Sheet feeding apparatus and recording apparatus

A sheet feeding apparatus includes a discharge rotary body, a pinch rotary body, a drive transmission rotary body and a regulation member. The discharge rotary body feeds and discharges a sheet from a recording section. The pinch rotary body is disposed facing the discharge rotary body for pinching and feeding the sheet along the discharge rotary body. The drive transmission rotary body has a circumferential surface contacting a circumferential surface of the discharge rotary body with a pressure exerted in a direction different from a straight line drawn between rotary centers of the discharge rotary body and the pinch rotary body, for rotationally driving the discharge rotary body. The regulation member contacts the discharge rotary body when deformation of the discharge rotary body exceeds a predetermined quantity arising due to pressure from the drive transmission rotary body and regulates deformation of the discharge rotary body from exceeding the predetermined quantity.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a sheet feeding apparatus for feeding sheets by 
rotary bodies and a recording apparatus equipped with the sheet feeding 
apparatus and, more particularly, to a sheet feeding apparatus, a 
recording apparatus and the like capable of preventing a discharge rotary 
body from deforming. 
2. Description of Related Art 
Recording apparatuses such as printers, photocopiers, facsimile machines, 
and the like, or as output machines for composite electronics apparatus 
including computers and the like or for work stations, ordinarily include 
plural rollers for feeding sheets, to guide the sheets to a recording 
section at which recording means is provided and to feed the sheets out of 
the recording section. FIG. 12 shows a serial type ink jet recording 
apparatus as a recording apparatus thus having plural rollers for feeding 
sheets. In the recording apparatus, a feeding roller 50 feeds onto a 
platen 51 a recording sheet, to which images are recorded by serially 
scanning an ink jet recording head 52, and then the recording sheet is 
discharged outside the apparatus by a discharge roller 53. 
Regarding drive power transmission to the feeding roller 50 and the 
discharge roller 53, a transmission roller 54 resiliently urged in arrow K 
direction by a spring or the like is made to contact both of the feeding 
roller 50 and the discharge roller 53, and the drive power transmitted 
from a power source not shown to the discharge roller 50 is further 
transmitted to the discharge roller 53 by way of the transmission roller 
54. 
Although such mechanism in which the drive power is transmitted to the 
discharge roller 53 by way of the transmission roller 54 makes the 
structure simple and has benefit that numbers of parts become unnecessary, 
the discharge roller 53 always receives force exerted in arrow L direction 
by contact of the transmission roller 54. This force is around 50 to 60 
grams load and not so large, but the discharge roller 53 may be deformed 
in arrow L direction if receiving force exerted in arrow L direction while 
left for a long period of time. If the discharge roller 53 is thus 
deformed, the outer periphery of the roller 53 vibrates much more and may 
affect the feeding of the recording sheet. Accordingly, the strength of 
the discharge roller 53 needs to be durable against the load exerted from 
the transmission roller 54. However, where compact and inexpensive 
recording apparatuses are in demand, the discharge roller 53 may lose the 
strength when made with a smaller diameter thereof. Otherwise, the 
discharge roller 53 made of a particular material having such a strength 
that the discharge roller 53 is prevented from becoming deformed may 
increase the costs for the roller, so that it still remains as a problem 
to design recording apparatuses compact and inexpensive. 
SUMMARY OF THE INVENTION 
This invention is created in seeking solution to those problems, and has an 
object to provide a compact and inexpensive sheet feeding apparatus and 
recording apparatus in which a discharge rotary body is hardly deformed by 
a load exerted from a drive transmission rotary body. 
It is another object of the invention to provide a compact sheet feeding 
apparatus and recording apparatus capable of preventing sheet feeding 
accuracy from being impaired by regulating deformation of a discharge 
rotary body with a regulating member even where the discharge rotary body 
is made smaller, as well as capable of producing high definition images. 
It is yet another object of the invention to provide a sheet feeding 
apparatus including: a discharge rotary body for feeding and discharging a 
sheet from a recording section; a pickup rotary body disposed in facing 
the discharge rotary body for picking up and feeding the sheet along the 
discharge rotary body; a drive transmission rotary body having a 
circumferential surface contacting a circumferential surface of the 
discharge rotary body with a pressure exerted in a direction different 
from a straight line drawn between the rotary centers of the discharge 
rotary body and the pickup rotary body, for rotationally driving the 
discharge rotary body; and a regulation member for regulating deformation 
of the discharge rotary body due to pressured contact between the 
circumferential surfaces of the discharge rotary body and the drive 
transmission rotary body. 
