20d are connected to a connecting portion provided at the left end as viewed from the downstream side in the paper conveyance direction in Fig. 4 in the coupling piece to be arranged in a lateral row, which is substantially horizontal. Also, orientation of the midway portions of the all the ink supply tubes 20a to 20d is changed from left to right between the intermediate fixing portion (fixing member 33) and the connecting portion. A phase of the row (array) of all the ink supply tubes 20a to 20d are twisted and arranged so as to be changed to the substantially horizontal direction on the connecting portion side from the substantially vertical direction on the fixing members 33 side. As a result, although the respective ink supply tubes 20a to 20d are bent independently from each other, all the ink supply tubes 20a to 20d are easily bundled together. Of course, all the ink supply tubes 20a to 20d are separated independently from each other between the fixing member 33 (intermediate fixing portion) and the connecting portion.
Further outside a width (short sides of a sheet of paper P) of a sheet of paper P to be conveyed, an ink receiving portion is disposed at one end (right end as viewed from the downstream side in the paper conveyance direction in Fig. 4 in the embodiment) and a maintenance unit is disposed at the other end (left end as viewed from the downstream side in the paper conveyance direction in Fig. 4). Both of the ink receiving portion and the maintenance unit are not shown in the drawings. This configuration allows the recording head 4 to regularly eject ink at a flushing position provided in the ink receiving portion, to prevent ink from clogging nozzles during recording operation. The ink receiving portion receives the thus ejected ink. The maintenance unit is located to face the carriage 5 in a standby position. A cap portion of the maintenance unit covers surfaces of the nozzles of the recording head 4 from below, and performs recovery process for selectively sucking ink for each color or removing bubbles in an ink buffer tank (not shown) of the recording head 4. In addition, when the carriage 5 laterally moves to approach the maintenance unit, a cleaner (cleaning blade), which is not shown, wipes out the nozzle surfaces to perform cleaning.
In this embodiment, a flexible flat cable 40 is provided for transmitting command signals, which cause ink to be selectively ejected from the nozzles of the recording head 4 mounted on the carriage 5, from a control unit (not shown) provided in the housing 2. The flexible flat cable 40 is disposed substantially parallel to the direction in which the ink supply tubes extend, in a region (a movable region, an non-bundled region or an unconstrained region) through which the ink supply tubes 20a to 20d pass when the carriage 5 reciprocates in the Y-axis direction (main scanning direction) (see Fig. 4).
Also, a convexly curved direction of the curved midway portions of the ink supply tubes 20 is set to be opposite to that of a curved midway portion of the flexible flat cable 40, with respect to the direction in which the carriage 5 reciprocates. This configuration allows the ink supply tubes 20 and the flexible flat cable 40 to be arranged at almost the same height (within almost the same horizontal plane) in the vertical direction. As a result, the entire image recording apparatus 1 can be reduced in thickness.
Further, a pair of registration rollers (conveying rollers) 27 are disposed on the upstream side of the platen 26 for sending a sheet of paper P to a position below the recording head 4. A bearing (mounting part) (not shown) for a driving shaft 50 of the paper feeding arm 6a and paper discharging rollers 28 for conveying a sheet of paper P, for which recording has been made, to the paper discharging unit 10 are disposed on the downstream of the platen 26 (see Figs. 2, 5 and 6).
Next, a configuration of a paper feeding device will be described in detail. In this embodiment, the paper feed cassette 3 is configured to receive a plurality of stacked sheets of paper P so that short sides of the sheets of paper P serving as recording media, which are cut into, for example, A4 size, letter size, legal size or other size extend in a direction (a direction orthogonal to the paper showing Fig. 2, the main scanning direction and the Y-axis direction) orthogonal to the paper conveyance direction (the sub-scanning direction and the X-axis direction). In addition, an auxiliary supporting member 3a, which supports a rear end of long paper P such as a legal size paper, is mounted at a front end (corresponding to the front face of the housing 2) of the paper feed cassette 3 so as to be movable in the X-axis direction (see Figs. 7 to 10). Fig. 2 shows a state where the auxiliary supporting member 3a is disposed at a position where the auxiliary supporting member 3a protrudes out of the housing 2. When a sheet of paper P such as an A4 size paper, which may be received in the paper feed cassette 3 (i.e., which does not protrude out of the housing 2 through the opening portion 2a), is used, the auxiliary supporting member 3a can be received in the accommodating portion 3b so that the auxiliary supporting member 3b does not obstruct paper feeding.
