JPH11216919A - Image-recording apparatus, and method for transferring recording medium in image-recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a leading end part and a tail end part of a recording medium moving below an ink-jet head from curling and waving. SOLUTION: A recording medium S held and transferred by a transfer roller 105 and a transfer roller 106 moves under an ink-jet head 102. At this time, a sucking member 116A regulating a position of the recording medium S in a thicknesswise direction sucks a leading end part of the recording medium S and moves together with the recording medium S. The recording medium S held and transferred also by a transfer roller 107 and a spur 108 moves under the ink-jet head 102. At this time, the sucking member 116A sucks a rear end part of the recording medium S and moves together with the recording medium S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image recording apparatus for recording an image on a fed recording medium, and a recording medium conveying method in the image recording apparatus.

[0002]

2. Description of the Related Art FIG. 14 shows an overall configuration of a conventional example (conventional example) of an ink jet printer.

First, the components will be described.

Reference numeral 100 denotes a pressure plate on which the recording medium S is loaded. The pressure plate 100 is at the illustrated position (home position) before the start of paper feeding, but rises to a predetermined position by the start of paper feeding, and returns to the illustrated position again when the feeding of one recording medium S is completed. .

Reference numeral 101 denotes a feed roller (feed roller) for feeding the recording medium S stacked on the pressure plate 100 in order from the uppermost recording medium. Roller 1
Reference numeral 01 is at a position shown in the figure (home position) before the start of sheet feeding, starts one rotation clockwise by the start of sheet feeding, and stops at the position shown in the figure. With this rotation, the uppermost recording medium is paid out.

Reference numeral 102 denotes an ink jet head that prints a predetermined image by discharging ink. The inkjet head 102 performs printing while moving in a main transport direction (a direction perpendicular to the paper surface) by a carriage (not shown). Reference numeral 103 denotes an ink tank that supplies ink to the inkjet head 102.

Reference numeral 104A denotes the ink jet head 10
A platen 2 holds the recording medium S during printing and guides the movement of the recording medium S. The recording medium S moves horizontally on the platen 104A.

Reference numeral 105 denotes an ink jet head 102
Is a transport roller that transports (sub-transports) the recording medium S to be printed on the upstream side of. The transport roller 105 transports the recording medium S while nipping the recording medium S between the transport rollers 106. The transport roller 106 is moved by a biasing means (not shown) to the transport roller 10.
It is biased in five directions.

Reference numeral 107 denotes the ink jet head 102
Is a transport roller that transports (sub-transports) the recording medium S to be printed on the downstream side of. The transport roller 107 transports the recording medium S while nipping the spur 108 therebetween. The spur 108 is urged in the direction of the transport roller 107 by urging means (not shown). Here, the spur 108 is used in order to eliminate image stains due to ink.

Reference numerals 109 and 110 indicate the feeding roller 10.
1 to feed the recording medium S
And a guide member for guiding to the nip of the transport roller 106.

Reference numeral 111 denotes the conveying roller 107 and the spur 10
Reference numeral 8 denotes a paper discharge tray for stacking the printed recording medium S discharged outside the apparatus.

Next, the operation of the present printer will be described.

When a paper feed start signal is input, the pressure plate 10
0 rises to a predetermined position. Then, the feeding roller 101 rotates clockwise. This allows
The uppermost recording medium S on the pressure plate 100 is fed out.

The recording medium S fed by the feeding roller 101 is conveyed to a predetermined position (a position where the first printing is performed) by the conveying rollers 105 and the conveying rollers 106, and stops moving. Here, the inkjet head 102
Moves in the main transport direction while discharging ink, and performs the first printing.

Thereafter, the transport roller 105 transports the recording medium S by a predetermined amount and stops, that is, repeats so-called intermittent transport. During this time (while the transport roller 105 is stopped), the inkjet head 102 performs the second and subsequent printing.

The recording medium S at the time when the first to Nth printings are being performed is only sandwiched between the upstream transport rollers 105 and the transport rollers 106, but the Nth and subsequent printings are not performed. At the time of transport
07 and the spur 108. Also,
The recording medium S at the time when the final printing is being performed is in a state where the recording medium S is sandwiched only by the downstream conveying roller 107 and the spur 108.

The recording medium S on which printing has been completed for the final time in this manner is discharged onto the discharge tray 111 by the conveying roller 107 and the spur 108.

