JP2002248819A - Platen, its supporting structure, and recorder equipped with supporting structure of platen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely facilitate adjustment of platen gap or eliminate the need thereof. SOLUTION: A platen 7 is disposed oppositely to a recording head 1 through an interval. A plurality of ribs 7a for supporting a recording sheet 6 are provided in the surface of the platen 7 facing the recording head 1. The platen 7 is provided, at four corners thereof, with abutting parts 7b protruding toward the direction facing the recording head 1. A stay 32 fixed with an adjusting screw 33 is secured to the upper part of each abutting part 7b. The platen 7 is urged in the direction facing the recording head 1 by means of a spring 31 disposed below and the abutting parts 7b are abutted against the forward end of respective adjusting screws 33 by the urging force of the spring 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet (including general recording paper, special paper, OHP film, etc.) using a recording head. For the sake of convenience, the term sheet is used for convenience).
In particular, in order to keep the interval between the recording head and the recording sheet constant, or to keep the interval between the recording head and the recording sheet non-contact and a predetermined interval suitable for a recording method (particularly, ink jet recording), the interval between the recording head and the recording sheet is set. The present invention relates to a platen, a support mechanism for the platen, and a recording apparatus having the support mechanism.

[0002]

2. Description of the Related Art A general printing apparatus has a carriage mounted with a printing head and supported by a guide shaft or the like so as to be movable in a main scanning direction, and conveying means for conveying a recording sheet in a direction intersecting the main scanning direction. And control means for controlling these. Such a device that performs a printing operation while moving the carriage is called a serial type. On the other hand, a type in which a recording head is fixed and supported and a recording operation is performed only by conveying a recording sheet is called a line type.

[0003] In any of the serial type and line type recording apparatuses, in order to perform high-quality recording, the distance (paper distance) between the recording head and the recording sheet is required in all recording areas by the recording head. Importantly, the recording apparatus is provided with a platen that supports the recording sheet in a recording area of the recording head. For example, in an ink jet recording apparatus, if the distance between the sheets at the one end and the other end of the recording area is different, there is a difference in the time required for the ink ejected from the recording head to reach the recording sheet. As a result, the landing position of the ink is shifted. Further, in the wire dot type recording apparatus, a difference occurs in the pressure applied to the recording sheet via the ink ribbon by the pins, and the change in the sheet distance appears as the density of dots. Further, also in a recording apparatus of a thermal system or a thermal transfer system, there is a difference in a pressing force when a recording head is pressed, which also appears as dot density.

[0004] Conventional platens are often molded integrally with resin because of their high dimensional accuracy and high degree of freedom in shape, etc. The surface of the platen has a smooth flat surface or a recording surface. In many cases, the shape has a plurality of ribs parallel to the sheet conveying direction and having a smooth surface. If there are ribs, the recording sheet is supported on the upper surface of the rib. Usually, the platen is attached to a chassis or the like of the recording apparatus, and is fixed after adjusting the position so that the distance from the recording head is a predetermined distance. That is, the adjustment of the sheet distance is performed not by adjusting the actual distance between the recording head and the recording sheet, but by adjusting the distance between the recording head and the recording sheet supporting surface of the platen. The distance between the recording head and the recording sheet support surface is called a platen gap.

FIG. 8 shows an example of a conventional platen formed of a resin. In the platen 100 shown in FIG. 8, a plurality of ribs 101 parallel to the recording sheet conveyance direction B are integrally formed on an upper surface 100a which is a surface facing the recording head. The height of each of the ribs 101 is equal, and the distance between the recording head and the recording sheet in the recording area is kept constant by the recording sheet passing over the platen 100 while being in contact with the upper surface of the rib 101. Can be recorded.

On the other hand, some recording apparatuses are capable of recording on thick recording sheets such as thick paper and envelopes, in addition to general recording paper. As described above, the sheet distance is very important in a recording apparatus. Therefore, a recording apparatus corresponding to a plurality of types of recording sheets having different thicknesses is provided with a platen gap setting mechanism. Even if the thickness of the recording sheet increases, the platen gap is increased by the increased amount. As a result, the inter-paper distance can be maintained at a predetermined interval. In addition, in the ink jet recording apparatus, depending on the type of the recording sheet, the recording sheet may absorb ink and swell to cause a phenomenon (cockling) in which the recording sheet itself undulates. In such a case, the platen gap may be increased to prevent the recording sheet from interfering with the recording head.

As a conventional platen gap setting mechanism of this type, an eccentric shaft rotatably supported by a chassis of a recording apparatus is passed through a carriage, and the eccentric shaft is rotated by an arbitrary angle to bring the carriage close to the platen. A configuration in which the platen gap is adjusted by moving the platen away from the platen is generally used.

[0008]

However, as the number of dots increases in a serial type recording apparatus for the purpose of increasing the throughput, the length of the recording head in the transport direction of the recording sheet also increases, and Not only in the width direction but also in the transport direction, the distance between sheets has a great effect on the recording quality. The distance between sheets is very important for a recording apparatus, and as the number of dots in the recording head increases, it becomes necessary to set the parallelism between the recording head and the platen with high accuracy.

