JP2799717B2 - Inkjet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ink jet method in which ink is applied to a recording sheet in a state where an ink jet head and a recording sheet are separated, and the ink is fixed to the recording sheet by evaporation of the ink. The present invention relates to an inkjet printer that performs recording.

[Conventional technology]

FIG. 7 is a longitudinal sectional view showing the overall configuration of this type of ink jet printer.

In FIG. 7, a recording sheet (recording medium) 1 such as a sheet of paper or a plastic thin plate is a cut sheet, and the cut sheets 1 stacked on a cut sheet feeder are a sheet feed roller 3 and a separation claw one by one from the top layer. 2 are fed separately. The fed recording sheet 1 is sandwiched between a paper feed roller (friction roller) 4 and a pinch roller 5 pressed against it, and is fed to a predetermined position by controlling the rotation amount of the paper feed roller 4.

Reference numeral 6 denotes an ink jet recording head (ink jet head). The recording head 6 is mounted on a carrier 7 and reciprocates the carrier 7 in a printing digit direction (a direction traversing the recording sheet 1), thereby making one line. It is configured to form a recording image one by one and perform paper feed (line feed).

That is, a plurality of ink ejection ports are formed vertically on the front surface (the surface opposing the recording sheet 1) of the recording head 6, and by controlling the movement of the carrier 7, the recording head 6 is moved to one end of the recording sheet 1. The main scanning is performed from the recording sheet 1 to the other end, and the recording sheet 1 is pitch-fed by the paper feed roller 4 and sub-scanned to record an image or a character over the entire area of the recording sheet 1. .

A heater unit 8 for fixing the recording ink on the recording sheet 1 is disposed along a sheet feed path on the downstream side (upper side) from a position facing the recording head 6. The heater section 8 also serves as a guide plate for the recording sheet 1,
In the illustrated example, a guide plate 8a that contacts and guides the back surface of the recording sheet 1 and a heating element 8b attached to the back surface of the guide plate 8a are provided. This promotes drying of the ink attached to the surface.

In the illustrated example, the heater unit 8 is installed in a range that covers the front surface of the recording head 6, and also has a function as a platen.

The recording sheet 1 that has passed through the heater unit 8 is discharged onto a stacker by a discharge roller 9 disposed above (discharge side) the heater 8 and spur rollers 10a and 10b pressed against the discharge roller 9.

An arm 13 is pivotally supported on a spindle 12 provided on the main body of the recording apparatus, and a roller support member 15 is pivotally supported on a spindle 14 provided on the arm 13.The pair of spur rollers 10a and 10b The arm 13 and the roller support member 15 are supported by a roller support member 15 and are pressed against the discharge roller 9 by urging the arm 13 and the roller support member 15 toward the discharge roller 9 with a spring (not shown).

A spur 16 is pivotally supported on the arm 13 to prevent the recording sheet from floating and coming into contact with the recording head 6 and becoming dirty.

[Problems to be solved by the invention]

In the conventional configuration of the above inkjet printer,
The recording surface (front) side of the recording sheet 1 is wet with the ink. However, moisture evaporates freely from the recording surface side, but on the back side, the guide surface 8a of the platen 8 and the recording sheet 1
The water vapor is hard to escape and cannot evaporate as much as the recording surface.

For this reason, there is a difference in the degree of drying between the back side and the front side of the recording sheet 1, which appears as a difference in the shrinkage ratio of the sheet. It warps.

As a result, the gap between the recording sheet 1 and the recording head 6 is reduced, and eventually the recording sheet 1 and the recording head 6 rub against each other, causing stains. Alternatively, there is a problem that even if the contamination does not occur, the recording sheet 1 becomes uneven, resulting in a deviation of the recorded image. There is also a problem that the head surface is wetted by the water vapor.