It is still further object of the invention to provide a recording 
apparatus including the construction for feeding sheet thus constituted, a 
platen for holding the sheet at the recording section at which the sheet 
is recorded, and a feeding rotary body for feeding the sheet on an 
upstream side of the recording section, wherein the platen is held by the 
feeding rotary body and forms the regulation member by a part thereof. 
It is yet a further object of the invention to provide an ink jet recording 
apparatus including the construction for feeding sheet thus constituted, a 
platen for holding the sheet at the recording section at which the sheet 
is recorded, a feeding rotary body for feeding the sheet on an upstream 
side of the recording section, and a head mounting portion, in facing the 
platen, recording means for recording the sheet by ink discharged from an 
ink outlet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Hereinafter, as a recording apparatus to which this invention can apply, an 
embodiment of the invention is described using a serial type ink jet 
recording apparatus. It is to be noted that the ink jet recording 
apparatus as an embodiment of a recording apparatus to which this 
invention can apply, is an ink jet recording apparatus mounting an ink jet 
head onto a head mounting portion and discharging ink from an ink outlet 
or orifice of the ink jet head toward the recording medium brought to a 
recording section and can include, as its recording means, a mechanism in 
which an ink jet head and an ink tank for supplying ink to the ink jet 
head are unitedly formed and mounted to the head mounting portion, in 
which, where an ink jet head and an ink tank are formed separately, the 
ink jet head has an ink tank holder for holding the ink tank and is 
mounted to the head mounting portion, or in which the ink jet head only is 
mounted to the head mounting portion while the ink tank is provided on a 
side of the recording apparatus body. The ink jet heads mounted to those 
head mounting portions can be a so-called full line type ink jet head in 
which ink outlets are arrayed across the overall width of the recording 
medium in a direction crossing to the feeding direction of the recording 
medium brought into the recording section, or a so-called serial type ink 
jet head mounted to a carriage as the head mounting portion for recording 
a line or several lines by reciprocally moving in a direction crossing to 
the feeding direction of the recording medium brought into the recording 
section. The recording means may include ink jet head or heads capable of 
discharging all or a part of black ink, yellow ink, magenta ink, cyan ink, 
or any other primers. Moreover, the ink jet head thus described can 
discharge ink or the like from 
the ink outlet using thermal energy generated by an electrothermal 
converter, which is disposed in an ink passage in fluid communication with 
the ink outlet, or using vibrations or volume changes of a piezoelectric 
device, which is provided in the ink passage. 
First Embodiment 
Referring to FIGS. 1 to 11, an embodiment of an ink jet recording apparatus 
using a sheet feeding apparatus according to this invention is described 
in detail. First, the entire constitution, and then, the constitution of 
the sheet feeding apparatus are described. 
Entire Constitution of the Recording Apparatus 
This recording apparatus is a recording apparatus for ink jet recording 
type and as shown in FIG. 1, feeds, sheet by sheet, sheets 2 set in a 
paper tray 1 in cooperation of a pickup roller not shown, and the sheets 2 
are then fed by a sheet feeding apparatus constituted of a feeding roller 
pair 3 and a discharge roller pair 4. In synchronism with this feeding, 
recording means disposed between the feeding roller pair 3 and the 
discharge roller pair 4 records in a prescribed manner, and the recording 
medium or sheets 2 are discharged outside the apparatus after images are 
recorded. 
The recording means employs an ink jet recording method. In the recording 
means, an ink jet cartridge 5 of a disposable type in which a recording 
head 5a and an ink tank 5b are formed in a united body and a platen 6 are 
facing each other. The cartridge 5 is mounted on a carriage 7, which is 
slidable along a guide shaft 8 and a guide rail 9 and engages an endless 
shaped timing belt 11 tensioned between pulleys 10a, 10b arranged around 
both ends of the guide shaft 8. The carriage 7 reciprocally moves in a 
direction crossing to the feeding direction of the recording sheet 2 when 
a carriage motor 12 drives the pulley 10a. The recording head, during this 
movement, discharges ink according to image signals, thereby recording in 
a prescribed manner on the recording sheet 2 supported by the platen 6 
from the back side of sheet 2. 
