U.S. patent application number 11/492917 was filed with the patent office on 2007-02-15 for roll holder device.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Akimasa Kaya.
Application Number | 20070034727 11/492917 |
Document ID | / |
Family ID | 37741719 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070034727 |
Kind Code |
A1 |
Kaya; Akimasa |
February 15, 2007 |
Roll holder device
Abstract
A roll holder device is composed of a first holder and a second
holder. The first holder is provided with a rotary-claw unit for a
forward rotation, which works when the first holder rotates in a
forward direction (clockwise direction). The rotary-claw unit
includes a rotary claw, a retainer, a compression spring, a stopper
and so forth. The rotary claw is rotatable around a shaft attached
to the retainer. The compression spring biases the retainer toward
the stopper in the clockwise direction. In attaching the first
holder to a recording-paper roll, the rotary claw abuts on and
rotates along an inner circumference of a core of the
recording-paper roll.
Inventors: |
Kaya; Akimasa; (Saitama,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
37741719 |
Appl. No.: |
11/492917 |
Filed: |
July 26, 2006 |
Current U.S.
Class: |
242/571.8 ;
242/572 |
Current CPC
Class: |
B65H 75/22 20130101;
B65H 75/242 20130101 |
Class at
Publication: |
242/571.8 ;
242/572 |
International
Class: |
B65H 75/24 20060101
B65H075/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2005 |
JP |
2005-217359 |
Jul 27, 2005 |
JP |
2005-217360 |
Claims
1. A roll holder device for a sheet roll in which a strip of a
sheet is wound around a cylindrical core, said roll holder device
comprising: a first holder attached to one end of said sheet roll;
a second holder attached to the other end of said sheet roll, said
first and second holders holding said sheet roll and integrally
rotating therewith; a fit portion equipped on at least one of said
first and second holders, said fit portion being squeezed into said
core and fitting to an inner circumference thereof; at least one
rotary member disposed at said fit portion, said rotary member
abutting on said inner circumference of said core and rotating in
attaching said fit portion to said core; and a rotary-member
biasing mechanism for projecting said rotary member from said fit
portion and for biasing said rotary member so as to press the inner
circumference of said core.
2. The roll holder device according to claim 1, wherein said core
is made of a paper.
3. The roll holder device according to claim 2, wherein each of
said first and second holders has said fit portion, and ends of the
respective fit portions are connected.
4. The roll holder device according to claim 2, wherein said
rotary-member biasing mechanism includes: a rotary-member support
shaft for rotatably supporting said rotary member, said
rotary-member support shaft extending in a direction perpendicular
to an attachment direction of said fit portion; a retainer for
retaining said rotary member via said rotary-member support shaft;
a retainer support shaft attached to said fit portion to rotatably
support said retainer, said retainer support shaft extending in
parallel to said attachment direction; and a biasing member for
biasing said retainer so as to pivot said retainer around said
retainer support shaft.
5. The roll holder device according to claim 4, wherein said
rotary-member biasing mechanism further includes: a stopper for
regulating a pivot of said retainer biased by said biasing
member.
6. The roll holder device according to claim 5, wherein said
biasing member is a compression spring.
7. The roll holder device according to claim 2, wherein said rotary
member is a disk.
8. The roll holder device according to claim 7, wherein a part of
said rotary member projects toward said core via an opening formed
in a circumference of said fit portion.
9. The roll holder device according to claim 8, wherein said rotary
member is movable between a first projection position where said
rotary member most projects from said fit portion, and a second
projection position where said rotary member is pushed back against
said rotary-member biasing mechanism in association with an
attachment operation of said fit portion to press said inner
circumference of said core.
10. The roll holder device according to claim 9, wherein when said
rotary member is kept in said second projection position, said
rotary member tilts relative to a normal line passing a contact
point of said inner circumference of said core.
11. The roll holder device according to claim 10, wherein there are
first and second types of said rotary members, said rotary member
of the first type pressing said inner circumference of said core in
a condition that the rotary member tilts in an anterior direction
of a time when said first and second holders rotate in a forward
direction, and said rotary member of the second type pressing said
inner circumference of said core in a condition that the rotary
member tilts in an anterior direction of a time when said first and
second holders rotate in a backward direction.