The degree of parallelism between the recording head and the platen is determined by the degree of component accuracy of the carriage holding the recording head and the chassis structure holding the platen. In particular, since the distance between papers is about 1 mm in an ink jet type recording apparatus, it is difficult to keep the platen gap within a predetermined range in the entire recording area widened by increasing the number of dots in the recording head only with component accuracy. is there. Therefore, it is necessary to adjust the platen gap in the manufacturing process of the recording apparatus. However, in a situation where the parallelism between the recording head and the platen must be set with high precision as described above, the adjustment for this adjustment is required. It takes a lot of man-hours, resulting in an increase in the manufacturing cost of the recording apparatus.

[0010] On the other hand, if the recording apparatus is not placed on a flat surface, the main body of the recording apparatus will be twisted, which may cause the platen gap to fluctuate. When an external force such as vibration or drop is applied to the recording apparatus during the physical distribution process or transportation of the recording apparatus, the recording apparatus main body may be twisted by the external force, and the platen gap may fluctuate.
In such a case, the user must readjust the platen gap, but it is much more difficult for the user to adjust the platen gap than in the manufacturing process. In particular, in a printing apparatus in which a platen gap can be set according to recording sheets having different thicknesses, it is extremely difficult for a user to change the platen gap while maintaining the parallelism between the printing head and the platen.

It is an object of the present invention to make adjustment of the platen gap extremely easy or unnecessary in a manufacturing process or the like.

Another object of the present invention is to make it possible to easily change the setting of the platen gap while allowing the parallelism between the recording head and the platen to be adjusted.

[0013]

In order to achieve the above object, a platen of the present invention supports a recording sheet on which recording is performed by a recording head while being conveyed in one direction, at a distance from the recording head. In the platen, a support portion for supporting the recording sheet, and a position integrally provided on the support portion, wherein the position of the platen is regulated by urging the platen toward the recording head by urging means. A striking portion which is struck by the regulating means, wherein the supporting portion is twisted as a whole by a reaction force received from the regulating means when the striking portion is biased by the biasing means. A rigid frame structure, and a frame structure provided at intervals in the width direction of the recording sheet to support the recording sheet; And having a recording sheet support member a plurality of deformable following the twisting of the over arm structure.

According to the above invention, the platen is provided with the abutting portion abutting against the regulating means for regulating the position of the platen, integrally with the supporting portion for supporting the recording sheet. In addition, the platen is
The platen is urged toward the recording head, and the position of the platen in the direction facing the recording head is regulated by abutting the abutting portion against the regulating means with the urging force of the urging means. As a result, The platen gap, which is the distance between the recording sheet support surface of the platen and the recording head, is determined.

In particular, a frame structure having such rigidity that the support portion is urged by the urging means so that the abutting portion is twisted as a whole by a reaction force received from the regulating means,
A structure having a plurality of recording sheet support members provided in the frame structure at intervals in the width direction of the recording sheet to support the recording sheet, and each of which can be deformed in accordance with the torsion of the frame structure Therefore, for example, when a recording apparatus using this platen is installed on a step or the like and the entire recording apparatus is twisted and the restricting means is also affected by the twist of the recording apparatus main body, the frame is accompanied by this twist. The structure is twisted, and the recording sheet supporting member is deformed in accordance with the torsion of the frame structure, and forms a continuous recording sheet supporting surface in a twisted state. by this,
The platen gap is properly maintained.

The platen support mechanism of the present invention is a platen support mechanism for supporting a recording sheet on which recording is performed by a recording head while being conveyed in one direction at a distance from the recording head. A support portion for supporting the recording sheet, and a butting portion provided integrally with the support portion outside a region of the support portion through which the recording sheet passes, wherein the platen includes the recording head. Urging means for urging the platen by the urging means, and the striking portion is struck by urging the platen by the urging means, and a portion of the recording head struck by the striking portion. And a restricting means whose position in the direction facing is variable.

Thus, as described above, the platen gap is determined by the platen abutting portion being abutted against the regulating means by the urging force of the urging means. Furthermore, by making the position of the portion where the platen abutment portion abuts against the recording head in the direction facing the recording head variable, the platen gap can be arbitrarily adjusted in a manufacturing process or the like. In this case, a means for releasing the urging force by the urging means and a platen disposed on the back side of the surface of the platen supporting the recording sheet and supporting the platen lowered by its own weight when the urging force is released by the releasing means. By further providing a platen receiving member, the platen gap can be adjusted by the regulating means, but the platen gap can be switched stepwise according to the recording sheet.

Further, the platen support mechanism of the present invention is a platen support mechanism for supporting a recording sheet on which recording is performed by a recording head while being conveyed in one direction at a distance from the recording head. The platen has an urging means for urging toward the recording head, and a regulating means against which the platen is abutted by the urging force of the urging means. In order to support the recording sheet and a frame structure which is integrally provided and has rigidity such that the striking portion is entirely struck by a reaction force received from the regulating means by being struck by the regulating means, and The recording sheets are provided on the frame structure at intervals in the width direction, and each is changed in accordance with the twist of the frame structure. And having a plurality of recording sheet supporting member as possible.

Thus, as described above, the platen gap can be properly maintained even when the entire recording apparatus is twisted and the restricting means is also affected by the twist of the recording apparatus main body. In particular, when the regulating means is a member whose position is defined with respect to the recording head, adjustment of the platen gap becomes unnecessary.

