JP2002337403A - Recording paper support device and large recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a paper gap from being affected by cockling by limiting an amplitude of cockling of a recording paper at a portion opposite to a recording head to a small value even in a recorder having a structure wherein a recording paper is sucked by a sucking hole provided in the vicinity of a rib at a downstream side and the recording paper is forcedly attracted to a lower guide plate. SOLUTION: A rib rising inclined face 341 positionally corresponds to a base rising inclined face 711, a rib top face 342 positionally corresponds to a base top face 712, and a rib lowering inclined face 343 positionally corresponds to a base lowering inclined face 713. Under the positional correspondences, the rib top face 342 is formed to be higher than the base top face 712 by 0.1-0.5 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a recording apparatus such as an ink jet printer, and is provided on a base plate and on the upper surface of the base plate in parallel at regular intervals in a direction perpendicular to the recording paper transport direction. The present invention relates to a recording paper support device having a plurality of ribs and defining a space between a head surface of a recording head and a recording paper passing over the ribs, and a large-sized recording device using the same.

[0002]

2. Description of the Related Art In a conventional ink jet printer, a recording paper supporting device which is provided on a side facing a recording head and supports a recording paper from the back side of the paper is provided with a rib provided on a base plate of the recording medium. Is about 2 mm, and the pitch between each rib is about 1 mm.
It is formed to 2 mm. Thereby, the distance between the head surface of the recording head and the recording paper passing over the ribs (hereinafter referred to as “paper gap”) is defined to be within a certain range that substantially aims at, and the paper generated when the paper is wet with ink is formed. The deflection of the paper due to the cockling phenomenon described above is released between the ribs to reduce the fluctuation of the paper gap.

[0003] In order to maintain the paper gap constant and realize stable paper conveyance even for paper of various sizes, large and small, the recording paper is positioned downstream of the ribs from the back side thereof. A flat lower guide plate provided with a suction port as described below is provided. That is, a large number of suction ports communicating with the suction fan are provided at predetermined positions in the vicinity of the downstream of the rib at predetermined intervals in the vertical and horizontal directions,
The suction force (negative pressure) of the suction port forcibly pulls the sheet to the upper surface of the flat lower guide plate, thereby preventing the sheet from floating and pressing the recording sheet against the top surface of the rib at the upstream side. The paper gap is kept constant.

[0004]

However, the recording paper is sucked by the suction port provided in the vicinity of the downstream side of the rib and is forcibly attracted to the lower guide plate, thereby preventing a large lifting of the recording paper. However, since the suction force acts on the recording paper at a position near the downstream of the rib, the suction force by the suction port affects a portion of the rib immediately upstream of the suction port. That is, the portion between the ribs of the recording paper has a weaker force than the suction force of the suction port portion, but is pulled downward by the force. Since the recording paper in this area is wet and loose with ink, the rib height is 2 mm.
If there is a certain degree, the portion between the ribs of the recording paper is elongated, the amplitude of cockling in the portion facing the recording head increases, and the effect of cockling to the extent not negligible appears on the paper gap. However, there is a possibility that the recording quality is degraded.

An object of the present invention is to provide a recording apparatus in which a suction port is provided at a position near a downstream side of a rib and suction is performed by the suction port to forcibly pull a recording sheet to a lower guide plate. A recording paper supporting device that can reduce the amplitude of cockling of the recording paper in a portion facing the recording head, thereby preventing the effect of cockling from appearing in the paper gap, and thereby reducing the possibility of deteriorating recording quality; An object of the present invention is to provide a large-sized recording apparatus provided with the recording apparatus.

[0006]

In order to achieve the above object, according to the present invention, a base plate and a base plate are arranged in parallel on a top surface of the base plate at regular intervals in a direction orthogonal to a recording paper conveying direction. And a plurality of ribs disposed on the recording paper support device, wherein the ribs define the distance between the head surface of the recording head and the recording paper passing over the ribs. A biasing means for biasing the recording paper toward a lower guide plate supporting the recording paper from the back side thereof is provided at a position near the center and substantially at the center of the adjacent rib, and the upper surface of the rib has a recording surface. The upper surface of the base plate is also formed with a rib ascending surface, a rib top surface, and a rib ascending surface from the upstream side to the downstream side in the paper conveyance direction, and the upper surface thereof also extends from the upstream side to the downstream side in the recording paper conveyance direction. Base up slope, base Surfaces, and is formed at a base edge inclined surface, the said ribs upward inclined surface base upward inclined surface,
The rib top surface and the base top surface, and the rib descending inclined surface and the base descending inclined surface are in a corresponding positional relationship, and the rib top surface is 0.1 mm from the base top surface.
mm to 0.5 mm higher, and the rib-down slope and the base-down slope are formed so that the height difference gradually increases toward the downstream side.