The recording head of the ink jet type used for this embodiment includes, 
as a constitution for discharging ink, liquid outlets (orifices) which are 
normally fine, liquid passages, energy operating portions formed at a part 
of the passages, and energy generating means for generating droplet 
forming energy to be operated to the liquid located at the operating 
portion. 
As the energy generating means for generating such energy, some recording 
method using an electromechanical converter such as a piezoelectric device 
or the like, using energy generating means in which an electromagnetic 
wave such as laser beam is emitted to produce heat which operates to 
discharge droplets, or using energy generating means in which liquid is 
heated by an electrothermal converter such as a thermal device having a 
heat generating resistor and is discharged, is used. 
The recording head used for the ink jet recording method in which liquid is 
discharged by thermal energy, among them, can arrange with a high density 
the liquid outlets (orifices) for forming droplets upon discharging the 
droplets for recording, and therefore can record with a high resolution. 
The recording head using an electrothermal converter as the energy 
generating means, among them, can be made compact easily, can adequately 
capitalize the progress in the technology in the latest semiconductor 
field and utilize the merits of IC (Integrated Circuit) technology and 
micro-fabrication technology in which reliability has been improved 
significantly, can be applicable for high density assemblies, and can 
render the manufacturing costs thereof inexpensive as well, so that the 
head is advantageous. 
The recording head of the embodiment has multiple nozzles and produces ink 
images on the recording sheet 2 by discharging ink from the outlet located 
on the tip of each nozzle according to film boiling pressure created in 
ink by heat selectively generated by the electrothermal converters 
provided in the nozzles. The carriage 7 takes a home position (right end 
of traveling area in FIG. 1) during a recording waiting situation and 
makes the ink jet cartridge 5 wait at the home position. Capping means 13 
for the recording head is arranged at that position, thereby preventing 
the nozzles of the recording head located at the home position from 
drying. 
Constitution of the Sheet Feeding Apparatus 
Referring to FIGS. 2 to 11, the constitution of the sheet feeding apparatus 
is shown. FIG. 2 is an illustration of the discharge roller pair 4 and its 
vicinity when seen in arrow A direction in FIG. 1; FIG. 3 is an 
illustration of the discharge roller pair and its vicinity when seen in 
arrow B direction in FIG. 2; FIG. 4 is an illustration of a cross section 
cut along IV--IV line in FIG. 3; FIG. 5 is an illustration of a cross 
section cut along V--V line in FIG. 3; FIG. 6 is an illustration of the 
discharge rollers, a regulation member and their vicinity. 
The recording sheet 2 is, as described above, to be fcd by the feeding 
roller pair 3 and the discharge roller pair 4. As shown in FIG. 5, the 
feeding roller pair 3 is constituted of a feeding roller 3a, as a feeding 
rotary body, receiving drive power from a motor not shown to be rotated 
and of a follower roller 3b rotationally driven by pushing the recording 
sheet 2 onto the feeding roller 3a, thereby conveying the supplied 
recording sheet 2 to be fed on the platen 6. 
The platen 6 is supported in a way that both ends thereof in a longitudinal 
direction are, from an upper side thereof, engaged respectively to 
bearings located on both ends of the feeding roller 3a. The platen 6 is 
constituted as to be positioned on an apparatus body frame in maintaining 
the set position by contacting projections (not shown) formed on the 
platen 6 to predetermined positions on the apparatus body frame even where 
the feeding roller 3a rotationally drives. Thus, the platen 6 is not 
attached to the apparatus body frame in a manner directly secured thereto, 
so that the platen 6 is never bent even when the apparatus body frame is 
caused to bend by load during drive of the apparatus, so that the platen 6 
can avoid from deforming, and so that the apparatus ensures the flatness 
to guide recording sheets to be fed. 