In each of the above-described inventions of the platen and the platen support mechanism, the abutting portions are preferably provided on both sides in the width direction of the recording sheet, outside the region where the recording sheet passes through the support portion. It is preferable that the recording sheet is provided on the upstream side and the downstream side of the recordable range of the recording head on the supporting portion in the transport direction of the recording sheet. In this case, the regulating means is provided corresponding to the position of the butting portion. Thereby, even when using a recording head with a large recordable range in the transport direction of the recording sheet in order to increase the recording throughput,
Since the platen gap is appropriately set on the upstream side and the downstream side in the transport direction of the recording sheet, high-quality recording can be performed.

Further, the present invention includes a recording apparatus for recording characters, images, and the like on a recording sheet by a recording head. The recording apparatus of the present invention comprises a conveying means for conveying the recording sheet, and the conveying means. And a holding means for holding a recording head for performing recording on the recording sheet conveyed by the recording head, and the platen support mechanism of the present invention for supporting the recording sheet at an interval from the recording head.

[0022]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the structure of a main part of an ink jet recording apparatus according to one embodiment of the present invention.
FIG. 2 is a schematic sectional view of the inkjet recording apparatus shown in FIG. 1 as viewed from the side.

The recording apparatus shown in the figure is provided with a means for generating thermal energy as energy used for discharging ink (liquid) among ink jet recording systems, and the state change of the ink is changed by the thermal energy. A recording head 1 of a type that causes the recording head 1 is mounted.
By using this method, higher density and higher definition of characters and images to be recorded are achieved. In particular, in the present embodiment, a heating resistor element is used as a means for generating thermal energy, the ink is heated by the heating resistor element to cause film boiling, and the ink is ejected by utilizing the pressure caused by bubbles generated at this time. However, the method of ejecting ink is not limited to this, and an electromechanical transducer element such as a piezo element is used to give mechanical vibration energy to the ink,
It is also possible to adopt a method of ejecting ink using the pressure due to this vibration.

The recording head 1 is detachably attached to the carriage 4 in a posture for discharging ink toward the recording sheet 6 (see FIG. 2) conveyed from the cassette 9, that is, a posture in which the ink discharge surface faces downward. It is installed. The carriage 4 has guide shafts 12 arranged in parallel with each other.
And slidably supported by the sub shaft 13 and
An arrow A shown in FIG. 1 along a guide shaft 12 and a sub shaft 13 is driven by a carriage drive motor (not shown).
It is configured to reciprocate in the direction (main scanning direction). Both ends of the guide shaft 12 and the sub shaft 13 are fixed to a left side plate 18 and a right side plate 19, respectively, which are fixed to the chassis 17. Especially sub shaft 1
3 is fixed to the left side plate 18 and the right side plate 19 by caulking, whereby a strong torsional rigidity is obtained.

The recording head 1 is provided with a plurality of nozzle rows for ejecting inks of different colors.
A plurality of independent ink tanks 2a to 2d are detachably mounted on the ink tank unit 2 in accordance with the color of ink ejected from the recording head 1. The ink tank unit 2 and the recording head 1 are connected by an ink tube 3 in which a plurality of tubes respectively corresponding to the colors of ink are connected, and each of the ink tanks 2 a to 2 d is attached to the ink tank unit 2, whereby The ink stored in the ink tanks 2a to 2d can be independently supplied to the nozzle rows corresponding to each ink color of the recording head 1.

The recording sheets 6 are stacked in a cassette 9 and separated one by one by a separation mechanism (not shown).
The sheet is sent to a U-turn transport path 11 formed by a U-turn roller 21 and a U-turn guide 22. U-turn roller 2
1 is rotatably supported, and the recording sheet 6 is sent to the U-turn conveyance path 11. The recording sheet 6 is U-turned by the U-turn conveyance path 11 and is rotationally driven by a feed motor (not shown). The recording head 1 is nipped by a conveying roller 23 and a pinch roller 24 that rotates following the rotation of the conveying roller 23, and is sent to a region facing the ink ejection surface of the recording head 1.

Below the recording head 1, a platen 7 is arranged at a predetermined distance from the recording head 1. The recording sheet 6 sent to the area facing the ink ejection surface of the recording head 1 is supported by the platen 7 and is in the direction intersecting with the moving direction of the carriage 4 (in the present embodiment, the direction orthogonal to the moving direction). The sheet is conveyed in the direction B, and is guided between a sheet discharge roller 25 that is rotationally driven by a drive source (not shown) and a spur 26 that rotates following the roller.

The recording sheet 6 is recorded on a platen 7 by discharging ink from the recording head 1. An area where recording can be performed by the recording head 1 is called a recording area. The platen 7 is wider than the width of the recording sheet 6 used in the recording apparatus, and is longer than the area where the nozzle array of the recording head 1 is formed in the transport direction of the recording sheet 6. 6 is large.

The recording sheet 6 on which recording by the recording head 1 is completed on the platen 7 is further conveyed in the direction of arrow B by the rotation of the discharge roller 25, and is discharged onto a discharge tray (not shown).

A recovery unit 14 is arranged in a reciprocating range of the recording head 1 and in a region outside the platen 7 so as to face the ink ejection surface of the recording head 1. The recovery unit 14 is a cap unit for capping the ink ejection surface of the recording head 1, and forcibly sucks ink from the recording head 1 with the ink ejection surface capped to increase the residual air bubbles in the nozzles and the viscosity of the ink. It has a suction mechanism for removing objects, a cleaning blade for wiping off stains on the ink ejection surface, and the like.

Here, the platen 7 will be described in detail with reference to FIGS.