Next, a configuration of a feeding unit 6 will be described. The driving shaft 50 made of a synthetic resin as shown in Fig. 7 is rotatably supported by shaft holes, which are respectively formed in a side plate in the main frame 21 and a pair of shaft supporting plates (both of them are not shown). A leading end of the driving shaft 50 is inserted into a base portion of the paper feeding arm 6a of the feeding unit 6 so as to protrude therefrom laterally. Also, with the rotational driving of the driving shaft 50, a paper feeding roller 6b rotates in a predetermined direction (counterclockwise in Fig. 6) through a gear transmission mechanism 6c provided in the paper feeding arm 6a. Further, A biasing member (for example, a torsion spring) (not shown) biases the paper feeding roller 6b so as to be always at a lower position than the bottom plate 21b.
Further, an inclined separating-plate 8, which will be described below in detail, for separating sheets of paper is disposed at a rear end (right side in Figs. 2, 7 and 10, and left side in Figs. 8 and 9) of the paper feed cassette 3. Further, a base end portion of the paper feeding arm 6a of the feeding unit 6 is mounted at the bottom plate 21b of the main frame 21 so as to be rotatable in the up-and-down direction. Sheets of paper P serving as recording media, which are stacked in the paper feed cassette 3, are separated one by one and conveyed by the paper feeding roller 6b provided at a lower end of the paper feeding arm 6a and an elastic separating pad 8a (composed of a plate spring in the embodiment) serving as a separating member provided at a central portion in a widthwise direction (Y-direction) on an inner face (surface) of the inclined separating-plate 8. A separated sheet of paper P is fed to the recording unit 7 provided in an upper portion (at a higher position) than the paper feed cassette 3, through the conveying-path member 9 as a U-turn path (paper conveying path) directing laterally upward, which is constructed as will be described below.
The paper discharging unit 10 to which a sheet of paper P recorded in the recording unit 7 is discharged with its recording surface upward is disposed above the paper feed cassette 3. The paper discharging port 10a communicating with the paper discharging unit 10 is open to be common to the front opening portion 2a of the housing 2.
Further, in a state where the auxiliary supporting member 3a of the paper feed cassette 3 is received in the accommodating portion 3b, a length of the paper feed cassette 3 in the X-axis direction and a length of the image reading device 12 and operation panel 14 in the X-axis direction are almost the same. Accordingly, since the image recording apparatus 1 becomes a rectangular parallelepiped having a substantially square shape in plan view, it is easy to package the image recording apparatus 1 at the time of packaging for shipment as a product, and a packaging box can also be reduced in size.
An overlap feeding preventing member 51 retains a sheet of paper P to be finally fed in the paper feed cassette 3 while the paper feeding roller 6b feeds a number of sheets of paper P (100 sheets in the embodiment) stacked horizontally on a bottom plate 3c of the paper feed cassette 3 made of a synthetic resin in a direction toward the conveying-path member 9 as the U-turn path. The overlap feeding preventing member 51 includes a base pad 52, such as cork, serving as a high frictional coefficient member and base plates 53 serving as a low frictional coefficient member. The base pad 52 is disposed in the bottom plate 3c of the paper feed cassette 3, which faces the paper feeding roller 6b. The base plates 53 are made of a metallic plate such as stainless steel.
In this embodiment, the base pad 52 and the base plates 53 are arranged in parallel in a direction orthogonal to the feeding (conveying) direction (indicated by an arrow in Fig. 12) of a sheet of paper P. Preferably, the base plates 53 are disposed on both sides of the single base pad 52 so as to be close to an end portion of a jump board 54 on the downstream of the conveyance direction (see Figs. 8, 9, 12 and 13). The jump board 54 is integrally formed with the bottom plate 3c to protrude therefrom and is high on the downstream side in the feeding direction. These two base plates 53 are fixed to an upper face of the bottom plate 3c with adhesive. A through hole 55 is formed in the up-and-down direction in the bottom plate 3c between the positions where the pair of base plates 53 are arranged. A base spring 56 serving as a supporting member having the base pad 52 fixed and supported on the upper surface thereof with adhesive is disposed in the through hole 55.
A cylindrical outermost circumferential member 6b1 of the paper feeding roller 6b is made of a material such as synthetic rubber. A material and surface shape (that is, frictional coefficient) of the outermost circumferential member 6b1 is determined so that when the paper feeding roller 6b is pressure-contacted with a sheet of paper P, a frictional force generated between the paper feeding roller 6b and the sheet of paper P contacted therewith exceeds a frictional force generated between the sheet of paper P contacted therewith and another sheet of paper P immediately below the sheet of paper P. In this embodiment, elastomer or ethylene propylene rubber (EPDM) is employed as the material making up the outermost circumferential member 6b1. Knurls are formed in a direction perpendicular to the conveyance direction on the surface of the outermost circumferential member 6b1.
