JPS5859878A - Supporter for printing head - Google Patents

Abstract

PURPOSE:To automatically adjust print gap according to the thickness of paper without the use of any detector by using a system in which the supporter of a printing head is contacted in a sliding manner with a following roller for feeding papers and the supporter moves upwards as the following roller moves. CONSTITUTION:When a printing paper 7 is supplied, the paper 7 is held by feed rollers 3 and at this time a following roller 3b moves upwards as much as the thickness of the paper 7. On the other hand, a fitting base 17 to which a printing head 1 is attached is pivotally supported on a carriage 6 by a pin 18 and contacted pressingly with the upper half face of the follow roller 3b through a bearing metal 19 while being pressed on the pin 18 by a spring 20. Thus, when the following roller 3b moves upwards, the fitting base 17 turns clockwise, and the printing head 1 is moved upwards according to the upward movement amount of the following roller 3b. In short, the print gap is adjusted according to the thickness of the paper 7 being supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support device for a print head in a printing device for a computer system. This invention relates to a print head support device that is automatically adjusted according to the thickness of the print head.

In a printing device that performs printing by a mechanical stamping operation, it is desirable to minimize the operating torque of the printing element in order to increase the printing speed. Especially in wire dot printers, where printing elements (pins) operate many times to form one character, reducing the pin stroke is an essential requirement to increase printing speed, and modern wire dot printers Printing is performed with the leading edge of the paper in contact with the printing paper. However, printing paper is of various thicknesses, and in order to make copies, printing is performed on several sheets one on top of the other. Therefore, in order to keep the tip of the print head in constant contact with the printing paper, the print gap must be adjusted according to the thickness of the paper being supplied and the number of copies.

Traditionally, this print gap adjustment has generally been done manually, but it is now possible to automatically adjust the print gap by providing a shoe or lobe at the tip of the print head that presses against the printing paper on the platen. There are known mechanisms in which the printing head is adjusted, or mechanisms in which a filler is brought into contact with the printing paper on a platen to detect the thickness of the paper and move the print head forward or backward. However, since such contacts such as shoes, rollers, or fillers are brought into contact with the printing paper, stains on the paper and printing ink caused by pressing carbon paper for copying may be transferred to these contacts. There is also a disadvantage that the paper becomes smeared due to the paper being moved, and that these contacts act as a frictional load when the paper is fed.

The object of the present invention is to provide an automatic print gap adjustment mechanism that does not have these drawbacks.It is an object of the present invention to eliminate the time and effort required for print gap adjustment, which has conventionally been done mainly manually, and to eliminate print gap setting errors. This was done with the aim of avoiding troubles caused by
The print head is moved forward and backward using the movement of the driven roller of the printing device, which has a feed roller for paper feeding consisting of a driven roller and a driven roller that are in pressure contact with the driven roller, and the print gap is adjusted. This is what I did.

Hereinafter, a detailed description will be given based on the embodiments shown in the drawings.

1 and 2 show a first embodiment of the present invention, and therefore show an embodiment that falls within the embodiment of claim 2. FIG. In the figure, 1 is a print head, 2 is a platen, 3 is a feed roller consisting of a drive roller 3a and a driven roller 3b pressed against this, 4 and 5 are guide rods mounted on a frame (not shown), and 6 is a guide rod. 4.5 a carriage slidably supported on 7;
is printing paper, 8, 9, 10 are paper guide plates, 11 is pin 1
A guide plate 13 is a tractor that rotates around 2 to change the traveling path of the paper 7. The feed roller 3 is provided in the immediate vicinity of the print head 1, and its drive roller 3
A is mounted on a frame (not shown) and is fixed to a moving shaft 14 and rotated at a fixed position, and a driven roller 3b is mounted on a support shaft 1 mounted on the frame (not shown), as shown in FIG.
The support frame 16 is pivoted around the support frame 16 and is pressed against the drive roller 3a. The guide plate 11 has the function of guiding the printing paper 7 towards the tractor 13 when it is a continuous sheet, and standing obliquely and discharging it downward when the printing paper 7 is a single sheet. is doing. In FIG. 2, the guide rods 4, 5 and carriage 6 are shown in phantom lines in order to more clearly illustrate the mechanism of the present invention.

1 has one print head installed, and this mounting base 17 has pin 1.
8 is pivotally supported on the carriage 6.

19 is a semi-cylindrical bearing metal attached to the print head mount 17; 20 is the print head mount 17 and the carriage 6;
, and is a friend tension spring. The print head 1 is mounted on a print head mount 17, and the print head mount 17 is biased around the pin 1B by a spring 20 and comes into contact with the upper half of the driven roller 3b via a bearing metal/I/19. ing.

Additionally, the drive roller 3a of the feed roller 3 is made of a high-friction material such as urethane rubber so as to provide sufficient frictional driving force to the printing paper 7, and the driven roller 3a
b is usually made of synthetic resin or metal to avoid transfer of printing ink. In the case of this first embodiment,
The driven roller 3b needs to be formed as a single undivided roller.