The present invention has been made in view of the above technical problems, and an object of the present invention is to reduce the difference in the degree of dryness by promoting the evaporation of moisture from both the front and back surfaces of the recording sheet 1. It is an object of the present invention to provide an ink jet printer which can eliminate the warpage of the image and the stain caused by the rubbing.

[Means for solving the problem]

The present invention has a platen provided in a recording area corresponding to an ink jet head, and a conveying unit that sends a recording sheet to the platen in contact with the surface of the platen, and the ink jet head and the recording sheet Is applied to the recording sheet in a state in which the recording sheet is separated from the recording sheet, and the ink is evaporated to fix the ink on the recording sheet. The above object is achieved by providing a configuration in which a plurality of concave portions separated from the recording sheet are provided in the width direction of the recording sheet.

[Action]

On the surface of the platen where the recording sheet fed to the platen is in contact, a plurality of recesses are provided in the width direction of the recording sheet along the feeding direction of the recording sheet and separated from the recording sheet. Moisture evaporated from the back of the recording sheet is removed, and the warpage of the recording sheet due to the difference in the degree of evaporation of the water between the front (recording surface) and the back of the recording sheet is reduced or eliminated.

〔Example〕

FIG. 1 is a perspective view showing a configuration example 20 of a fixing heater section of an ink jet printer as a related configuration of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. is there.

In FIGS. 1 and 2, a heater section 20 used as the heater section 8 in FIG. 7 has a front side guide plate (platen) 21 and a rear side planar heating element 22 integrally bonded or soldered. It has a joined structure, and a large number of through holes 23 penetrating it from the front to the back are formed in a desired distribution.

Each of the through holes 23 is for letting out water vapor generated from the recording sheet 1 by the heat of the heating element 22, and its distribution range extends over the entire width of the recording sheet 1 to be fixed.

Here, if the size of the through hole 23 is too large, the recording sheet 1 is not heated in the portion of the through hole 23,
The recording ink remains unfixed, and
If the pitch of 23 is too large, fixing is accelerated, but the effect of releasing water vapor is weakened.

According to the test results on a practical machine, a through hole 2
When 3 was arranged at a pitch of 3 to 5 mm, the difference in the degree of drying between the front and back of the recording sheet 1 was reduced, and the warpage of the recording sheet 1 was almost eliminated.

FIG. 3 is a perspective view showing a platen portion of the ink jet printer according to one embodiment of the present invention, and FIG. 4 is a partial cross-sectional view along line IV-IV in FIG.

3 and 4, a platen section 30 provided at the position of the heater section 8 also serving as a platen in FIG.
Indicates the front guide plate (platen) 31 and the back surface heating element
In this structure, grooves (recesses) 33 are formed on the surface of the guide plate 31 in contact with the back surface of the recording sheet 1 substantially in parallel with the feeding direction of the recording sheet 1. .

A large number of the grooves 33 are formed at a desired pitch over the entire width of the recording sheet 1.

Each groove 33 is formed so as to pass vertically through the guide plate 31, and the upper and lower ends thereof open to the outer space above and below the guide plate 31.

According to the embodiment of FIG. 3 and FIG.
The water vapor evaporated from the back surface of the recording sheet 1 can be constantly discharged to the external space through each groove 33. Therefore, the difference in the degree of drying between the front and back of the recording sheet 1 is reduced, and the warpage of the recording sheet 1 is greatly reduced or eliminated. Was completed.

Further, since each groove 33 is formed substantially in parallel with the feeding direction of the recording sheet 1, there is no problem such as paper jam due to the leading end of the recording sheet 1 being caught in feeding the sheet.

Further, as shown in FIG.
Since it does not penetrate through the hole, it is not necessary to form a hole or the like in the sheet heating element 32 on the back surface, and the bonding can be easily performed.

FIG. 5 is a perspective view showing another configuration example 40 of a fixing heater section of an ink jet printer as a related configuration of the present invention, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. It is.