According to the present invention, the rib-inclined surface and the base-inclined surface, the rib top surface and the base surface,
And the rib descending inclined surface and the base descending inclined surface are in a corresponding positional relationship, and under the positional relationship,
The top surface of the rib is 0.1 mm to 0.1 mm from the top surface of the base.
5 mm higher, ie rib height 0.1 mm
About 0.5 mm, which is considerably smaller than the conventional one, so that even if the portion between the ribs of the recording paper is pulled downward by the influence of the urging force such as the suction force or the like, the recording paper immediately contacts the base top surface. Contact and extension are suppressed. Therefore, the amplitude of cockling of the recording paper at the portion facing the recording head can be restricted to be small, thereby preventing the paper gap from being affected by cockling.

In addition, since the amplitude of cockling of a recording paper gradually increases to a certain scale with time, that is, with the progress of transport due to the wetting of the ink, the rib height remains 0.1 mm to 0.5 mm. In this way, there is no escape for wavy deformation (paper bending) due to cockling,
The generated cockling may be irregular and adversely affect the paper gap. However, according to the present invention, the rib descending inclined surface and the base descending inclined surface are formed so that the height difference gradually increases toward the downstream side, so that the wavy deformation (paper bending) due to cockling occurs. Even if the recording paper is conveyed while gradually increasing, the undulating deformation can be escaped, and the undulating deformation of the cockling can be stabilized in a regular manner.

According to a second aspect of the present invention, in the recording paper supporting apparatus according to the first aspect, a pitch of the plurality of ribs is formed to be 21 mm to 25 mm. According to the present invention, the rib pitch is set to 21 mm to 2 mm.
Since the thickness is set to 5 mm, cockling can be stabilized for a recording paper having a thickness of about 0.2 mm.

According to a third aspect of the present invention, in the recording paper supporting apparatus according to the first or second aspect, the top surface of the rib is formed on a horizontal plane parallel to the head surface of the recording head on the downstream side. It is characterized in that the upstream side is formed as a slight inclined surface having the horizontal plane as a top height.

Here, the slight inclined surface means an extremely small inclined surface capable of maintaining a function as a rib top surface defining a paper gap. According to the present invention, by providing the slight inclined surface, it is possible to reduce the conveyance resistance at the rib top surface of the recording paper conveyed while rubbing against the rib top surface, thereby stabilizing the conveyance.

According to a fourth aspect of the present invention, in the recording paper supporting apparatus of the second aspect, the top surface of the rib is
The downstream side is formed on a horizontal plane parallel to the head surface of the recording head, and the upstream side is formed on a slight inclined plane having the horizontal plane as a top height, between adjacent ribs, the base ascending plane and the base top surface. Is provided with a sub-rib, and the sub-rib ascending inclined surface is formed at the same position, the same inclination angle and the same height as the rib ascending inclined surface.

According to the present invention, a sub-rib is provided between the adjacent ribs and on the base-inclined surface and the base top surface, and the sub-rib has a sub-rib-inclined surface that is the rib-inclined surface. Is formed at the same position, the same inclination angle, and the same height as that of the recording paper. The interval can be made tight and the conveyance can be stabilized. Further, the sub-rib exerts the same function as the uppermost stream side portion of the rib top surface, and can stably define the paper gap.

According to a fifth aspect of the present invention, in the recording paper supporting apparatus of the fourth aspect, the height difference between the sub-rib top surface and the rib top surface gradually increases toward the downstream side. It is characterized by being formed in. According to the present invention, in the portion facing the recording head, the recording paper begins to be wet and deflected by the ink, and the deflection gradually grows as the transport progresses, but the top surface of the sub-rib faces the downstream side. Since the height difference with the rib top surface gradually increases, that is, the height of the sub-rib top surface gradually becomes lower than the height of the rib top surface, the height of the sub-rib surface is gradually reduced in accordance with the growth of the bending of the recording paper. You can escape.

