JPH0740626A - Printer - Google Patents

Abstract

PURPOSE:To always perform printing under specified printing conditions even the paper thickness varies. CONSTITUTION:On the both sides of a lower block A, fixed plates 2, 3 are provided. A platen 5 and paper feed shafts 6, 7 are provided between the fixed plates 2, 3. Paper feed rollers 9, 10 are respectively provided on the paper feed shafts so as to be integrally rotated. On one end of the paper feed shaft 6, a line feed knob 12 having a clutch part 12a and a tapered part is mounted. In an upper block B, a printing head 20 is provided through guide shafts 17, 18 transversely provided on a movable plate 15, which is shakably mounted on a support shaft 14 provided on an end part of the lower block. By pressing the line feed knob in an axial direction, the movable plate is pressed up by the tapered part. A head surface of a printing head is retracted from the platen so that paper of every thickness can be inserted. In addition, a projected part 22a ensuring a constant gap between paper and the head surface is provided on the printing head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer used as an output terminal of a computer.

[0002]

2. Description of the Related Art When printing on a paper such as a bankbook which has a different thickness of paper fed to a printing device or has a step or a binding thread, the printing operation is difficult. A printing device in which the distance from the head is immovable cannot respond to a change in printing conditions such as a change in paper thickness and cannot print. Therefore, as a countermeasure, a paper thickness sensor that detects the paper thickness of the paper inserted in the printing apparatus is generally provided, and the distance between the platen and the print head is adjusted according to the detected paper thickness. The adjustment of the gap is performed by moving the print head so as to change the head gap in response to the change of the paper thickness and setting the optimum head gap, which enables smooth paper feeding.

[0003]

However, if a sensor for detecting the paper thickness and an automatic head gap adjusting device are provided, the number of parts for that is increased, which causes a high cost and a space for providing the device. Therefore, there is a problem in that the size of the printing apparatus becomes large.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printing apparatus which can easily adjust the distance between the print head and the paper at low cost.

[0005]

In order to achieve the above-mentioned object, the printing apparatus of the present invention is provided with a support shaft provided so as to project each end on the outside of a pair of fixed base plates, and each fixed base plate. A platen fixed between them, a plurality of paper feed rollers that are integrally rotatable with a paper feed shaft whose both ends are supported by fixed base plates, and one end is swingably supported by both ends of the support shaft. A pair of movable base plates, a print head reciprocally movable via guide shafts supported at both ends by each movable base plate, and one end of the paper feed shaft. The paper feed shaft is manually rotated. And a line feed knob provided with a clutch portion that enables the tape and a taper portion that retracts the print head from the platen.

[0006] Preferably, the print head is provided with a protrusion that maintains a constant distance between the paper fed onto the platen and the head surface of the print head.

[0007]

With respect to the fixed base plate, the movable base plate is swingable about a support shaft, and the print head supported by the movable base plate allows a plurality of sheets to be loaded by the weight of the movable base plate including the supporting elements. Make elastic contact with the paper feed roller. When the paper thickness changes rapidly and the head gap cannot handle this,
When the line feed knob is pushed in the axial direction, the line feed knob and the paper feed shaft are integrally rotatably connected by the clutch, and paper feed by manual rotation becomes possible. At the same time, since the movable base plate is pushed up by the taper portion of the line feed knob, the print head rises and the head surface retreats from the platen, and it becomes possible to easily print on paper of different thickness.

If the print head is provided with a projection, when the paper is set between the platen and the print head, the projection provided on the print head contacts the paper surface, and the distance between the head surface of the print head and the paper is increased. Is constant, and printing can always be performed under the same conditions.

[0009]

An embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the printing apparatus in this embodiment is composed of a lower block A equipped with a platen and a paper feed roller, and an upper block B equipped with a print head.

As shown in FIG. 3, the lower block A is provided with fixed base plates 2 and 3 on both sides of a box-shaped frame 1. A paper guide 4 is provided at a predetermined height of the frame 1 so as to substantially cover the entire surface of the frame. A flat platen 5 is provided at a predetermined position of the paper guide 4 so as to be orthogonal to the fixed base plates 2 and 3. The upper surface of the platen 5 is slightly higher than the upper surface of the paper guide 4 (see FIG. 2).