FIG. 3 is a perspective view showing an example of a platen used in the recording apparatus shown in FIG. 1 together with a structure around the platen. FIG. 4 is a cross-sectional view of the platen shown in FIG. 3 taken along the transport direction of the recording sheet.

The platen 7 is a substantially plate-shaped member. On one surface of the platen 7, a plurality of ribs 7a formed along the conveying direction of the recording sheet 6 are provided in the width direction of the platen 7 (recording head 1). (In a direction parallel to the moving direction of FIG. 1) (see FIG. 1). The height of each rib 7a is equal, and the recording sheet 6
I support. Therefore, the distance between the recording head 1 and the recording sheet supporting surface of the platen 7, that is, the platen gap G is determined by the position and the posture of the platen 7.

Abutting portions 7 extending in the direction facing the recording head 1 are provided at both ends of the platen 7 in the width direction at the upstream end and the downstream end in the conveying direction of the recording sheet 6.
b are provided respectively. That is, the butting portion 7b
Is outside the range of the recording area, specifically, the moving direction of the recording head 1 is outside the range through which the recording sheet 6 passes, and the transport direction of the recording sheet 6 is They are provided at four corners of the platen 7 outside the ink dischargeable range. The upper end of each butting portion 7b is a flat surface.

At both ends in the width direction of the platen 7, biasing springs 31 are provided below the platen 7. The biasing spring 31 constantly biases the platen 7 in a direction to reduce the platen gap G.

On the other hand, the positions of the chassis 17 or the right side plate 18 and the left side plate 19 (see FIG. 1) corresponding to the respective abutting portions 7b of the platen 7 are respectively provided.
The four stays 32 extending upward are fixed. Each stay 32 is formed with a screw hole penetrating the stay 32 in the up-down direction. An adjusting screw 33 is screwed into each of the screw holes. The length of the adjusting screw 33 is sufficiently longer than the thickness of the stay 32. Even when the adjusting screw 33 is not completely screwed into the stay 32, the tip of the adjusting screw 33 protrudes from the stay 32, and the platen 7 abuts. It contacts the upper end surface of the portion 7b.

According to the configuration described above, the adjusting screw 32
Is rotated to change the amount of protrusion of the distal end of the adjusting screw 32 from the lower surface of the stay 32, whereby the position of the platen 7 in the height direction can be arbitrarily adjusted. That is,
By rotating the adjusting screw 32 in the screwing direction, the tip of the adjusting screw 32 pushes down the abutting portion 7 b against the urging force of the urging spring 31.
Is depressed. Conversely, by rotating the adjusting screw 32 in the loosening direction, the adjusting screw 32 moves upward, and accordingly, the abutting portion 7b is pressed against the tip of the adjusting screw 32 so that the abutting portion 7b is pressed against the tip of the adjusting screw 32. The platen 7 moves upward by the urging force.

The adjustment springs 32 are provided at four positions corresponding to the four corners of the platen 7, so that both ends in the moving direction of the recording head 1 and the upstream side and the downstream side in the conveying direction of the recording sheet 6 are respectively provided. , The platen gap G can be adjusted. As a result, the parallelism between the support surface of the recording sheet 6 by the platen 7 and the ink ejection surface of the recording head 1 can be adjusted with high accuracy. Therefore, even when the moving range of the recording head 1 is large in order to cope with the wide recording sheet 6 or when the recording head 1 having multiple nozzles is used for high throughput,
The position of the platen 7 can be adjusted so that the platen gap is constant over the entire area of the recording area. As a result, the distance between sheets becomes constant over the entire area of the recording area. High-quality recording is possible.

As described above, according to this embodiment, the platen 7 is urged upward from below, and the platen 7 is pressed against the platen 7 from above by the adjusting screw 32.
Are regulated to adjust the position of the platen 7 in the height direction and the attitude of the platen 7 (parallelism with the recording head 1). Therefore, these adjustments can be easily performed in the manufacturing process of the recording apparatus and the like.

Incidentally, the optimum sheet distance for recording differs depending on the type of the recording sheet 6. For example, when forming a high-definition image or the like using inkjet paper,
It is preferable that the inter-paper distance be as small as possible in order to prevent the above-described cockling phenomenon from occurring in the ink jet-dedicated paper and to increase the accuracy of the ink landing position. On the other hand, when characters and the like are formed on plain paper, the cockling phenomenon easily occurs on plain paper, and a certain degree of variation in the landing position of ink is allowed. Therefore, interference between the recording head 1 and the recording sheet 6 is reduced. In order to eliminate the gap, it is better that the distance between sheets is large to some extent. Therefore, the adjusting mechanism of the platen 7 in the present embodiment can be used for adjusting the sheet distance according to the purpose of use of the recording apparatus. As a result, a mechanism relating to the adjustment of the platen 7 can be shared by the printing apparatuses having different usage purposes, and as a result, the cost of the printing apparatus can be reduced.

In the present embodiment, the platen 7 in which the plate-shaped member is provided with the ribs 7a has been described as an example. However, if the recording sheet 6 can be supported over the entire recording area, the platen may have any shape. It is not limited. Further, the example in which the adjusting screw 32 is provided on each of the different stays 32 has been described, but a common stay may be used on the upstream side and the downstream side of the recording sheet 6, or the chassis 17 or If the right side plate 18 and the left side plate 19 may have a portion that substitutes for a stay, the stay is not necessarily required. Further, when the number of nozzles of the recording head 1 is small and the difference in the platen gap between the upstream side and the downstream side in the transport direction of the recording sheet 6 has little effect on the recording quality, both ends of the platen 7 in the width direction may be used. A configuration in which the position of the platen 7 is adjusted at one position each may be adopted.

