Sheet delivery mechanism for a printer

A sheet passage is formed so as to extend from a sheet feed position via a printing position to a sheet delivery position, delivery rollers driven by a driving unit are disposed between the printing position and the sheet delivery position on the sheet passage, pressure rollers are disposed on one side of the sheet passage so as to be in contact respectively with the delivery rollers disposed on the other side of the sheet passage, a back sheet guide is disposed between the delivery rollers and the sheet delivery position, and a printed sheet delivered by the delivery rollers and guided by the back sheet guide is transferred to a printed sheet storage unit by sheet transfer arms. Thus, the time required to transfer the printed sheet from the delivery rollers to the printed sheet storage unit is extended so that the time between the delivery of the preceding sheet to the printed sheet storage unit and the delivery of the succeeding sheet to the printed sheet storage unit is extended to prevent the smearing of the preceding printed sheet previously stored in the printed sheet storage unit with the ink by the succeeding printed sheet.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a sheet delivery mechanism for a printer, 
such as an ink-jet printer. 
2. Description of the Related Art 
A well-known sheet delivery mechanism incorporated into an ink-jet printer 
is shown in FIG. 16. The ink-jet printer has a substantially U-shaped 
sheet passage 103 extending from a sheet feed position 100 via a printing 
position 101 to a sheet delivery position 102. 
An ink-jet print head 2 is disposed at the printing position 101. The 
ink-jet print head 2 is mounted on a carriage, not shown, and reciprocated 
in directions perpendicular to a sheet feed direction. The ink-jet print 
head 2 jets ink particles on a sheet P for printing in synchronism with 
the reciprocating movement of the ink-jet print head 2 and the advancement 
of the sheet P. 
A feed roller 3 feeds, in cooperation with a leaf plate 4, a sheet P from a 
sheet feed tray 6 disposed at the sheet feed position 100 or a sheet P 
inserted by hand into a hand-feed passage 110 toward the ink-jet print 
head 2. The feed roller 3 rotates in the direction of the arrow (FIG. 16) 
to feed the sheet pressed thereto by the leaf plate 4 toward the ink-jet 
print head 2. 
A sheet delivery mechanism 10A for delivering a printed sheet P printed by 
the ink-jet print head 2 comprises a delivery roller 11 for advancing the 
printed sheet P in a delivering direction indicated by the arrow E, and a 
pressure roller 12 for pressing the printed sheet P against the delivery 
roller 11. The delivery roller 11 is disposed behind the ink-jet print 
head 2 on the sheet passage 103 and supported for rotation in the 
direction of the arrow (FIG. 16). The pressure roller 12 is biased by a 
spring or the like toward the delivery roller 11 to press the printed 
sheet P against the delivery roller 11. The pressure roller 12, in 
general, comprises spur wheels each having a saw-toothed circumference to 
avoid the transfer of the ink from the printed sheet P to the pressure 
roller 12. 
The feed roller 3 rotates to pull out a sheet P from the sheet feed tray 6 
and to insert the sheet P in the sheet passage 103, and the ink-jet print 
head 2 prints characters or the like on the sheet P in a portion of the 
sheet P positioned opposite to the ink-jet print head 2. Then, the printed 
sheet P is delivered by the cooperative action of the delivery roller 11 
and the pressure roller 12 to a delivery tray 15 disposed at the delivery 
position 102. The printed sheet P is placed in the delivery tray 15 with 
its printed surface facing up. 
In FIG. 16, denoted by 19 is a sheet guide serving also as a platen for 
supporting the sheet P in a flat state and guiding the same to the 
delivery roller 11. 
Problems in this related art will be described hereinafter. When the 
printed sheet P is delivered to the delivery tray 15 by the delivery 
roller 11 of the sheet delivery mechanism of the printer shown in FIG. 16, 
the printed sheet P slides along the printed surface of the printed sheet 
P printed in the preceding printing cycle and stored in the delivery tray 
15. Accordingly, if the ink printed on the preceding printed sheet P is 
half dried, the printed surface of the preceding printed sheet P 
previously stored in the delivery tray 15 and the backside of the 
succeeding printed sheet P are smeared. Such a problem has become 
increasingly remarkable in recent years in which printing speed has been 
progressively increased and a plurality of kinds of ink have become used 
selectively for versatile printing modes. 
To solve such a problem, a printer capable of delivering printed sheet P so 
that the same will not touch the preceding printed sheet P is proposed in 
U.S. Pat. No. 4,728,963. 