Below the paper guide 4, there is provided a pair of paper feed shafts 6 and 7, both ends of which are supported by fixed base plates 2 and 3. One paper feed shaft 6 can be rotationally driven by a line feed motor (not shown), and the other paper feed shaft 7 can be fixed to the fixed base plate 2
It interlocks with one of the paper feed shafts 6 via a timing belt 8 provided on the outer side of.

A pair of paper feed rollers 9 and 10 are attached to the paper feed shafts 6 and 7, respectively, and a part of the outer periphery of each roller is guided through a window 4a provided in the paper guide. Exposed on the upper surface of. The upper portions of the outer circumferences of the paper feed rollers 9 and 10 have the same height as the upper surface of the platen 5.

The right end portion of one paper feed shaft 6 is longer than that of the other paper feed shaft 6, and a clutch wheel 11 constituting a meshing clutch is attached to the lengthened portion so as to rotate integrally with this shaft. . On the right side of the clutch vehicle 11, a line feed knob 12 that can move forward and backward with respect to the clutch vehicle
Is provided.

The line feed knob 12 has a clutch wheel 11 at the left end.
Is provided with a brim-shaped clutch portion 12a capable of engaging with
The right side is a parallel portion 12b formed in parallel by a predetermined width, and the right side is provided with a tapered portion 12c that thickens the right side. On the right side of the tapered portion 12c, a knob portion 12d having a shape that can be easily operated by hand is formed. A compression spring 13 is inserted inside the insertion hole 12e of the paper feed shaft provided at the center of the line feed knob, and the biasing force of this spring separates the clutch portion 12a of the line feed knob from the clutch wheel 11. It is out of mesh. Set the line feed knob 12 to the compression spring 1
When pressed to the left against the urging force of 3, the clutch car 1
1 and the clutch portion 12a are meshed with each other, the paper feed shaft 6 can be manually rotated, which allows manual paper feed.

The vicinity of the rear ends of the fixed base plates 2 and 3 on both sides is formed to be higher than the installation surface of the paper guide 4.
The raised part has a support shaft 14 with both ends protruding left and right.
Is provided.

As shown in FIG. 1, at both ends of the support shaft 14, movable base plates 15 and 1 constituting an upper block B are formed.
6 is swingably supported. Each movable ground plane 15, 16
Are located outside the fixed ground planes 2 and 3, respectively, and the lower side has a width lower than the upper side of the fixed ground plane, and both ground planes are partially arranged in parallel.

One of the paper feed shafts 6 provided in the lower block A has a hole (not shown) provided in the right movable base plate 15.
It protrudes to the right through the. The diameter of this hole is slightly larger than the maximum diameter of the taper portion 12c of the line feed knob, and when the line feed knob 12 is in the normal position, the hole is in a state in which it can be supported by the parallel portion 12b of the line feed knob. Has become.

As shown in FIG. 4, guide shafts 17 and 18 are provided between the movable base plates 15 and 16 on both sides of the upper block B.
Are installed side by side, and the carrier 1 is attached to both of these guide shafts.
9 is provided so as to be reciprocally movable. The carrier 19 has a wire dot type print head 2 having a downward head surface.
0 is installed. A detachable ribbon cassette 21 is attached to the print head 20. A part of the ink ribbon is always interposed between the head surface of the print head 20 and the platen 5 and can print on a sheet (not shown).

As shown in FIG. 2, a ribbon mask 22 is provided at the lower end of the print head 20 to avoid contact of the ink ribbon with the paper during movement of the print head. On the lower surface of the ribbon mask 22, a pair of protrusions 22a is formed before and after the surface facing the platen 5 so as to keep the distance between the paper and the head surface 20a of the print head constant.

In the upper block B, paper feed rollers 9 and 10 are provided.
Paper holding plate 2 made of a leaf spring at a position facing each other.
3 and 23 are provided. The paper pressing plate 23 is composed of a leaf spring body formed in an arc shape, and is supported by the upper block B so that its outer peripheral surface can elastically contact the outer peripheral surfaces of the paper feed rollers 9 and 10.

As shown in FIGS. 1 and 4, the movable base plate 1 on the right side
5, a motor plate 24 is attached, and a carrier driving motor 25 is provided on this motor plate. The motor 25 is a belt 25 wound around a drive pulley 25a.
The carrier 19 can be moved back and forth via b.