FIGS. 3 and 4 show the biasing spring 31.
Although a compression coil spring is shown, any urging means such as a leaf spring or a torsion coil spring can be used as long as it can urge the platen 7 upward. The position of the platen 7 biased by the biasing means is not particularly limited. However, if the position of the abutting portion 7b in the facing direction with respect to the recording head 1 is significantly different, depending on the structure and material of the platen 7, There is a concern that the platen 7 itself may be bent by the urging force of the urging means, and the distance between the sheets may be partially reduced. Therefore, it is preferable that the position of the abutting portion 7b and the biasing position by the biasing means in the direction facing the recording head 1 be as close as possible.

In this embodiment, the position of the platen 7 is regulated by the adjusting screw 33. However, the means for regulating the position of the platen 7 is not limited to the adjusting screw 33. Any cam mechanism or link mechanism that can be moved up and down can be used.

Next, another embodiment of the present invention will be described.

FIG. 5 is a perspective view of a platen according to another embodiment of the present invention. The platen 40 shown in FIG.
5 can be used in place of the platen 7 of the recording apparatus shown in FIG. 2, and in the following description, the platen 40 shown in FIG. 5 is described as being applied to the recording apparatus shown in FIGS. I do. In FIG. 5, the platen 40 is shown in the direction in which the recording sheet conveyance direction (the direction of arrow B) is opposite to that in FIG.

The platen 40 extends in the direction of movement of the recording head 1 (in the direction of arrow A) and has two width members 41 arranged parallel to each other. Side plate member 43 for firmly holding both ends
Are arranged at regular intervals in the moving direction of the recording head 1,
It has a plurality of conveyance guide members 42 integrated with each width direction member 41 so as to be parallel to the conveyance direction of the recording sheet 6. The transport guide member 42 is the platen 7 shown in FIG.
The rib 7b has the same function as the rib 7b, and supports the recording sheet 6 on the upper surface of the transport guide member 42.

The side plate member 43 has portions extending upstream and downstream of the conveyance guide member 42 in the conveyance direction of the recording sheet 6, respectively. Shaft 1
3, butting portions 43a and 43b. The width direction member 41 and the side plate member 43 are designed and assembled so that the upper surfaces of the abutting portions 43a and 43b are on the same plane when the platen 40 alone, that is, no external force is applied to the platen 40.

A projecting portion 43c is integrally provided on the outer surface of each side plate member 43. An urging spring 44 for urging each of the protruding portions 43c upward is disposed below each of the protruding portions 43c, and the urging spring 44 urges the protruding portion 43c, whereby the entire platen 40 is urged. Are biased upward. Although the torsion coil spring is shown in FIG. 5 as the biasing spring 44, the same as that used to bias the platen in the above-described embodiment is used.

The width direction member 41 and the side plate member 43 are not deformed so as to be warped in the direction in which the recording sheet 6 is conveyed and in the direction facing the recording head 1, but are pressed against each other by the urging force of the urging spring 44. The width direction member 41 is so rigid that the members 43a and 43b can be twisted as a whole by the reaction force received from the struck member.
The material and shape of the side plate member 43, and the structure of the connection between them are selected. For example, the width direction member 41 and the side plate member 43
Is made of iron or aluminum and has a thickness of 0.5 to 1.2.
mm.

In this embodiment, in particular, the width direction member 41 is
0.8mm thickness, width (different from the width of the platen itself)
Was made of a plate member made of iron or aluminum having a thickness of 9.5 mm so that the thickness direction became parallel to the transport direction of the recording sheet 6. In addition, the urging force applied to each protruding portion 43c was set to 400 g.

When the frame structure composed of the width member 41 and the side plate member 43 is twisted as described above, the conveyance guide member 42 is so formed as to be easily elastically deformed in accordance with the twist. 41 and the side plate member 43 are made of a material having lower rigidity. The transport guide member 42 having such properties is preferably made of resin.

According to the present embodiment, when the recording apparatus is installed on a flat surface, the entire recording apparatus is not twisted, and the guide shaft 12 and the sub shaft 13 remain parallel. , The platen 40 also has each abutting portion 4
3a and 43b are evenly pressed by the guide shaft 12 and the sub shaft 13, and no twisting occurs. Further, as described above, the guide shaft 12 and the sub shaft 1
3 is fixed to the left side plate 18 and the right side plate 19, respectively, and the carriage 4 on which the recording head 1 is mounted is
The recording head 1 is supported by the guide shaft 12 and the sub shaft 13, and the positions of the guide shaft 12 and the sub shaft 13 with respect to the recording head 1 are defined. Therefore, even if the position of the platen 40 is not particularly adjusted, the platen 40 is held parallel to the ink ejection surface of the recording head 1, and the platen gap is kept constant over the entire range of the recording area.

When the recording apparatus is placed on a step or when an external force such as vibration or drop is applied, the recording apparatus as a whole may be slightly twisted. When the entire recording apparatus is twisted, the relative positional relationship between the guide shaft 12 and the sub-shaft 13 is also twisted, and the recording head 1 also moves while twisting instead of moving in parallel.