12. The roll holder device according to claim 2, wherein said
rotary member and said rotary-member biasing mechanism compose a
unit, and a plurality of said units are disposed at regular
intervals in a circumferential direction of said fit portion.
13. The roll holder device according to claim 1, further
comprising: a holder interlocking mechanism for connecting said
first and second holders, said holder interlocking mechanism
generating an attractive force, by which said holders attract each
other, when an interval of said holders is predetermined length or
less in attaching said first and second holders to said sheet roll,
wherein a condition of F1<F2 is satisfied when F1 represents
attachment resistance caused by pressing said rotary member against
said inner circumference of said core and F2 represents said
attractive force generated by said holder interlocking
mechanism.
14. The roll holder device according to claim 13, wherein said
first holder has a rod passing therethrough, and said rod projects
to the outside of said second holder through a bearing of said
second holder when said first and second holders are attached to
said sheet roll.
15. The roll holder device according to claim 14, wherein both ends
of said rod projecting from said first holder and said second
holder are settable to a pair of support members and the following
condition is satisfied: LA<LB<LC wherein LA represents an
interval of the completely interlocked first and second holders, LB
represents an interval of said support members, and LC represents
said predetermined length of said first and second holders.
16. The roll holder device according to claim 13, wherein said
rotary-member biasing mechanism includes: a rotary-member support
shaft for rotatably supporting said rotary member, said
rotary-member support shaft extending in a direction perpendicular
to an attachment direction of said fit portion; a retainer for
retaining said rotary member via said rotary-member support shaft;
a retainer support shaft attached to said fit portion to rotatably
support said retainer, said retainer support shaft extending in
parallel to said attachment direction; and a biasing member for
biasing said retainer so as to pivot said retainer around said
retainer support shaft.
17. The roll holder device according to claim 16, wherein said
biasing member is a compression spring.
18. The roll holder device according to claim 13, wherein said
holder interlocking mechanism includes: a first engagement member
disposed in one of said first and second holders, said first
engagement member being formed in a triangle shape having first and
second incline surfaces located at both sides of its central top
portion; a projection disposed in the other of said first and
second holders to project in a radial direction of the holder, said
projection coming into contact with said first engagement member in
connecting said holders; a biasing member for biasing said first
engagement member in said radial direction to sequentially slide
said first and second incline surfaces on said projection in
connecting said holders, said biasing member generating said
attractive force when sliding said second incline surface on said
projection; and a second engagement member for engaging with said
first engagement member after sliding said second incline surface
on said projection.
19. The roll holder device according to claim 18, wherein said fit
portion is equipped on said first holder, said first engagement
member and said biasing member are disposed in said second holder,
and said projection and said second engagement member are disposed
in said fit portion.
20. The roll holder device according to claim 19, wherein said
biasing member is a compression spring, and said second engagement
member is a hole formed in a circumference of said fit portion.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a roll holder device
comprising a pair of holders attached to both ends of a sheet roll,
in which a strip of a sheet is wound around a core, and rotating
together with the sheet roll.
BACKGROUND OF THE INVENTION
[0002] A photographic printer and a color thermal printer employ a
recording-paper roll in which a strip of a recording paper is wound
around a cylindrical core. The recording paper is drawn out of the
recording-paper roll and an image is recorded thereon. After that,
the recording paper is cut in a prescribed size.
[0003] At a time when the recording-paper roll is set to a paper
feeder of the printer, the recording-paper roll is mounted on a
roll holder device so as to be rotatably supported. The roll holder
device comprises a pair of holders attached to both ends of the
recording-paper roll. The holder has a fit portion fitting to an
inner circumference of the core, and a rod supported by support
members disposed in the paper feeder.
[0004] The recording-paper roll is integrally rotated with the pair
of the holders. In a known manner for rotating the recording-paper
roll, a drive gear is formed on one of the holders to rotate the
recording-paper roll via this drive gear. In this manner, however,
the holder slips relative to the core if the holder is loosely
engaged with the core. In consideration of this, techniques for
preventing the holder from slipping are proposed.
[0005] As to the technique for preventing the holder from slipping,
it is known that a key is formed on the holder and a key groove
engaging with the key is formed on the core. In this technique,
however, it is required to form the key and the key groove with
great accuracy. Although this technique is advantageous in a case
using a plastic core, it is difficult to adopt this technique in a
case using a paper core, since the manufacturing cost remarkably
increases.
