JP2003118180A - Recording medium transport device, recording device provided with the transport device, and recording medium suction unit in the recording device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce cockling of a recording medium in a recording apparatus.
Effectively prevent spur marks due to spur rollers.
To be The suction hole corresponds to a suction hole in a conventional suction structure.
The part is drawn into the suction chamber 106 (area S₃) And suction holes 108 (surface
Product S₁) And the suction hole 108 (area S ₁) Small
By forming a through hole with a diameter,
To increase the utilization rate of negative pressure that can be used
The suction chamber 106 forming the facing surface has a larger area.
Form as a dent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium conveying device, a recording device provided with the conveying device, and a recording medium suction unit in the recording device, and more particularly to sucking and holding the recording medium in a recording portion of the recording device. For technology.

[0002]

2. Description of the Related Art Conventionally, for example, in an ink jet printer or an ink jet plotter, after a recording medium is fed to a recording portion by a paper feed roller, it is pressed by a paper discharge roller (drive roller) and a spur roller as a driven roller thereof. While there is a configuration that discharges. Figure 11
(A), (b), (c) is a figure which shows only the recording part in such an inkjet printer etc., and the principal part of the conveyance apparatus of a recording medium.

That is, in such an ink jet printer or the like, as shown in FIG. 11A, the recording medium 10 is fed into the recording portion 14 by the paper feed roller 12 (and its driven roller 12a), and then the paper discharge roller. (Drive roller) 1
6 and the spur roller 16a as a driven roller thereof are pressed and discharged. In this case, the pressing force of the spur roller 16a is set so that the recording medium 10 is not scratched (spur trace).

[0004]

However, as shown in FIG. 11 (a).
In an inkjet printer provided with the recording medium transporting device as shown in FIG. 3, for example, when an image in which a large number of ink particles are ejected such as a solid image is recorded on the recording medium 10, the recording medium 10 is There is a case where a large amount of ink is absorbed to cause so-called cockling, which swells in a wavy shape on the recording head 18 side as shown in FIG. 11B. When this cockling occurs, the distance between the recording medium 10 and the recording head 18 becomes narrow, and the flying distance of the ink particles varies, which causes uneven recording, or the recording medium 10 comes into contact with the recording head 18 and becomes dirty. There was a problem that caused it. Also in the recording medium conveying device shown in FIG. 11A, if the span between the paper feed roller 12 and the paper discharge roller 16 is relatively short, the above cockling is held within an allowable range to cause the above problem. It is also possible to prevent

However, in an ink jet printer or the like, in the near future, in order to further increase the recording speed, the number of nozzles for each color nozzle array is increased, or nozzle rows of a plurality of colors are arranged in the recording medium conveyance direction. In these cases, the dimensions of the recording head are
As shown in (c), it becomes longer in the recording medium conveyance direction.
As the recording head 10 becomes longer, the span between the paper feed roller 12 and the paper discharge roller 16 also becomes longer.
In a configuration in which 2 (and the driven roller 12a thereof) and the paper discharge roller 16 (and the spur roller 16a as the driven roller thereof) are conveyed and discharged, this cockling cannot be prevented at all and exceeds the allowable range. Depending on the model, such as an ink jet printer having such a large head length, there may be a situation in which the configuration itself of sandwiching and conveying and discharging the two rollers is not established.

Further, such cockling is relatively small when a special paper such as an ink jet printer is used as a recording medium, and is large when a plain paper is used. For this reason, in designing an inkjet printer or the like, the paper gap [Fig. 11 (a)] is usually taken into consideration in consideration of the amount of paper lifting caused by cockling when plain paper is used.
The distance A] between the recording medium 10 and the recording head 18 in FIG. However, if the paper gap is large in this way, the ink particles ejected from the nozzles of the recording head will undergo flight bending even when using special paper that does not require it, and the deviation of the landing point will be that large. This may hinder the improvement of print quality.

Further, when the recording medium 10 is lifted up by the cockling, the floating recording medium 10 is shown in FIG.
As shown by arrow B in (b), as a result of being pressed against the spur roller 16a, the recording medium 10 has a spur trace by the spur roller 16a as shown in FIG. This spur mark is particularly noticeable on plain paper with a large cockling, which is one of the causes of lowering the printing quality.