However, each abutting portion 43 of the platen 40
Since a and 43b are pressed against the guide shaft 12 and the sub-shaft 13 by the urging member, when the relative positional relationship between the guide shaft 12 and the sub-shaft 13 is twisted, the above-described frame structure of the platen 40 also The abutting portions 43a and 43b are surely secured to the guide shaft 12
If a biasing force such that the guide shaft 12 and the sub-shaft 13 are pressed against each other is applied, the guide shaft 12 and the sub-shaft 13 are twisted in the same manner. When the frame structure of the platen 40 is twisted, the transport guide member 42 is also twisted following the twist of the frame structure, and the recording sheet supporting surface formed on the upper surface of each transport guide member 42 is also continuously twisted. To form a finished surface.

As described above, the abutment 43 of the platen 40 against the guide shaft 12 and the sub-shaft 13 supporting the carriage 4 on which the recording head 1 is mounted.
The platen 40 can be deformed in accordance with the change even when the relative positional relationship between the guide shaft 12 and the sub shaft 13 is changed by employing a structure in which the platen 40a and 43b are abutted. The gap does not change. Moreover, the position reference of the platen 40 is based on the guide shaft 12 and the sub shaft 1 that support the carriage 4.
3 and only a minimum number of components are interposed between the recording head 1 and the platen 40. Therefore, the parallelism of the platen 40 with respect to the recording head 1 can be set with high accuracy without adjusting the positions of the carriage 4 and the platen 40.

In this embodiment, the guide shaft 12 and the sub shaft 13 are used as members for supporting the carriage 4.
However, a plate member can be used instead of the shaft. However, when a plate member is used, the abutting portions 43a and 43b of the platen 40 are abutted against the back surface of the plate member, and the platen gap varies by the tolerance of the plate thickness of the plate member. Regarding the accuracy of the platen gap, it is more advantageous to use a shaft than to use a plate member as a member for supporting the carriage 4.

In this embodiment, the abutting portions 43a and 43b of the platen 40 are abutted against the guide shaft 12 and the sub-shaft 13. However, when such a configuration is difficult due to the layout of the recording apparatus. May be configured to determine the transport direction of the recording sheet 6 and to abut the shaft of the transport roller 23 and the shaft of the discharge roller 25 that are close to the platen 40. Alternatively, similarly to the above-described embodiment, a configuration may be adopted in which stays are provided on the right side plate 18 and the left side plate 19, and the abutting portions 43a and 43b abut against these stays.

In the case where the abutting portions 43a and 43b are abutted against the stay, the position of the platen 40 can be adjusted by adjusting screws, as in the example shown in FIG. When the abutting portions 43a and 43b are configured to abut against the adjustment screw, the adjustment of the platen gap can be performed by a unit without the platen 40 attached. This eliminates the need to adjust the platen gap in a state where the recording apparatus has been completed, thereby facilitating the adjustment. Further, by adopting a configuration in which the position of the platen 40 can be adjusted by the adjusting screw, the positional error of the recording head 1 due to the dimensional accuracy of the carriage 4 can be absorbed by the adjusting screw, so that the dimensional accuracy of the carriage 4 is roughly set. can do.

Further, in the present embodiment, since the adjustment of the platen gap is basically unnecessary, if the adjustment screw is used to adjust the platen gap, both the upstream side and the downstream side in the conveying direction of the recording sheet 6 are used. It is not necessary to be able to make adjustments in any of the above, and one of them may be configured to abut against the above-described shaft or plate member.

In the configuration in which the adjustment of the platen gap is not required as in this embodiment, the platen 40
The dimensional accuracy and rigidity of the member against which the abutting portions 43a and 43b are abutted and the members related thereto are important. As described above, the sub shaft 13 is caulked by the left side plate 18 and the right side plate 19. For example, when the abutting portions 43 a and 43 b are configured to abut against the guide shaft 12 and the sub shaft 13, Similarly to the above, the guide shaft 12 is further caulked to the left side plate 18 and the right side plate 19, so that higher rigidity can be obtained. In addition, since the left and right plates 18 and 19 are made of the same component, the dimensions of the two can be basically the same.
It is possible to increase the precision of the degree of parallelism with the structure 3 and to secure the rigidity.

FIG. 6 is a perspective view showing a platen according to still another embodiment of the present invention, together with its peripheral structure. The platen 57 shown in FIG. 6 can be used in place of the platen 7 of the recording apparatus shown in FIGS. 1 and 2, similarly to the platen shown in FIG. The following description will be made assuming that the illustrated platen 57 is applied to the recording apparatus illustrated in FIGS.

The platen 57 has basically the same structure as the platen shown in FIG. That is, the plate-shaped member has a plurality of ribs 57a on one surface and abutment portions 57b at four corners, respectively.
1, the platen 57 is urged upward, and each abutting portion 5
The position and parallelism of the platen 57 in the height direction and the degree of parallelism can be adjusted by abutting the adjustment screw 7b against the adjustment screw 63. Although not shown in FIG. 6, each adjusting screw 63 is attached to the stay similarly to FIG.

In this embodiment, the platen gap is further increased according to the recording sheet 6 to be used, the first platen gap G1 shown in FIG. 7A and the first platen gap G1. It is possible to switch between two stages with the second platen gap G2 shown in FIG. Hereinafter, the configuration and operation of the portion related to the switching of the platen gap will be described with reference to FIGS.