[0006] As to the technique for preventing the holder from slipping
on the paper core, it is known to utilize a claw member, which is
formed at the fit portion of the holder, and a spring for biasing
the claw member in a radial direction toward the outside (see
Japanese Patent Laid-Open Publication No. 2003-246508, for
instance). The top of the claw member is a pointed claw biting into
the inner circumference of the core.
[0007] In the technique utilizing the claw member and the spring,
when the biasing force of the spring is strong, the claw member
strongly bites so that slipping is surely prevented. However, there
arises a problem in that friction increases at a time when the
holder is attached to the core. Consequently, operability of the
holder deteriorates. In particular, when a user hurriedly performs
the attachment operation of the holder, sometimes the holder is
incompletely attached to the recording-paper roll. If the holder
incompletely attached to the recording-paper roll is set to the
paper feeder, a width of the recording paper is not sufficiently
regulated. Thus, there arise problems in that the recording paper
skews at the rotational drive time and printing is not performed
within a proper area. Meanwhile, when the biasing force of the
spring is weak, the friction of the attachment time is small so
that the holder is easily attached to the core. However, there
arises a problem in that the holder slips, since the claw member
does not strongly bite. Further, when the user attaches the holder
to the core, a hand of the user is likely to be damaged by
contacting with the claw member.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing, it is a primary object of the
present invention to provide a roll holder device in which a holder
is surely prevented from slipping relative to a sheet roll after
attachment of the holder.
[0009] It is a second object of the present invention to provide a
roll holder device having excellent operability and high
safeness.
[0010] It is a third object of the present invention to provide a
roll holder device in which a holder is adapted to be surely
attached to a sheet roll.
[0011] In order to achieve the above and other objects, the roll
holder device according to the present invention comprises a first
holder and a second holder, which are attached to both ends of a
sheet roll formed by winding a strip of a sheet around a
cylindrical paper core. The holders hold the sheet roll and
integrally rotate therewith. At least one of the first and second
holders is provided with a fit portion for fitting to an inner
circumference of the core. The roll holder device further comprises
at least one rotary member disposed at the fit portion, and a
rotary-member biasing mechanism by which the rotary member is
biased to protrude from the fit portion. The rotary member abuts on
and rotates along the inner circumference of the core at an
attachment time of the roll holder device. The rotary-member
biasing mechanism presses the rotary member against the inner
circumference of the core at the attachment time.
[0012] In a preferred embodiment, the rotary-member biasing
mechanism includes a rotary-member support shaft for rotatably
supporting the rotary member, a retainer for retaining the rotary
member via the rotary-member support shaft, a retainer support
shaft for rotatably supporting the retainer, and a bias member for
biasing the retainer so as to pivot the retainer around the
retainer support shaft. The rotary-member support shaft is attached
to the retainer so as to extend in a direction perpendicular to an
attachment direction of the roll holder device. The retainer
support shaft is attached to the fit portion so as to extend in
parallel to the attachment direction.
[0013] It is preferable that the rotary member is a disk and is
movable between a first projection position and a second projection
position. In the first projection position, the rotary member most
protrudes from the fit portion. In the second projection position,
the rotary member is pushed back against the rotary-member biasing
mechanism in association with the attachment operation to press the
inner circumference of the core. When the rotary member is kept in
the second projection position, it is preferable that the rotary
member tilts relative to a normal line passing a contact point of
the inner circumference of the core. In virtue of this, when the
roll holder device rotates, the rotary member is strongly pressed
against the inner circumference of the core so that the roll holder
device is surely prevented from slipping.
[0014] It is preferable to provide first and second types of the
rotary members. The rotary member of the first type presses the
inner circumference of the core in a condition that the rotary
member tilts in an anterior direction of a time when the first and
second holders rotate in a forward direction. The rotary member of
the second type presses the inner circumference of the core in a
condition that the rotary member tilts in an anterior direction of
a time when the first and second holders rotate in a backward
direction.
[0015] It is preferable to dispose the rotary members and the
rotary-member biasing mechanisms at predetermined intervals in a
circumferential direction of the fit portion. In this case, uniform
force is applied to the core when the roll holder device rotates.
Thus, the sheet roll is prevented from being biased during
rotation.
