JP2002211055A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a recording sheet 7 from being floated at a low cost and in a simple structure irrespective of a condition of the recording sheet 7 and to improve image quality to be recorded. SOLUTION: This recorder comprises a pair of conveyance rollers 10 for conveying a recording sheet 7 to a recording position for performing the recording by a recording head by nipping the recording sheet 7, a pair of discharge rollers 14 for conveying the recording sheet 7 by nipping the recording sheet 7 at a downstream side of the pair of conveyance rollers 10, and a platen 18 that supports the recording sheets 7 at a position opposite to the recording head 1 between the pair of conveyance rollers 10 and the pair of discharge rollers 14. The platen 18 has a concave shape having a curvature with a center O at the side of the recording head 1. The pair of conveyance rollers 10 and the pair of discharge rollers 14 urge the recording sheet 7 such that the recording sheet 7 moves along the curvature of the platen 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for recording on a recording sheet by recording means.

[0002]

2. Description of the Related Art In an ink jet type recording apparatus, a recording head mounted on a carriage moving in a direction perpendicular to a conveying direction of a recording sheet is scanned to record one line of image, and this recording is completed. Thereafter, a predetermined amount of pitch conveyance is performed, and thereafter, the operation of recording the image of the next row on the stopped recording sheet is repeated, whereby the recording of the image is performed on the recording sheet.

Conventionally, in the case of recording by the ink jet system, a difference in the density of ink causes a difference in expansion and contraction of the fibers constituting the recording sheet, so that the recording sheet during recording has a so-called cockling uneven portion. It is also known that a sheet before recording may be curled, and the recording sheet is in various states at the time of recording.

In particular, when high-quality printing of image data or the like is performed, the feeding width of the recording sheet is reduced, the image data is arbitrarily divided, and the number of carriage scans is increased for printing. The method of eliminating unevenness is used. However, when the feed width is small, the recording time increases, so that the amplitude of the irregularities on the recording sheet increases, and the sheet floats from the platen holding the recording sheet to the recording head at the recording position. As a result, the recording head may come into contact with the recording sheet and the quality of the image may be impaired. Therefore, it is required that the sheet does not float. Further, in order to perform clear and high-quality printing, it is required to set the distance between the surface of the printing sheet and the printing head as narrow as possible.

In order to meet these demands, conventionally, a plurality of small-diameter holes (small holes) are provided in a platen, and a recording sheet is sucked by using a negative pressure generating means so as to adhere to the platen.

[0006]

However, when the recording sheet is sucked using the negative pressure generating means, the size of the apparatus is increased and the cost is increased. In addition, since intake and exhaust are performed, there is a problem that the sound is loud.

Further, when printing on a small-sized recording sheet, if a part of the plurality of small holes provided in the platen is located outside the recording sheet and is opened, the suction efficiency is reduced, Poor reliability. Conversely, if all of the plurality of small holes are arranged so as to be covered by the recording sheet, a suction force cannot be exerted on a large-sized recording sheet over the entire surface, resulting in poor reliability. In order to solve this problem, when a small-sized recording sheet is used, a means for closing a small hole located outside the recording sheet is required, and the configuration becomes expensive and complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a recording sheet from floating, regardless of the state of the recording sheet, with a low-cost and simple configuration. It is another object of the present invention to improve the quality of recorded images.

[0009]

In order to achieve the above object, a typical configuration of the present invention is a first transporting means for nipping and transporting a recording sheet to a recording position where recording is performed by a recording means, A second transporting means for nipping and transporting the recording sheet downstream of the one transporting means, the first transporting means and the second transporting means;
A recording device having a platen that supports the recording sheet at a position facing the recording device between the recording device and the conveyance device, wherein the platen has a concave shape having a curvature having a center of curvature on the recording device side, The first transport means and the second transport means are configured to bias the recording sheet so as to follow the curvature of the platen.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A recording apparatus according to this embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a recording apparatus according to the present invention, and FIG. 2 is a schematic perspective view around a recording position.