In this embodiment, a torsion coil spring is used as the biasing spring 61. The biasing spring 61 is supported by inserting its coil-shaped portion into the spring support member 67. First arm portion 61a of biasing spring 61
Extends below the platen 57 and can abut on a projection 57c provided on the lower surface of the platen 57.
The second arm portion 61b of the biasing spring 61 is provided with a stopper 68
Accordingly, in the normal state where the first platen gap G1 is provided, the position is regulated such that the first arm portion 61a is pressed by the projection 57c and a force for urging the platen 57 upward acts.

The biasing spring 61 is located closer to the base than the contact portion of the biasing spring 61 with the projection 57c of the first arm portion 61a.
A release shaft 64 for elastically deforming the first arm portion 61a away from the protrusion 57c is disposed. The release shaft 64 is a shaft extending across the two urging springs 61 along the width direction of the platen 57, and is provided rotatably. The release shaft 64 has a D-shaped cross section, and a part of the outer peripheral surface is a flat surface 64a. A switching lever 65 is connected to one end of the release shaft 64. By operating the switching lever 65, the release shaft 64 is switched between the position shown in FIG. 7A and the position shown in FIG. Rotated.

A platen receiver 66 is arranged below the platen 57, that is, on the back side of the surface supporting the recording sheet 6. The platen receiver 66 supports the platen on the upper surface 66a when the second platen gap G2 is set. Therefore, the upper surface 66 of the platen receiver 66
The dimension “a” is defined such that the platen gap becomes the second platen gap G2 over the entire range of the recording area when the platen 66 is mounted.

Next, switching of the platen gap in this embodiment will be described with reference to FIG.

In the state shown in FIG. 7A, the release shaft 6
4 is the first arm portion 61 of the biasing spring 61.
a, and the release shaft 64 and the biasing spring 61 are not in contact with each other. Therefore, the platen 57 is urged upward by the urging spring 61 so that the abutting portion 57b comes into contact with the adjusting screw 63, and thereby the platen gap is reduced to the first position.
Of the platen gap G1.

From this state, the switching lever 65 is rotated.
7B, the position of the flat surface 64a of the release shaft 64 changes, so that the release shaft 64 pushes down the first arm portion 61a of the biasing spring 61. As a result, the urging force of the urging spring 61 applied to the platen 57 is released, so that the platen 57 descends by its own weight and is supported on the platen receiver 66. As a result, the platen gap is changed to the second platen gap G2.
Becomes

As described above, by switching the application and release of the urging force for urging the platen 57 upward, the position and the parallelism of the platen 57 in the height direction can be adjusted. Also, the platen gap can be easily switched according to the recording sheet 6.

The present invention has been described with reference to typical embodiments. In the above-described embodiment, the serial type inkjet recording apparatus has been described. However, the present invention can be applied to a line type recording apparatus,
Further, as long as a platen gap is required, the present invention can be applied to various types of recording apparatuses other than the ink jet type.

[0073]

As described above, according to the present invention, the platen gap is set only by urging the platen toward the recording head by providing the platen with the abutting portion which is brought into contact with the regulating means. Can be. In addition, the abutting portion is located outside the area where the recording sheet of the supporting portion passes,
It is possible to record in the transport direction of the recording sheet by providing it on both sides in the width direction of the recording sheet and in the transport direction of the recording sheet upstream and downstream of the recordable range of the recording head on the support portion. Even when a recording head with a larger range is used, the platen gap is appropriately set on the upstream side and the downstream side in the conveying direction of the recording sheet, so that high-quality recording by the recording head can be realized. it can.

In particular, in the platen, the support portion has a frame structure having the specific rigidity as described above, and a plurality of recording sheet support members each deformable in accordance with the torsion of the frame structure. Thus, even if the printing apparatus using this platen is twisted due to being installed on a step or the like, an appropriate platen gap can be maintained.

On the other hand, in the platen support mechanism, the regulating means has a structure in which the position of the portion where the platen abutment portion abuts in the direction facing the recording head is variable, so that the platen gap is manufactured. It can be arbitrarily adjusted in a process or the like. In this case, the platen gap can be adjusted by the regulating unit by further including a unit for canceling the urging force by the urging unit, and a platen receiving member disposed on the back surface side of the platen supporting the recording sheet. With this configuration, the platen gap can be switched stepwise according to the recording sheet.

In the platen support mechanism, the platen has a frame structure having a specific rigidity as described above, and a plurality of recording sheet support members each capable of deforming in accordance with the torsion of the frame structure. By doing so, even if the entire recording device is twisted,
An appropriate platen gap can be maintained. In particular, when the regulating means is a member whose position is defined with respect to the recording head, it is not necessary to adjust the platen gap.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of a main part of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of the inkjet recording apparatus shown in FIG. 1 as viewed from the side.

FIG. 3 is a perspective view showing an example of a platen used in the recording apparatus shown in FIG. 1 together with a structure around the platen.

FIG. 4 is a cross-sectional view of the platen shown in FIG. 3 taken along a conveying direction of a recording sheet.

FIG. 5 is a perspective view of a platen according to another embodiment of the present invention.

FIG. 6 is a perspective view showing a platen according to another embodiment of the present invention together with a structure around the platen.

FIG. 7 is a cross-sectional view for explaining the operation of the platen shown in FIG. 6, taken along the conveying direction of the recording sheet.