FIG. 15 shows the overall configuration of another conventional example (conventional example) of an ink jet printer.

The basic configuration of this printer is the same as that of the printer shown in FIG. In the case of this printer, platen 1
The recording medium S on 04B is sucked by air from below the platen 104B and is sucked with a suction force that can move.

A small hole 104-1 for air suction is formed in the platen 104B over the entire area. Platen 1
An air suction duct 112 is provided on the lower surface side of 04B. The air suction duct 112 is provided with a fan 113 as an exhaust means.

When the fan 113 is driven, the inside of the air suction duct 112 becomes in a negative pressure state, and the recording medium S is attracted to the platen 104B through the small hole 104-1 of the platen 104B.

FIG. 16 shows the configuration of a recording medium sub-transport portion of another conventional example (conventional example) of an ink jet printer.

The recording medium sub-transport section is shown in FIGS.
Role of the transport rollers 105 and 107 and the platen 104A (104B) in the printer of FIG.

In the recording medium sub-transport section, rollers 300,
Endless belt (rubber belt) wound around 301
At 302, the recording medium S is conveyed. In this case, the recording medium S is adsorbed to the belt 302.

The belt 302 has a large number of small holes 302-1 for air suction over the entire area. An air suction duct 303 is provided inside the belt 302. The air suction duct 303 is provided with a not-shown exhaust means (a fan or the like).

The drive is transmitted to one of the rollers 300 and 301 to rotate the belt 302 in the sheet recording medium sub-conveying direction (the direction of the arrow). Then, the exhaust unit is driven. As a result, the inside of the air suction duct 303 becomes in a negative pressure state, and the recording medium conveyance state is adjusted.

The suction force of the air suction duct 303 is applied to the recording medium S on the belt 302 by the small holes 3 of the belt 302.
Work via 02-1. Thus, the recording medium S is conveyed in the direction of the arrow while being attracted to the belt 302.

[0028]

However, the above-described conventional ink jet printer has the following problems. In recent years, as the image quality of the ink jet printer has been improved, the gradation expression closer to a photograph has been performed. In addition, the amount of ink to be ejected per unit area has been increased by using dark and light inks, or by applying the same ink multiple times. For this reason, the phenomenon that the recording medium S curls or undulates due to printing has become more serious.

In particular, immediately before the leading end of the recording medium reaches the downstream conveying roller pair 107, 108, the recording medium S is only sandwiched between the upstream conveying roller pairs 105, 106. It is difficult to control curls and undulations. FIG. 17 shows a state in which curling has occurred, and FIG. 18 shows a state in which waving has occurred.

The curl or waving occurs when the trailing end of the recording medium S falls out of the nip of the pair of conveying rollers 105 and 106 on the upstream side, and the recording medium S moves on the pair of conveying rollers 107 and 108 on the downstream side.
The same is true when the object is pinched only.

The side edge S1--of the curled recording medium S1 (FIG. 17) or the wavy recording medium S2 (FIG. 18).
When 1, S2-1 is turned up more than the distance from the nozzle surface (lower surface) of the inkjet head 102 to the platen 104A, it collides with the inkjet head 102 during printing and a jam occurs (problem). In addition, when the central portions of the recording media S1 and S2 are lifted, the recording media and the ink jet head 102 rub against each other, and stain the recording media (problem).

Recently, in an ink jet printer, the number of nozzles of the ink jet head 102 tends to increase in order to shorten the printing time. For this reason, the size of the inkjet head 102 in the sub-transport direction increases, and the distance (L) between the upstream transport roller pairs 105 and 106 and the downstream transport roller pairs 107 and 108 tends to increase. This also increases the above problem.

The above problem can be solved by increasing the distance between the nozzle surface of the ink jet head 102 and the platen 104A. However, in the case of this countermeasure, it is said that the ink landing accuracy is deteriorated due to the nozzle skew. This causes a problem and is not preferable in practical use.

Further, the above-mentioned conventional ink jet printer has the following problems.

In the case of this printer, since the recording medium S being printed is adsorbed to the platen 104B, there is no problem as described above. However, when printing the leading end of the recording medium S, the small holes 104 on the downstream side are used. The recording medium has not yet reached -1. Therefore, this part is released to the atmosphere, and as a result, the suction pressure does not increase due to the leak, and the desired suction force is not generated.