(Schematic Configuration and Operation of Recording Apparatus) As shown in FIG. 1, the recording apparatus of the present invention
A scanning mechanism A which carries a recording by scanning a carriage 2 with a recording head 1 as recording means, a pair of transport rollers 10 and a pair of discharge rollers 14 for transporting a recording sheet 7;
Transport mechanism B having a platen 18 for holding the recording sheet 7 at a recording position facing the recording head 1 between the two roller pairs
And

When recording an image, the recording apparatus conveys the recording sheet 7 onto a platen 18 by a pair of conveying rollers 10. When performing a recording operation on the platen 18, the recording apparatus scans the recording head 1 mounted on the carriage 2 that moves in a direction orthogonal to the conveying direction of the recording sheet 7 to record an image for one line. Is completed, a predetermined amount of pitch conveyance is performed, and thereafter, the operation of recording the image of the next row on the recording sheet 7 stopped again is repeated, thereby recording an image on the recording sheet 7. afterwards,
The recording sheet 7 on which the image is recorded is discharged outside the apparatus by the discharge roller pair 14, and the recording of the image is completed.

(Structure of Scanning Mechanism A) The scanning mechanism A includes a recording head 1, a carriage 2 on which the recording head 1 is removably mounted and scanned, and a carriage 2 in a main scanning direction (a conveying direction of the recording sheet). Guide rail 3 for slidably guiding the carriage 2 so as to scan in a direction perpendicular to
And a support rail 5 for maintaining the posture of the carriage 2 via a guide roller 4 attached to the carriage 2, and a timing belt 6 for scanning the carriage 2. The recording head 1 is provided with nozzles 1a for ejecting ink droplets to the recording sheet 7 at the time of recording an image. It is arranged to eject drops.

(Recording Unit of Scanning Mechanism A) A recording head 1 as a recording unit records an image on a recording sheet conveyed by a conveying unit. As a recording method in this apparatus, an ink jet recording method of discharging ink droplets from the recording head 1 for recording is used. That is, the recording head 1 has a fine liquid ejection port (orifice), a liquid path, an energy action section provided in a part of the liquid path, and an energy for generating ink droplet forming energy to act on the liquid in the action section. Generating means.

As an energy generating means for generating such energy, a recording method using an electromechanical transducer such as a piezo element, an electromagnetic wave such as a laser is irradiated to generate heat, and an ink droplet is ejected by the action of the heat. There are a recording method using an energy generating means, and a recording method using an energy generating means for discharging a liquid by heating a liquid by an electrothermal converter such as a heating element having a heating resistor.

Among them, a recording head used in an ink jet recording method for discharging a liquid by thermal energy has a high density of liquid discharge ports (orifices) for discharging a recording ink droplet to form a discharge ink droplet. Since they can be arranged, high-resolution recording can be performed. Among them, a recording head using an electrothermal transducer as an energy generating means is advantageous because it can be easily made compact, easily mounted at a high density, and inexpensively manufactured.

In this embodiment, the ink droplets are ejected by energizing the electrothermal transducer in accordance with a recording signal, and utilizing the film boiling caused by the thermal energy to grow bubbles generated in the ink droplets. The recording is performed by discharging ink droplets from the discharge ports by contraction.

Next, the configuration of the nozzle 1a of the recording head 1 will be described. As shown in FIG. 1, the recording sheet 7 is conveyed along a platen 18 having a curvature described later. Therefore, when ink droplets are ejected vertically downward from the nozzles 1a of the recording head 1, unevenness occurs in the image from upstream to downstream in the transport direction because the intervals of the ink droplets adhering to the recording sheet 7 are not equal. .

For this reason, in the present embodiment, the arrangement of the nozzles 1a in the transport direction of the recording head 1 is radially shifted from the center of curvature O of the platen 18 so that the landing intervals of the ink droplets in the transport direction of the recording sheet 7 are equal. Are arranged at the same angle Δx, and the ink droplets are also arranged radially.
, The landing intervals in the conveying direction to the recording sheet 7 become equal, and the quality of the image to be recorded can be improved.