On the other hand, in recent years, a hollow box-shaped suction portion has been mainly provided on the conveying surface of the recording medium, and the recording medium is sucked by a suction pump or the like through a plurality of suction (through) holes provided in the suction portion. Various products have been proposed (Japanese Patent Laid-Open No. 63-3037).
No. 81, JP-A-3-270, etc.). Among them, as a means for eliminating the above-mentioned cockling, there is also a proposal to suck or adsorb the recording medium to the platen or the like through the suction holes.

However, in each case, only the through hole is formed in the hollow box-shaped suction portion for suction, and it is difficult to prevent the above-mentioned cockling over the entire surface of the recording medium in the recording portion. Further, as a result of the portion of the recording medium protruding from the recording portion being lifted and pressed against the spur roller 16a as indicated by the arrow B in FIG. 11B, the spur trace may be attached to the recording medium 10. It cannot be prevented.

Further, in the conventional example described in the above publication,
If the suction force is too strong, it will be transported (paper feed) because the hollow box-shaped suction part has only a through hole opened for suction.
It may cause a decrease in accuracy. For this reason, at present, the paper is fed in the direction of gravity (the paper's own weight is used to feed the paper).
The fact is that it has not been put to practical use except for some large format printers.

Therefore, a first object of the present invention is to more effectively prevent cockling of a recording medium in a recording apparatus,
This is to prevent spur rollers from spurring marks.

A second object of the present invention is to prevent cockling as described above, thereby making it possible to set an appropriate paper gap, thereby enabling high quality recording on a recording medium. Especially.

[0013]

In order to solve the above problems, the present inventor has made a recording medium conveying surface provided with a plurality of suction holes on the recording medium ejection side of a recording apparatus, and the plurality of suction holes. A suction unit having a decompression chamber communicating with the decompression chamber and a suction unit for sucking air in the decompression chamber is provided, and the recording medium is sucked through a suction hole provided in the suction unit.
In the suction structure, the relationship between the total area of the suction holes and the suction force is examined in detail. (1) The larger the total area of the suction holes, the more the utilization rate of the negative pressure that can be used for the pump characteristics. And (2) the smaller the area of the surface of the suction hole facing the recording medium becomes, the more the force for sucking the recording medium cannot be generated. Then, various studies have been repeated on whether cockling can be prevented more effectively than in the conventional example without lowering the conveyance (paper feed) accuracy of the recording medium.

As a result, each of the plurality of suction holes provided in the suction unit has a through hole portion communicating with the decompression chamber,
If the area of the suction surface facing the recording medium is formed by a suction chamber that is larger than the cross-sectional area of the through-hole portion, cockling can be prevented more effectively than in the conventional example, and the recording medium is highly accurate. We have found that it can be transported and discharged.

That is, the recording medium conveying device according to the first aspect of the present invention sucks the recording medium conveying surface having a plurality of suction holes, the decompression chamber communicating with the plurality of suction holes, and the air in the decompression chamber. A suction unit including a suction unit, and a recording medium supplied onto the recording medium conveyance surface of the suction unit while adsorbing the recording medium onto the recording medium conveyance surface via the suction hole by the suction unit and upstream of the suction unit. A recording medium conveying device that conveys the recording medium to the downstream side, each of the plurality of suction holes of the suction unit faces a recording medium and a through-hole portion that communicates with the decompression chamber. The suction surface has a larger area than the cross-sectional area of the through hole.

Further, in the recording medium conveying device according to a second aspect of the present invention, the plurality of suction chambers each include a recess formed on the recording medium conveying surface, and are separated from each other by a partition wall. It is characterized by being

Further, in the recording medium conveying apparatus according to the third aspect of the present invention, each of the recesses is formed by partitioning in the main scanning direction and the sub scanning direction.

Further, in the recording medium carrying device according to the fourth aspect, the suction surfaces of the plurality of suction chambers are formed by recesses each having a substantially rectangular shape.