FIG. 8 is a perspective view of an example of a conventional platen.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Ink tank part 2a, 2b, 2c, 2d Ink tank 3 Ink tube 4 Carriage 6 Recording sheet 7, 40, 57 Platen 7a, 57a Rib 7b, 43a, 43b, 57b Abutment part 12 Guide shaft 13 Sub Shaft 14 Recovery unit 17 Chassis 18 Left side plate 19 Right side plate 23 Conveying roller 24 Pinch roller 25 Discharge roller 26 Spur 31, 61 Urging spring 32 Stay 33, 63 Adjusting screw 41 Width member 42 Transport guide member 43 Side plate member 64 Release Shaft 65 Switching lever 66 Platen receiver

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C058 AB05 AC07 AC11 AD01 AE09 AF04 AF08 AF20 AF23 AF54 AF63 DA03 DA11 DA28 DA32 DB26 DC09 DC22

Claims (17)

[Claims] 1. A platen for supporting a recording sheet on which recording is performed by a recording head while being conveyed in one direction at a distance from the recording head, wherein: a supporting portion for supporting the recording sheet; And an abutting portion which is abutted against a regulating means for regulating the position of the platen when the platen is urged toward the recording head by an urging means. The portion has a rigid frame structure that is urged by the urging means so that the abutting portion is twisted as a whole by a reaction force received from the restricting means, and the recording sheet is supported to support the recording sheet. A plurality of recording sheet supports provided on the frame structure at intervals in the width direction of the recording sheet and each of which can be deformed in accordance with the torsion of the frame structure A platen comprising: 2. The platen according to claim 1, wherein the abutting portions are provided on both sides in a width direction of the recording sheet outside an area of the support portion through which the recording sheet passes. 3. The printing apparatus according to claim 2, wherein the abutting portion is provided on an upstream side and a downstream side of a recordable range of the recording head on the support portion in a conveying direction of the recording sheet. Platen. 4. The platen according to claim 1, wherein rigidity of said recording sheet support member is lower than rigidity of said frame structure. 5. The frame structure is made of a metal,
The platen according to claim 1. 6. The platen according to claim 1, wherein the recording sheet support member is made of a resin. 7. A platen support mechanism for supporting a recording sheet, on which recording is performed by a recording head while being conveyed in one direction, at a distance from the recording head, wherein the platen supports the recording sheet. A support portion, and a butting portion provided integrally with the support portion outside a region of the support portion through which the recording sheet passes, wherein the platen is urged toward the recording head. The urging means, the platen is urged by the urging means, the abutting portion is abutted, and the position of the portion abutted by the abutting portion in the direction facing the recording head is A platen support mechanism, comprising: a regulating means that is variable. 8. A frame structure having a rigidity such that the supporting portion is urged by the urging means so that the abutting portion is twisted as a whole by a reaction force received from the regulating means, and A plurality of recording sheet support members provided on the frame structure at intervals in a width direction of the recording sheet to support the sheet, and each of the recording sheet support members can be deformed in accordance with a twist of the frame structure. 8. The platen support mechanism according to 7. 9. A canceling means for canceling the urging force by the urging means, wherein the canceling means is disposed on a back side of a surface of the platen supporting the recording sheet, and wherein the urging force is canceled by the canceling means. The platen support mechanism according to claim 7, further comprising: a platen receiving member that supports the platen lowered by its own weight. 10. A platen supporting mechanism for supporting a recording sheet on which recording is performed by a recording head while being conveyed in one direction at a distance from the recording head, wherein the platen is biased toward the recording head. An urging unit; and a regulating unit against which the platen is abutted by the urging force of the urging unit. The platen is provided with an abutting unit that abuts against the regulating unit and is provided with the abutting unit. A frame structure having such rigidity that the part is twisted as a whole by a reaction force received from the restricting means when the part is abutted against the restricting means, and an interval in the width direction of the recording sheet to support the recording sheet A plurality of recording sheet support portions provided on the frame structure with a space therebetween, and each of which can be deformed in accordance with the torsion of the frame structure. And a platen supporting mechanism. 11. The platen support mechanism according to claim 10, wherein said restricting means is a member whose position is defined with respect to said recording head. 12. The platen support mechanism according to claim 11, wherein the member whose position is defined with respect to the recording head is a member that supports a holding unit for holding the recording head. 13. The printing apparatus according to claim 1, wherein the holding unit is a carriage that detachably holds the recording head, and a member that supports the holding unit supports the carriage so as to be movable in a direction intersecting a conveying direction of the recording sheet. The platen support mechanism according to claim 12, which is a guide member that performs the operation. 14. The abutting portion and the regulating means are provided on both sides in the width direction of the recording sheet outside an area of the support portion through which the recording sheet passes.
The platen support mechanism according to any one of claims 7 to 13. 15. The printing apparatus according to claim 15, wherein the abutting portion and the regulating portion are provided upstream and downstream of a recordable range of the recording head on the support portion in a transport direction of the recording sheet. Item 15. A platen support mechanism according to Item 14. 16. A conveyance unit for conveying a recording sheet, a holding unit for holding a recording head for performing recording on the recording sheet conveyed by the conveyance unit, and an interval between the recording sheet and the recording head. A recording apparatus comprising: the platen support mechanism according to claim 7, wherein the support mechanism supports the platen. 17. The recording head according to claim 1, wherein the recording head is an ink jet recording head that performs recording by discharging ink.
7. The recording device according to 6.