Similarly, a material and surface shape of the base pad 52 are determined so that when the paper feeding roller 6b is pressure-contacted with a sheet of paper P while the paper feeding roller 6b rotates, a frictional force generated between the base pad 52 and the sheet of paper P contacted with the base pad 52 exceeds a frictional force generated between the sheet of paper P contacted with the base pad 52 and another sheet of paper P immediately above the sheet of paper P. In this embodiment, cork is employed as the material making up the base pad 52.
Also, a material and surface shape of the base plates 53 are determined so that when the paper feeding roller 6b is pressure-contacted with the last one sheet of paper P while the paper feeding roller 6b rotates, a frictional force generated between the paper feeding roller 6b and the sheet of paper P contacted with the paper feeding roller 6b exceeds a frictional force generated between (a) both the base pad 52 and the base plates 53 and (b) the paper P contacted with the base pad 52 and base plates 53. In this embodiment, a stainless steel plate having a small surface roughness is employed as the base plates 43. Alternatively, a nickel-plated steel plate may be employed.
Also, a width W1 (dimension in the direction orthogonal to the feeding direction) of the outermost circumferential member 6b1 is set so as to extend over at least the widthwise midway portions of the base plates 53 on both sides of the base pad 52 (see Fig. 13).
The base spring 56 composed of the metal plate spring having spring elasticity is attached so that an engaged hole 56a formed in a base portion of the base spring is engaged with a engaging claw 54a integrally formed with a lower face of the jumping board 54 so as not to drop out of the engaging claw 54a. Further, a positioning hole 56b such as a round hole, which is formed in the vicinity of the engaged hole 56a in the base portion of the base spring 56, is closely engaged with a projection 54b protruding from the lower face of the jumping board 54 so that a protruding direction of the base spring 56 is not deviated in the left and right directions. In this way, the base spring 56 is supported by the bottom plate 3c in a cantilevered fashion, and the leading end (free end) of the base spring 56 is elastically biased toward the upper side of the through hole 55.
The leading end (free end on the downstream side in the feeding direction) of the base spring 56 includes a regulating piece 57 bent to have a U-shaped section for preventing floating. With this configuration, in a state where the outermost circumferential member 6b1 of the paper feeding roller 6b does not presses the base pad 52 downward (including a state (referred to as a no-load state) where the outermost circumferential member 6b1 does not press the base pad 52 via a sheet of paper P on the bottom plate 3c), a leading edge (upper edge) of the regulating piece 57 abuts against the lower face of the bottom plate 3c in the vicinity of the through hole 55 to regulate the base pad 52 so that a portion of the surface (upper face) of the base pad 52 on the base spring 53, which is located at a position corresponding to a contact portion with the paper feeding roller 6b, does not protrude upward beyond a predetermined value (about 0.5 mm in this embodiment) from the surface (upper face) of the base plates 53 a height of which is fixed at the corresponding position. In addition, that predetermined value varies depending on the plate thickness, material, or shape in plan view of the base spring 56. The predetermined value may be designed so that when the last second sheet of paper P is fed, the base pad 52 is prevented from becoming the same height as the base plates 53 due to a pressure contact force of the paper feeding roller 6b. Further, the height position of the surface of the base pad 52 on the upstream side in the feeding direction is set to be almost equal to the height position of the surface (upper face) of the base plates 53 at the corresponding position. Also, the surface of the base pad 52 is set so that the base pad 52 and the base plates 53 are substantially parallel to each other when the base pad 52 is pushed in by the paper feeding roller 6b, and thereby the base pad 52 and the base plates 53 have the same height.
In this embodiment, the base spring 56 is formed in a substantially trapezoidal shape in plan view, in which a width at its base end portion is larger than that at its free end portion. The base plates 53 are formed in a substantially trapezoidal shape in plan view, in which a width on the upstream side in the feeding direction is smaller than that on the downstream side, contrary to the base spring 56 (see Figs. 8 and 9).
In this manner, the widthwise dimension of the base plates 53, which is required when they are disposed on both right and left sides of the base spring 56, can be decreased as much as possible. Also, a bending sectional area of the base spring 56 can be increased. Thus, any stress concentration can be relieved.