According to a fifth aspect of the present invention, there is provided the recording medium carrying apparatus, wherein each of the plurality of suction chambers has a suction surface formed by a substantially circular recess.

Further, in the recording medium carrying device according to the sixth aspect, the width dimension of the wall top portion of the partition wall is smaller than the dimension or the diameter dimension of one side of the suction surface of the suction chamber. Is characterized by.

Further, in the recording medium conveying device according to the seventh aspect, the wall top portion of the partition wall is formed in a linear shape having an area of substantially zero.

In the recording medium carrying device according to the present invention, at least the top of the partition wall in the main scanning direction is formed in a linear shape having an area of approximately 0.

According to a ninth aspect of the present invention, there is provided a recording device including the recording medium conveying device.

Further, the suction unit according to claim 10 is
A recording medium suction holding unit having a plurality of suction holes, a decompression chamber integrally formed with the recording medium suction holding unit and communicating with the plurality of suction holes, and a suction unit for sucking air in the decompression chamber. In a suction unit for sucking the recording medium supplied onto the recording medium suction holding section onto the recording medium suction holding section via the suction hole by the suction means, each of the plurality of suction holes is provided. It is characterized in that it is formed by a through hole communicating with the decompression chamber and a suction chamber having an area of a suction surface facing the recording medium larger than a cross-sectional area of the through hole.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described.

FIG. 1 is a view showing the main structure of a suction unit according to the first embodiment of the present invention, (a) is a plan view thereof, and (b) is a sectional view thereof. As shown in FIG. 1B, the suction unit 100 of the present embodiment is formed in the shape of a hollow box having an upper and lower two-stage structure composed of an upper suction section 101 and a lower suction force generation section 104. Suction unit 101
As shown in FIGS. 1A and 1B, is a decompression chamber 102 (area S ₂ ) formed inside, and a plurality of suction chambers each formed as a substantially rectangular recess on the conveyance surface of the recording medium. 10
6 (area S ₃ ) and a plurality of suction holes 108 (area S ₁ ) extending in the vertical direction so that these suction chambers 106 communicate with the decompression chamber 102. The suction force generation unit 104 communicates with the decompression chamber 102 of the suction unit 101 and the communication hole 11
0, and has a pump 112 (flow rate Q) internally equipped with a centrifugal fan.

Here, the basic principle of the present invention as a premise of this embodiment will be described. Now, as shown in FIG. 1 (b), the suction hole 108 has a sectional area S _{1 in} the direction perpendicular to the streamline, a flow velocity U ₁ , a static pressure P ₁ , and a decompression chamber 102 portion,
The cross-sectional area in the direction perpendicular to the streamline is S ₂ , the flow velocity is U ₂ , and the static pressure is P.
₂ , ρ is the density of air, and P ₀ is the atmospheric pressure (atmospheric pressure) outside the suction unit 100.

The flow of the flow rate Q of the pump 112 causes the flow in the path of the outside → the suction hole 108 → the decompression chamber 102. At this time, the outside → suction hole 108 and suction hole 10
The change in dynamic pressure in the decompression chamber 102 is replaced with static pressure at a certain rate, and added to the static pressure in the outside and the suction holes 108, respectively.

[0029] That is, the external → the suction hole 108, the external dynamic pressure 0, since the dynamic pressure of the suction hole 108 becomes ρU ₁ ^2/2, change of the dynamic pressure, 0-ρU ₁ ^2/2 Next to
The static pressure P ₁ in the suction hole 108, which is the sum of the external static pressure and a certain proportion of the dynamic pressure change, is

[0030]

[Equation 1] Becomes

Similarly, from the suction hole 108 to the decompression chamber 102
Is the dynamic pressure of the suction hole 108 is ρU₁ ^Two/ 2, decompression chamber 102
Dynamic pressure is ρU_Two ^TwoSince it is / 2, the change in dynamic pressure
Is ρU ₁ ^Two/ 2-ρU_Two ^Two/ 2, therefore the suction hole
A reduction that is the sum of the static pressure in 108 and the rate of change in dynamic pressure.
Static pressure P in the pressure chamber 102_TwoIs

[0032]

[Equation 2] Becomes

Here, ζ ₁ is a loss coefficient due to the contraction flow at the inlet portion, and is estimated to be 0 to 0.15. ζ ₂ is a loss coefficient due to sudden expansion, and is close to 1 if the ratio of S ₂ and S ₁ is large. From the above, here, ζ ₁ = 0, ζ ₂
= 1.