On the other hand, the discharge roller pair 4 is constituted of a 
discharge roller 4a as a discharge rotary body rotating upon transmission 
of drive power and of a spur 4b driven to rotate in pushing the recording 
sheet 2 onto the roller 4a. The discharge roller pair 4 serves for 
discharge of the recording sheets 2 after recording. The spur 4b is a 
rotary body having a small contact area to the recording sheets 2 and 
capable of pushing the recording sheets 2 to the discharge roller 4a 
without interfering the ink images even in contacting the recorded ink 
images. 
A transmission roller 15, as a drive transmission rotary body, in which a 
spring 14 resiliently urges the roller 15 in arrow a direction in FIG. 5 
is, by its circumferential surface, in pressured contact with both 
circumferential surfaces of the feeding roller 3a and the discharge roller 
4a and transmits the drive power transmitted from a motor not shown to the 
feeding roller 3a and further to the discharge roller 4a through itself. 
The discharge roller 4a is, as shown in FIGS. 1, 2, extending in a width 
direction of the recording sheets 2 to be fed (or in a crossing direction 
to the sheet feeding direction), and as shown in FIG. 2, low rigid or 
sheet contact portions 4a1 are arranged on the roller 4a in being spaced 
with each other of a predetermined interval in the longitudinal direction 
of the roller 4a. The sheet contact portions 4a1 are in contact with the 
recording sheets 2 to be discharged and are made by fitting rubber rings 
or attaching thermoplastic elastomer material by bicolor or outsert 
molding and arc portions having less-hardness than other portion of the 
discharge roller 4a. A small diameter portion 4a2 is formed around the 
center of the discharge roller 4a in the longitudinal direction thereof 
with a smaller diameter than the outer diameter size of the sheet contact 
portions 4a1 to which the recording sheets 2 contact. 
The discharge roller 4a is urged by the transmission roller 15, as 
described above, in a direction of arrow a in FIG. 5. The discharge roller 
4a receives a weight load from the transmission roller 15 in a normal 
direction of the point at which the discharge roller 4a contacts the 
transmission roller 15, or in a direction of arrow b in FIG. 4. This load 
is more than 70 grams and less than 90 grams, relatively small and does 
not form force to deform the discharge roller 4a in a moment. However, if 
the load is made left for a long period of time and is exerted to the 
roller 4a, the discharge roller 4a may be deformed. When the deformation 
is large, the recording sheets 2 fed by the discharge roller 4a may move 
up and down, thereby having a possibility to make the ink jet recording 
head 5a and the recording sheets 2 contact to each other. 
In this embodiment, as shown in FIG. 4, a regulation member 16 in a hook 
shape is provided at a position of the small diameter portion 4a2 of the 
discharge roller 4a to solve the problem above. The regulation member 16 
constitutes a part of the platen 6 supported at the feeding roller 3a in 
the manner described above and is in contact with the circumferential 
surface of the discharge roller 4a with a predetermined circumferential 
angle at a position on an extension line c drawn between the rotary 
centers of the transmission roller 15 and the discharge roller 4a or so 
beyond the position on the extension line c as to cover the small diameter 
portion 4a2 of the discharge roller 4a. The regulation member 16 is 
arranged around the center of the discharge roller 4a in the longitudinal 
direction thereof, and when the discharge roller 4a tends to be deformed 
due to the weight load received from the transmission roller 15, the small 
diameter portion 4a2 of the discharge roller 4a contacts the lower portion 
of the regulation member 16, thereby restricting further deformations. 
Accordingly, the regulation member 16 can surely prevent the discharge 
roller 4a from deforming due to the weight load received from the 
transmission roller 15. 
It is important that the ink jet recording head 5a and the recording sheet 
2 maintain a constant space between them (normally about 1 millimeter) in 
the recording section and do not contact to each other. Since the 
recording sheets 2 do not move up and down due to deformation of the 
discharge roller 4a (deformation in a different direction from the axial 
direction) on the downstream side of the recording section, the apparatus 
can obtain the non-contact state in which the ink jet recording head 5a 
and the recording sheet 2 maintain a constant space between them (normally 
about 1 millimeter) in the recording section. 
The regulation member 16 is disposed at a position such that the top of the 
member 16 does not contact the recording sheet 2 discharged by the 
discharge roller 4a, or at a position lower than the outer periphery of 
the sheet contact portions 4a1 of the discharge roller 4a. The regulation 
member 16, therefore, will not affect the recording sheets 2 to be fed. 