As shown in FIGS. 17 and 18, the sheet delivery mechanism of this 
previously proposed printer has a platen 19A supported for turning in the 
direction of the arrow, and a printed sheet storage unit having top rails 
9A for temporarily supporting a printed sheet P in a horizontal position. 
The platen 19a is turned in the direction of the arrow when delivering the 
printed sheet P to allow the printed sheet P to fall by gravity from the 
top rails 9A into the stacker, not shown, of the printed sheet storage 
unit. 
The ratio of an area for installing the printed sheet storage unit 9A to an 
area required for installing the printer is large, the size of the printer 
is increased inevitably and the printer cannot be miniaturized. 
SUMMARY OF THE INVENTION 
Accordingly, it is a first object of the present invention to provide a 
sheet delivery mechanism for a printer, having a small construction and 
capable of preventing smearing the printed sheet when delivering the same. 
A second object of the present invention is to provide a sheet delivery 
mechanism for a printer, capable of surely delivering a sheet to a 
delivery position. 
A third object of the present invention is to provide a sheet delivery 
mechanism for a printer, capable of delivering a sheet without generating 
noise. 
A fourth object of the present invention is to provide a sheet delivery 
mechanism for a printer, facilitating the removal of sheets jammed in a 
sheet passage. 
A fifth object of the present invention is to provide a sheet delivery 
mechanism for a printer, capable of being easily assembled. 
According to the present invention, a sheet passage is formed so as to 
extend from a sheet feed position via a printing position to a sheet 
delivery position, delivery rollers driven by a driving unit are disposed 
between the printing position and the sheet delivery position on the sheet 
passage, pressure rollers are disposed on one side of the sheet passage so 
as to be in contact respectively with the delivery rollers disposed on the 
other side of the sheet passage, a back sheet guide is disposed between 
the delivery roller and the sheet delivery position, and a printed sheet 
delivered by the delivery rollers is transferred to a printed sheet 
storage unit disposed at the sheet delivery position by sheet transfer 
arms. Thus, the time required to transfer the sheet from the delivery 
rollers to the printed sheet storage unit is extended so that the time 
between the delivery of the preceding sheet to the printed sheet storage 
unit and the delivery of the succeeding sheet to the printed sheet storage 
unit is extended. Accordingly, the ink printed on the preceding sheet 
dries up before the succeeding sheet slides along the printed surface of 
the preceding sheet and, consequently, the sheets delivered to the printed 
sheet storage unit are not smeared with the ink.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A sheet delivery mechanism in a first embodiment according to the present 
invention will be described hereinafter with reference to FIGS. 1 to 8. In 
the following description, parts like or corresponding to those previously 
described with reference to FIG. 16 are denoted by the same reference 
characters and the description thereof will be omitted. 
Referring to FIG. 1, a carriage 8 having a head holding unit 60 for holding 
an cartridge type ink-jet print head 2 is supported for sliding on a 
carriage guide shaft 8a. A feed roller 3 consisting of three sections is 
extended for rotation about an axis parallel to that of the carriage guide 
shaft 8a. A detachable sheet guide unit 61 is disposed above the feed 
roller 3. The sheet guide unit 61 comprises, in an integral unit, six 
delivery rollers 11, six pressure rollers 12, four sheet transfer arms 21, 
i.e., sheet delivery means, a sheet curling device 50, and a sheet guide 
19 serving also as a platen. When the sheet guide unit 61 is disposed in 
place, the sheet guide 19 is positioned opposite to the ink-jet print head 
2. The sheet guide unit 61 will be described in detail later. 
The outer circumference of each pressure roller 12 is formed in a 
saw-toothed surface having a small contact area to prevent the transfer of 
the ink from a printed sheet P to the pressure roller 12. The pressure 
rollers 12 are supported for rotation on a shaft 12a included in the sheet 
guide unit 61. The pressure rollers 12 are arranged at equal intervals 
along the width of the printed sheet P to press the printed sheet P 
against the delivery rollers 11. The plurality of pressure rollers 12 are 
necessary to prevent the smearing of the sheet P with the ink and the like 
resulting from the interference between the sheet P and the component 
parts, such as the cartridge of the ink-jet print head 2, due to the 
deformation of the sheet P, such as wavy deformation. 