(Configuration of Transport Mechanism B) In the transport mechanism B, a transport roller pair 10 as a first transport unit is provided upstream of the recording head 1 in the transport path of the recording sheet 7 and downstream of the recording head 1. A discharge roller pair 14 as a second conveying means is provided on the side, and a platen 18 for holding the recording sheet 7 at a recording position facing the recording head 1 between the conveyance roller pair 10 and the discharge roller pair 14 is provided. I have.

The conveying roller pair 10 on the upstream side of the conveying path of the recording sheet 7 has an upstream conveying roller 8 and a driven roller 9 which is pressed against the upstream conveying roller 8 by a biasing spring 11 and is driven to rotate. . Since the rotation center of the driven roller 9 is located at a position shifted downstream in the conveyance direction from the rotation center of the upstream conveyance roller 8, the conveyance roller pair 10 sends the recording sheet 7 obliquely downward and urges the platen 18. To be transported. That is, the driven roller 9 applies the recording sheet 7 to the platen 18.
It has a role of an urging roller for urging.

As shown in FIG. 2, there are a plurality of driven rollers 9 in the longitudinal direction with respect to the upstream conveying roller 8. If each driven roller 9 is configured to be independently biased against the upstream transport roller 8 by the biasing spring 11, the recording sheet 7 can be appropriately adjusted in accordance with the deformation amount of each part of the recording sheet 7.
Can be energized.

The platen 18 is disposed at a recording position facing the recording head 1 and holds the recording sheet 7. Further, the recording head 1 has a concave center having a center of curvature O and a radius of curvature R so as to urge the recording sheet against the platen 18 as the recording sheet is conveyed.

The discharge roller pair 14 on the downstream side of the conveying path of the recording sheet 7 has a spur 13 which is pressed against the downstream conveying roller 12 by an urging spring 15 and is driven to rotate. The spur 13 has a small contact area with the recording sheet 7 so as not to disturb the image even when the recording surface comes into contact with the recording surface after recording. Since the rotation center of the spur 13 is located at a position shifted to the upstream side in the conveyance direction from the rotation center of the upstream conveyance roller 8, the discharge roller pair 14 sends the recording sheet 7 obliquely upward and urges the platen 18. Plays the role of power roller.

As shown in FIG. 2, there are a plurality of spurs 13 in the longitudinal direction with respect to the downstream side transport roller 12. Each spur 13
Are independently driven by the biasing spring 15 on the downstream side transport roller.
If the recording sheet 7 is configured to be biased, the recording sheet 7 can be appropriately biased in accordance with the deformation amount of each part of the recording sheet 7.

(Operation of Transport Mechanism B) The behavior of the recording sheet 7 guided by the platen 18 will be described. FIG. 3 is an explanatory diagram of the curl of the recording sheet, and FIG. 4 is an explanatory diagram of the state of the recording sheet at the recording position.

As shown in FIG. 4, in the process in which the recording sheet 7 is conveyed from the conveying roller pair 10 to the recording position, the driven roller 9 moves downstream from the rotation center of the upstream conveying roller 8 as described above. Since the rotational center is located at the shifted position, the urging force of the driven roller 9 is
It also acts in the direction in which the recording sheet 7 is urged against the platen 18 without being absorbed. For this reason, the recording sheet 7 conveyed from the conveying roller pair 10 is
It is transported while being urged obliquely from above with respect to 18.

The recording sheet 7 urged obliquely to the platen 18 is curved between the transport roller pair 10 and the platen 18. Due to this urging force, for example, even if a curl as shown in FIG. 3 is generated on the recording sheet 7, a force for correcting the curl acts and the recording sheet 7 is conveyed along the platen 18. Therefore, the recording sheet 7 does not come into contact with the recording head 1.