When the above (1) and (2) are summarized by this coefficient value,

[Equation 3]

[0035]

[Equation 4] Becomes

[0036] That is, the pressure _{P 2} of the pressure _{P 1} and the decompression chamber 102 of the suction holes 108, compared to the external pressure _{P 0,} are both only equal ρU ₁ ^2/2 reduced pressure.

Here, when the reduced pressure from the atmospheric pressure P ₀ is expressed as ΔP,

[Equation 5]

Further, the flow velocity U ₁ depends on the flow rate Q of the suction hole 108.
Is the value obtained by dividing the total area ΣS ₁ of

[Equation 6]

From the above, the equations (3) and (4) are

[Equation 7] Is expressed as

When the cross-sectional area of the suction chamber 106 in the direction perpendicular to the streamline is S ₁ , the suction force of the recording medium for each suction chamber is ΔP · S ₃ , and the total suction force is ΔP · ΣS ₃ . To be done.

FIG. 2 shows a typical pump (centrifugal fan) characteristic and the characteristic of the equation (7) in the form of a graph. In this pump characteristic, a plurality of utilization rates of the reduced pressure amount (P ₀ -P) are generated. 2 shows how the total area ΣS ₁ of the suction holes 108 changes depending on whether it is large or small. In the graph of FIG. 2, the vertical axis represents the amount of reduced pressure (P ₀ −
P), the horizontal axis indicates the flow rate Q of the pump 112.

In FIG. 2, the total area ΣS ₁ of the suction holes 108
ΔP according to equation (7) when the value is large and when it is small
If the intersections (a) and (b) of each curve representing the curve and the curve representing the pump (centrifugal fan) are obtained, the usable pressure reduction amount (P ₀ −P) is obtained, and the total area of the plurality of suction holes 108 is obtained. It can be seen that the smaller ΣS ₁ is, the higher the utilization rate of the generated decompression amount is, as compared with the larger ΣS ₁ .

The curve in FIG. 2 is a curve representing ΔP according to the equation (7) when the suction hole 108 is covered with the recording medium and the total area ΣS ₁ of the suction hole 108 becomes small (the curve is a curve. Correspondence, curve corresponds to the curve). From the figure, it can be seen that the smaller the total area ΣS ₁ when the plurality of suction holes 108 are opened is, the smaller the change in the amount of reduced pressure that is generated is. This indicates that the smaller the total area ΣS ₁ of the plurality of suction holes 108 is, the smaller the change in the amount of reduced pressure generated in the recording medium of various widths is. Therefore, effective cockling prevention and stable recording medium conveyance can be obtained.

On the other hand, as described above, the suction force of the recording medium in each suction chamber 106 is ΔP · S ₃ , and the total suction force is ΔP · Σ.
Since it is represented by S ₃ , after all, the total area of the suction holes 108 is S
_It can be concluded that the smaller ₁ is, the better, and the larger the area S ₃ of the suction chamber 106 formed on the conveying surface of the recording medium is, the larger.

That is, Japanese Patent Laid-Open No. 63-303781,
Considering the suction holes (through holes) in the conventional suction structure described in Japanese Patent Application Laid-Open No. 3-270, etc., (1) The larger the total area of the suction holes, the more practically it is used for the characteristics of the pump. Pay attention to two points: the utilization rate of the negative pressure that can be reduced decreases, and (2) the smaller the area of the surface of the suction hole facing the recording medium becomes, the more the force for sucking the recording medium cannot be generated. Various investigations have been repeated on what kind of suction structure can be used to prevent cockling more effectively than the conventional example without lowering the accuracy of conveyance (paper feed) of the recording medium.

