JP2575161B2 - Printer ejection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge device for a printer, and more particularly, to a discharge device for a printer including a discharge roller and a sheet pressing member for pressing a recording sheet against the discharge roller.

[Conventional technology]

In recent years, as printers using cut sheets are frequently used, it has been attempted to mount a cut sheet feeder on the printer as an option. In this case, in general, even if the feeder is externally provided, it is necessary to provide a power separately for that purpose, so that the number of parts is increased and the cost is increased. Therefore, the development of a printer equipped with a cut sheet feeder has been promoted.

When such a feeder is installed, the space from the feeding mechanism to the discharging mechanism must be provided in a limited space. In particular, regarding the discharging mechanism, the sheet after the printer is not held long by the platen roller, and It is necessary to discharge accurately so as not to adversely affect the record.

FIG. 7A shows a general configuration example of a conventional printer provided with this type of cut sheet feeder. In this drawing, reference numeral 1 denotes a discharge roller attached to a predetermined position of a discharge roller shaft 1A, which is formed of a material having a large coefficient of friction such as rubber, and has a sheet (for example, recording paper) on its outer peripheral portion during discharge.
Axially parallel engagement grooves for retaining the trailing edge of the
1B is provided around. 2 is a platen roller and 3 is a friction roller. Reference numeral 4 denotes a spur holder having a built-in spur for pressing the sheet against the discharge roller 1A. The spur holder is rotatably mounted on a spur shaft 5 at a position facing the discharge roller 1 and has a spur lever (spur shaft). It is biased toward the discharge roller 1 by a spring 8 via a mounting plate 7. Reference numeral 9 denotes a recording head, for example, an ink jet recording head that discharges ink droplets to record characters and images on a recording sheet, and 10 denotes a stacker that discharges the recording sheet.

The cut sheets for recording are stacked on a pressure plate 11, from which they are fed one by one by a feed roller 12 and a separation claw 13, and a pinch roller 14, a friction roller 3 and a sheet pan shown in FIG. The sheet is guided by the roller 15 to reach the position of the platen roller 2, further moved upward by the platen roller 2, and pressed against the discharge roller 1 by the sheet pressing spur 16 and the discharge spur 17. Seat holding spur
16 is biased toward the discharge roller 1 via the spur shaft 5 by the spring force of the spring 8 shown in FIG. 7A, and the discharge spur 17 is biased toward the discharge roller by the compression spring 18, whereby the sheet 6 can be held in tension at the correct recording position. 5A is attached to the spur shaft 5,
This is a pin for holding the compression spring 18 between the spur holder 4 and the compression spring 18.

When the sheet 6 reaches the recording position of the platen roller 2 in this manner, ink droplets are ejected from the inkjet recording head 5 and recording is performed on the sheet 6. The inkjet recording head 5 is mounted on a carriage 20 driven by a carrier motor 19, and reciprocates in a main scanning direction along a guide shaft 21. Further, the platen roller 2 performs sub-scanning in the direction of arrow R (clockwise) every time printing of one line is completed, and moves the sheet 6 to the upper side of the discharge roller 1.

The trailing end of the sheet 6 after the recording is guided by the gear-shaped ejection spur 17 and falls into the engagement groove of the ejection roller 1, and the entire sheet 6 is stored on the stacker 10 by the rotation of the ejection roller 1 in the direction of the arrow. You. At this time, the discharge spur 17 is
Is sent to the stacker 10 without being returned to the spur holder 4 side.

[Problems to be solved by the invention]

However, in such a conventional printer ejection device, for example, the state of tension when the sheet 6 is held by the platen roller 2 differs as shown in FIG. 7B depending on whether the sheet 6 is strong or weak. At the recording position, the distance between the recording head 9 and the sheet 6 is different because of the swelling as indicated by the solid line.

In addition, regarding sheets of various sizes, even when the trailing end of the sheet is released from being held by the pinch roller 14, the sheet is reliably discharged, and the pitch feed is maintained so that accurate recording is performed. In order to perform the compression, the spring force of the compression spring 18 must be strong. However, in such a case, the above-mentioned swelling tends to be further increased, and the occurrence of such swelling is an obstacle in reducing the interval between the recording head 9 and the sheet 6 in order to improve recording quality and recording speed. Had become.

Further, as shown in FIG. 7C, there is a possibility that the rear end of the sheet 6 touches the ink ejection surface of the recording head 9 during the discharge stroke due to its stiffness, thereby soiling the sheet 6.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems by always keeping the distance between the sheet and the recording head correctly and constant, thereby obtaining high-quality recording, and making use of the material of the recording sheet. It is an object of the present invention to provide a discharge device of a printer in which the conveyance and discharge are surely performed regardless of the above.

[Means for solving the problem]

A discharge device of a printer according to the present invention that can achieve this object includes a discharge roller that is driven and rotated, a recording sheet that is urged toward the discharge roller and presses the recording sheet against the discharge roller, and rotates with the rotation of the discharge roller. A discharge member of a printer for discharging the recording sheet recorded on the platen by a recording head facing the platen, wherein a contact position of the rotation member with respect to the discharge roller is adjusted by the platen. And a position closer to the platen than a contact start position between the discharge roller and the recording sheet, which corresponds to a shortest path of the recording sheet from to the discharge roller.

Here, it is preferable that the rotating body has a spur shape with irregularities formed on the outer peripheral edge, and it is effective that the recording head is an ink jet recording head.

[Operation] According to the present invention, predetermined recording is performed by the recording head on the recording sheet carried on the platen. The recorded recording sheet is fed between a driving and rotating discharge roller and a rotating body urged by the discharge roller, and is discharged to the outside by a frictional force generated therebetween.