When the suction force is increased to obtain a suction force that overcomes curling and waving, the conveying roller pair 105, 1
A suction force superior to the nip force of the transfer rollers 06, 107, and 108 is generated, and the recording medium S remains attached to the platen 104B during the intermittent feeding, and the conveyance roller pairs 105, 106, and 10
A slippage occurs between the recording medium S and the recording medium S, and accurate paper feeding cannot be performed. If the suction force is released in conjunction with the intermittent feeding to avoid this, the recording medium S is curled up when releasing the suction, and a gap is formed. A desired suction force cannot be obtained due to generation.

The conventional ink jet printer has the following problems.

When the recording medium S is conveyed while being attracted to the belt 302 as in this printer, the expansion and contraction of the belt 302 and the unevenness of the thickness of the belt 302 hinder high-precision sub-conveyance. The unevenness of the thickness of the belt 302 will be further described. The belt 302 has rollers 300 and 3
The inner periphery of the portion wound around 01 is contracted, and the outer periphery is elongated. Then, the product of the average radius of the outer radius and the inner radius multiplied by the angular velocity is the transport speed of the belt 302. Therefore, when the thickness of the belt 302 changes, the outer peripheral radius (= roller radius + belt thickness) changes, and the average radius and the transport speed change.

In recent years, the definition of recording pixels has been advanced, and
It is possible to print at 720 dpi and dpi, and with high image quality, the required accuracy of the feed amount of sub-conveyance is several tens μm to several μm.
m, and the non-uniformity of the thickness of the belt, which exists in units of several hundred μm, has become a level that cannot be ignored.

The above-described problem also occurs in an image recording apparatus other than the ink jet printer (for example, a thermal recording type, a sublimation type thermal transfer type, etc.).

Accordingly, the present invention has been made in view of the above-described circumstances, and it is possible to convey a recording medium in a state in which curling or waving does not occur, and to provide a high-precision feeding amount of the recording medium. It is possible. It is an object of the present invention to provide an image recording apparatus and a recording medium conveying method in the image recording apparatus.

[0042]

According to the present invention, there is provided an image recording apparatus for conveying a flat recording medium under an image recording means, wherein the image recording means records an image on the recording medium. Related to the device.

In order to achieve the above object, the present invention provides a first nipping / conveying means located on the upstream end side of the image recording means for nipping / conveying a recording medium; A second nipping / transporting means for nipping and transporting the recording medium at a position between the first nipping / transporting means and the second nipping / transporting means, wherein the first nipping / transporting means and the second First position regulating means for integrally moving with the recording medium moving between the nipping and conveying means and regulating the position in the thickness direction of the leading end or the rear end of the recording medium. .

In order to achieve the above object, the present invention provides a first nipping and conveying means which is located upstream of the image recording means for nipping and conveying a recording medium, and which is located at a downstream side of the image recording means. A second nipping / conveying means for nipping and conveying the recording medium, and being located between the first nipping / conveying means and the second nipping / conveying means, wherein the first nipping / conveying means and the second nipping A first position regulating means for integrally moving with the recording medium moving between the conveying means and regulating a position in a thickness direction of a leading end or a trailing end of the recording medium; Position control means is integrally coupled to the leading end of the recording medium in the vicinity of the first nipping and conveying means, and the first position regulating means is separated from the leading end of the recording medium in the vicinity of the second nipping and conveying means. And wherein the first position regulating means is provided with a recording medium near the first nipping and conveying means. Integrally coupling the end portion, the first Noichi regulating means is detached from the rear end of the recording medium in the vicinity of the second clamping conveying means, characterized in that.

[0045]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIGS. 1 to 4 show the overall structure of an ink jet printer according to a first embodiment of the present invention. FIG. 5 shows a configuration of a recording medium sub-transport unit of the printer. The present invention is applied to the recording medium sub-transport section.

In describing the structure of the present ink jet printer, the same members as those of the above-described conventional ink jet printer (FIG. 14) are denoted by the same reference numerals. Description is omitted.

In this printer, the platen 104c
The leading end and the trailing end of the recording medium S moving upward are prevented from floating from the platen 104c. The configuration related to this will be described in detail.

Recording medium S moving on platen 104c
A suction member 116A that moves integrally with the recording medium S while adsorbing the recording medium S, as means for preventing the front end and rear end of the recording medium S from floating above the platen 104c;
And spurs 117 and 118 for holding the recording medium S. The spurs 117 and 118 are urged in the direction of the platen 104c by urging means (not shown).