When the base plates 53 serving as a low frictional coefficient member is made of a plate material including metal such as stainless, wear resistance thereof is high and the frictional coefficient of a surface is low. Thus, the feeding operation of the last sheet of paper P can be reliably performed in comparison with a case where the surface of the bottom plate 3c made of the synthetic resin is used as the low frictional coefficient member. Further, an upward guiding portion 3e having a slope surface, which is low on the upstream side in the feeding direction of a sheet of paper P and becomes high toward the downstream side in the feeding direction, is integrally formed between the base pad 52 and the base portion of the inclined separating-plate 8 (see Fig. 9 and 12) on the surface of the bottom plate 3c. According to this structure, in a state where an amount of sheets of paper P stacked in the paper feed cassette 3 has decreased, a leading end of a sheet of paper P fed by the paper feeding roller 6b abuts against a higher position of the inclined separating-plate 8 than the base portion of the inclined separating-plate 8, so that operation of feeding the sheet of paper P upward can be smoothly performed. In addition, the upward guiding portion 3e may include a flat portion, which is substantially parallel to the surface of the bottom plate 3c at a high portion of the guiding portion and extends toward the base portion of the inclined separating-plate 8.
Moreover, in the direction orthogonal to the feeding direction (Y direction; and a widthwise direction of a sheet of paper P) of the sheet of paper P, the surface of the inclined separating-plate 8 is formed into a convex curved surface (see Fig. 9), which (a) protrudes toward leading edges of the sheets of paper P on a central portion in the widthwise direction thereof, at a portion in the vicinity of a saw-like separating pad 8a serving as a separating member, which is located on a central portion in the widthwise direction of the sheets of paper P; and (b) retreats from the leading edges of the sheets of paper P as approaching both end potions of the sheets of paper P in the widthwise direction thereof. In this way, the surface of the inclined separating-plate 8 is the convex curved surface, so that the leading edges of the fed sheets of paper P on the central portion in the widthwise direction thereof reliably sliding contacts with the separating pad 8a to be subject to separating action of the sheets of paper P before the both end portions of the sheets of paper P in the widthwise direction thereof abut against the inclined separating-plate 8.
In addition, freely rotating rollers 60 for smoothly guiding the sheet of paper P in a direction toward the conveying-path member 9 are attached on both right and left sides of the separating pad 8a in the vicinity of the upper end of the inclined separating-plate 8 (see Figs. 8, 9 and 18) . Also, the inclined separating-plate 8 is formed separately from the paper feed cassette 3 so as to be detachably mounted on the leading end of the paper feed cassette 3 (see Fig. 19).
Next, a configuration in which the paper feeding arm 6a automatically moves up or down when the paper feed cassette 3 is inserted into or removed from the bottom portion of the housing 2 will be described. A substantially flat-plate shaped cam follower member 58, which is parallel to the driving shaft 50 and integrally protrudes from the paper feeding arm 6a made of a synthetic resin, is disposed on a lower face side of the bottom plate 21b of the main frame 21. The cam follower member 58 extends above a cam portion 59 on the upper face of the side plate 3d in the paper feed cassette 3 (see Fig. 7). Also, the cam follower member 58 is set so that the cam follower member 58 approaches approximately the lower face of the bottom plate 21b so as to be substantially parallel thereto in a state where most part of the rotated and raised paper feeding arm 6a and paper feeding roller 6b is housed on an upper face side of the main frame 21 through an opening 21c (see Fig. 6) of the bottom plate 21b.
The cam portions 59, which come into sliding contact with the cam follower member 58 according to advancing or retreating (movement in the X-axis direction) of the paper feed cassette 3 to move up or down the paper feeding arm 6a and the paper feeding roller 6b integrally, are integrally formed on upper end surfaces of the opposite right and left lateral plates 3d, which are opposite end portions in the Y-axis direction, sandwiching therebetween the bottom plate 3c of the accommodating portion for the papers P in the paper feed cassette 3 made of a synthetic resin (see Figs. 7 to 9).
According to this structure, when the paper feed cassette 3 is inserted through the front opening portion 2a of the housing 2, and then the lower face of the cam follower member 58 abuts against a start end (a side nearer to the inclined separating-plate 8 serving as a bank member) of the cam portion 59, the cam follower member 58 is pushed up with the advancing movement of the paper feed cassette 3, and the paper feeding arm 6a and the paper feeding roller 6b rotates upward integrally with the cam follower member 58. Then, the paper feeding roller 6b and the paper feeding arm 6a go beyond the upper side of the inclined separating-plate 8. In a state where the paper feeding arm 6a and the paper feeding roller 6b are raised, the paper feeding arm 6a and the paper feeding roller 6b are accommodated in an upper space (within the main frame 21) of the bottom plate 21b through the opening 21c. At that time, the flat cam follower member 58 is also brought into abutment or close contact with the lower face of the bottom plate 21b. Accordingly, the up-and-down rotation operation of the paper feeding arm 6a and the paper feeding roller 6b can be ensured, without increasing a height of vertical space between the bottomplate 21b of the main frame 21 and the paper feed cassette 3. In other words, a height from the paper feed cassette 3 to the bottom plate 21b of the main frame 21 can be reduced, so that it is possible to provide the compact image recording apparatus 1 a total height of which is decreased.