[0016] According to the present invention, the rotary member abuts
on and rotates along the inner circumference of the core at the
attachment time of the roll holder device so that attachment
resistance is reduced. Consequently, the attachment operation is
easily performed. In addition, the rotary member is strongly
pressed against the inner circumference of the core after the
attachment so that the holder is surely prevented from
slipping.
[0017] The roll holder device further comprises a holder
interlocking mechanism for connecting the first and second holders
by an attractive force. The holder interlocking mechanism generates
the attractive force when the first and second holders approach
each other within a predetermined length. At the attachment time of
the holder, attachment resistance is caused by pressing the rotary
member against the inner circumference of the core. When F1
represents the attachment resistance and F2 represents the
attractive force generated by the holder interlocking mechanism, a
condition of F1<F2 is satisfied.
[0018] The first and second holders have a rod, which projects to
the outside of the interlocked holders. The rod is settable to a
pair of support members. When LA represents an interval of the
completely interlocked first and second holders, LB represents an
interval of the support members, and LC represents the
predetermined length of the first and second holders wherein the
attractive force is generated, a condition of LA<LB<LC is
satisfied.
[0019] The holder interlocking mechanism includes a first
engagement member, a projection, a biasing member and a second
engagement member. The first engagement member is disposed in one
of the first and second holders and is formed in a triangle shape.
The first engagement member further has first and second incline
surfaces located at both sides of its central top portion. The
projection is disposed in the other of the first and second holders
so as to extend in a radial direction. The first engagement member
abuts on the projection at the attachment time. The biasing member
biases the first engagement member in the radial direction, and in
this state, the first and second incline surfaces slide on the
projection at the attachment time. When the second incline surface
slides on the projection, the attractive force is generated. After
the second incline surface has slid on the projection, the first
engagement member engages with the second engagement member.
[0020] According to the present invention, it is possible to surely
attach the first and second holders to the sheet roll. Thus, the
sheet roll is accurately regulated in a width direction. The first
and second holders are prevented from being set in an incomplete
attachment state. A user can perform the setting operation without
carefully confirming whether the first and second holders are
completely attached or not at the attachment time. In virtue of
this, the setting operation is simplified.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective view showing a paper tray and a roll
holder device attached to a recording-paper roll;
[0022] FIG. 2 is an exploded perspective view of the
recording-paper roll and the roll holder device;
[0023] FIG. 3 is a section view of the roll holder device taken in
an axial direction;
[0024] FIG. 4 is a section view of the roll holder device taken in
a radial direction;
[0025] FIG. 5 is an explanatory illustration showing an angle,
which is formed by a radial direction of a rotary claw and a
normal-line direction regarding a contact point of an inner
circumference of a core, under the condition that the rotary claw
is kept in a press position;
[0026] FIG. 6 is an explanatory illustration showing an attractive
force generated by an interlocking mechanism;
[0027] FIG. 7 is an explanatory illustration showing an interval of
holders in a state that the holders attract each other;
[0028] FIGS. 8A and 8B are explanatory illustrations explaining an
attachment operation of the roll holder device;
[0029] FIG. 9 is an explanatory illustration showing the rotary
claw biting an inner circumference of a core; and
[0030] FIGS. 10A and 10B are explanatory illustrations explaining
the attachment operation of the roll holder device in a case that
the first holder is incompletely attached.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] As shown in FIG. 1, a recording-paper roll 3 in which a
strip of a recording paper 2 is wound in a roll form is used in a
state that a roll holder device 4 is attached to both ends thereof.
A paper tray 5 is fitted into a printer body, which is not shown,
so as to be pulled out. The paper tray 5 is pulled out to set the
recording-paper roll 3 to which the roll holder device 4 is
attached. After that, the paper tray 5 is pushed into the printer
body to load the recording-paper roll 3 therein.
[0032] The paper tray 5 is provided with two support plates 10 and
11 having support concaves 10a and 10b formed in a U-like shape. A
rod 12 of the roll holder device 4 is supported by the concaves 10a
and 11a. Two guide rails 13 and 14 are fixed to the paper tray 5.
The guide rails 13 and 14 are respectively provided with ridges 13a
and 14a formed in a longitudinal direction. The ridges 13a and 14a
are guided when the paper tray 5 is moved.
