JPH089251B2 - Recording sheet holding device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet holding device in a recording device such as a printer or a facsimile, and particularly, in a liquid jet recording device or the like, the recording sheet is held by a suction surface provided in its recording portion. The present invention relates to a recording sheet holding device configured to hold and feed a sheet by a sheet feeding roller.

[Prior art]

In a recording device such as a printer or a facsimile, a plurality of dot forming bodies provided in a recording head are used as recording information (image signals).
The dot pattern is formed on the sheet-shaped recording medium (recording sheet) held in the recording section by driving in accordance with the above, and recording is performed by feeding the recording sheet for one line or at a desired pitch. There is.

Further, the recording apparatus can be classified into a thermal type, an inkjet type, a wire dot type, and the like depending on the recording type.

In such a recording apparatus, it is necessary to hold the supplied recording sheet at an accurate position in the recording section and to feed the sheet accurately. As a recording sheet holding device therefor, there are a structure using a platen roller which also serves as a sheet feeding roller, a structure combining a fixed platen and a sheet feeding roller, and a structure utilizing an air suction force.

The present invention relates to a recording sheet holding device of the type that utilizes this air suction force.

FIG. 3 shows the structure of a conventional recording sheet holding device of this type.

In FIG. 3, the recording sheet 1 is the first drive roller 2A.
And a first feed roller 2 composed of a first driven roller 2B is fed to a recording portion formed between the recording head 3 and the suction means 4, and the recording sheet 1 passing through this recording portion is fed to the second driving roller. Second consisting of 5A and second driven roller 5B
It is conveyed to the discharge side by the feed roller 5 of.

The suction means 4 is installed along the conveyance path of the recording sheet 1 and has a suction surface 4B formed with a plurality of air suction pores 4A.
Is configured to suck and hold the recording sheet 1 on the suction surface 4B with a negative pressure suction force having a desired strength by sucking air in the direction of arrow A with a blower.

The recording head 3 is, for example, an inkjet head.

By the way, in the conventional configuration, the suction surface 4B having the pores 4A
Is an extension line of the recording sheet holding position P of the first feed roller 2.
And the recording sheet holding position Q of the second feed roller 5 is passed.

That is, the recording sheet 1 in the recording unit is adsorbed to the suction surface 4B in a state of extending on the straight line connecting the sheet sandwiching positions P and Q by the rollers on the upstream side and the downstream side, and the sheet width direction of the recording head 3 By the scanning movement of 1, the recording of one line corresponding to the height of the vertical arrangement of the plurality of recording elements, (scanning width) is obtained, and the recording sheet 1 remains attracted to the suction surface 4B by the suction force. In this state, the second feed roller 5 feeds the sheet in the Y direction at a feed pitch corresponding to the recording width (height in the feed direction of one line) H. At this time, the first feed roller 2 is not driven, but simply rotates around.

In this case, since the sheet is fed so that the lowest point I of the portion recorded by the recording head 3 becomes the highest point II,
On the suction surface 4B, there is always a place M where the recorded recording sheet is located.

In such a configuration, the swelled recording sheet 1 which has been recorded with ink moves to the position B between the second feed roller 5 and the recording head 3 by sheet feeding,
Before the next sheet feeding is performed, the length of the portion of the recording sheet 1 at the position B is extended, and there is no escape area for the extended portion, which causes wrinkles and bulges in the direction of arrow X and rises from the suction surface 4B. .

The wrinkle generated on the recording sheet 1 is
Cannot grow upward from the point Q, which is nipped by the feed roller, and therefore, as shown in FIG. 4A, the wrinkle W has a smaller holding force than the holding force at the point Q. It grows to the surface 4B side. Therefore, the platen (suction surface)
A phenomenon occurs in which the portion of the recording width (recording height) H of the recording sheet 1 floats from the suction surface 4B together with the M portion of the recording sheet 1 swollen on 4B.

When the recording sheet 1 floats up from the suction surface 4B, the negative pressure suction force acting on the recording sheet weakens, and when the suction force weakens, the floating of the recording sheet 1 further increases, causing a vicious circle.

When recording is performed with the recording sheet 1 floating in this manner, a straight line is recorded as a curved line, and in the worst case, the recording sheet 1 contacts the recording head 3 and the recording image is not only dirty but also the recording head There was a case where 3 was damaged.