According to a sixth aspect of the present invention, in the recording paper supporting apparatus according to the fifth aspect, the sub-rib top surface has a position at the downstream end and a height at the downstream end of the base top surface. And is formed so as to coincide with the height. According to the present invention, the position and height of the downstream end of the sub-rib top surface coincide with the position and height of the downstream end of the base top surface. It is effective because it can be integrated with the role of the top surface.

According to a seventh aspect of the present invention, the paper supply unit, the recording unit, and the paper discharge unit are arranged in an upper, middle, and lower positional relationship, and the paper supply unit passes through the recording unit, and the discharge unit. A large-sized recording apparatus in which a paper transport path toward a paper section is formed almost straight from a diagonally upper back side to a diagonally lower front side, wherein the recording section is a recording paper positioned on a side facing a recording head. As a supporting device, a recording paper supporting device according to any one of claims 1 to 6 is provided.
According to the present invention, in a large-sized recording apparatus, the suction port is often provided, so that the effect of applying the present invention is remarkable.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part of a recording paper supporting apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the recording paper supporting apparatus, and FIG. FIG. 3B is a cross-sectional view taken along line BB of FIG. 1, and FIG. 3 is a plan view of a main part of a portion where a suction port is provided. FIG.
FIG. 5 is a schematic vertical sectional view of a large-sized printer provided with the recording paper supporting device. FIG. 5 shows a printing section (recording section) of the large-sized printer, more precisely, conveyance before and after a printing section in a paper conveyance path. FIG. 6 is a diagram showing a surface structure, and FIG. 6 is a schematic front view of the large printer.

The structure of the large printer according to this embodiment will be described. As shown in FIG. 4, the paper feeding unit 30, the printing unit 7
And the paper discharge unit 8 are arranged in an upper, middle, and lower positional relationship. A paper transport path from the paper supply unit 30 to the paper discharge unit 8 via the printing unit 7 is formed substantially straight from the diagonally upper back side to the diagonally lower front side. The paper feed unit 30 can feed both the roll paper 3 and the cut sheet (FIG. 5) including the large rigid thick paper 21. Specifically, the roll paper 3 is attached to the paper feed unit 30 by two spindles 4 and 5 so that the roll paper 3 can be removed at the time of replacement, and the rigid cardboard 21 is, as shown in FIG.
The paper feed unit 30 is configured so that it can be set by placing it on the front side slope. In the present embodiment, the roll paper cover 28 provided on the front surface of the loaded roll paper 3 is formed so as to also serve as the support portion 29 in the set state of the cut sheet including the rigid thick paper 21.

The printing unit 7 includes an ink jet type print head 22 and a platen 33 (FIG. 5) which is a main part of a recording paper supporting device which is disposed to face the head surface of the print head 22. Flat paper feed guide 31 acting as a paper transport surface on the upstream side of print head 22
And a lower guide plate 23 acting as a sheet transport surface on the downstream side. In the present embodiment, the paper transport surface on the upstream side of the print head 22 by the paper feed guide 31 and the paper transport surface on the downstream side of the print head 22 by the lower guide plate 23 have a step d (see FIG. 5). The paper transport surface on the downstream side of the print head 7 has a stepped structure lowering to the back side. In the figure, reference numeral 5
Reference numeral 2 denotes a front cover.

The structure of the printing unit 7 will be described in more detail with reference to FIG. A sheet transport surface on the upstream side of the print head 22 by the paper feed guide 31 and a lower guide plate 23
The paper feed surface on the downstream side of the print head 22 is provided with a step d with the platen 33 as a boundary. That is, the sheet placement surface of the platen 33 is determined by the plurality of ribs 34 protruding from the upper surface of the platen 33, and the level of the sheet feed guide 31 is
The level of the lower guide plate 23 is substantially the same as that of FIG.

The lower guide plate 23 downstream of the print head 22 is provided with a suction port 25 composed of a plurality of small holes communicating with a suction chamber (not shown). The recording paper 4 passes through the suction port 25.
0 is sucked from the back surface side to suppress the floating of the sheet, to make it flat, and to firmly hold the sheet on the sheet conveying surface. The suction ports 25 are formed side by side in the horizontal direction. In the present embodiment, five rows of the suction ports 25 are provided at predetermined intervals. The suction port 25, together with the suction chamber and the suction fan 24, constitutes an urging means for urging the recording paper toward the lower guide plate 23 which supports the recording paper from the back side.