The regulation member 16 allows the discharge roller 4a to be readily 
mounted to the apparatus from the lower side since the regulation member 
16 is open at its lower side. 
Referring now to FIG. 6, relation between the regulation member 16 and the 
discharge roller 4a is described. The discharge roller 4a has a span of 
210 millimeters and is supported by its both ends. Whole portion except 
sheet contact portion 4a1 of discharge roller 4a is a member made of ABS 
(acrylonitrile-butadiene-styrene), polycarbonate, polyacetal, and the 
small diameter portion 4a2 is a member having a diameter of 6 millimeters 
(namely, in this embodiment, designed in a range of 5.95 to 6.00 
millimeters). The regulation member 16 is arranged in a non-contact state 
with space d to the outer periphery of the small diameter portion 4a2 of 
the discharge roller 4a. The space d is set to meet a range of 
e.ltoreq.d.ltoreq.(3/2)e where e represents the maximum deformation amount 
permissible as for individual parts of the discharge roller 4a. The 
maximum deformation amount e is in this specification defined by the 
differential amount between the closest and farthest points of the 
circumferential surface of the roller 4a with respect to the members 
facing the circumferential surface of the roller 4a. 
In this invention, any space d is permissible as far as the range of 
e.ltoreq.d.ltoreq.(3/2)e is met where e is the maximum deformation amount. 
For example, if the permissible maximum deformation amount e of the 
discharge roller 4a is 0.2 millimeter, the space d of the regulation 
member 16 with respect to the discharge roller 4a is set to a range of 0.2 
millimeter.ltoreq.d.ltoreq.0.3 millimeter. The discharge roller 4a becomes 
hardly deformed due to the weight load received from the transmission 
roller 15 by making the set value of the space d closer as much as 
possible to the deformation amount e. 
The platen 6 in this embodiment is, as shown in hatching in FIG. 1, formed 
on a front side (to which the recording sheet contacts) thereof with an 
inclined surface portion 6a beginning at a downstream side of the 
recording section 18 of the recording head in the sheet feeding direction 
(hereinafter simply referred to as "downstream") and getting lowered on 
the downstream side. Regarding the inclined surface portion 6a, as shown 
in FIG. 4, the length from a start point portion 6a1 to an end point 6a2 
of the inclined surface portion 6a is set to 6 millimeters in this 
embodiment; the difference between the high and low points is 0.5 
millimeter; the surface 6a is formed to be lowered moving toward to the 
downstream side. 
In the ink jet recording apparatus, it is confirmed that the recording 
sheet 2 after recording may corrugate or cockle upward or downward with 
respect to the recording face when recording duty is high, and this 
phenomenon is called "cockling." When such cockling occurs, this affects 
even unrecorded areas of the recording sheet 2. More specifically, the 
recording sheet 2, when cockled, changes the distance between the nozzle 
of the ink jet head and the surface of the recording sheet in the 
recording section of the recording head, thereby maybe impairing the 
recording quality. 
The inclined surface portion 6a serves for preventing cockling. Since the 
surface of the platen 6 is lowered, the recording sheet 2 will cockle only 
downward even if such cockling occurs, so that the nozzle and the surface 
of the recording sheet may not contact to each other, it is to be noted 
that the inclined surface portion 6a may be formed on the downstream side 
of the recording section 18 and such a downstream portion may be adequate 
if the minimum plane is guaranteed which is capable of supporting the 
recording sheet 2 when the recording sheet 2 is recorded. 
The regulation member 16 described above is formed on the downstream side 
of the end point 6a2 of the inclined surface portion 6a, and the top 
surface of the regulation member 16 is formed at a lower position than the 
end point 6a2 of the inclined surface portion 6a, so that the regulation 
member 16 will never affect the recording sheets 2 fed over the inclined 
surface portion 6a. 