The contact position of the rotating body with respect to the discharge roller is located closer to the platen than the contact start position between the discharge roller and the recording sheet corresponding to the shortest path of the recording sheet from the platen to the discharge roller. It will be pressed against the platen side.

When a spur-shaped one having irregularities formed on the outer peripheral edge is adopted as the rotating body, the rotating body comes into a point contact state with the recording surface of the recording sheet, and the rotating body rotates along with the movement of the recording sheet. .

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which the form of a spur unit 26 comprising a plurality of spurs 16 and 17 and their spur holders 4 and the like is different from the case of the conventional example shown in FIG. 7B.
That is, the different points will be described with reference to FIGS. 2A and 2B. In these figures, it is assumed that the platen roller 2 also serves as the friction roller 3 shown in FIG. First, in FIG. 2A, 1B is a sheet 6
Is a contact point obtained on the side of the discharge roller 1 when the sheet is held between the platen 2 and the discharge roller 1. Therefore, in this case, the sheet 6 is kept along the shortest path between the discharge roller 1 and the platen roller 2.

Therefore, in this embodiment, the sheet press spur 16 as the rotating body of the present invention is maintained at the position shown in FIG.
The sheet is pressed against the discharge roller 1 at a position closer to the platen 2 than 1B, that is, at the recording position side. Accordingly, 1C indicates a contact point of the sheet pressing spur 16 with respect to the discharge roller 1. Returning to FIG. 1, in this example, the spur unit 26 is configured so that the sheet holding spur 16 is maintained in such a state, and thus the friction roller 3 and the discharge unit 26 are formed.
Can be kept pressed against the surface of the platen 2, and the distance between the sheet 6 and the recording head 9 at the recording position P can always be kept correct and constant.

FIG. 3A shows a second embodiment of the present invention. In this example, the platen is a flat fixed platen 22, the fixed platen 22 is disposed obliquely above the friction roller 3, and furthermore, the discharge roller 1 and the spur unit (not shown here, Of these, only the sheet press spur 16 is shown) is shown.

Also in this case, except for the sheet press spur 16, the discharge roller 1
3B, the contact of the sheet 6 with the discharge roller 1 is 1B, as shown in FIG. 3B. 16 is a contact 1C for pressing the recording sheet 6
3A is a position where the sheet 6 is pressed toward the platen 22 as shown in FIG. 3A, and the sheet 6 can be pressed against the surface of the platen 22 as in the first embodiment.

FIG. 4 shows a third embodiment of the present invention. This example shows a case where the present invention is applied to a printer in which the stacker 10 is located on the recording head 9 side with respect to the discharge roller 1. Also in this case, the sheet 6 sent to the discharge roller 1 is pressed toward the platen roller 2 by the sheet pressing spur 16 at a position 1C closer to the platen than the contact point 1B in contact with the discharge roller 1, so that the sheet 6 is It can be kept pressed against the surface.

In the above-described embodiments, the ink jet recording apparatus has been mainly dealt with. However, the present invention is not limited to this, and includes a sheet discharging apparatus irrespective of a heat-sensitive method, a thermal transfer method, a wire dot method, or the like. Although the present invention has been described mainly for a rotating body that can be widely applied to a printer and that has a spur-shaped rotating body, any rotating body that rotates together with a recording sheet pressed against a discharge roller may be used. It is not limited to the embodiment.

〔The invention's effect〕

According to the discharge device of the printer of the present invention, the contact position of the rotating body with respect to the discharge roller is positioned closer to the platen than the contact start position between the discharge roller and the recording sheet corresponding to the shortest path of the recording sheet from the platen to the discharge roller. Let
As a result, the recording sheet is pressed against the platen, so that the recording sheet can be stably kept in contact with the platen, and the recording sheet bulges from the platen to the recording head due to its stiffness. Therefore, the interval between the recording sheet and the recording head can be prevented from becoming unstable, and the interval between the recording sheet and the recording head is set to be narrower for high quality recording and speed improvement. This makes it possible to prevent the trailing edge of the recording sheet from contacting the recording head.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a first embodiment of the present invention, FIGS. 2A and 2B are explanatory diagrams relating to the first embodiment, and FIGS. 3A and 3B are diagrams showing a second embodiment of the present invention. FIG. 4 is a configuration diagram schematically showing a third embodiment of the present invention, FIG. 5A is a perspective view showing an example of the configuration of a conventional printer ejection device, FIGS. 5B and 5C. FIG. 3 is an explanatory view showing two examples of a defective sheet holding state by a conventional printer discharge device. 1 ... discharge roller, 1B, 1C ... contact point, 2 ... platen roller, 3 ... friction roller, 4 ... spur holder, 5 ... spur shaft, 5A ... pin, 6 ... sheet, 9 ... Recording head, 10: Stacker, 14: Pinch roller, 16: Sheet press spur, 17: Discharge spur, 17A: Discharge press roller, 18: Compression spring, 22: Fixed platen, 26: Discharge Unit.

Claims (3)

(57) [Claims] A discharge roller that is driven and rotated; and a rotating body that is urged toward the discharge roller to press a recording sheet against the discharge roller and rotate with the rotation of the discharge roller. In a discharge device of a printer for discharging the recording sheet recorded on the platen by an opposing recording head, a contact position of the rotator with respect to the discharge roller is a position of the recording sheet from the platen to the discharge roller. A discharge device for a printer, wherein the discharge device is located closer to the platen than a contact start position of the discharge roller and the recording sheet corresponding to a shortest path. 2. The discharging device for a printer according to claim 1, wherein said rotating body has a spur shape with irregularities formed on an outer peripheral edge. 3. An apparatus according to claim 1, wherein said recording head is an ink jet recording head.