As a result, first, as a basic structure, a portion corresponding to the suction hole in the conventional suction structure is formed in the suction chamber 106.
Formed by the (area S ₃₎ and the suction hole 108 (the area S _1), the suction holes 108 (area S ₁₎ by forming a small-diameter through-holes, the use of negative pressure available for the characteristic of the pump In addition to increasing the rate, the suction chamber 106 forming the surface facing the recording medium is formed as a substantially rectangular recess having a larger area so that a large suction force can be generated on the recording medium [FIG. See a) and (b)]. It should be noted that the suction chamber 106 is not limited to a rectangular shape in plan view, but may be a circle, an ellipse,
It was confirmed that the effect is also obtained in the diamond shape.

Next, a second embodiment of the present invention will be described with reference to FIGS. Since the basic structure of the suction unit according to the second embodiment is substantially the same as that of the first embodiment described above, the same parts are designated by the same reference numerals, and detailed description thereof will be omitted. To do. That is,
In this embodiment, as shown in FIGS. 5A and 5B, the plurality of suction chambers 106 ′ are formed by partitioning the respective recesses formed on the recording medium transport surface with a partition wall 107 ′. ing. The partition walls 107 'are formed along the main scanning direction and the sub scanning direction, respectively. The suction surface of each of the plurality of suction chambers 106 'is formed by a substantially rectangular recess. The suction surfaces of each of the plurality of suction chambers 106 ′ may be formed by a recess having a substantially circular shape. In the suction unit according to the second embodiment, the partition wall 10
The top portion 107't of 7'is formed in a linear shape having an area of approximately 0.

Here, the operation and effect of the suction unit according to the second embodiment will be described in comparison with the above-described first embodiment and the conventional example.

FIG. 3 is a diagram showing a function and effect of the suction unit of the conventional example as a comparative example, FIG. 4 is a diagram showing a function and effect of the suction unit according to the first embodiment as a comparative example, FIG.
[Fig. 8] is a view showing the action and effect of the suction unit according to the second embodiment.

First, the function and effect of the conventional suction unit will be described. As shown in FIG. 3A, the suction force is Δ
P · A ₁ (ΔP = P ₀ −P), and ΔP = P ₀ −P
Is the same as the suction unit of the first and second embodiments, but the suction force is small because the area (cross-sectional area) A _{1 of} the surface of the suction hole 31 facing the recording medium 10 is the smallest.

When the recording medium 10 absorbs a large amount of ink such as a solid image, as shown in FIG. 3B, the upper portion of the suction hole 31 of the recording medium 10 is sucked and sucked. The portion between the holes 31 and 31 is largely lifted because the force pressing it downward does not work. The above-mentioned JP-A-63-303781 and JP-A-3-2
As is apparent from the drawings disclosed in Japanese Patent Publication No. 70, etc., since the distance between the suction holes is very wide, this cock ring must be wide and large, and the height at which it rises is also high. It will be expensive.

Next, the function and effect of the suction unit of the first embodiment will be described. As shown in FIG. 4A, the suction force is represented by ΔP · A ₂ (ΔP = P ₀ −P), and ΔP =
P ₀ -P is the same as the suction unit of the conventional example and the second embodiment, but the area (cross-sectional area) A _{2 of} the surface of the suction chamber 106 facing the recording medium 10 is larger than that of the conventional example. The power will be greater.

Then, even if the recording medium 10 absorbs a large amount of ink such as a solid image, as shown in FIG. 4B, the upper portion of the suction chamber 106 of the recording medium 10 is sucked and adsorbed ( Although it is dented, the portion between the suction chambers 106 and 106 (the top portion 107t of the partition wall 107) does not exert a downward pressing force and thus rises. This suction chamber 1
The part between 06 and 106 (the top 107 of the partition wall 107)
If t) is relatively small, this cockling can be small and small. From this point of view, it is desirable that the width of the top portion 107t of the partition wall 107 between the suction chambers 106 is as small as possible. At least the top 107t of the partition wall 107
It is necessary that the width dimension of is smaller than the dimension or the diameter of one side of the suction surface of the suction chamber 106.