As shown in FIG. 5, a paper feed roller 50 is disposed immediately upstream of the set of the print head 22 and the platen 33. The paper feed roller 50 is a set of a drive roller 35 and a driven roller 36. And a driven roller 36 is provided so as to be able to contact and separate from the drive roller 35 by a rotating lever 37. The reason for requiring the contact / separation mechanism is to separate the driven roller 36 from the drive roller 35 (release state) when aligning the recording paper so that the recording paper can easily pass therethrough. That is, the leading edge of the recording paper is inserted into the paper transport path from obliquely above by passing the leading edge of the recording paper 40 through the print area (below the print head 22) of the printing unit 7,
The leading end of the recording paper is formed so as to be aligned with a horizontal line 38 as a set mark on the lower guide plate 23. Here, the horizontal line 38 is also used at the most downstream position of the row of the suction ports 25 (see FIGS. 5 and 6).

Further, as shown in FIG. 6, a vertical line 39 for positioning the recording paper 40 in the vertical direction is located at the outermost end position of the suction area of the many suction ports 25 (in this embodiment, (Right end). After the alignment is completed, the driven roller 36 is moved to the driving roller 35.
Then, the drive roller 35 is rotated backward to return the leading end of the recording paper, and is stopped at the printing start position.
Here, the horizontal line 38 and the vertical line 39 serving as set marks serve to prevent skew conveyance of the recording paper in advance by performing alignment of the leading end of the recording paper using these.

In the present embodiment, the paper feed unit 30 is configured to be capable of feeding the roll paper 3 as the recording paper 40 as shown in FIG. 5, but the roll paper sent to the paper transport path is provided. 3 is a print head 22 downstream of the print head 22.
The cutter 41 arranged on the carriage 2 at a fixed distance from the printer 2 cuts the print unit at a predetermined length for each print unit. In the case of the present embodiment, the cutter 4
Reference numeral 1 denotes a configuration in which the solenoid 42 is driven from the near side to the far side of the transport surface against the return spring 43 by the solenoid 42.

The paper discharge section 8 is a section for receiving printed paper. When the roll paper 3 is marked by the paper discharge switching lever 26, the stack cloth 27 is spread on the front of the printer, or the printed paper is printed. Is guided to the lower portion of the printer main body, or is retracted to a position (the position in FIG. 4) which does not hinder the ejection of the rigid cardboard when printing rigid cardboard.

Here, a specific structure of the recording paper supporting apparatus according to one embodiment of the present invention will be described with reference to FIGS. In the recording paper supporting apparatus of the present embodiment, the platen 33 includes a base plate 71 and a plurality of ribs disposed on the upper surface of the base plate 71 at regular intervals in a direction orthogonal to the recording paper conveyance direction. 34. By the rib 34, the head surface of the print head 22 and the rib 34
It specifies the distance from the recording paper passing above.

As shown in FIG. 1, a lower guide plate 23 for supporting the recording paper from the back side thereof is disposed downstream of the platen 33. The suction ports 25 as urging means for urging toward the lower guide plate 23 are provided vertically and horizontally at a position near the downstream side of the rib 34 and at a position substantially corresponding to the center of the adjacent rib 34. Have been.

The rib 34 has an upper surface inclined upward from the upstream side to the downstream side in the recording paper conveying direction.
1, a rib top surface 342, and a rib downward inclined surface 343. The base plate 71 also has a base upward slope 711, a base top slope 712, and a base fall slope 7 from the upstream side to the downstream side in the recording paper transport direction.
13 are formed. The rib ascending surface 341, the base ascending surface 711, and the rib top surface 342.
And the base top surface 712, and the rib descending inclined surface 343 and the base descending inclined surface 713 are formed so as to have a corresponding positional relationship. In FIG.
Reference numeral 4 denotes a chamfer.

Under the above positional relationship, the rib top surface 342
Is higher in the range of 0.1 mm to 0.5 mm than the top surface of the base, and is 0.2 mm higher in the present embodiment. Further, as shown in FIG. 2, the rib descending inclined surface 343 and the base descending inclined surface 713 are formed so that the height difference gradually increases toward the downstream side. In the present embodiment, the width of the rib top surface 342 is formed to be about 2 mm. The plurality of ribs 34 provided at regular intervals in a direction orthogonal to the recording paper conveyance direction has a pitch of 21 mm to 25 mm.
In this embodiment, the thickness is set to 24 mm within the range of mm.