After the trailing edge of the printed sheet P has arrived at the delivery 
rollers 11, the sheet transfer arms 21 are turned by a transfer arm 
driving device, not shown, to push the trailing edge of the printed sheet 
P with their sheet pushing portions 23 to transfer the printed sheet P to 
a printed sheet storage unit 15. After transferring the printed sheet P to 
the printed sheet storage unit 15, the sheet transfer arms 21 return to 
their standby position. 
The sheet curling device 50 is disposed between the delivery rollers 11 and 
the printed sheet storage unit 15 on a sheet passage 103 to curl the 
printed sheet P delivered by the delivery rollers 11 in a direction 
perpendicular to a delivering direction indicated by the arrow E in FIG. 
2. As shown in FIG. 3, the sheet curling device 50 of the first embodiment 
has sheet curling members 51. As shown in FIGS. 3 and 4, each sheet 
curling member 51 has an inclined surface inclined to the sheet delivering 
direction indicated by the arrow E, an inclined surface inclined to the 
direction of the arrow J parallel to the axis of the deliver rollers 11, 
and an inclined surface inclined to a direction indicated by the arrow K 
perpendicular to the directions indicated by the arrows E and J. The sheet 
curling members 51 are disposed opposite to each other. The distance 
between the respective portions of the sheet curling members 51 with which 
the sheet P comes into contact first is substantially equal to the width 
of the sheet P. The distance between the corresponding portions of the 
sheet curling members 51 decreases toward the back. 
A portion of the sheet guide 19 extends to a portion of the sheet passage 
103 between the delivery rollers 11 and the printed sheet storage unit 15, 
and a back guide surface 62 is formed in that portion. The sheet curling 
members 51 of the sheet curling device 50 are formed on the back guide 
surface 62. 
A mechanism for detachably mounting the sheet guide unit 61 on the ink-jet 
printer will be described hereinafter. Referring to FIGS. 5 to 8, a 
delivery roller gear 64 and an idle gear 65 for transmitting the rotation 
of a feed roller gear 63 coaxially fixed to the feed roller 3 to the 
delivery rollers 11 are supported one one side wall of the sheet guide 
unit 61. The delivery roller gear 64 is fixed to the shaft supporting the 
delivery rollers 11. 
The sheet guide unit 61 is set detachably on the main frame of the ink-jet 
printer by a setting device 66. The setting device 66 comprises 
positioning projections 67 projecting from the opposite side walls of the 
sheet guide unit 61, guide rails 68 formed on the main frame of the 
ink-jet printer, and sheet guide stoppers 69 formed on the main frame of 
the ink-jet printer. The positioning projections 67 slide along the guide 
rails 68 to position the sheet guide unit 61 at a predetermined position, 
where the feed roller gear 63 and the idle gear 65 engage. The sheet guide 
stoppers 69 retain the sheet guide unit 61 positioned at the predetermined 
position. The sheet guide stoppers 69 are supported pivotally by a shaft 
70 on the main frame. A retaining finger 71 having a projection capable of 
engaging with the rear end 61a of the sheet guide unit 61 is formed on the 
free end of each sheet guide stopper 69. 
The printed sheet P delivered by the delivery rollers 11 is pushed backward 
at its trailing edge by the sheet pushing portions 23 of the turning sheet 
transfer arms 21 into the printed sheet storage unit 15. The printed sheet 
P is not transferred directly to the printed sheet storage unit 15; the 
printed sheet P is transferred along the back guide surface 62 to the 
printed sheet storage unit 15. Accordingly, the printed sheet P is 
transferred to the printed sheet storage unit 15 in a time period longer 
than a time period in which the printed sheet P may be transferred 
directly to the printed sheet storage unit 15 by a time period necessary 
for the printed sheet P to move along the back guide surface 62 and, 
consequently, the ink printed on the printed surface of the preceding 
printed sheet P previously transferred to the printed sheet storage unit 
15 is dried up before the succeeding printed sheet P is transferred to the 
printed sheet storage unit 15 and hence the printed sheets P are never 
smeared with the ink. 
The sheet P is curled in a direction perpendicular to the sheet delivering 
direction indicated by the arrow E in FIG. 4 by the sheet curling device 
50. FIG. 4 shows the curled sheet P as viewed along the sheet delivering 
direction. When the sheet P is thus curled, the second moment of area of 
the sheet P is increased to enhance the resistance of the sheet P against 
bending in the direction of the length of the sheet P, i.e., the direction 
of the arrow E. Accordingly, the sheet P will not be caused to droop by 
gravity on the printed sheet storage unit 15 and restrained from sliding 
along the printed surface of the preceding printed sheet P stored in the 
printed sheet storage unit 15. Therefore, even if the ink printed on the 
preceding printed sheet P has not been dried or fixed perfectly, the 
printed surface of the preceding printed sheet P will never be smeared by 
the succeeding printed sheet P. 