Referring to FIG. 7, relation between a nip position of the recording sheet 
2 by means of the feeding roller 3a and the follower roller 3b and the 
recording section 18 of the recording head 5a is described. The recording 
head 5a, as described above, is integrated with the ink tank 5b to form 
the ink jet cartridge 5 as a united body, which is replaceable. The 
recording head 5a in this embodiment has sixty-four nozzles to discharge 
ink; the nozzles are arrayed with equal space between them in the same 
direction to the sheet feeding direction (pitch between the nozzles is 
about 0.0705 millimeter in this embodiment). Accordingly, when the 
farthest nozzle from the nip position of the feeding roller pair 3 is 
called as to the first nozzle, the distance from the first nozzle to the 
last nozzle, or sixty-fourth nozzle, is about 4.44 millimeters. The area 
recorded by one nozzle column of the 4.44 millimeter-length corresponds to 
the recording area 18 of the recording head 5a in this embodiment. In this 
embodiment, a distance f from the nip position of the feeding roller pair 
3 to the last nozzle position of the recording head 5a is about 6.23 
millimeters, and whether the apparatus can record stably from the rear end 
of the recording sheet 2 to any front portion is dependent on the 
distanced. In the following description, ink is discharged from the 
recording head 5a carried on and moved with the carriage, and an area on 
which image is recorded on the recording sheet 2 is referred as to 
recordable area. 
When the distance from the rear end of the recordable area of the recording 
sheet 2 to the sheet rear end is longer than the distance f from the nip 
position of the feeding roller pair 3 to the last nozzle position of the 
recording head 5a (6.23 millimeters in this embodiment), for example, when 
it is 7 millimeters, the apparatus can record stably because the rear end 
of the recording sheet 2 is held between the feeding roller 3a and the 
follower roller 3b when the recording head 5a records images on the 
recording sheet 2. Such a stable recording can be made up to the position 
of 7 millimeters from the rear end of the recording sheet 2 on the 
downstream side in the sheet feeding direction in a situation that the 
rear end of the recording sheet 2 is held between the feeding roller 3a 
and the follower roller 3b, when the recording head 5a is for monochrome 
or mono-color, or namely, when an ink jet cartridge ("monochrome 
cartridge") having a black ink is used. 
If a full color or multicolor image is to be recorded under the condition 
as described above, the monochrome cartridge must be replaced with an ink 
jet cartridge unitedly having respective inks of yellow, magenta, and cyan 
("full color cartridge"). Now, referring to FIGS. 8, 9, relation between a 
nip position of the recording sheet 2 by means of the feeding roller 3a 
and the follower roller 3b for the full color recording and the recording 
section 18 of the recording head 5a incorporating the full color cartridge 
is described. 
Although the sixty-four nozzles are arrayed with equal space between them 
in the sheet feeding direction and all nozzles discharge the same color 
ink in the recording head of the monochrome cartridge shown in FIG. 7, 
sixty-four nozzles similarly are arrayed with equal space between them in 
the sheet feeding direction in the recording head of the full color 
cartridge. The recording head 5a of the full color cartridge uses, among 
the sixty-four nozzles, as shown in FIG. 8, first to sixteenth, sixteen 
nozzles located on the discharge roller side for discharging yellow (Y) 
ink, twenty-fifth to fortieth, sixteen nozzles for discharging magenta (M) 
ink, forty-ninth to sixty-fourth. sixteen nozzles for discharging cyan (C) 
ink. The full color images are formed by superposing on the recording 
sheets inks in the order of cyan, magenta, and yellow in feeding of the 
recording sheet by a sixteen-nozzle pitch, or pitch feeding every 1.13 
millimeters. As shown in FIG. 8, to avoid mixing of colors, no nozzle is 
used for discharging ink between yellow and magenta and between magenta 
and cyan, or eight nozzles from the seventeenth nozzle to the 
twenty-fourth nozzle and eight nozzles from the forty-first nozzle to the 
forty-eighth nozzle. 
Regarding the recording of the full color images, the sixty-fourth nozzle 
records with the cyan ink onto an arbitrary single pixel on the recording 
sheet, and then, the recording sheet is fed by 1.13 millimeters toward the 
discharge roller pair. After feeding of 1.13 millimeters, the 
thirty-second nozzle records with the magenta ink; subsequently, the 
recording sheet is fed toward the discharge roller pair again; and then, 
the sixteenth nozzle records with the yellow ink, thereby forming full 
color images. To complete a full color image, conversely, the sheet must 
be fed more extra three pitches (3.39 millimeters in this embodiment) in 
comparison with the monochrome or mono-color image recording, because the 
yellow ink has to be recorded finally. 