5 and 6, a heater section 40 used as the heater section 8 in FIG. 7 includes a guide member (platen) 41 formed of a mesh on the front side and the guide member 41.
And a substrate 43 joined to the back surface of the sheet heating element 42 and supporting the whole.

The mesh forming the guide member 41 has a structure in which a thin wire (including various cross sections such as a round cross section and a thin cross section) such as a metal or a plastic is vertically and horizontally assembled. Water vapor generated from the back surface of the recording sheet 1 sent along the member 41 can easily escape to the outside from the upper and lower ends and the left and right ends through the space between the meshes 41.

The dimensional structure of the mesh 41 can be appropriately selected in consideration of the water evaporation degree of the front and back surfaces of the recording sheet 1.

According to the embodiment of FIG. 5 and FIG.
The water vapor evaporated from the back surface of the recording sheet 1 can be constantly discharged to the outside from the edge through the inside of the guide member (platen) 41 having the mesh structure. One warpage can be significantly reduced or eliminated.

Further, the mesh 41 can be made thinner than a plate member such as a metal plate, and the distance between the recording sheet 1 and the sheet heating element 42 can be reduced. In both cases, it is easy to sufficiently maintain the heating effect (heater effect).

In the structure of FIG. 6, if a layer of a heat insulating material is provided between the substrate 43 and the planar heating element 42, the effect of efficiently transmitting the heat of the heating element 42 can be obtained in addition to the above-described effect. Can be

Also, in FIG. 6, the mesh can be formed by a heating wire covered with an insulating material. In this case, the structure can be simplified by removing the planar heating element 42.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, there is provided a platen provided in a recording area corresponding to an ink jet head, and a conveying means for feeding a recording sheet to the platen in contact with the surface of the platen. An ink jet printer that performs ink jet recording in which the ink is applied to the recording sheet in a state where the ink jet head and the recording sheet are separated from each other, and the ink is evaporated to fix the ink on the recording sheet. Has a configuration in which a plurality of recesses are provided in the width direction of the recording sheet along the feeding direction of the recording sheet and separated from the recording sheet, so that recording on the platen can be performed without catching the leading end of the recording sheet. While feeding the sheet in contact with the surface of the platen,
Since the moisture evaporated from the back of the recording sheet can be removed from between the back and the concave portion of the recording sheet, the warpage of the recording sheet due to the difference in the degree of evaporation of the moisture between the front (recording surface) and the back of the recording sheet is reduced or Thus, it is possible to prevent the recording sheet from being stained and the image from being displaced.

It also has the effect of reducing the wetting of the head surface by water vapor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a configuration of a fixing heater section of an ink jet printer as a related configuration of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a perspective view showing a platen portion of the ink jet printer according to one embodiment of the present invention, and FIG.
FIG. 5 is a partial cross-sectional view taken along line IV-IV in FIG. 5, and FIG. 5 is a perspective view showing another configuration example of a fixing heater section of an ink jet printer as a related configuration of the present invention.
FIG. 5 is a cross-sectional view taken along the line VI-VI in FIG. 5, and FIG. 7 is a vertical cross-sectional view showing the overall configuration of an ink jet printer that performs ink jet recording in which ink is fixed on a recording sheet by evaporation of the ink. . 1 ... Recording sheet, 4 ... Paper feed roller, 6 ... Recording head, 7 ... Carrier, 9 ... Discharge roller, 30 ... Platen part, 31 ... Platen (guide plate), 32 ... Surface Heating element, 33 ... recess (groove).

Claims (1)

(57) [Claims] A platen provided in a recording area corresponding to an ink jet head; and conveying means for feeding a recording sheet to the platen in contact with a surface of the platen, wherein the ink jet head and the recording sheet are provided. An ink jet printer that performs ink jet recording in which ink is applied to the recording sheet in a state where the recording sheet is separated from the recording sheet, and the ink is evaporated to fix the ink on the recording sheet. An ink jet printer, wherein a plurality of concave portions along the width of the recording sheet are provided along the width of the recording sheet.