[0033] The guide rails 13 and 14 are provided with lock pins 15 and
16, which are locked by a lock mechanism not shown when the paper
tray 5 is contained in the printer body. The paper tray 5 is
provided with a flap 18 being rotatable around a shaft 17. The flap
18 is urged by a spring in a circumferential direction of the shaft
17, and is rotated by a hand inserted into an under portion of the
flap 18. By swinging the flap 18 against the spring, it is possible
to release the lock of the lock mechanism. Incidentally, the lock
is adapted not to be released during transportation of the
recording paper 2, even if the flap 18 is handled. Thus, it is
prevented that the paper tray 5 is mistakenly pulled out during the
transportation of the recording paper 2. Thus, a harmful influence
is not exerted on operations for transporting the recording paper
and for recording an image.
[0034] As shown in FIG. 2, the recording-paper roll 3 is formed by
winding the strip of the recording paper 2 around a cylindrical
paper core 20. The roll holder device 4 comprises a first holder 21
and a second holder 22. The first holder 21 is attached to one end
of the recording-paper roll 3 and the second holder 22 is attached
to the other end thereof.
[0035] As shown in FIGS. 2 and 3, the first holder 21 comprises a
flange 30, a circular protrusion 33 (see FIG. 1) disposed at the
outside of the flange 30, and a bearing 34 (see FIG. 1) rotatably
supported by the rod 12. The first holder 21 is provided with a fit
portion 31 disposed at the inside of the flange 30. The interior of
the fit portion 31 is provided with two rotary-claw units 28 for
forward rotation and two rotary-claw units 29 for backward
rotation. These rotary-claw units prevent the first holder 21 from
slipping relative to the recording-paper roll 3.
[0036] The flange 30 is a thin plate substantially having a regular
dodecagon shape. The flange 30 confronts one end of the
recording-paper roll 3 to regulate movement thereof in a width
direction. The fit portion 31 is formed in a cylindrical shape, and
an outer diameter thereof is substantially identical with an inner
diameter of the core 20. The fit portion 31 is provided with a step
35 to engage with a step 76, which is described later, in
association with an attachment operation. The fit portion 31 is
further provided with engagement holes 36 to engage with engagement
pieces 77, which are described later, in association with the
attachment operation. The engagement holes 36 are formed by four so
as to have predetermined intervals in a circumferential direction
of the fit portion 31. Furthermore, the fit portion 31 is provided
with a projection 31b projecting toward the inside thereof.
[0037] A gear 37 (see FIG. 1) is formed on the periphery of the
circular protrusion 33. The gear 37 meshes with an actuator of the
printer body, which is not shown, when the paper tray 5 (see FIG.
1) is inserted into the printer body. By means of the actuator, the
roll holder device 4 is rotated in forward and backward directions.
When the roll holder device 4 is rotated in the forward direction,
the recording paper 2 is drawn out of the recording-paper roll 3.
When the roll holder device 4 is rotated in the backward direction,
the recording paper 2 is rewound to the recording-paper roll 3.
[0038] The second holder 22 comprises a flange 70, a fit portion 71
disposed at the inside of the flange 70, an interlocking mechanism
72 for connecting the holders, two circular protrusions 73 and 74
disposed at the outside of the flange 70, and a bearing 75
rotatably supported by the rod 12.
[0039] The flange 70 is a thin plate substantially having a regular
dodecagon shape, similarly to the flange 30. The flange 70
confronts the other end of the recording-paper roll 3. The fit
portion 71 is formed in a cylindrical shape, and an outer diameter
thereof is identical with that of the fit portion 31. The fit
portion 71 is provided with the step 76.
[0040] As shown in FIG. 4, the rotary-claw unit 28 for the forward
rotation comprises a rotary claw 38 and a biasing mechanism 45 for
biasing the rotary claw 38. The rotary-claw unit 28 works when the
respective holders 21 and 22 rotate in the forward direction
(clockwise direction). The biasing mechanism 45 includes a shaft
39, a retainer 40, a support shaft 41, a compression spring 42 and
a stopper 44. The two rotary-claw units 28 are disposed at symmetry
positions about the rod 12. Incidentally, the rotary-claw units for
the forward rotation may be provided by three or more. In this
case, it is preferable to dispose the rotary-claw units at constant
intervals in a circumferential direction of the fit portion 31.