For example, when recording is made to the position of 7 millimeters from 
the rear end of the recording sheet on the downstream side in the sheet 
feeding direction, the rear end of the recording sheet is held between the 
feeding roller 3a and the follower roller 3b until the completion of 
recording by the last nozzle of the recording head 5a (at a position of 
(7-6.23) from the rear end of the recording sheet on the downstream side 
in the sheet feeding direction) in the case of the monochrome or 
mono-color image recording. However, in the case of the full color image 
recording, as shown in FIG. 9, the full color image will not be completed 
yet if at least the sixteenth nozzle for discharging the yellow ink of the 
recording head 5a does not operate to record. Since the distance from the 
nip position of the feeding roller pair 3 to the sixteenth nozzle is 9.61 
millimeters, which is longer than the distance of 7 millimeters above, 
recording may be made in a situation that the rear end of the recording 
sheet is away from the nip position of the feeding roller pair 3 when 
recording is made up to the position of 7 millimeters from the rear end of 
the recording sheet on the downstream side in the sheet feeding direction. 
In this situation, it may raise a problem that the rear end of the 
recording sheet would become floating, but such floating of a certain 
degree may be suppressed by pushing force of the spur 4b provided on the 
downstream side of the recording section 18 of the recording head 5a. 
However, where various recording sheets are used, floating of the rear end 
of the recording sheet sometimes cannot be suppressed when, e.g., a rigid 
recording sheet likewise a post card is used. 
Referring to FIGS. 10, 11, a full color image recording is shown in which 
recording is made on a rigid recording sheet likewise a post card. In FIG. 
10, the spur 4b is arranged on a vertical line of the discharge roller. If 
the recording sheet 2 is to be recorded while the sheet 2 is away from the 
nip position of the feeding roller pair 3 using the apparatus shown in 
FIG. 10, the recording sheet if rigid likewise a post card may rotate in 
arrow g direction around a contact point between the discharge roller 4a 
and the spur 4b as a rotational center, thereby floating the rear end 
thereof, possibly contacting the ink discharge face of the recording head 
5a, because the portion on the downstream side of the contact point is 
longer than the portion on the upstream side of the point in the recording 
sheet. The spur 4b in this situation pushes the recording sheet 2, but 
cannot suppress such floating of the read end of the sheet even by pushing 
force of the spur 4b, because the operation point of the pushing force of 
the spur 4b is the identical to the rotational center of the recording 
sheet 2. 
To solve such a problem, in this embodiment as shown in FIG. 11, the spur 
4b for pushing the recording sheet 2 toward the discharge roller 4a is 
located on an upstream side of the discharge roller 4a in the sheet 
feeding direction. Specifically, the rotational center of the spur 4b is 
shifted by about 2.5 millimeters toward the recording section from the 
rotational center of the discharge roller 4a. The operation point of the 
pushing force of the spur 4b is therefore positioned on the upstream side 
in the sheet feeding direction of the rotational center of the recording 
sheet 2. As a result, the pushing force of the spur 4b (in arrow h 
direction in FIG. 11) can suppress the floating of the rear end of the 
recording sheet 2, thereby allowing the apparatus to stably record even 
when the rear end of the recording sheet is away from the nip position of 
the feeding roller pair 3. 
As described above, in this embodiment, the regulation member 16 regulates 
the deformation of the discharge roller 4a around the center thereof in 
the longitudinal direction, so that such deformation due to load of the 
transmission roller 15 can be suppressed within a quite small amount even 
where the discharge roller 4a is driven by transmission of the 
transmission roller 15, and so that the deformation on the outer periphery 
of the discharge roller 4a can consequently be suppressed in a quite small 
amount. Accordingly, an ink jet recording apparatus capable of recording 
with high definition can be provided. 
Since the regulation member 16 for regulating the deformation above is 
provided at the discharge roller 4a which needs strength thereof, the 
deformation of the discharge roller 4a can be suppressed in a quite small 
amount even when the diameter of the discharge roller 4a is made smaller 
than the prior art. The deformation of the discharge roller 4a can be 
suppressed within a quite small amount even when the roller is made of an 
ordinary material without using any particular material having strength 
thereof against such deformation, so that an apparatus recordable with 
high definition can be made compact readily and be provided inexpensively. 