Next, the function and effect of the suction unit of the second embodiment will be described. As shown in FIG.
The suction force is represented by ΔP · A ₃ (ΔP = P-P0), and ΔP
= P-P0 is similar to the suction unit of the conventional example and the first embodiment, but the area (cross-sectional area) A _{3 of} the surface of the suction chamber 106 'facing the recording medium 10 is the same as that of the conventional example and the first embodiment. Since it is larger than that of the embodiment, the suction force is maximized.

Even if the recording medium 10 absorbs a large amount of ink such as a solid image, as shown in FIG. 5B, the upper portion of the suction chamber 106 'is sucked and adsorbed by the recording medium 10. Although (recessed), the portion between the suction chambers 106 'and 106' (the top portion 107't of the partition wall 107 ') is formed in a linear shape with an area of approximately 0, and therefore does not rise.

By the way, usually, the paper as a recording medium has a direction in which the fibrous material of the paper is elongated, and cockling is unlikely to occur in this direction, and is likely to occur in a direction orthogonal to this direction. Further, the cockling has a unique cycle in relation to the fiber quality of the paper thus stretched. For example, with A4 plain paper, the fiber quality of the paper extends in the vertical direction (the paper feeding direction or the sub-scanning direction when fed to the printer), and therefore cockling occurs in the sub-scanning direction. It is difficult and is likely to occur in the main scanning direction. Therefore, in the second embodiment, the partition wall 107 'is formed along each of the main scanning direction and the sub-scanning direction, and the top portions 107't of the partition wall 107' are both formed in a linear shape with an area of about 0. However,
At least the top portion 107 'of the partition wall 107' in the main scanning direction
It is preferable to form t in a linear shape having an area of approximately 0.

As described above, in the second embodiment,
Even if a large amount of ink such as a solid image is absorbed in the recording medium 10 by using plain paper, it hardly rises as shown in FIG. It is possible to set it.
Therefore, it is possible to improve the recording image quality when recording is performed using special paper.

[0058]

FIG. 6 shows an ink jet printer as a recording device to which the present invention is applied, FIG. 7 shows a recording medium conveying device as a main part thereof, and FIGS. FIG. 8 is a plan view showing an embodiment of the suction unit, FIG. 9 is a front view thereof, and FIG. 10 is a side view thereof.

As shown in FIG. 6, this ink jet printer basically has a recording sheet 10 'stored in a sheet tray 212 of an automatic sheet feeding (ASF) unit 202 obliquely attached to the printer body 200. Recording medium conveying device 220 for conveying the recording medium in the conveying direction D at the time of recording
Thus, the recording head 10 and the suction unit 100 located below the recording head 18 are fed to the recording unit 14, and the recording paper 10 ′ after recording is discharged to the outside of the printer main body 200. However, a manual paper feed port 204 (see FIG. 7) not shown in FIG. 6 is formed on the back side of the printer body 200, and the recording paper 10 ′ that is inserted and fed from the manual paper feed port 204 is also provided. ,
Similarly, at the time of recording, the recording medium conveying device 220 feeds the recording medium 14 to the recording unit 14, and the recording sheet 1 after recording
0 ′ is discharged to the outside of the printer main body 200. Incidentally, in FIG. 6, the printer main body 200 includes a support frame 200a,
Outer cover 200b and discharge port 20 for recording paper 10 '
0c is included. As the recording paper 10 ', various papers such as OHP film, tracing paper, and postcard can be used in addition to the special paper for the ink jet printer and the plain paper.

The recording medium conveying device 220 includes a suction unit 100 for sucking and holding the recording sheet 10 'during recording.
And a recording medium conveying unit that conveys the recording sheet 10 ′ from the upstream side to the downstream side of the suction unit 100. The recording medium transport unit includes a paper feed roller 221 that picks up and feeds the recording papers 10 ′ stored in the paper tray 212 one by one, and the recording paper 10 ′ to the recording head 18.
And the paper feed roller 12 which is fed between the suction unit 100 and the driven roller 12a, and the recording paper 10 'after recording.
It has a paper discharge roller 16 for discharging the sheet to the outside of the recording section and a spur roller 16a as a driven roller thereof. A structure in which the suction unit 100 can be moved in the discharge direction (see FIG. 10)
By setting the discharge roller 16 and the spur roller 16a,
It is also possible not to provide. Reference numeral 225 is a paper guide member disposed at a predetermined portion such as between these rollers. Further, in FIG. 7, the alternate long and short dash line L indicates the recording medium transport device 2
2 shows a conveyance path of the recording paper 10 ′ conveyed by 20.