When the cam follower member 58 is located at a descending portion of the cam portion 59 after going across the uppermost position thereof, the paper feeding arm 6a and the paper feeding roller 6b, which are biased downward, rotate downward. Then, the paper feeding roller 6b can be brought into abutment with the uppermost sheet of paper P of papers, which are stacked in the accommodating portion 3b.
When the paper feed cassette 3 is advanced to the innermost position in the housing 2 (a set state), if one end (lower end) of the cam follower member 58 in the paper feeding arm 6a, which has rotated downward, abuts against the lowermost position of the cam portion 59, the paper feeding roller 6b can abut against the overlap feeding preventing member 51 (see Figs. 7 and 12).
In this way, since the feeding unit 6 is provided with the cam follower member 58, which is located below the bottom plate 21b of the main frame 21, and the paper feed cassette 3 is provided with the cam portion 59 for at least temporarily raising and rotating the feeding unit 6 as well as the cam follower member 58 according to the advancing or retreating movement of the paper feed cassette 3 with respect to the inside of the housing 2 (main body case), the feeding unit 6 can be automatically elevated according to the advancing and retreating operation of the paper feed cassette 3, which results in that operation becomes simple.
The conveying-path member 9 serving as the U-turn path (conveying-path member), which conveys a sheet of paper P from the upper end of the inclined separating-plate 8 to the recording unit 7, is manufactured by injection-molding a synthetic resin so as to have a plate portion 9a of a lateral U-shape in side view. At a back face (rear face) of the conveying-path member 9 on both right and left sides thereof, elastic engaging portions 62 and elastic knob portions 63 are integrally formed with the plate portion 9a (see Fig. 15). The conveying-path member 9 is insertable into an inside of the housing 2 through an opening defined at a rear end of the housing 2 at an upper end of the inclined separating-plate 8 of the paper feed cassette 3 pushed into the bottom portion of the housing 2. The conveying-path member 9 can be mounted on the housing 2 in a predetermined posture and can be detached therefrom. Therefore, when paper jamming occurs, it is easy to detach the conveying-path member 9 from the housing 2, thereby dealing with the paper jamming easily.
As shown in Figs. 6, 10, and 14 to 18, a plurality of ribs 61, which extend parallel to the conveyance direction of a sheet of paper P, protrude integrally from the plate portion 9a at appropriate intervals in the widthwise direction (Y direction) orthogonal to the conveyance direction. In this case, a sectional shape of each rib 61 is laterally symmetrical with respect to the center in the widthwise direction of a sheet of paper P. Each rib 61 has a gentle slope 61a at an obtuse angle θ1 toward an outside in the widthwise direction of a sheet of paper P (see Fig. 20). The obtuse angle θ1 is an angle defined between a surface of the plate portion 9a and the gentle slope 61a, and is preferably in a range of 130 degrees to 140 degrees. According to this structure, when a sheet of paper P having a width approximately equal to a distance between a pair of right and left ribs 61 and 61 is conveyed, even if a conveying position of the sheet of paper P is a little deviated in the widthwise direction of the sheet of paper P, a side edge of the sheet of paper P along the conveyance direction is placed so that a sliding resistance thereof against the slope 61a at the obtuse angle θ1 is small. Accordingly, it is possible to prevent occurrence of problems that, as in a related art including stripe ribs standing upright from a surface of a plate portion, the side edge of the sheet of paper P conveyed is hit against and constrained by the upright lateral faces of the stripe ribs, and consequently the paper P meanders to cause paper jamming, or undulating stripes (referred to as corrugations), which extend along the conveyance direction, are created on the surface of the paper P.
As shown in Fig. 14, similar to the inclined separating-plate 8, an envelope curve, which connects an inner face of the plate portion 9a of the conveying-path member 9 and the leading ends of the plurality of the ribs 61, respectively on the upstream side of the paper conveyance direction, is formed into a convex curved surface, which protrudes at a central portion of the conveying-path member 9 in the widthwise direction and retreats gradually as approaching end portions of the conveying-path member 9 in the widthwise direction. Accordingly, both left and right side portions of the leading edge of the sheet of paper P in the widthwise direction, which is conveyed along the inner face (surface) of the conveying-path member 9, hardly touch the inner face (surface) of the plate portion 9a, which makes it possible to reduce conveying resistance.