The suction member 116A is configured to suction the recording medium S by an air suction force. This suction member 116A
1 sucks the leading end of the recording medium S at the position shown in FIG. 1 and moves integrally with the recording medium S to the position shown in FIG. And FIG.
Release the suction state at the position of. At the position shown in FIG. 2, the leading end of the recording medium is pressed by the spur 118, and does not rise from the platen 104c. Subsequently, the leading end of the recording medium is pressed by the spur 117, and the conveying roller 107 and the spur 108
Enter the nip.

The suction member 116A sucks the rear end of the recording medium S at the position shown in FIG. 3 and moves integrally with the recording medium S to the position shown in FIG. Then, the suction state is released at the position shown in FIG.

The timing at which the suction member 116A sucks the leading end of the recording medium at the position shown in FIG. 1, the timing at which the suction member 116A releases the suction state at the position shown in FIG. 2, and the suction member 116A at the position shown in FIG. The timing at which the suction member 116A releases the suction state at the position shown in FIG. 4 is determined by the timing at which the suction member 116A releases the suction state at the position shown in FIG. Is determined using the information from In other words, the timings of FIGS. 1 and 2 use information that detects the front end of the recording medium, and the timings of FIGS. 3 and 4 use information that detects the rear end of the recording medium.

The suction member 116A is movable along a guide shaft 120 parallel to the platen 104c. A plurality of suction units 121-1, 121-2, 121 provided on the suction member 116A are provided on the platen 104c.
-3, 121-4 corresponding to the rectangular guide groove 122-
1, 122-2, 122-3, and 122-4 are formed (see FIG. 5). Guide shaft 120 and groove 122-1,1
Reference numerals 22-2, 122-3, and 122-4 are along the recording medium transport direction.

When the suction member 116A moves along the guide shaft 120, the suction portions 121-1, 121-2, 121
-3, 121-4 are grooves 122-1, 122-2, 122
-3, 122-4. Each suction unit 121-1,
A plurality of air suction holes (nozzles) 123 are formed on the upper surfaces of 121-2, 121-3, and 121-4. The upper surfaces of the suction units 121-1, 121-2, 121-3, and 121-4 have substantially the same height as the upper surface of the platen 104c.

The suction portions 121-1, 1 of the suction member 116A
21-2, 121-3 and 121-4 have an exhaust port 12 therein.
4, a hose 125, a solenoid valve 126, and a hose 127 communicate with an exhaust pump 128. The solenoid valve 126 and the exhaust pump 128 are fixed at predetermined positions.

When the exhaust valve 128 is driven with the electromagnetic valve 126 closed, each of the adsorption sections 121-1, 121-2, 12
The inside of 1-3 and 121-4 is in a negative pressure state, and each suction unit 12
1-1, 121-2, 121-3, and 121-4 suck the recording medium S through a plurality of air suction holes 123. When releasing the suction state of the recording medium S, the electromagnetic valve 126 is opened and the exhaust pump 128 is stopped. By doing so, the suction units 121-1, 121-2, 121-3, 12
The vacuum condition in 1-4 is quickly released.

When the suction member 116A sucks the leading end or the trailing end of the recording medium at the position (home position) in FIGS. 1 and 3, the conveying roller pair 105, 106 or 10
It moves to the position shown in FIGS. 2 and 4 integrally with the recording medium S which moves downstream by the conveying force of 7, 108. When the suction state is released at the position shown in FIGS. 2 and 4, the spring returns to the position shown in FIGS. 1 and 3 by the pulling action of the return spring 132 described later.

FIG. 6 shows a structure for returning the suction member 116A released from the suction state at the positions shown in FIGS. 2 and 4 to the position (home position) shown in FIGS.

Here, the means for returning the suction member 116A is a return spring (coil spring) 132 which is connected to the suction member 116A via the wire 131 guided by the wire guides 129 and 130.

The return spring 132 is pulled and extended as the suction member 116A moves integrally with the recording medium S (not shown) in the direction of arrow X1. Then, when the suction member 116A releases the suction state and enters the free state, the suction member 116A is moved in the direction of the arrow X2 with the reducing restoring force. The suction member 116A moves in the arrow X2 direction to a position (home position) regulated by the stopper 133.

Next, the operation of the ink jet printer will be described with reference to FIG. 1 to 4 for this description.