Further, when the suction surface 4B is arranged on a straight line connecting the sandwiching points P and Q on the inlet side and the outlet side as shown in FIG. 3, the suction surface 4B may change the points P and Q depending on the accuracy of each component. There is a possibility of shifting from the connecting straight line in a direction away from the recording head 3. When the suction surface 4B is displaced from the straight line between the sandwiching points P and Q to the opposite side of the recording head 3 in this way, the recording sheet 1 is sucked onto the suction surface 4B.
There is also a problem that it is not adsorbed on the sheet 4B, wrinkles frequently occur due to the swelling of the sheet 1, and the sheet is lifted from the suction surface 4B, and normal recording cannot be performed.

〔Purpose〕

An object of the present invention is to solve the above-mentioned problems of the prior art, and even if wrinkles due to swelling occur in the recording sheet, it is possible to prevent the influence thereof from reaching the suction surface, and thus the recording sheet floats from the suction surface. Another object of the present invention is to provide a recording sheet holding device capable of eliminating stains on the recording sheet and deterioration of the recording quality due to it.

[Means for achieving the purpose]

The recording sheet holding device of the present invention includes a first feed roller that nips a recording sheet and guides it to a recording position, a suction unit that is disposed at the recording position and sucks the recording sheet, and a state in which the suction unit sucks the recording sheet. A second feed roller for feeding a predetermined amount of the recording sheet, and an ink jet recording head for performing recording with a predetermined recording width in the sheet feeding direction on a portion of the recording sheet suction-held by the suction means, An extension line of the suction surface of the suction means projects toward the recording head side from the recording sheet holding position of the second feed roller, and a squeezed corner portion of the recording sheet is formed on the downstream side of the suction means in the sheet feeding direction. After a predetermined amount of the sheet is fed by the second feed roller, a part of the recording portion one time before is removed from the suction means. It is intended to achieve the target.

〔Example〕

Hereinafter, FIG. 1 shows an embodiment of a recording sheet holding device according to the present invention.

In FIG. 1, the recording sheet 1 is a first feed roller 2
Is fed through the recording position formed between the recording head 3 and the suction surface 4B of the suction means 4, and the recording sheet 1 exiting from the recording position is adsorbed by the suction surface 4B, and the second feeding roller 5 The sheet is fed by a predetermined pitch.

However, in this embodiment, the extension line of the suction surface 4B is
As shown in FIG. 1, the second feeding roller 5 is arranged so as to project toward the recording head 3 side by an interval α from the sheet holding position Q of the second feeding roller 5.

That is, the recording sheet 1 is guided so as to be sandwiched in a bent state at the exit side edge (point R) of the suction surface 4B.

Further, the suction surface 4B is arranged such that its extension line protrudes toward the recording head 3 side by an interval β even with respect to the sheet nipping position P of the first feed roller 2.

The recording sheet holding device according to one embodiment of the present invention shown in FIG. 1 is different from the conventional structure shown in FIG. 3 in the above-described points, and has substantially the same structure in other points. The parts to be performed are respectively represented by the same numbers and symbols.

According to the structure of the embodiment shown in FIG. 1, first, the recording sheet 1 is stretched in a bent state at the exit side edge R of the suction surface 4B, so that the suction surface 4B and the second feed roller 5 are Holding point Q
Even when the portion of the recording sheet 1 located between the recording sheet 1 and the recording sheet 1 swells due to the ink transferred at the time of recording and wrinkles are generated on the surface, the bending point (corner) R exists. ), The sheet wrinkle W is prevented from proceeding beyond the point R and further, and the recording sheet 1 is prevented from floating on the suction surface 4B.

Further, when the recording is completed once (for one line) and the sheet is fed in the direction of the arrow Y at a pitch corresponding to the recording width H in a state where the recording sheet 1 is attracted to the suction surface 4B, the recording sheet 1 is squared. Since the part R is squeezed, it was possible to remove even fine sheet wrinkles.

Further, since the suction surface 4B projects toward the recording head 3 side more than the sheet holding positions P and Q, the sheet holding position Q may project to the recording head 3 side even when the dimensional accuracy of the parts is low. Therefore, it is possible to prevent wrinkles and floating of the recording sheet 1 due to this arrangement error.

According to the embodiment structure shown in FIG. 1, the suction surface 4B is projected toward the recording head 3 side even with respect to the first feed roller 2 (projection amount β).
Therefore, even at the corner portion S of the entrance side edge of the suction surface 4B, the ironing effect of the recording sheet 1 can be obtained as in the case of the above-mentioned corner portion R, and fine sheet wrinkles can be removed more reliably. Became possible.

Further, the corner S is a suction surface due to the low dimensional accuracy of the parts.
Since it is possible to eliminate the possibility of protruding toward the recording head 3 side from 4B, that is, the possibility of occurrence of an arrangement error as in the conventional structure, it is possible to prevent the recording sheet 1 from floating on the suction surface 4B.