Since the printed sheet storage unit 15 stores the printed sheets P in an 
inclined position and the sheet passage 103 has a substantially U-shaped 
shape, the area of the projection of the sheets P stored in the sheet feed 
tray and the printed sheet storage unit 15 on a horizontal plane is 
smaller than the area of the sheets P, so that the area required to 
install the ink jet printer is relatively small. 
Thus, the ink-jet printer can be formed in a small size, the smearing of 
the printed surfaces of the printed sheets P is prevented and the sheets P 
can be smoothly delivered. 
Since the sheet guide unit 61 comprises the delivery rollers 11, the 
pressure rollers and the associated parts in an integral unit, the ink-jet 
printer can be easily assembled. 
Furthermore, since the sheet guide unit 61 is detachable from the ink-jet 
printer, sheets P jamming the sheet passage 103 can be easily removed. 
When removing the sheet guide unit 61 from the ink-jet printer, the sheet 
guide stoppers 69 are turned to disengage the retaining fingers 71 from 
the rear end 61a of the sheet guide unit 61 and the sheet guide unit 61 is 
pulled out from the ink-jet printer. When the sheet guide unit 61 is 
pulled out, the positioning projections 67 slides along the guide rails 68 
formed on the main frame of the ink-jet printer, so that the sheet guide 
unit 61 can be smoothly pulled out. FIG. 6 shows the sheet guide unit 61 
pulled out from the ink-jet printer. When the sheet guide unit 61 is thus 
removed from the ink-jet printer, sheets P jamming the sheet passage can 
be recognized and the jamming sheets P can be easily removed. Since the 
feed roller 3 consists of three sections, wide spaces for moving the hand 
are secured to further facilitate removing the jamming sheets. When 
mounting the sheet guide unit 61 on the ink-jet printer, the sheet guide 
unit 61 is inserted in the main frame so that the positioning projections 
67 slide along the guide rails 68 and the retaining fingers 71 of the 
sheet guide stoppers 69 are brought into engagement with the rear end 61a. 
Thus, the sheet guide unit 61 is positioned and held in place so that the 
feed roller gear 63 and the idler gear 65 engage. 
Since the sheet curling members 51 of the sheet curling device 50 are 
formed on the back sheet guide surface 62, the sheet P is curled by the 
sheet curling device 50 after the sheet P has passed the delivery rollers 
11. Therefore, the sheet P is not curled at a position corresponding to 
the delivery rollers 11 and the pressure rollers 12 and the pressure 
rollers 12 are not lifted up by the curled sheet P. Thus, the sheet P is 
transferred surely by the delivery roller 11 to the printed sheet storage 
unit 15. 
A sheet delivery mechanism in a second embodiment according to the present 
invention will be described hereinafter with reference to FIGS. 9 to 12. 
In the second embodiment, pressure rollers 13 are arranged at 
predetermined intervals along a direction parallel to the common axis of 
delivery rollers 11, i.e., along the direction of the arrow J, and 
supported individually in contact with delivery rollers 11, respectively, 
as shown in FIG. 9. 
More concretely, each pressure roller 13 has an integral shaft 13a, and the 
opposite ends of the shaft 13a are slidably fitted in grooves 17 formed in 
a roller holder 16. The pressure roller 13 and the shaft 13a may be 
separate members. The roller holder 16 is detachably joined to a 
predetermined portion of a sheet guide unit 61. 
Thus, the pressure rollers 13 can be individually moved toward and 
separated from the corresponding delivery rollers 11. 
Each pressure roller 13 is pressed against the corresponding delivery 
roller 11 by a predetermined pressure applied thereto by a plate spring 
18. The plate spring 18 is attached to the roller holder 16 so as to press 
the shaft 13a toward the delivery roller 11, allowing the free rotation of 
the shaft 13a. The respective positions of the right and left recesses 
formed in the right and left edges of the spring plate 18 and the opposite 
side edges of the spring plate 18 are determined by projections 16a formed 
on the roller holder 16. When the pressure roller 13 is put on the roller 
holder 16, the spring plate 18 is flexed and does not fall off the roller 
holder 16. 