When a print start command comes, first, the pressure plate 100 raises the uppermost recording medium to a predetermined position.
Subsequently, the feeding roller 101 rotates clockwise (S100). As a result, the uppermost recording medium S is fed out from the pressure plate 100, and the guide members 109 and 11 are fed.
It is sent between 0.

Subsequently, it is confirmed whether or not the recording medium detecting means 119 has detected the leading end of the recording medium S (S101). When the detection is made, a timer is started at this time (S10).
2). The transport rollers 105 and 107 rotate at a constant speed in the counterclockwise direction (S103). Thus, the recording medium S is ready to be conveyed.

After the recording medium S is ready to be conveyed, the feeding roller 10 that has made one rotation stops rotating (S10).
4). At this point, the leading end of the recording medium S has already been sandwiched between the nips of the conveying roller pairs 105 and 106. Also,
The pressure plate 100 starts to descend.

Subsequently, it is checked whether or not the count time of the timer has reached T1 (S105). When T = T1, the rotation of the transport rollers 105 and 107 is stopped (106).

FIG. 1 shows a state at the time when the rotation of the conveying rollers 105 and 107 is stopped. At this time, the leading end of the recording medium S conveyed by the conveying roller pairs 105 and 106 is the upper surface of the adsorbing portions 121-1, 121-2, 121-3, and 121-4 of the adsorbing member 116A located at the home position. Is covered.

Subsequently, the suction member 116A suctions the leading end of the recording medium S (S107).

That is, the electromagnetic valve 126 is closed and the exhaust pump 128 is driven. By doing so, the suction member 11
6A is in a negative pressure state, and the recording medium S is in the air suction hole 12A.
Each suction portion 121 of the suction member 116 is sucked through the suction member 3.
-1, 121-2, 121-3, and 121-4.

Subsequently, printing by the inkjet head 102 is started (S108).

In this case, the feed (main transport) of the ink jet head 102 and the feed (sub transport) of the recording medium S are performed alternately, and printing proceeds.

The recording medium S is transported by a pair of transport rollers 105 and 106.
When the recording medium S is sent, the adsorption member 116A that is adsorbing the leading end of the recording medium S also moves integrally with the recording medium S. Therefore, no curl or waving occurs at the leading end of the recording medium S.

Since the force of the suction member 116A for sucking the recording medium S has a force that overcomes the return force of the return spring 132 (FIG. 6), the recording medium S is integrated with the suction member 116A when the recording medium S is fed. Has been maintained.

The force by which the suction member 116A sucks the recording medium S does not affect the conveyance of the recording medium S at all, and only the return force of the return spring 132 affects the conveyance of the recording medium S. In consideration of this point, the pair of transport rollers 105, 1
No slip occurs at 06, 107 and 108.

Subsequently, it is confirmed whether or not the number of intermittent feedings of the recording medium S by the pair of conveying rollers 105 and 106 has reached N1 (S109), and when N = N1, the printing is interrupted (S110). The number of intermittent feeds is counted from the start of printing in S108.

When the printing is interrupted in S110, the suction member 116A has reached the downstream limit point, and the leading end of the recording medium S has reached the position where it can be pressed by the spur 118. FIG. 2 shows this state.

Subsequently, the suction member 116A releases the suction of the recording medium S (S111).

That is, the electromagnetic valve 126 is opened and the exhaust pump 128 is stopped. By doing so, the suction member 11
6A is lost, the suction member 116A and the recording medium S
Then, the suction member 116A is released from the integrated state, and is returned to the home position by the return spring 132 (S112).

When the suction member 116A returns to the home position along the guide shaft 120, the leading end of the recording medium S is already pressed by the spur 118, so that the suction member 116
A is not affected. Also, the suction member 116A
The leading end of the recording medium S after the suction of the recording medium S is released is pressed by the spurs 118 and 117 so that the pair of conveying rollers 107 and 10 is pressed.
Since it reaches the nip of No. 8, no curling or waving occurs, and no jam or ink stain occurs.

Subsequently, printing is restarted (S113).

Subsequently, it is confirmed whether or not the recording medium detecting means has detected the trailing end of the recording medium S (S114). When the detection is made, it is determined whether or not the number of intermittent feedings of the recording medium S has reached N2. After confirmation (S115), when N = N2, printing is interrupted (S116).

When the printing is interrupted in S116, the trailing end of the recording medium S has reached the position shown in FIG. 3, that is, the position immediately before passing through the nip of the pair of transport rollers 105 and 106.