The recording head 18 has guide shafts (parallel to each other) arranged in parallel along directions E and F (main scanning direction) orthogonal to the conveyance direction D (paper feeding direction or sub-scanning direction) of the recording paper 10 '. Carriage 23 slidably supported by (not shown)
The carriage 230 is mounted on a guide shaft (not shown) by a timing belt driven by the DC motor 32. The recording head 18 has a nozzle row composed of a plurality of nozzles such as 96 nozzles for each color, and prints ink supplied for each color from the ink cartridge 233 detachably mounted on the carriage 230. Fine ink particles are ejected onto the recording paper 10 'from all or some of the plurality of nozzles according to the data.

The suction unit 100 is arranged at a position facing the recording head 18 with the conveyance path L of the recording paper 10 'interposed therebetween, and the suction unit 101 in the upper stage and the suction force generation unit 10 in the lower stage.
It is formed in the shape of a hollow box composed of two upper and lower stages.
As shown in FIG. 7, the suction unit 101 includes a decompression chamber 102 formed inside, and a plurality of suction chambers 106 (area S ₃ ) each formed as a substantially rectangular recess on the transport surface of the recording sheet 10 ′. , The suction chamber 106 and the decompression chamber 102 respectively.
A plurality of suction holes 1 extending vertically to communicate with
08 (cross-sectional area S ₁ ). In the present embodiment, the suction chamber 106 is formed such that the area S _{3 of the} suction surface facing the recording paper 10 ′ is larger than the cross-sectional area S ₁ of the suction hole 108. The suction force generation unit 104 communicates with the decompression chamber 102 of the suction unit 101 via a communication hole 110, and has a pump 112 (flow rate Q) equipped with a centrifugal fan inside. The pump 112 is attached to a predetermined position below the decompression chamber 102 in a state of communicating with the decompression chamber 102 via the communication hole 110, and the centrifugal fan operates during recording.

The recording paper 10 'stored in the paper tray 212 by a host computer (not shown) or the like.
When a recording command for the ASF unit 20 is input,
The second paper feed roller 221 is rotationally driven to move the paper tray 21.
The recording papers 10 'stored in 2 are picked up and sent one by one, and the paper feed roller 12 and the like are driven to rotate so that the recording papers 10' are fed between the recording head 18 and the suction unit 100. Transport.

On the other hand, in the suction unit 100, the centrifugal fan starts operating. As a result, the suction force of the pump 112 acts on the suction hole 108 and the suction chamber 106 via the communication hole 110 and the decompression chamber 102, and the suction suction state is established.

Subsequently, the recording sheet 1 sent to the recording section
0'is sucked and adsorbed on the recording medium conveying surface of the suction unit 100, and is conveyed while maintaining a close contact state. At the same time, while the recording head 18 moves above the recording sheet 10 'in the main scanning directions E and F, ink particles are ejected onto the recording sheet 10' to perform image recording. The recording sheet 10 ′ after this image recording is finished is the discharge roller 16
After being sent out from the recording section by the spur roller 16a as a driven roller and the like, or the suction unit 100
Is sent out from the recording unit by the movement of, and then discharged to the outside of the printer body.

At this time, as described above, the recording sheet 10 '
Does not float up due to the cockling, so even if the spur roller 16a is used, there is no spur mark.

[0067]

As described above, according to the present invention, cockling of the recording medium can be effectively prevented in the recording apparatus. Stable transportation can be obtained for recording media of various sizes.

Further, since the recording medium can be at least recessed without being lifted up, the recording medium is not pressed against the spur roller. As a result, the spur trace is attached to the recording medium (even if the spur roller is used). It doesn't.

Further, since cockling on plain paper can be prevented, the paper gap can be made small, and the printing accuracy on special paper can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of a suction unit according to a first embodiment of the present invention, (a) is a plan view thereof,
(B) is the sectional view.