The rib top surface 342 of the rib 34 is formed on a horizontal surface 3421 parallel to the head surface of the print head 22 on the downstream side, and is formed on a slight inclined surface 3422 having the horizontal surface 3421 as a top height on the upstream side. . The slight inclined surface means an extremely small inclined surface that can maintain the function as the rib top surface 34 that defines the paper gap.

A sub-rib 80 is provided between the adjacent ribs 34 and on the base upward inclined surface 711 and the base top surface 712. The sub-rib 80 has the sub-rib up-slope surface 801 formed at the same position, the same slant angle and the same height as the rib up-slope surface 341. Furthermore,
As shown in FIG. 2B, the sub-rib top surface 802 is formed so that the height difference from the rib top surface 342 gradually increases toward the downstream side. In the present embodiment, the sub-rib top surface 802 is formed such that the position and height of the downstream end 804 coincide with the position and height of the downstream end 714 of the base top surface 712.

As shown in FIGS. 1 and 3, the lower guide plate 23, which is located downstream of the recording head 22 and supports the recording paper from its back side, faces the upper surface of the lower guide plate 23. Suction ports 25 are provided as urging means for urging the recording paper, and auxiliary ribs are provided between the adjacent suction ports 25 in the direction orthogonal to the recording paper conveyance direction of the lower guide plate 23. 90 are provided. In the present embodiment, the auxiliary rib 90 has a rib height of about 2 mm and a width of about 2 mm, and is formed to be long in the recording paper transport direction. As described above, a plurality of the suction ports 25 are provided at predetermined intervals also in the recording paper transport direction, and as shown in FIG. 3, the suction ports 25 are vertically and horizontally arranged at predetermined intervals. . The suction port 25 is provided on the downstream side with the suction guiding groove 2.
50 are formed, so that air is easily sucked from the direction of the guide groove 250.

The suction port 25 is connected to the platen 33
The auxiliary rib 90 is provided at a position substantially corresponding to the center between the adjacent ribs 34 on the upper side, and the auxiliary rib 90 is provided at a substantially central position between the adjacent suction ports 25 in a direction orthogonal to the recording paper conveyance direction. They are arranged in a line. In FIG. 3, reference numeral 91 denotes a mounting hole for mounting the lower guide plate 23.

Next, the operation of the above embodiment will be described.
According to the present embodiment, the positions at which the rib rising slope 341 and the base rising slope 711, the rib top 342 and the base top face 712, and the rib falling slope 343 and the base falling slope 713 correspond to each other. Under the positional relationship, the rib top surface 342 is formed to be 0.1 mm to 0.5 mm higher than the base top surface 712. That is, since the rib height is about 0.1 mm to 0.5 mm, which is considerably smaller than the conventional one, the portion of the recording paper between the ribs is pulled downward by the influence of the urging force such as the suction force. However, the contact with the base top surface 712 immediately is prevented from being extended. Therefore, the recording head 22
The amplitude of the cockling of the recording paper at the portion facing the paper gap can be restricted to be small, thereby preventing the paper gap from being affected by the cockling.

The recording paper is wetted with the ink, and the amplitude of the cockling gradually increases with time, that is, with the progress of conveyance, to a certain scale, so that the rib height remains 0.1 mm to 0.5 mm. In this way, there is no escape for wavy deformation (paper bending) due to cockling,
The generated cockling may be irregular and adversely affect the paper gap. However, according to the present embodiment, the rib-down slope 343 and the base-down slope 713 are formed so that the height difference gradually increases toward the downstream side. Even if the recording paper is conveyed while the deflection is gradually increasing, the undulating deformation can be escaped, and the undulating deformation of the cockling can be stabilized in a regular manner. The pitch of the plurality of ribs is 2
Since it is formed in a thickness of 1 mm to 25 mm, cockling can be stabilized with respect to a recording paper having a thickness of about 0.2 mm.

The top surface 342 of the rib is formed on the horizontal surface 3421 parallel to the head surface of the recording head 22 on the downstream side, and is formed on the slight inclined surface 3422 having the horizontal surface 3421 as the top height on the upstream side. , Rib top surface 34
Thus, it is possible to reduce the conveyance resistance of the recording paper conveyed while rubbing on the top surface 342 of the rib, thereby stabilizing the conveyance.