A plurality of rollers 64 freely rotating are provided at least a central portion of the conveying-path member 9 in the widthwise direction of the sheet of paper P (see Figs. 14, 16 and 17B). The plurality of rollers 64 are arranged at appropriate intervals along the conveyance direction of the sheet of paper P. Suffixes a, b, c and d are added to the respective rollers 64 sequentially from the upstream side. Also, a diameter of a roller 64 disposed on the upstream side in the conveyance direction is larger than that of another roller 64 disposed on the downstream side.
In this embodiment, the most downstream roller 64c and an upstream roller 64d adjacent thereto have almost the same diameter. Also, in this embodiment, two rollers 64 having the same diameter are provided with appropriate spacing therebetween in the widthwise direction of the sheet of paper P.
The plate portion 9a of the conveying-path member 9 is integrally formed with an accommodating portion 66, which allows the respective rollers 64a to 64d and their supporting shafts 65 to be exposed toward a surface on which paper P passes (see Figs. 14, 15, 16 and 17A). Supporting portions 67 for supporting the supporting shaft 65 protruding from both ends of the respective rollers 64a to 64d are concavely formed in the accommodating portion 66 as an opening groove having a substantially semicircular arc shape in section.
A cover member 68 made of a synthetic resin is detachably disposed on the surface of the accommodating portion 66 so as to expose at least a part of a peripheral surface of each of the rollers 64a to 64d and to cover the supporting portion 67 for each supporting shaft 65 (see Figs. 14, 16 and 17A). Also, the cover member 68 is curved in a lateral U-shape in side view so as to extend along the surface of the plate portion 9a. Window holes 68a, which allows a part of the peripheral surface of each of the rollers 64a to 64d to be exposed are defined in a wide surface of the cover member 68 at predetermined corresponding positions. A lower portion of the cover member 68 defines a recess 70, which engages with a projection 69 projecting from the plate portion 9a. Further, an upper end of the cover member 68 is formed with a engaging claw 72, which engages with an engaged step portion 71 formed at an upper end of the plate portion 9a (see Fig. 16). With this configuration, the configuration of the supporting portions 67 of the rollers 64a to 64d can be made simple, and assembling and replacement works of the respective rollers 64a and 64d can be facilitated.
As described above, the diameter of the roller 64a on the upstream side in the conveyance direction is made large and a height by which a peripheral surface of the roller 64a protrudes from the cover member 68 is made small, whereby an angle between the surface of the cover member 68 and the peripheral surface of the roller 64a is an obtuse angle approximate to 180 degrees. As a result, resistance, which is caused when the leading edge of the sheet of paper P, which shifts upward from the inclined separating-plate 8, contacts the peripheral surfaces of the rollers 64a, can be extremely decreased. The conveying operation of the sheet of paper P to the downstream side in the plate portion 9a, which is curved in a U-shape, can be performed smoothly, which is effective in preventing occurrence of paper jamming.
In addition, a diameter of each of the rollers 64a to 64d increases sequentially as approaching from an end portion of each roller to a central portion of each roller. Preferably, the maximum diameter portion of the rotating peripheral surface of the roller is formed into a cylindrical surface, or the entire rotating peripheral surface of the roller is formed into a convex curved surface. Thereby, a stripe is not formed on a recording surface (facing a front face of the plate portion 9a) of the sheet of paper P conveyed, and an image recording quality in the subsequent recording unit 7 is not deteriorated. Moreover, if an intersecting portion between the rotating peripheral surface of each of the rollers 64a to 64d and an end surface of each of the rollers 64a to 64d is removed (rounding the intersecting portion), it becomes possible to prevent the stripe from occurring in the recording surface of the sheet of paper P reliably, to thereby further stabilize the image recording quality.
In this embodiment, the maximum stack amount of sheets of papers P in the paper feed cassette 3 is set to about 100 sheets for normal paper and the height (H1) of stack is set to about 10 mm. Correspondingly to this, the height (vertical height from the upper face of the bottom plate 3c to the upper end of the inclined separating-plate 8) of the inclined separating-plate 8 is increased so that a sheet of paper P fed around the time of the maximum stack can be smoothly transferred to the lower end of the plate portion 9a of the conveying-path member 9. Preferably, an upper edge 8b of the inclined separating-plate 8b extends to a position higher than a lower edge of the plate portion 9a so that the inclined separating-plate 8 covers the front face side of the plate portion 9a, that is, partially overlaps the plate portion 9a (see Figs. 17A and 18).