FIG. 2 is a graph showing a pump (centrifugal fan) characteristic, and in this pump (centrifugal fan) characteristic, the utilization rate of the reduced pressure amount (P ₀ -P) generated is such that the total area ΣS ₁ of the plurality of suction holes 108 is The graph which shows how it changes with a large case and a small case.

FIG. 3 is a diagram showing a function and effect of a suction unit of a conventional example as a comparative example.

FIG. 4 is a diagram showing a function and effect of the suction unit according to the first embodiment as a comparative example.

FIG. 5 is a diagram showing the function and effect of the suction unit according to the second embodiment.

FIG. 6 is a diagram showing an inkjet printer as a recording apparatus to which the present invention is applied.

7 is a diagram showing a recording medium conveying device as a main part of the inkjet printer of FIG.

FIG. 8 is a plan view showing an embodiment of a suction unit of the recording medium conveyance device of FIG.

9 is a front view showing an embodiment of a suction unit of the recording medium conveyance device of FIG.

10 is a side view showing an embodiment of a suction unit of the recording medium carrying device of FIG.

11 (a), (b), and (c) are views showing only a main part of a recording unit and a recording medium conveying device in a conventional inkjet printer or the like.

FIG. 12 is a diagram showing a spur trace of an image recorded by a conventional inkjet printer.

[Explanation of symbols]

10 recording media 100 suction unit 102 Decompression chamber 108 through hole 106, 106 'suction chamber 107,107 'Partition wall 107t, 107't Partition wall top 112 pumps

Claims (10)

[Claims] 1. A suction unit having a recording medium carrying surface provided with a plurality of suction holes, a decompression chamber communicating with the plurality of suction holes, and a suction unit for sucking air in the decompression chamber, and the suction unit. Recording medium conveying means for conveying the recording medium supplied onto the recording medium conveying surface of the unit from the upstream side to the downstream side of the suction unit while adsorbing the recording medium onto the recording medium conveying surface via the suction hole by the suction means. In a recording medium transporting device comprising: a suction unit, each of the plurality of suction holes has a through hole communicating with the decompression chamber, and an area of a suction surface facing the recording medium has a cross section of the through hole. A recording medium conveyance device formed by a suction chamber having a larger area. 2. The recording medium carrying device according to claim 1, wherein each of the plurality of suction chambers is composed of a respective recess formed on the recording medium carrying surface and is formed by being partitioned by a partition wall. A recording medium conveying device characterized by the above. 3. The recording medium carrying device according to claim 2, wherein each of the recesses is formed by partition walls in the main scanning direction and the sub scanning direction. 4. The recording medium conveying device according to claim 2, wherein the suction surfaces of the plurality of suction chambers are formed by recesses each having a substantially rectangular shape. 5. The recording medium conveying device according to claim 1, wherein the suction surfaces of the plurality of suction chambers are formed by recesses each having a substantially circular shape. 6. The recording medium carrying device according to claim 4 or 5, wherein a width dimension of a wall top portion of the partition wall is formed smaller than a dimension or a diameter dimension of one side of a suction surface of the suction chamber. A recording medium conveying device characterized by the above. 7. The recording medium conveying apparatus according to claim 4 or 5, wherein the top of the partition wall is formed in a linear shape having an area of substantially zero. 8. The recording medium conveying device according to claim 4, wherein at least a top of the partition wall in the main scanning direction is formed in a linear shape having an area of substantially zero. 9. A recording apparatus comprising the recording medium conveying apparatus according to claim 1. 10. A recording medium suction holding unit having a plurality of suction holes, a decompression chamber integrally formed with the recording medium suction holding unit and communicating with the plurality of suction holes, and air in the decompression chamber. A suction unit configured to suction the recording medium supplied onto the recording medium suction holding unit onto the recording medium suction holding unit via the suction hole by the suction unit. A suction unit in which each of the holes is formed by a through hole communicating with the decompression chamber and a suction chamber having an area of a suction surface facing the recording medium larger than a cross-sectional area of the through hole. .