The roller holder 16 is provided with a plurality of projections 16b to 
keep the pressure roller 12 in place when the roller holder 16 is removed 
from the sheet guide unit 61. 
When the printed sheet P is a stiff sheet, such as a thick paper sheet or 
an envelope, a portion of the sheet P extending before a sheet curling 
device 50 is curled considerably as well as a portion of the sheet P 
extending after the sheet curling device 50. Accordingly, in some cases, 
the pressure rollers 13 pressing the side portions of the sheet P, which 
are curled greatly, among the pressure rollers 13 are lifted up by the 
curled side portions of the sheet P and the curled side portions of the 
sheet P are not pressed firmly against the delivery rollers 11. However, 
the other pressure rollers 13 presses the sheet P firmly against the 
delivery rollers 11 without being adversely affected by the lifted 
pressure rollers 13 and hence the printed sheet P can be surely advanced 
by the delivery rollers 11. 
Accordingly, the printed surface of the printed sheet P is not smeared even 
if the printed sheet P is a stiff one and the printed sheet P can be 
smoothly delivered. 
A sheet delivery mechanism in a third embodiment according to the present 
invention will be described hereinafter with reference to FIGS. 13 to 15. 
The third embodiment is featured by an arm driving mechanism 30 for 
driving sheet transfer arms 21. The sheet transfer arms 21 are turned to 
push the sheet P at its trailing edge, after the trailing edge of the 
sheet P has reached delivery rollers 11, to transfer the sheet P to a 
printed sheet storage unit 15, and returned to their standby positions 
indicated by alternate long and two short dashes lines in FIG. 2 after 
transferring the sheet P to the printed sheet storage unit 15. Each of the 
sheet transfer arms 21 has a base end supported for turning on a shaft 22 
and provided with a driven sector gear 24, and a free end having a sheet 
pushing portion 23. 
Each sheet transfer arm 21 is urged toward its standby position, i.e., in 
the direction of the arrow H (FIG. 13), by a spring 27, i.e., a biasing 
means. 
Each sheet transfer arm 21 abuts on and is positioned at the standby 
position by a positioning member 29, i.e., a positioning means. 
As shown in FIG. 13, the arm driving mechanism 30 comprises a gear wheel 31 
provided with a driving sector gear 34 engaged with the driven sector gear 
24 of the sheet transfer arm 21 to turn the sheet transfer arm 21 through 
a predetermined angle in a direction opposite the direction in which the 
sheet transfer arm 21 is urged by the spring 27, i.e., the direction of 
the arrow H (FIG. 13) and capable of turning about an axis 31a, and a 
driving gear mechanism 41 for turning the gear wheel 31 in a predetermined 
direction (in this embodiment, a counterclockwise direction as viewed in 
FIG. 13). As shown in FIG. 14, the gear wheel 31 is provided with a first 
cam 35 at a position after the driving sector gear 34 with respect to the 
predetermined turning direction. The first cam 35 has a cam surface 36 
defined by a curve of successive points at distance R1 from the axis 31a 
decreasing with angle measured in the direction of turning. The gear wheel 
31 is provided with a first gear portion 32 and a second gear portion 33 
in addition to the driving sector gear 34. 
The sheet transfer arm 21 is provided on its base end with a second cam 25 
having a cam surface 26 in contact with the cam surface 36 of the first 
cam 35 and defined by a curve of successive points at distance R2 from the 
shaft 22 continuously increasing with angle measured in the direction in 
which the sheet transfer arm 21 is biased by the spring 27, i.e., the 
direction of the arrow H (FIG. 13). The cams 25 and 35 are separated from 
each other when the sheet transfer arm 21 is returned to the standby 
position. 
The driving gear mechanism 41 has a single motor 42 for selectively driving 
either the feed roller 3 or the sheet transfer arms 21. 
More concretely, the driving gear mechanism 41 comprises a pinion 43 
mounted on the output shaft of the motor 42, a sun gear 44 engaged with 
the pinion 43, a swing member 45 supported for swing motion about the axis 
44a of the sun gear 44 in either one or the other direction depending on 
the direction of rotation of the sun gear 44, a planet gear 46 supported 
on one end of the swing member 45 so as to be in engagement with the sun 
gear 44 and to engage with the gear wheel 31 when the sun gear 44 is 
rotated in the normal direction, i.e., in a counterclockwise direction as 
viewed in FIG. 13, and a feed gear 80 which transmits the rotation of the 
sun gear 44 to the feed roller 3, i.e., to a gear 3a fixed to the feed 
roller 3, when the sun gear is rotated in the reverse direction. The feed 
gear 80 is a one-way gear which rotates only when the output shaft of the 
motor 42 rotates in the reverse direction, i.e., in a counterclockwise 
direction as viewed in FIG. 13, to rotate the feed roller 3 clockwise. 