As shown in Figs. 9, 10, 11, 17B, 18 and 19, in order to close a gap formed between a based portion of the inclined separating-plate 8 and a rear edge of the bottom plate 3c of the paper feed cassette 3 due to forming the inclined separating-plate 8 into the convex curved surface, the base portion of the inclined separating-plate 8 is integrally formed with supplementary ribs 73 having an appropriate length and a substantially triangular section shape, at predetermined intervals in the Y direction. When the sheets of paper P is fed in proximity to the bottom plate 3c in a state where the stacked amount of sheets of paper P is small, the existence of the supplementary rib 73 permits the leading edge of the sheet of paper P to be reliably guided to the upper side of the inclined separating-plate 8 without the leading edge of the sheet of paper P being fitted into the gap.
Figs. 21 to 23 show a configuration, which can maintains an engaging state where the paper feed cassette 3 is substantially horizontally inserted through the opening portion 2a of the lower accommodating portion of the housing 2 and can easily release the engaging state when the paper feed cassette 3 is pulled out. Specifically, the lower face of the paper feed cassette 3 made of the synthetic resin is integrally formed with reinforcing ribs 76 elongating in the insertion direction toward the opening portion 2a. The reinforcing rib 76 is integrally formed with a cam portion 77 having a substantially trapezoidal shape in downward side view. A plurality of (two in this embodiment) the reinforcing ribs 76 and the cam portion 77 are provided in the Y direction at appropriate intervals. On the other hand, the bottom face of the housing 2 made of the synthetic resin is integrally formed with a coupling piece 79, which couples with the paper feed cassette 3 in a direction (Y direction) orthogonal to the insertion direction (X direction) of the paper feed cassette 3 (see Figs. 22 and 23).
When the paper feed cassette 3 is substantially horizontally inserted into the housing 2, the lower edge of the cam portion 77 comes into sliding-contact with the upper face of the coupling piece 79. At a position where the insertion of the paper feed cassette 3 into the housing has completed, the cam portion 77 is located in an inward space of a rear edge 79a of the coupling piece 79, and the lower edge of the cam portion 77 falls into a space below the upper face of the coupling piece 79 (see a solid line in Fig. 23). To the contrary, as the paper feed cassette 3 is pulled out, the leading edge of the cam portion 77 abuts against the rear edge 79a of the coupling piece 79. Then, the cam member is constituted by the cam portion 77 and the coupling piece 79 so that the lower edge of the cam portion 77 moves to the front side of the housing 2 substantially horizontally while riding on the upper face of the coupling piece 79 (see two-dotted chain line in Fig. 23).
Further, a plate-shaped engaging claw 80 and a pair of guiding plates 81 on the left and right side of the engaging claw protrude downward and are formed integrally between the front end reinforcing plate 78 of the paper feed cassette 3 and the cam portion 77 of the paper feed cassette 3 (see Figs. 21 to 23). The engaging claw 80 elongates in the Y direction and is flat in the X direction. Both the guiding plates 81 elongate in the Y-direction and are flat in the X direction. On the other hand, the front end of the coupling piece 79 is formed with engaged portion 82 corresponding to positions of the engaging claw 80 and the pair of guiding plates 81. The engaged portion 82 includes a projection 83, which holds the pushed-in state of the engaging claw 80, and guide grooves (invitation grooves) 84, which are provided on both right and left sides of the projection 83, elongate in the X direction and open at their front ends (see Figs. 22 and 23).
In the above configuration, as the paper feed cassette is pushed into the housing 2, the lower edge of the cam portion 77 rides on the upper face of the coupling piece 79. In this state, the lower edge of the engaging claw 80 is also pushed in while the lower edge of the engaging claw 80 lightly comes into sliding-contact with the upper face of the projection 83. After the lower edge of the engaging claw 80 goes beyond the rear end of the projection 83 at almost the same timing (at the time of complement of push-in) as when the front edge of the cam portion 77 has moved beyond the rear edge 78a of the coupling piece 79, the paper feed cassette 3 descends in a substantially horizontal state, and the engaging claw 80 is obstructed by the rear end surface of the projection 83, so that the set state of the paper feed cassette 3 with respect to the housing 2 can be held.
When the paper feed cassette 3 is pulled out, as described above, the lower edge of the cam portion 77 rides on the upper face of the coupling piece 79, whereby the front end of the paper feed cassette 3 is lifted up by an appropriate distance (see transition from a solid-line state to a two-dotted line state shown in Fig. 23). Thus, at this timing, the lower edge of the engaging claw 80 also lightly comes into sliding contact with the upper face of the projection 83. Accordingly, the disengagement of the engaging claw 80 from the engaged portion 82 can be promoted. Further, it is possible to lessen deformation, wear or whitening of resin, which may be caused by violent collision of the lower edge of the engaging claw 80 with the projection 83 due to the repeated advancing and retreating (attaching or detaching) operation of the paper feed cassette 3. Also, it is possible to provide a user with click feeling when the paper feed cassette is pushed in or pulled out.