In the process in which the recording head 1 performs recording on the recording sheet 7 at the recording position on the platen 18, when the recording sheet 7 absorbs the moisture contained in the ink droplets, the recording sheet 7 swells and the recording head 1 side Then, the recording sheet 7 floats. At this time, since the above-described urging force is acting on the recording sheet 7, the occurrence of floating of the recording sheet 7 is suppressed.

When recording is sequentially performed, the leading end of the recording sheet 7 in the transport direction is the lowermost point 18 a of the concave portion of the platen 18.
To reach. At the lowermost point 18a of the concave portion, the displacement of the curvature of the platen 18 in the transport direction changes from below to above. Therefore, the recording sheet 7 is urged by the platen 18 while being curved upward from below along the curvature of the platen 18. The urging force of the recording sheet 7 to the platen 18 suppresses the floating of the recording sheet 7 due to the swelling of the recording sheet 7 while the leading end of the recording sheet 7 is conveyed to near the discharge roller pair 14.

The recording sheet 7 is moved from the recording position to a pair of discharge rollers.
In the process of being transported to 14, the spur 13 is, as described above,
Since the rotation center is located at a position shifted to the upstream side from the rotation center of the downstream conveyance roller 12, the urging force of the spur 13 is not absorbed only by the downstream conveyance roller 12 and the recording sheet 7 is transferred to the platen 18. It also acts in the direction of urging. For this reason, the recording sheet 7 conveyed to the discharge roller pair 14
Is conveyed while being urged obliquely from above with respect to the platen 18.

The recording sheet 7 urged obliquely to the platen 18 as described above is curved between the discharge roller pair 14 and the platen 18. Due to this urging force, for example, even if a curl as shown in FIG. 3 is generated on the recording sheet 7, a force for correcting the curl acts and the recording sheet 7 is conveyed along the platen 18. Therefore, the recording sheet 7 does not come into contact with the recording head 1.

As described above, in the present invention, the recording sheet 7 is urged against the platen 18 having a curvature by the conveying roller pair 10 and the discharging roller pair 14, so that the recording sheet 7 before recording is applied. Curl has occurred,
Even when cockling occurs in the recording sheet 7 during recording, the floating of the recording sheet 7 can be suppressed. For this reason, the interval between the recording head 1 and the platen 18 can be narrowed, the flight distance of the ejected ink droplet is shortened, and the accuracy of the ink droplet adhering position can be increased. In addition, since the floating of the recording sheet 7 can be suppressed without increasing the number of parts, the floating of the recording sheet can be prevented with a low-cost and simple configuration regardless of the state of the recording sheet.

Furthermore, since the nozzles 1a of the recording head 1 are configured to eject ink droplets radially from the center of curvature O of the curvature of the platen 18 at an equal angle, the ink droplets can be ejected to the recording sheet 7 at equal intervals. And high-quality images can be recorded.

(Other Embodiments) In the above-described embodiment, the ink jet recording method is used as the recording means. However, an electric current is supplied to the electrothermal transducer according to a recording signal, and the thermal energy applied by the electrothermal transducer is used. It is more preferable that the ink is ejected from an ejection port to perform recording by the growth and shrinkage of bubbles generated in the ink by utilizing film boiling in the ink.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record.

Such a recording head may have a configuration satisfying its length by a combination of a plurality of recording heads, or a configuration as a single recording head integrally formed.

In addition, even in the case of the serial type described above, the recording head fixed to the carriage or mounted on the carriage enables electrical connection with the apparatus main body and supply of ink from the apparatus main body. A replaceable chip type recording head or a cartridge type recording head in which an ink tank is provided integrally with the recording head itself may be used.

It is preferable to add a preliminary auxiliary means such as a recording head recovery means provided as a configuration of the recording apparatus of the present invention since the effect of the present invention can be further stabilized. Specific examples include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal conversion type or another heating element or a combination thereof,
Performing a preliminary ejection mode in which ejection is performed separately from printing is also effective for performing stable printing.