The range of swing motion of the swing member 45 is limited by a stopper 
49. The motor 42 is controlled for operation in the normal direction or 
the reverse direction by a predetermined procedure by a motor control 
means, not shown. In this embodiment, the motor control means is part of a 
main controller for controlling the ink-jet printer. 
The sun gear 44 is rotated counterclockwise when the pinion 43 is rotated 
clockwise, as viewed in FIG. 13, by the motor 42. Then, the swing member 
45 turns counterclockwise about the axis 44a to bring the planet gear 46 
and the gear wheel 31 into engagement and, consequently, the gear wheel 31 
is rotated counterclockwise. In this state, any rotative driving force is 
not transmitted through the feed gear 80 to the feed roller 3 and hence 
the feed roller 3 remains stationary. 
The sun gear 44 is rotated clockwise when the pinion 43 is rotated 
counterclockwise by the motor 42. Then, the swing member 45 turns 
clockwise about the axis 44a to disengage the planet gear 46 from the gear 
wheel 31. Consequently, any rotative driving force is not transmitted to 
the gear wheel 31 to hold the gear wheel 31 stationary and, on the other 
hand, rotative driving force is transmitted through the feed gear 80 to 
the feed roller 3 to rotate the feed roller 3 clockwise. 
The printed sheet P on which specified matters have been printed with the 
ink-jet print head 2 is pressed against the delivery rollers 11 by the 
pressure rollers 12 and advanced in the sheet delivering direction 
indicated by the arrow E in FIG. 2. After the arrival of the trailing edge 
of the printed sheet P at the delivery rollers 11, the arm driving 
mechanism 30 drives the sheet transfer arms 21 to push the printed sheet P 
at its trailing edge with the sheet pushing portions 23 of the sheet 
transfer arms 21 into the printed sheet storage unit 15. After pushing the 
printed sheet P into the printed sheet storage unit 15, the sheet transfer 
arms 21 are returned to the standby position indicated by alternate long 
and two short dashes lines in FIG. 2 by the arm driving mechanism 30. 
More concretely, after the arrival of the trailing edge of the printed 
sheet P at the delivery rollers 11, the driving gear mechanism 41 turns 
the gear wheel 31 of the arm driving mechanism 30 in a predetermined 
direction, i.e., in a counterclockwise direction as viewed in FIG. 13. 
Then, the driving sector gear 34 of the gear wheel 31 and the driven 
sector gear 24 of the sheet transfer arm 21 are engaged and the sheet 
transfer arm 21 is turned by the gear wheel 31 on the shaft 22 through a 
predetermined angle against the resilience of the spring 27 (FIGS. 15(a) 
and 15(b)) to push the printed sheet P at its trailing edge with the sheet 
pushing portion 23 into the printed sheet storage unit 15. 
As the gear wheel 31 rotates, the driving sector gear 34 and the driven 
sector gear 24 are disengaged. Then, the sheet transfer arm 21 is turned 
by the resilience of the spring 27 toward the standby position, i.e., in 
the direction of the arrow H (FIG. 13) until the same is stopped by the 
positioning member 29 (FIGS. 15(c) and 15(d)). During the turning of the 
sheet transfer arm 21 toward the standby position, the cam surface 36 of 
the first cam 35 of the gear wheel 31 is sliding contact with the cam 
surface 26 of the second cam 25 of the sheet transfer arm 21 to restrain 
the sheet transfer arm 21 from rapid turning toward the standby position. 
Thus the collision of the sheet transfer arm 21 with the positioning member 
29 is avoided and hence the generation of noise is prevented. Since the 
breakage of the sheet transfer arm 21 is prevented by avoiding the 
collision between the sheet transfer arm 21 and the positioning member 29, 
the durability of the ink-jet printer is improved. 
The returning speed of the sheet transfer arm 21 can be determined properly 
by properly designing the respective shapes of the respective cam surfaces 
26 and 36 of the cams 25 and 35.