Further, a sub-rib 80 is provided between the adjacent ribs 34 and on the base upward inclined surface 711 and the base top surface 712, and the sub-rib upward inclined surface 80 is provided.
1 is formed at the same position, the same inclination angle and the same height as the above-mentioned rib ascending surface 341, the following operational effects can be obtained. That is, when the leading edge of the recording paper in a state where the cockling phenomenon does not occur reaches the rib top surface 342 through the rib ascending surface 341, the actual rib interval may be close and the conveyance thereof may be stabilized. it can. Further, the sub rib 80
Has the same function as the uppermost stream side portion of the rib top surface 342, and can stably define the paper gap.

Further, since the sub-rib top surface 802 is formed so that the height difference with the rib top surface 342 gradually increases toward the downstream side, the following operation and effect can be obtained. In a portion facing the recording head 22, the recording paper starts to be wet and deflected by the ink, and the deflection gradually grows as the paper is transported. However, the sub-rib top surface 802 faces the rib top toward the downstream side. The height difference with the surface 342 gradually increases. Therefore, the height of the sub-rib top surface 802 is
Since the recording paper gradually becomes lower than the height of 2, the recording paper can be released in response to (following) the growth of the bending of the recording paper.

The position and height of the downstream end 804 of the sub-rib top surface 802 coincide with the position and height of the downstream end 714 of the base top surface 712.
02 can be effectively integrated with the role of the base top surface 712 at the most downstream portion thereof.
Also, a lower guide plate 23 located downstream of the recording head 22
Since the auxiliary ribs 90 are provided between the adjacent suction ports 25 provided in the suction port 25, the cockling of the recording paper generated and grown at a position upstream of the suction port 25 is removed by the suction port 2.
In the vicinity of 5, there is no irregular disturbance. That is, the generated peak portion of the cock ring is constrained by the auxiliary rib so as to maintain the peak state, so that it is not drawn to the valley side and collapsed. Therefore, the fluctuation of the paper gap can be reduced, and the deterioration of the recording quality can be prevented.

The plate 33 provided at a position facing the recording head 22 includes a base plate 71 and the base plate 7.
And a plurality of ribs 34 arranged in parallel at regular intervals in a direction orthogonal to the recording paper transport direction.
4, the gap between the head surface of the recording head 22 and the recording paper passing over the ribs 34 is defined, and the deflection of the recording paper due to cockling is released between the ribs. The lower guide plate 23 is provided next to the suction port 25 and the suction port 25 is provided at a position substantially corresponding to the center of the rib 34 adjacent to the lower guide plate 23. Of the lower guide plate 23 by the suction port 25.
And the crest of the cock ring is restrained by the auxiliary rib 90, and the crest is maintained. Therefore, the regularity of the generated cockling can be more effectively maintained.

Further, since the auxiliary rib 90 is provided at a substantially central position between the adjacent suction ports 25,
The position of the auxiliary rib 90 is the rib 3 on the platen 33.
4 (the direction perpendicular to the recording paper transport direction), and the regularity of the generated cockling can be maintained even more effectively. Further, since the auxiliary ribs 90 are arranged in a line in a direction orthogonal to the recording paper conveying direction, the regular arrangement of the generated cockling can be maintained even more effectively by this single-line arrangement structure. it can.

[0042]

According to the present invention, there is provided a recording apparatus having a structure in which a suction port is provided at a position near a downstream side of a rib, and suction is performed by the suction port to forcibly pull a recording sheet to a lower guide plate. In addition, the amplitude of cockling of the recording paper in the portion facing the recording head can be restricted to a small value, whereby the effect of cockling on the paper gap can be prevented, and the possibility of deterioration in recording quality can be reduced.

That is, according to the present invention, since the rib top surface is formed to have a rib height of about 0.1 mm to 0.5 mm, which is considerably smaller than the conventional one, it is affected by the urging force such as the suction force. Even if the portion of the recording paper between the ribs is pulled downward, the recording paper immediately contacts the top surface of the base and is prevented from extending. Therefore, the amplitude of cockling of the recording paper at the portion facing the recording head can be restricted to be small, thereby preventing the paper gap from being affected by cockling.