[0041] The rotary claw 38 has a disk shape and is provided with an
edge portion 38a formed by cutting a part of an anterior side of a
time when the first holder 21 rotates in the forward direction. The
edge portion 38a bites into an inner circumference 20a (see FIG. 2)
of the core 20. The rotary claw 38 is rotatable around the shaft 39
attached to the retainer 40, which is rotatable around the support
shaft 41 attached to the fit portion 31. The shaft 39 is
perpendicular to the support shaft 41 extending in parallel to the
rod 12.
[0042] The compression spring 42 biases the retainer 40 in the
clockwise direction around the support shaft 41. A moving range of
the retainer 40 in the biasing direction is regulated by the
stopper 44. The rotary claw 38 moves between a projection position
where a part thereof projects from an opening 43 formed in the fit
portion 31, and a press position where the rotary claw 38 is
pressed against the inner circumference 20a of the core 20 as shown
in FIG. 5. The rotary claw 38 is pushed toward the inside of the
fit portion 31 in association with the attachment operation of the
roll holder device 4.
[0043] When the rotary claw 38 is kept in the press position, the
rotary claw 38 tilts relative to a normal line 47 passing a contact
point of the inner circumference 20a of the core 20. An angle
formed by the rotary claw 38 and the normal line 47 is represented
by .theta.A. In FIG. 5, a radial direction of the rotary claw 38 is
represented by a line 46. In particular, the rotary claw 38 for the
forward rotation is adapted to tilt in an advancing direction when
the first holder 21 rotates in the forward direction (clockwise
direction). In other words, the line 46 is adapted to be located at
an anterior side of the normal line 47 in the advancing direction.
In virtue of this, the rotary claw 38 is strongly pressed against
the inner circumference 20a of the core 20 when the first holder 21
is rotated in the forward direction.
[0044] The two rotary-claw units 29 for the backward rotation are
disposed at symmetry positions about the rod 12, and work when the
respective holders 21 and 22 are rotated in the backward direction
(counterclockwise direction). The rotary-claw unit 29 is composed
of a rotary claw 48 and a biasing mechanism 55 for biasing the
rotary claw 48.
[0045] A structure of the rotary claw 48 is similar to that of the
rotary claw 38. In this regard, an edge portion 48a formed on the
rotary claw 48 is different in a point that the cut part thereof is
located at an anterior side of a time when the first holder 21 is
rotated in the backward direction.
[0046] A structure of the biasing mechanism 55 is similar to that
of the biasing mechanism 45. The biasing mechanism 55 includes a
shaft 49, a retainer 50, a support shaft 51, a compression spring
52, and a stopper 54. In this regard, the retainer 50 is different
in a point that the compression spring 52 biases the retainer 50 in
the counterclockwise direction around the support shaft 51. The
rotary claw 48 moves between a projection position where a part
thereof projects from an opening 53 formed in the fit portion 31,
and a press position where the rotary claw 48 is pressed against
the inner circumference 20a of the core 20. The rotary claw 48 is
pushed toward the inside of the fit portion 31 in association with
the attachment operation of the roll holder device 4.
[0047] When the rotary claw 48 is kept in the press position, the
rotary claw 48 tilts relative to a normal line 57 passing a contact
point of the inner circumference 20a of the core 20. An angle
formed by the rotary claw 48 and the normal line 57 is represented
by .theta.B. In FIG. 5, a radial direction of the rotary claw 48 is
represented by a line 56. The rotary claw 48 is strongly pressed
against the inner circumference 20a of the core 20 when the first
holder 21 is rotated in the backward direction.
[0048] Although the attachment operation for inserting the first
holder 21 into the recording-paper roll 3 is described later,
resistance occurs during the attachment operation of the first
holder 21. This resistance is defined as attachment resistance
represented by F1. The attachment resistance F1 is adapted to be
reduced in comparison with that of a conventional device.
[0049] As shown in FIG. 6, the interlocking mechanism 72 includes
the engagement piece 77 and a compression spring 78 for urging the
engagement piece 77 toward the outside in a radial direction. The
engagement piece 77 is disposed inside a guide hole 79 formed in
the fit portion 71. The engagement piece 77 has a mountain-like
shape including a first incline surface 77a and a second incline
surface 77b. The second holder 22 is pushed against the first
holder 21 until a certain position, and the second incline surface
77b of the engagement piece 77 abuts on the projection 31b. At this
time, the engagement piece 77 receives a force from the projection
31b. By virtue of an axial component of the force received by the
engagement piece 77, the holders attract each other. This force is
defined as attractive force represented by F2. Compared with the
attachment resistance F1, a relation of F1<F2 is maintained.