Next, the operation will be described. When the paper is not fed to the printing device, the movable base plate 15,
Print head 20 provided on the upper block B via 16
Is swingable about the support shaft 14, and the paper pressing plates 23, 23 press the paper feed rollers 9, 10 by the weight of the entire upper block. Here, the paper feed roller 10 and the paper pressing plate 2 which are located on the inlet side for a paper having an arbitrary thickness
3 and inserts the line feed knob 12 in the axial direction, the movable base plate 15 on the right side is pushed up by the taper portion 12c. As a result, the movable base plate 16 and the print head 20 on the left side, which are integral with this, are also pushed up, so that the print head 20 rises and the head surface 20a retracts from the platen 5, increasing the head gap. Here, when the line feed knob 12 is manually rotated, the paper feed shaft 6 is rotated, and the paper feed rollers 9 and 10 integrated therewith are interlocked to feed the paper between the platen 5 and the head surface 20a without any trouble. .

When the line feed knob 12 is released, the line feed knob returns to its original position by the urging force of the compression spring 13.
The clutch portion 12a and the clutch wheel 11 are disengaged,
The paper feed rollers 9 and 10 can be rotated by a line feed motor (not shown). At the same time, the upper block B pushed up by the taper portion 12c descends and the paper pressing plate 2
The sheet is pressed against the outer peripheral surfaces of the sheet feed rollers 9 and 10 via the sheet 3.

When the line feed knob 12 is pressed in this manner, the head surface 20a of the print head is retracted from the platen 5, and the paper feed rollers 9 and 10 can be manually rotated. Therefore, even when printing on a thick material or a paper having a step, it is possible to print by manually feeding the paper onto the platen without causing any trouble. In this way, if you feed the paper between the platen and the head surface by operating the line feed knob,
Since the head gap is adjusted only by that, the paper is automatically fed when the thickness of the paper is not changed.

A protrusion 22 is provided on the lower surface of the ribbon mask to keep the distance between the head surface of the print head and the paper constant.
Since a is provided, the protrusion allows the printing surface of the paper to be pressed against the platen, so that printing can always be performed under constant pressure and at constant intervals.

Further, by replacing the projection 22a for pressing the paper with a rotatable object such as a ball, it is possible to further smoothly feed the paper.

[0028]

According to the present invention, since the paper can be fed with the print head retracted from the platen by operating the line feed knob, it is possible to print on a paper having a different paper thickness and a paper having a step or a binding thread. Sometimes paper can be easily fed. Moreover, since a sensor for detecting the paper thickness, a train wheel for retracting the print head from the platen, etc. are not required, the structure is simplified and the manufacturing cost of the printer is reduced.

Further, since the print head is provided with the protrusions for keeping the distance between the paper and the head surface of the print head constant, it is possible to always press the paper with a constant pressure, thereby improving the printing accuracy. It becomes possible.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an embodiment of a printing apparatus of the present invention.

FIG. 2 is an enlarged cross-sectional view of a C-C portion of FIG.

FIG. 3 is a plan view showing a lower block.

FIG. 4 is a plan view showing an upper block.

[Explanation of symbols]

 2, 3 Fixed base plate 5 Platen 6,7 Paper feed shaft 9,10 Paper feed roller 12 Line feed knob 12a Clutch part 12c Tapered part 14 Support shaft 15,16 Movable ground plate 17,18 Guide shaft 20 Print head 20a Head surface 22a Projection part

Claims (2)

[Claims] 1. A support shaft provided so that each end projects outside a pair of fixed ground plates, a platen fixed between the fixed ground plates, and both ends supported by the fixed ground plates. A plurality of paper feed rollers provided so as to be rotatable integrally with the paper feed shaft, a pair of movable base plates whose one ends are swingably supported by both ends of the support shaft, and supported by the movable base plates. A print head reciprocally movable via a guide shaft, a clutch unit attached to one end of the paper feed shaft for allowing the paper feed shaft to be manually rotated, and the print head retracted from the platen. A printer comprising: a line feed knob provided with a taper portion. 2. The print head according to claim 1, wherein the print head is provided with a protrusion that maintains a constant distance between the paper fed onto the platen and the head surface of the print head. Printing device.