Subsequently, the suction member 116A suctions the rear end of the recording medium S (S117). As a result, curling and waving do not occur at the rear end of the recording medium S.

Subsequently, printing is restarted (S118).

Subsequently, the number of intermittent feeds of the recording medium S is N
3 is checked (S119), and when N = N3, printing is interrupted (S120).

At S120, when printing is interrupted, the suction member 116A has reached the downstream limit point, and the rear end of the recording medium S has reached the most downstream area of the ink jet head 102. FIG. 4 shows this state.

Subsequently, the suction member 116A releases the suction of the recording medium S (S121), and the suction member 116A returns to the home position (S122).

When the suction member 116A returns to the home position along the guide shaft 120, the recording medium S is nipped by the conveying roller pairs 107 and 108 and the spur 11
7, 118, the suction member 11
It is not affected by 6A. Also, the suction member 116
The trailing end of the recording medium S after the suction by A is released is pressed by the spurs 118 and 117 and the conveying rollers 107 and 1 are pressed.
Since the ink reaches the nip of 08, no curling or waving occurs, and no jam or ink contamination occurs.

Subsequently, printing is restarted (S123).

Subsequently, it is confirmed whether or not the number of intermittent feeds of the recording medium S has reached a predetermined number N4 (S124).
When N4 is reached, printing ends (S125).

Subsequently, in order to discharge the printed recording medium S onto the discharge tray 111, a pair of transport rollers 107, 10
8 is rotated by a predetermined number of revolutions (S126), and the printing operation is completed. <Second Embodiment> FIGS. 8 and 9 show the overall structure of an ink jet printer according to a second embodiment of the present invention. FIG. 10 shows a configuration of a recording medium sub-transport unit of the printer. The present invention is applied to the recording medium sub-transport section.

The present printer and the printers shown in FIGS. 1 to 4 differ in the configuration of the recording medium sub-transport section. Here, only the differences between the two will be described.

FIG. 8 shows a state in which the adsorbing member 116B adsorbing the leading end of the recording medium S has reached the downstream limit point. In this embodiment, at this time, the leading end of the recording medium S is already sandwiched between the nips of the conveying roller pairs 107 and 108 (difference).

FIG. 9 shows a state in which the suction member 116B sucks the rear end of the recording medium S at the home position.
In the present embodiment, the rear end of the recording medium S is
Suction can be performed just before passing through the nip at 05 and 106 (difference).

The difference is that the suction portions 121-5, 121-6, 121-7, and 121 of the suction member 116B are used.
−8 can be inserted into the nip of the conveying rollers 105 and 106 and 107 and 108. That is, the suction portions 121-5, 121-6, 121-7, and 121-8 of the transport rollers 105 and 107.
Rubber lining portions 105A and 107
A is not provided (cut portions 105B, 107B), so that the suction portions 121-5, 121-6, 121-7, 1
21-8 are conveying rollers 105, 106 and 107, 10
The nip of 8 can be inserted.

In the case of the present printer, the spurs 117 and 118 used in the printers shown in FIGS. 1 to 4 become unnecessary. Further, the rear end of the recording medium S is
Since the suction by the suction member 116B can be performed immediately before passing through the nip at 5, 106, the rear end of the recording medium S is less curled or wavy than the printer shown in FIGS. <Third Embodiment> FIG. 11 shows another configuration example for returning the suction member 116A to the home position.

Here, the means for returning the suction member 116A is a leaf spring 135 with a constant tension wound around the reel 134. The reel 134 is fixed at a predetermined position, and the tip (reinforced) 135-1 of the leaf spring 135 is fixed.
Is fixed to the suction member 116A with screws 136 or the like.

When the suction member 116A moves in the direction of arrow X1, the leaf spring 135 is pulled out from the reel 134. When the suction member 116A releases the suction of the recording medium S and enters the free state, the leaf spring 135 is moved to the reel 134.
The suction member 116A is moved in the direction of the arrow X2 by the restoring force returning to the inside. <Fourth Embodiment> FIG. 12 shows another configuration example for returning the suction member 116A to the home position.

Here, the means for returning the suction member 116A is a weight 139 connected to the suction member 116A via a wire 138 guided by a wire guide 137.