When the suction means 4 and the feed rollers 2 and 5 on the input side and the output side are arranged as described with reference to FIG. 1, a sheet guide 9 as shown in FIG. It is preferable to eliminate the cause of the occurrence of the sheet jam (sheet clogging) phenomenon at the initial stage of sheet feeding by providing the.

The sheet guide 9 is movably attached to a retracted position as indicated by a chain double-dashed line 9A in FIG. 2 so as not to interfere with the scanning movement of the recording head 3 during recording.

In the structure of the embodiment shown in FIG. 1, the first and second
Of the feed rollers 2 and 5 from the suction surface 4B, that is, the offset amounts α and β are set to, for example, about 0.5 mm to 3 mm,
The angles Θ1 and Θ2 between the conveyance path of the recording sheet 1 and the extension line of the suction surface 4B are set to about 3 to 10 degrees.

If the offset amounts α and β are excessively set, the frictional resistance at the corners R and S increases during sheet feeding, which may adversely affect sheet feeding accuracy.

In addition, the suction surface 4B of the recording sheet 1 and the second feed roller 5
Between the points II and Q in FIG. 3 corresponds to the unrecordable area (leading edge margin) on the leading edge side of the recording paper from the recording position on the first line. Making the offset amounts α and β of 4B larger than necessary should be avoided from the viewpoint of increasing this useless unrecordable area.

If the portion between the points II and Q in FIG. 3 of the recording sheet 1, that is, the recording portion B one time before is on the suction surface 4B, the flatness of the suction surface 4B of the recording sheet 1 is obtained. Therefore, it is preferable that the recording portion B just before this is separated from the suction portion as shown in FIG. However, in practice, if more than half, preferably 70% or more of the B portion of the recording sheet 1 is out of the suction portion, the flatness of the sheet on the suction surface 4B is hardly affected.

〔effect〕

As is clear from the above description, according to the recording sheet holding apparatus of the present invention, the first feed roller that holds the recording sheet and guides it to the recording position, and the suction unit that is arranged at the recording position and sucks the recording sheet. A second feed roller for feeding a predetermined amount of the recording sheet sucked by the suction means, and recording with a predetermined recording width in the sheet feeding direction with respect to a portion of the recording sheet sucked and held by the suction means. And an extension line of a suction surface of the suction means projecting toward the recording head side from a recording sheet holding position of the second feeding roller, and a downstream side of the suction means in the sheet feeding direction. The recording sheet has a squeezed corner portion on the side, and after a predetermined amount of the sheet is fed by the second feeding roller, a part of the recording portion one time before is discharged from the suction means. Even if wrinkles occur due to swelling of the recording sheet due to ink impregnation, it is possible to prevent the wrinkles from advancing at the corners and prevent the suction surface from being affected. A recording sheet holding device capable of preventing floating of the recording sheet on the suction surface and deterioration of the recording quality due to the lifting, and removing fine wrinkles of the recording sheet by the ironing effect of the corners. Will be provided.

[Brief description of drawings]

1 is a schematic side view of a recording sheet holding device according to the present invention, FIG. 2 is a schematic side view showing a state in which a sheet guide is provided in the device of FIG. 1, and FIG. 3 is a conventional recording sheet holding device. FIG. 4 is a schematic side view, and FIG. 4 is a schematic plan view illustrating the wrinkle transmission state of the recording sheet. 1 ... Recording sheet, 2 ... First feed roller, 3 ... Recording head, 4 ... Suction means, 4B ... Suction surface, 5 ... Second
Feed rollers, P, Q ... Recording sheet nip position, α, β
…… Projection amount (offset amount).

Claims (2)

[Claims] 1. A first sheet for nipping a recording sheet to guide it to a recording position.
Feed roller, a suction means arranged at the recording position for sucking the recording sheet, a second feed roller for feeding a predetermined amount of the recording sheet sucked by the suction means, and the suction of the recording sheet. An inkjet recording head that performs recording with a predetermined recording width in the sheet feeding direction on the portion suctioned and held by the suction means, and an extension line of the suction surface of the suction means is a recording sheet holding position of the second feeding roller. More than the recording head, a squeezed corner portion of the recording sheet is formed on the downstream side of the suction means in the sheet feeding direction, and is 1 after the predetermined amount of sheet feeding by the second feeding roller. A recording sheet holding device, wherein a part of the recording portion before the rotation is removed from the suction means. 2. An extension line of a suction surface of the suction means is the first
2. The recording sheet holding device according to claim 1, wherein the feeding roller protrudes toward the recording head side from a recording sheet holding position.