Claims

An image recording apparatus comprising:
a main body (2);

an image recording unit (7) that forms an image on a recording medium (P);

a conveying path through which the recording medium (P) is fed to the image recording unit (7), the image recording unit (7) and the conveying path being disposed in the main body (2);

a feed cassette (3) disposed at a lower portion of the main body (2) and below the image recording unit (7) so as to be movable forward and rearward, the feed cassette (3) being capable of accommodating a stack of recording media (P) therein;

a feeding roller (66) that feeds the recording medium (P) from the stack on the feed cassette (3); and

a separating unit (8a) that is disposed at an end portion of the feed cassette (3) to separate the recording medium (P) from the stack wherein:
the conveying path comprises a conveying-path member (9) having a plate portion of a U-shape in a side view;

the conveying-path member (9) includes a plurality of freely rotatable rollers (64a, 64b, 64c, 64d) provided at a central portion thereof in a widthwise direction perpendicular to a conveyance direction of the recording medium (P);

the plurality of freely rotatable rollers (64a, 64b, 64c, 64d) are arranged at predetermined intervals in the conveyance direction of the recording medium (P); characterised in that

the feeding roller (6b) is separated from the plurality of freely rotatable rollers (64a, 64b, 64c, 64d) and feeds the recording medium (P) from the stack on the feed cassette (3) in a direction away from the feeding roller (6b) towards the conveying-path member (9);

the separating unit (8a) cooperates with the feeding roller (6b) to convey the separated recording medium (P) upward to the conveying-path member (9); and

a diameter of one of the freely rotatable rollers (64a), located upstream in the conveyance direction, is larger than that of another of the freely rotatable rollers (64b), located downstream in the conveyance direction.
The image recording apparatus according to claim 1, wherein a diameter of each roller (64a, 64b, 64c, 64d) gradually increases from an end portion of each roller to a central portion of each roller.
The image recording apparatus according to claim 1 or 2, wherein a corner of an intersecting portion between a peripheral surface of each roller (64a, 64b, 64c, 64d) and an end surface of each roller is removed.
The image recording apparatus according to any preceding claim, wherein:
the conveying-path member (9) further comprises an accommodating portion that accommodates therein the rollers and shafts of the rollers (64a, 64b, 64c, 64d) while exposing the rollers and the shafts to a surface of the conveying-path member (9) along which the recording medium passes; and

a cover member is detachably disposed on the surface of the conveying-path member (9) along which the recording medium passes to expose at least a part of each roller (64a, 64b, 64c, 64d) and cover the shafts of the rollers.
The image recording apparatus according to any one of claims 1 to 3, wherein:
a surface of the conveying-path member (9) on which the recording medium slides is formed into a convex curved surface, on an upstream side in the conveyance direction of the recording medium (P); and

the convex curved surface protrudes at the central portion of the conveying-path member (9) in the widthwise direction and retreats gradually as approaching end portions of the conveying-path member (9) in the widthwise direction.
The image recording apparatus according to claim 1 or 2, wherein:
the conveying-path member (9) further comprises a plurality of ribs protruding from a surface along which the recording medium (P) passes, the ribs elongating in the conveyance direction of the recording medium (P) and being arranged at predetermined intervals at positions outer than the rollers (64a, 64b, 64c, 64d); and

each rib has a cross section in the widthwise direction of the recording medium (P) in which each rib inclines outward at an obtuse angle in the widthwise direction.
The image recording apparatus according to claim 6, wherein:
a surface defined by the conveying-path member (9) and the ribs on which the recording medium (P) slides is formed into a convex curved surface, on an upstream side in the conveyance direction of the recording medium (P); and

the convex curved surface protrudes at the central portion of the conveying-path member (P) in the widthwise direction and retreats gradually as approaching end portions of the conveying-path member (P) in the widthwise direction.
The image recording apparatus according to any one of claims 1 to 7, wherein:
the separating unit (8) comprises a separating member (8) that abuts against leading edges of the recording media (P) at the central portion in the widthwise direction to separate the recording media (P) one by one; and

the separating unit (8) further comprises a plate member having a convex curved surface that protrudes to the leading edges of the recording media in a vicinity of the separating member and retreats from the leading edges of the recording media (P) as approaching end portions of the recording media (P) in the widthwise direction.
The image recording apparatus according to claim 8, wherein a rib is integrally formed with a base portion of the separating unit (8) to close a gap formed between a bottom plate of the feed cassette and the base portion of the separating unit (8) having the convex curved surface.
The image recording apparatus according to any one of claims 8 to 9, wherein:
a friction member is disposed at a bottom plate of the feed cassette to face the feeding roller (6b);

an upward guiding portion is disposed on the bottom plate on a downstream side from the friction member in the conveyance direction of the recording medium (P) and between a base portion of the separating unit and the friction roller (6b), the upward guiding portion being low on a friction-member side and being gradually high toward a base-portion side.
The image recording apparatus according to any one of claims 1 to 10, wherein:
the separating unit (8) comprises an inclined plate member; and

an upper edge of the inclined plate member extends to a position higher than a lower edge of the conveyance-path member (9) on a recording medium-receiving surface of the conveying-path member (9) so that the inclined plate member partially overlaps the conveyance-path member.
The image recording apparatus according to any one of claims 1 to 11, wherein:
the feed cassette (3) comprises an engaging claw on a lower surface of a front end portion, the engaging claw engaging with an engaged portion provided in the main body when the feed cassette (3) is completely pushed into the main body (2) of the image recording apparatus; and

a cam member is provided between a lower surface side of a bottom plate of the feed cassette (3) and the main body (2), the cam member guiding and elevating the feed cassette (3) while the feed cassette (3) is being pulled out from the main body (2), to facilitate the engaging claw to be released from the engaged portion.
The image recording apparatus according to any one of claims 1 to 12, wherein the conveying-path member (9) is detachably attached to the main body (2) of the image recording apparatus.