When the suction member 116A moves in the direction of arrow X1, the weight 139 is pulled by the suction member 116A and rises. Then, the suction member 116 </ b> A
When the suction is released to release the suction, the suction member 116A
Is moved by the descending weight 139 in the direction of the arrow X2. <Fifth Embodiment> FIG. 13 shows another configuration example for returning the suction member 116A to the home position.

Here, the means for returning the suction member 116A is an endless belt (toothed belt) 142 wound around the pulleys 140 and 141. Pulley 14
The drive is transmitted to either one of 0 and 141 via a clutch.

The endless belt 142 is installed below and parallel to the guide shaft 120. The suction member 116 </ b> A is coupled to the endless belt 142 via a coupling member 143.

FIG. 13 shows a state in which the suction member 116A is located at the home position. At this time, the coupling member 143 has turned on the switch 144. At this time,
The clutch that transmits the drive to the pulley 140 or 141 is off.

As the suction member 116A moves in the direction of arrow X1, the endless belt 142 rotates counterclockwise. Then, when the suction member 116A reaches the downstream limit point, the coupling member 143 turns on the switch 145.

When the switch 145 is turned on, the suction member 11 is turned on.
6A releases the suction of the recording medium S, and at the same time, the clutch is turned on and the drive is transmitted to the pulley 140 or 141.

As a result, the endless belt 142 rotates clockwise, and the suction member 116A moves in the arrow X2 direction. When the coupling member 143 turns on the switch 144, the clutch is turned off, and the endless belt 142 stops.

In the above embodiment, the exhaust pump 12 is used as a means for bringing the inside of the suction member 116A into a negative pressure state.
Although 8 is used, a negative pressure state may be set using a cylinder, a bellows-like member, or the like.

The means for returning the suction member 116A to the home position is not limited to the means in the above embodiment,
A solenoid or the like may be used.

Further, the recording medium 116A is attached to the suction member 116.
As a method of causing the recording medium to be attracted, there is a method other than air suction, a method of electrostatically attracting using a charge, a method of magnetizing a recording medium and attracting magnetically.

The timing at which the leading end or the trailing end of the recording medium is attracted to the attracting member 116A,
The timing at which the suction of the leading end or the trailing end of the recording medium from A is released is determined by counting the timer,
The control may be performed by the number of drive pulses of a pulse motor for driving the drive units 05 and 107.

Although the ink jet printer of the above embodiment uses an ink jet head that ejects ink while moving (main transporting), a so-called full line ink jet head in which nozzles corresponding to the width of a recording medium to be printed are arranged. The present invention is also effective for an ink jet printer using a (fixed head).

The present invention is not limited to the ink jet type printer, but is also applicable to a thermal recording type and sublimation type thermal transfer type printer.

The present invention is effective not only for recording media (cut paper) fed one by one, but also for recording media (roll paper) fed continuously.

[0112]

As described above, according to the present invention,
First holding and conveying means (conveying roller 105, conveying roller 10
6) The position of the leading end of the recording medium S that moves under the image recording unit (inkjet head 102) in the thickness direction is moved by the position regulating unit (the suction members 116A and 116B) that moves integrally with the recording medium. The position where the thickness of the rear end of the recording medium conveyed by the second nipping conveyance means (conveying roller 107, spur 108) and moving under the image recording means is moved in the thickness direction. It was regulated by regulation means.

Therefore, even if the recording medium ink is ejected, for example, no curl or waving occurs at the leading end and the trailing end of the recording medium.

Therefore, for example, even if the ink ejection amount per unit area is increased to obtain rich gradation expression, or if the number of nozzles is increased to shorten the recording time, the nozzle surface and the recording medium are not changed. Even if the distance between them is reduced to increase the ink landing accuracy, jamming and ink contamination do not occur.

In the case of a method in which the recording medium is conveyed while being attracted by a belt, the feed amount of the recording medium varies due to unevenness in the thickness of the belt and expansion and contraction of the belt. In this case, the recording medium can be sent with high precision, and from this point, it is possible to cope with high definition of the recording pixels.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an overall configuration of an ink jet printer according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the overall configuration of the ink jet printer according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing the overall configuration of the ink jet printer according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing the overall configuration of the ink jet printer according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of a recording medium sub-transport unit of the ink jet printer of FIGS. 1 to 4;

FIG. 6 is a side view showing a configuration of a unit for returning the suction member to a home position.