[0050] In a condition that the holders are completely joined, a
holder interval is represented by LA (see FIG. 3). The holder
interval is a distance extending from an end of the circular
protrusion 33 of the first holder 21 to an end of the circular
protrusions 73 and 74 of the second holder 22. Moreover, a distance
between the support plates 10 and 11 of the paper tray 5 is
represented by LB (see FIG. 1). As shown in FIG. 7, when the second
holder 22 is pushed and the holders attract each other, the holder
interval is represented by LC. In this regard, the interval LC is
equal to LA plus LD, wherein LD represents a length of the incline
surface 77b orthogonally projected toward the rod 12. The device of
this embodiment is adapted to satisfy a relation of
LA<LB<LC.
[0051] An operation of the above structure is described below. The
paper tray 5 is drawn out of the printer body and the used
recording-paper roll is removed. Thus, it becomes possible to place
the unused recording-paper roll 3.
[0052] In attaching the roll holder device 4 to the recording-paper
roll 3, the first holder 21 and the second holder 22 may be
attached in this order or in a reverse order thereof. In this
embodiment, the former order is adopted.
[0053] First of all, as shown in FIG. 8A, the first holder 21 is
squeezed in the condition that the fit portion 31 of the first
holder 21 fits to the inner circumference of the core 20 of the
recording-paper roll 3. When the first holder 21 is squeezed, an
outer circumference 31a of the fit portion 31 slides on the inner
circumference 20a of the core 20. In the meantime, such as shown in
FIG. 9, the rotary claws 38 and 48 of the rotary-claw units 28 and
29 abut on the inner circumference 20a and are pressed against this
circumference 20a by the biasing force of the respective
compression springs 42 and 52. The rotary claws 38 and 48 are moved
from the projection position to the press position.
[0054] As the first holder 21 is further squeezed, the rotary claws
38 and 48 move along the inner circumference 20a while rotating
around the shafts 39 and 49. By squeezing the first holder 21 until
a place where the inside surface of the flange 30 abuts on the end
of the recording-paper roll, the attachment of the first holder 21
is completed. The edge portions 38a and 48a of the rotary claws 38
and 48 slightly enter the inner circumference 20a.
[0055] As described above, the rotary claws 38 and 48 abut on the
inner circumference 20a of the core 20 and rotate at the attachment
time so that the attachment resistance F1 is reduced. Thus, the
attachment is easily performed. In addition, the rotary claws 38
and 48 strongly press the inner circumference 20a of the core 20
after the attachment.
[0056] Successively, as shown in FIG. 8B, the second holder 22 is
squeezed in the condition that the fit portion 71 of the second
holder 22 fits to the inner circumference 20a of the core 20. An
outer circumference 71a of the fit portion 71 slides on the inner
circumference 20a of the core 20, and then, the incline surface 77a
of the engagement piece 77 abuts on the projection 31b. As the
second holder 22 is further squeezed, the top of the engagement
piece 77 gets over the projection 31b and the incline surface 77b
abuts on the projection 31b. The attractive force F2 is
automatically caused between the first and second holders 21 and
22. The attractive force F2 applied to the second holder 22 is
shown in FIG. 8B. Since the holders attract each other, the
engagement piece 77 enters the engagement hole 36 and engages
therewith to interlock the holders. The interval of the holders
becomes LA. In this way, the attachment of the roll holder device 4
is completed.
[0057] In the above, the first holder 21 is surely attached to the
recording-paper roll 3 before attaching the second holder 22.
However, when the user hurriedly performs the operation, sometimes
the first holder 21 is incompletely attached. Even in such a case,
the roll holder device 4 of the present invention can be surely
attached. Referring to FIG. 10, is described an attachment
operation performed in the case that the first holder 21 is
incompletely attached.
[0058] As shown in FIG. 10A, the first holder 21 is not squeezed
until the position where the inner surface of the flange 30 abuts
on the end of the recording-paper roll 3. In this condition, the
second holder 22 is squeezed and the inner surface of the flange 70
abuts on the other end of the recording-paper roll 3 such as shown
in FIG. 10B. As the second holder 22 is further squeezed, the top
of the engagement piece 77 gets over the projection 31b, and then,
the incline surface 77b abuts on the projection 31b. The attractive
force F2 is automatically caused between the first and second
holders 21 and 22. Since the attractive force F2 is greater than
the attachment resistance F1, the holders attracts each other
without regard to the attachment resistance F1. By the way, in FIG.