The types and number of recording heads mounted on the carriage are, for example, not only those provided for one color ink but also a plurality of inks having different recording colors and densities. May be provided in plurality. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, and may be a combination of a plurality of print heads integrally formed. To at least one of the full-color devices.

In addition, in the above-described embodiment, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature, or an ink jet recording system The ink itself
Generally, the temperature is controlled within the range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in the stable ejection range. Good. In addition, actively prevent the temperature rise due to thermal energy by using the energy of the state change from the solid state of the ink to the liquid state,
Alternatively, an ink that solidifies in a standing state for the purpose of preventing evaporation of the ink is used, and in any case, the ink is liquefied by application of heat energy according to a recording signal, and a liquid ink is discharged, or a recording sheet is used. Can be applied to the case where an ink having a property of being liquefied for the first time by thermal energy, such as one which starts to solidify at the time when the temperature reaches.

Further, as the form of the above-described ink jet recording apparatus, in addition to the one used as an image output terminal of an information processing apparatus such as a computer, a copy apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function And the like.

In the above-described embodiment, five driven rollers 9 and 11 downstream conveying rollers 12 and 11 spurs 13 are provided. However, the present invention is not limited to this. It can be adjusted appropriately according to the size of the paper.

[0044]

As described above, according to the present invention, the platen has a concave shape having a curvature on the recording means side, and the first transport means and the second transport means are adapted to follow the curvature of the platen. Since the recording sheet is configured to be biased at a low speed, the recording sheet can be prevented from being lifted regardless of the state of the recording sheet with a low-cost and simple configuration, and the image quality to be recorded can be improved accordingly. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of a recording apparatus of the present invention.

FIG. 2 is a schematic perspective view around a recording position.

FIG. 3 is an explanatory diagram of curling of a recording sheet.

FIG. 4 is an explanatory diagram of a state of a recording sheet at a recording position.

[Explanation of symbols]

 A: Scanning mechanism B: Transport mechanism O: Center of curvature R: Curvature radius 1: Recording head 1a: Nozzle 2: Carriage 3: Guide rail 4: Guide roller 5: Support rail 6: Timing belt 7: Recording sheet 8: Upstream side Conveying roller 9 ... Followed roller 10 ... Conveying roller pair 11 ... Urging spring 12 ... Downstream conveying roller 13 ... Spur 14 ... Discharge roller pair 15 ... Urging spring 18 ... Platen 18a ... Concave lowermost point

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65H 29/20 B41J 3/04 101Z 3F053 29/70 103B F-term (Reference) 2C056 EA24 FA03 FA10 HA02 HA07 HA22 HA29 HA30 HA34 2C057 AF30 AG04 AG12 AG99 AN01 BA03 BA13 2C058 AB16 AB17 AC07 AE02 AE09 AF20 AF23 AF31 DA12 2C059 AA22 AA26 AA74 AB01 3F049 AA01 CA02 DA11 DA12 LA01 LB03 3F053 HA08 HB12 LA01 LB03

Claims (3)

[Claims] A first conveying means for nipping and conveying a recording sheet to a recording position where recording is performed by a recording means; and a second conveying means for nipping and conveying the recording sheet downstream of the first conveying means.
In a printing apparatus, comprising: a transport unit; and a platen that supports the recording sheet at a position facing the recording unit between the first transport unit and the second transport unit, wherein the platen is located on the recording unit side. It has a concave shape having a curvature with a center of curvature, wherein the first transporting means and the second transporting means are configured to urge the recording sheet along the curvature of the platen. Recording device. 2. A recording apparatus according to claim 1, wherein said recording means ejects ink droplets at an equal angle radially from a center of curvature of said curvature of said platen. 3. The recording apparatus according to claim 2, wherein the recording means supplies electricity to the electrothermal transducer according to a signal,
A recording apparatus for discharging ink droplets by using thermal energy generated by the electrothermal transducer.