FIG. 7 is a flowchart illustrating the operation of the inkjet printer of FIGS. 1 to 4;

FIG. 8 is a sectional view showing the overall configuration of an ink jet printer according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an overall configuration of an inkjet printer according to a second embodiment of the present invention.

FIG. 10 is a perspective view illustrating a configuration of a recording medium sub-transport unit of the inkjet printer of FIGS. 8 and 9;

11 is a side view (FIG. 11 (a)) and a perspective view (FIG. 11 (b)) showing the configuration of another means for returning the suction member to the home position.

FIG. 12 is a side view showing the configuration of another means for returning the suction member to the home position.

FIG. 13 is a side view showing the configuration of another means for returning the suction member to the home position.

FIG. 14 is a cross-sectional view illustrating the overall configuration of a conventional inkjet printer.

FIG. 15 is a cross-sectional view illustrating the overall configuration of another conventional inkjet printer.

FIG. 16 is a perspective view showing a configuration of a recording medium sub-transport unit in still another conventional inkjet printer.

FIG. 17 is a perspective view illustrating a problem in the inkjet printer of FIG. 14;

FIG. 18 is a perspective view illustrating a problem in the inkjet printer of FIG.

[Explanation of symbols]

Reference Signs List 102 Inkjet head (image recording means) 105 Conveyance roller (first nip conveyance means) 106 Conveyance roller (first nip conveyance means) 107 Conveyance roller (second nip conveyance means) 108 Spur (second nip conveyance means) 116A, 116B Suction member (first position restricting means) 117, 118 Spur (second position restricting means) 119 Recording medium detecting means S Recording medium

Claims (6)

[Claims] 1. An image recording apparatus in which a flat recording medium is conveyed below an image recording means and the image recording means records an image on the recording medium, wherein the recording is performed by being positioned upstream of the image recording means. A first nipping and conveying means for nipping and conveying the medium, a second nipping and conveying means for nipping and conveying the recording medium positioned downstream of the image recording means, the first nipping and conveying means, and the second The thickness of the leading end or the trailing end of the recording medium, which is located between the nipping and conveying means and moves integrally with the recording medium moving between the first nipping and conveying means and the second nipping and conveying means. An image recording apparatus comprising: first position regulating means for regulating a position in a direction. 2. A second position regulating means in the thickness direction of a recording medium moving between the first nipping and conveying means and the second nipping and conveying means in the vicinity of the second nipping and conveying means. The image recording apparatus according to claim 1, further comprising a position regulating unit. 3. When the first position regulating means is separated from the leading end of the recording medium, the leading end of the recording medium is already in the second position.
The image recording apparatus according to claim 1, wherein the image recording apparatus is in a state of being held by the holding conveyance means. 4. When the first position regulating means is integrally coupled to a rear end of the recording medium, the rear end of the recording medium is still in the first position.
The image recording apparatus according to claim 1, wherein the image recording apparatus is in a state of being held by the holding conveyance means. 5. A detecting means for detecting a leading end and a trailing end of a recording medium upstream of the first nipping and conveying means, wherein the first detecting means detects a leading end and a trailing end of the recording medium based on information that the leading end is detected.
A time when the position regulating means is integrally coupled to the leading end of the recording medium and a time when the position regulating means is detached from the leading end.
2. The image recording apparatus according to claim 1, wherein a timing when the position regulating means is integrally coupled to the rear end of the recording medium and a timing when the position restricting means is separated from the rear end are set. 6. An image recording apparatus in which a flat recording medium is conveyed below an image recording means and the image recording means records an image on the recording medium, wherein the recording is performed by being located upstream of the image recording means. A first nipping and conveying means for nipping and conveying the medium, a second nipping and conveying means for nipping and conveying the recording medium positioned downstream of the image recording means, the first nipping and conveying means, and the second The thickness of the leading end or the trailing end of the recording medium, which is located between the nipping and conveying means and moves integrally with the recording medium moving between the first nipping and conveying means and the second nipping and conveying means. A first position regulating means for regulating the position in the direction, wherein the first position regulating means is integrally coupled to a leading end of the recording medium in the vicinity of the first nipping and conveying means, If the position regulating means is located near the tip of the recording medium in the vicinity of the second nipping and conveying means. The first position regulating means is integrally coupled to the rear end of the recording medium in the vicinity of the first nipping and conveying means, and the first position regulating means is in the vicinity of the second nipping and conveying means Wherein the recording medium is detached from the rear end of the recording medium.