10B, the attractive force F2 and the attachment resistance F1
applied to the second holder 22 and the recording-paper roll 3 are
shown. The holders are completely interlocked and the interval
thereof becomes LA. In this way, the attachment of the roll holder
device 4 is completed in the case that the first holder 21 is
incompletely attached before attaching the second holder 22.
[0059] The recoding-paper roll 3 to which the roll holder device 4
is attached is set to the paper tray 5 in a state that both ends of
the rod 12 are supported by the support plates 10 and 11. At this
time, in order to set the first and second holders 21 and 22 to the
support plates 10 and 11, it is necessary to make the holder
interval shorter than LC by hand. In making the holder interval
shorter than LC, the holders automatically attract each other and
the holder interval becomes LA. The first and second holders 21 and
22 are surely attached. Thus, the first and second holders 21 and
22 are prevented from being set in an incomplete attachment state.
The user can perform the setting operation without carefully
confirming whether the first and second holders 21 and 22 are
completely attached or not at the attachment time. In virtue of
this, the setting operation is simplified.
[0060] After setting the recording-paper roll 3, the paper tray 5
is pushed into the printer body to lard the recording-paper roll 3
in the printer body. Upon pushing the paper tray 5 into the printer
body, the gear 37 meshes with the actuator disposed in the printer
body. By means of the actuator, the gear 37 is driven so that the
first and second holders 21 and 22 are rotated in the forward and
backward directions.
[0061] In response to an instruction for advancing the recording
paper 2, the first and second holders 21 and 22 are rotated in the
forward direction (clockwise direction in FIG. 9). At this time,
the edge portion 38a of the rotary claw 38 deeply bites into the
inner circumference 20a of the core 20 so that the recording-paper
roll 3 surely rotates together with the roll holder device 4
without slipping. As the recording-paper roll 3 rotates, the
recording paper 2 is advanced. On the advanced recording paper 2,
an image is recorded. The recorded area is cut and discharged from
the printer body.
[0062] After the image recording operation, an instruction for
rewinding the recording paper 2 is outputted to rotate the first
and second holders 21 and 22 in the backward direction
(counterclockwise direction in FIG. 9). At this time, the edge
portion 48a of the rotary claw 48 deeply bites into the inner
circumference 20a of the core 20 so that the recording-paper roll 3
surely rotates together with the roll holder device 4 without
slipping. As the recording-paper roll 3 rotates in the backward
direction, the recording paper 2 is rewound.
[0063] When the recording paper 2 of the roll 3 is wholly used, the
paper tray 5 is drawn out and the roll holder device 4 is detached
from the used recording-paper roll. In applying a force to separate
the second holder 22 from the core 20a and the first holder 21, the
engagement piece 77 exits from the engagement hole 36. Then, it
becomes possible to detach the second holder 22. After detaching
the second holder 22, a force is applied to separate the first
holder 21 from the core 20. Upon this, the rotary claws 38 and 48
rotate along the inner circumference 20a of the core 20 and the
first holder 21 is detached. After that, the roll holder device 4
is attached to the unused recording-paper roll. The above-described
operations are repeated.
[0064] In the above embodiment, the recording paper is used as a
sheet. However, the sheet may be a paper to be used for another
purpose excepting the image recording. Moreover, the sheet may be
made of a material excepting the paper.
[0065] In the above embodiment, the rotary claws for the forward
and backward rotations are provided. However, either of the rotary
claws for the forward and backward rotations may be merely
provided. In the above embodiment, the rotary claws of the same
sort are provided by two. However, the sole rotary claw may be
provided, and the rotary claws may be provided by three or
more.
[0066] In the above embodiment, the holders are interlocked in
association with the attachment. However, the respective holders
may be provided with the rotary claws without interlocking the
holders.
[0067] Although the present invention has been fully described by
way of the preferred embodiments thereof with reference to the
accompanying drawings, various changes and modifications will be
apparent to those having skill in this field. Therefore, unless
otherwise these changes and modifications depart from the scope of
the present invention, they should be construed as included
therein.
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