More specifically, in this embodiment, since the regulation member 16 and 
the platen 6 are formed in a united body, the structure can be simplified, 
thereby simplifying the assembling processes, and reducing the 
manufacturing costs. 
The outer diameter of the discharge roller 4a can be made smaller, so that 
the spur 4b located on the upstream side of the discharge roller 4a can be 
placed closer to the recording section 18 of the recording head 5a. 
Therefore, even after the rear end of the recording sheet 3 comes away 
from the feeding roller 3a and the follower roller 3b, the recording sheet 
2 is held at a position closer to the recording section by the discharge 
roller 4a and the spur 4b, thereby enabling the apparatus to record by ink 
jet in a better way. 
More specifically, the spur 4b for pushing the recording sheet to the 
discharge roller 4a is shifted on the upstream side of the vertically 
extended line of the discharge roller 4a in the sheet feeding direction, 
and therefore, the spur 4b can prevent the rear end of the recording sheet 
from floating by the pushing force of the spur even after the rear end of 
the recording sheet 3 comes away from the nip position of the feeding 
roller pair 3. As a result, a recording sheet so rigid as likewise a post 
card can be recorded stably. When recording full color images using the 
full color cartridge, the apparatus recordable in monochrome or mono-color 
and multicolor in interchanging the monochrome and full color cartridges 
having the nozzles arrayed in the same direction as the sheet feeding 
direction, can stably record on the same area as in the case of the 
monochrome or mono-color image recording using the monochrome cartridge. 
Accordingly, the full color ink jet recording apparatus can realize a 
stable recording onto the same area as the monochrome ink jet recording 
apparatus, though having the same size as the monochrome or mono-color ink 
jet recording apparatus. 
In the embodiment above, although the regulation member is provided at a 
single portion around the center of the discharge rotary body and 
simplifies the structure by being formed in a united body with the platen, 
the structure of the regulation member is not limited to this, can be 
arranged at plural portions, and can be formed in a united body with the 
frame of the recording apparatus. By providing spring means additionally, 
the regulation member can be urged in the opposite direction to the 
pushing direction of the transmission roller, as a matter of course. 
Other Embodiments 
The ink jet recording apparatus described above can be used for an image 
output terminal apparatus for information process apparatus such as 
computers, for a photocopier incorporating a scanner or the like, for a 
facsimile machine having transmitting and receiving functions, and the 
like. 
Although the embodiment above exemplifies that the sheet feeding apparatus 
constituted of the feeding roller pair 3, the discharge roller pair 4, the 
regulation member 16, etc. is employed for the ink jet recording 
apparatus, the sheet feeding apparatus can be used not only for such a 
recording apparatus but also for other apparatus such as a scanner. 
Although in the embodiment above, the ink jet recording type recording 
apparatus is exemplified as a recording apparatus of a non-contact 
recording type in which the recording means records in a non-contacting 
state, this invention is not limited to such apparatuses, and for example, 
the invention effectuates a recording apparatus, e.g., in which recording 
is made in a state in non-contacting a sheet using a sublimation type 
thermal head. 
Although the embodiment above exemplifies that the single regulation member 
for regulating the deformation of the discharge roller is provided around 
the center in the longitudinal direction thereof, this invention is not 
limited to this structure, and the regulation members can be provided at 
plural portions in the longitudinal direction. In that case, the 
regulation members can be provided in being equally spaced with each other 
or in being diversified in the longitudinal direction at a single portion 
at which deformation of the permissible maximum deformation amount of the 
discharge roller occurs or at a number of portions around the single 
portion, depending on the length of the discharge roller in the 
longitudinal direction, positions at which the transmission roller is 
attached for transmitting the drive power to the discharge roller, and the 
like. 
As described above, the sheet feeding apparatus is formed with the 
regulation member for regulating deformation of the discharge rotary body 
according to the embodiment, thereby rendering the regulation member to 
regulate the deformation of the discharge rotary body even if the 
discharge rotary body is made smaller, thereby preventing the sheet 
feeding accuracy from being impaired. 
Accordingly, when the sheet feeding apparatus is employed for a recording 
apparatus such as an ink jet recording apparatus, the apparatus can he 
made compact and inexpensive as well as obtainable of high definition 
images.