Further, since the amplitude of the cockling gradually increases to a certain scale with time, that is, with the progress of conveyance as the recording paper gets wet with the ink, if the rib height is kept small as described above, the cockling causes There is no place for relief of waving deformation (paper bending), and the generated cockling may be irregular, adversely affecting the paper gap. However, according to the present invention, the rib descending inclined surface and the base descending inclined surface are formed so that the height difference gradually increases toward the downstream side, so that wavy deformation (paper bending) due to cockling is caused. Even if the recording paper is conveyed while gradually increasing, the undulating deformation can be escaped, and the undulating deformation of the cockling can be stabilized in a regular manner.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a recording paper supporting apparatus according to an embodiment of the present invention.

2A and 2B are cross-sectional views of the recording paper supporting device, wherein FIG. 2A is a cross-sectional view taken along line AA of FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB of FIG.

FIG. 3 is a plan view of a main part of a portion where a suction port is provided.

FIG. 4 is a schematic longitudinal sectional view of a large-sized printer provided with the recording paper supporting device.

FIG. 5 is a diagram illustrating a structure of a transport surface before and after a printing unit (recording unit) of the large-sized printer, more precisely, a printing unit in a paper transport path.

FIG. 6 is a schematic front view of the large printer.

[Explanation of symbols]

 7 Printing section 22 Recording (printing) head 23 Lower guide plate 25 Suction port (biasing means) 33 Platen 34 Rib 341 Rib rising slope 342 Rib top face 343 Rib falling slope 344 Beveling section 71 Base plate 711 Base rising slope Surface 712 Base top surface 713 Base down slope 714 Downstream end 80 Sub-rib 801 Sub-rib up slope 802 Sub-rib top surface 804 Downstream end 90 Auxiliary rib

Claims (7)

[Claims] 1. A printing apparatus comprising: a base plate; and a plurality of ribs disposed on an upper surface of the base plate at predetermined intervals in a direction orthogonal to a recording paper conveyance direction, the ribs being disposed in parallel with the head surface of the recording head. What is claimed is: 1. A recording paper supporting device configured to define an interval between a recording paper and a recording paper passing over the rib, wherein the recording paper is disposed at a position near a downstream side of the rib and at a position substantially corresponding to a center of an adjacent rib. Biasing means for biasing toward the lower guide plate supported from the side, the upper surface of the rib is a rib rising inclined surface from the upstream side to the downstream side in the recording paper transport direction, the rib top surface, And the base plate also has an upper surface formed by a base rising slope, a base top face, and a base falling slope from the upstream side to the downstream side in the recording paper transport direction, The rib-inclined inclined surface and the The slope-up slope, the rib top and the base top, and the rib-down slope and the base-down slope are respectively in a corresponding positional relationship, and the rib top is 0 degrees from the base top. .1 mm to 0.
The recording paper supporting device, wherein the height is formed to be 5 mm higher, and the rib-down slope and the base-down slope are formed so that the height difference gradually increases toward the downstream side. 2. The recording paper supporting apparatus according to claim 1, wherein the plurality of ribs have a pitch of 21 mm to 25 mm. 3. The top surface of the rib according to claim 1, wherein the downstream surface is formed on a horizontal plane parallel to the head surface of the recording head, and the upstream surface is formed on a slight inclined surface having the horizontal surface as a top height. A recording paper support device. 4. The recording medium according to claim 2, wherein the top surface of the rib is formed on a horizontal plane parallel to the head surface of the recording head on the downstream side.
The upstream side is formed on a slight inclined surface having the horizontal plane as the top height, and a sub-rib is provided between the adjacent ribs and on the base-inclined inclined surface and the base top surface. The recording paper supporting device, wherein the inclined surface is formed at the same position, the same inclination angle and the same height as the rib rising inclined surface. 5. The recording paper supporting device according to claim 4, wherein the sub-rib top surface is formed so that a height difference from the rib top surface gradually increases toward the downstream side. 6. The recording apparatus according to claim 5, wherein the sub-rib top surface is formed so that the position and height of the downstream end thereof coincide with the position and height of the downstream end of the base top surface. Paper support device. 7. A paper feeding unit, a recording unit, and a paper discharging unit are arranged in an upper, middle, and lower positional relationship, and a paper transport path from the paper feeding unit to the paper discharging unit via the recording unit is obliquely upward. 7. A large-sized recording device which is formed almost straight from the back side to the diagonally lower front side, wherein the recording unit is a recording paper support device located on the side facing the recording head. A large-sized recording apparatus comprising the recording paper supporting device according to any one of the preceding claims.