21 in FIG. 2 is a wedge piece fixed to a frame (not shown);
A tension spring 22 is stretched between the support frame 16° and the frame and urges the driven roller 3b upward. These members 21 and 22 are attached to the print head 1 when inserting paper, etc.
This is provided to release the driven roller 3b upward, and when the print head 1 comes to the home position (the left end position in FIG. 2), the print head mounting base 17 moves to the wedge piece 21.
The print head 1 is rotated in a direction in which it rides on the slope and escapes upward, and the bearing metal 1v19 also moves upward at the same time, so that the driven roller 3b is moved upward by the force of the spring 22. That is, in this embodiment, the driven roller 3b is always urged upward by the spring 22, and the print head mount 17, which is urged by the spring 20, pushes down the driven roller 3b against the force of the spring 22. , the slave roller 3b is brought into pressure contact with the drive roller 3a.

When the printing paper 7 is fed to the printing device configured as described above, the feed roller 3 grips the printing paper 7,
At this time, the driven roller 3b moves upward by the thickness of the paper 7. The upward movement of this driven roller 3b causes the print head mounting base 1 to
7 is rotated around the cloth in FIG. 1, so the print head 1 is moved upward according to the amount of upward movement of the driven roller 3b, and the print gap is adjusted according to the thickness of the supplied paper 7. It turns out.

FIGS. 3 and 4 show a second embodiment belonging to the embodiment described in claim 3. FIG. In this second embodiment, a guide rod 4a slidingly supports a carriage 6a.

One of the rollers 5a is mounted on a frame (not shown), and the other roller 5a is mounted on a support frame 16 that pivotally supports the driven roller 3b of the feed roller.
6 is swingably supported around the guide rod 4a. The print head 1 is fixed to the carriage 6a by a placket 2-3, and does not have members such as the holding shaft 15, the print head mounting base 17, and the tension spring 20 shown in the first embodiment. In this second embodiment,
The print gap is adjusted by swinging the carriage 6a itself by the movement of the driven roller 3b. That is, when the printing paper 7 is fed, the feed roller 3 grips it and the driven roller 3b moves upward by the thickness of the paper 7. The upward movement of the driven roller 3b causes the support frame 16 to rotate around the guide rod 4a, and this rotation causes the guide rod 5a to move upward, causing the carriage 6a to rotate around the guide rod 4a, thereby rotating the print head 1. By moving it upward, the print gap is adjusted according to the thickness of the paper 7.

Reference numeral 24 in FIG. 4 is an eccentric cam loosely fitted and supported by the shaft 14 of the drive roller 3a, and 25 is a lever mounted on the eccentric cam 24, which has the same function as the wedge piece 21 in FIG. ,
That is, when inserting paper, etc., operate the lever 25 to rotate the eccentric cam 24, bring the eccentric cam 24 into contact with the support frame 16 and move it upward, and the print head 1 and the driven roller 3
This is provided to allow the air to escape upward. Although a spring for pressing the driven roller 3b against the driving roller 3a is not shown in FIG. 4', the spring can be provided in any manner as required.

As explained above, according to the print head support device of the present invention, the print head moves upward according to the movement of the feed roller, so the print gap is automatically adjusted according to the thickness of the printing paper, making it easy to use. This eliminates the need for extensive print gap adjustment work, and prevents troubles caused by print gap adjustment errors. Furthermore, according to the mechanism of the present invention, there is no need to bring the contact for detecting the thickness of the printing paper into contact with the printing paper.
There is no risk of contaminating the printing paper with this contact.
Since no extra load is applied to the printing paper even during line feeding of the paper, it is extremely effective as a print head support device having an automatic print gap adjustment function.

[Brief explanation of the drawing]

1 and 2 are views showing a first embodiment of the present invention, with FIG. 1 being a side view and FIG. 2 being a perspective view of the main parts. Third
3 and 4 show the second embodiment, with FIG. 3 being a side view and FIG. 4 being a perspective view of the main parts. In the figure, 1 is a print head, 2 is a platen, 3 is a feed roller, 3a is a drive roller, 3b is a driven roller, 4.4a
, 5.5a is the guide rod, 6゜6a is the carriage,
7 is printing paper, 13 is a tractor, 16 is a support frame, 17 is a print head mounting base, 18 is a pin, 19 is a bearing metal, 2
0 is a tension spring. Agent: Patent Attorney Takao NishiFigure 3Figure 4

Claims (3)

[Claims] (1) Print head (1) A drive port provided at a fixed position immediately adjacent to the -ra (3a) and a driven roller (3a) that is in pressure contact with it.
3b) and a feed roller for feeding paper (7) (
3) is a support device for a print head (1) in a printing device having a fulcrum shaft (1B), (4a) that is substantially fixedly provided with respect to a platen (2). The print head (
1), and these members (17) and (6a) are attached to the support frame (3b) of the driven roller (3b) or the driven roller (3b).
16) A support device for a print head, characterized in that it is brought into sliding contact with a lorado (5a) mounted in parallel with a driven roller (3b). (2) The member (17) is pivotally supported by a carriage (6) that moves parallel to the platen (2) and is in sliding contact with the upper surface of the driven roller (3b).
) to force the driven roller (3b) to press the spring (20
), the print head support device according to claim 1. (3) The member recited in claim 1 is mounted on a carriage (
6a), and this carriage (6a) is connected to the platen (2).
) is mounted on a supporting frame (16) for the Lorado (4a) and the driven roller (3b) fixedly provided in parallel with the Lorado (5).
A support device for a print head according to claim 1, wherein the print head support device is slidably supported by a).