JP2834892B2 - Scan head support plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a support plate for a scanning head, such as a print head or a contact image sensor, which is used by being pressed against a platen.

[0002]

2. Description of the Related Art As a scanning head used while being pressed against a platen, a thermal print head for printing and a contact image sensor for reading are known. Among them, a thermal print head will be described as an example. The thermal print head itself is a device in which a heating resistor as a printing element is arranged in a scanning direction on a ceramic substrate. Normally, instead of applying a pressing force directly to the thermal print head itself (hereinafter referred to as a thermal print head substrate) and pressing it against the platen, the thermal print head substrate is mounted on a support plate that also functions as a heat sink. The support plate is pressed against the platen.

FIG. 2 shows a conventional general support plate 2. A thermal print head substrate (see reference numeral 12 in FIG. 1) is mounted on the support plate 2. Guides 10, 10 for guiding a rotation shaft (not shown) of the platen are provided at both ends of the support plate 2.
A pin hole 2d for inserting a pin on a pallet, which will be described later, is formed near the center edge.

[0004] As shown in FIG. 4, a thermal print head substrate 12 is fixed on the support plate 2.
Has a heating resistor 13 arranged in the print scanning direction. The head substrate 12 is electrically connected to a flexible substrate (not shown in particular) provided on the printed circuit board 16, and the flexible substrate is pressed against the head substrate 12 by a pressing rubber 22 of a pressing cover 21 attached to the circuit substrate 16 with screws 25. At the same time, the head substrate 12, the circuit substrate 16 (including the flexible substrate), and the pressing cover 21 are integrally fixed to the support plate 2. Note that a connector 20 for external connection is connected to the circuit board 16.

[0005]

When the head substrate 12 is mounted on the support plate 2, it is necessary to accurately determine the position of the heating resistor 13 on the head substrate 12 and the platen in view of the printing scan. is there. For this purpose, in FIG. 4, it is necessary to improve the positional accuracy of the heating resistor 13 and the guide 10 in the X direction. Usually, as shown in FIG. The support plate 2 is set by inserting the pins 103 provided on the upper pallet 101 into the pin holes 2d formed in the support plate 2. Thereafter, the head substrate 12 having the heating resistor 13 is positioned and mounted on the support plate 2 using the recognition mark 102 provided on the pallet 101 with a certain degree of accuracy.

In the design of the scanning head, particularly high assembling accuracy is required for the dimension a (heating resistor 1) shown in FIG.
3 and the guide 10), the recognition mark 102 and the pin 103 on the pallet 101 and the pin hole 2d of the support plate 2 are used as described above to obtain this dimensional accuracy. However, such positioning is inferior in accuracy because position accuracy is obtained indirectly. To improve the accuracy, the fitting tolerance (D-d) between the pin 103 and the pin hole 2d is required.
Is strict, and the positional accuracy between the pin 103 and the recognition mark 102 is also required to be strict. As a result, the processing accuracy of the support plate 2 and the pallet 101 is increased, so that the manufacturing cost of the support plate 2 and the pallet 101 is increased, and the suspension during automatic conveyance (particularly at the time of detachment) is increased.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a scanning head capable of easily recognizing the positioning at the time of assembly and improving the positioning accuracy of the head substrate on the support plate without increasing the cost. It is to provide a support plate.

[0008]

In order to achieve the above object, a support plate of a scan head according to the present invention is provided with a scan head body made of ceramic, and has platens provided at both ends of the support plate. An index for visually positioning the scanning head main body with respect to the support plate is provided near each guide of the rotating shaft. In the support plate of the present invention, since one visual index is provided near each guide, the recognition for positioning is changed from the conventional recognition mark and the heating resistor to the index and the heating resistor. Then, the conventional fitting error between the pin and the pin hole and the error between the pin and the recognition mark are eliminated, so that the positioning can be performed more directly and the positional accuracy (the positional accuracy between the support plate and the heating resistor) is increased.

In the present invention, the index formed on the support plate is not particularly limited as long as it serves as a mark for positioning the thermal print head substrate as the scan head body on the support plate. Indicators include, for example, through holes,
In the case of this inner through-hole, for example, a convex portion, a concave portion, and the like, the diameter of the inner through-hole does not need to be too large, and is not more than 1.0 mm, preferably about 0.5 mm. However, it is important that the position where the index is provided is formed near the edge of the support plate so that the index is not hidden when the scanning head main body is mounted on the support plate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a support plate of a scanning head according to the present invention will be described based on embodiments. The support plate shown in FIG. 1 is applied to a thermal print head, and FIG. 1 is an exploded perspective view thereof. The support plate 2 is formed by pressing a steel plate and formed. The edges 2a and 2b are bent downward, and holes 7 and 7 are formed in the center.

A guide 10 having a notch for receiving a rotating shaft (not shown) of the platen is provided at the end 2c of the supporting plate.
10 are integrally formed. Groove-shaped concave portions 11, 11 for reinforcing the base end portions of the guides 10, 10 are formed by squeezing. The support plate 2 has one through hole 2e (two in total) in the vicinity of each guide 10 as an index, which is a feature of the present invention, in the print scanning direction. In the present embodiment, the diameter of the through hole 2e is about 1.
0 mm. Near the center of the support plate 2, two pin holes 2d for inserting pins of a pallet are formed.

The thermal print head substrate 12 is formed by forming an electrode pattern (not shown) and a heating resistor 13 on a ceramic substrate and mounting a driving IC (not shown). These driving ICs are covered and protected by a resin mold 14. This thermal printhead substrate 1
2 is adhered on the support plate 2, and the positioning at this time will be described later.

On the upper surface of the printed circuit board 16, a flexible board 17 is further stacked. Flexible board 17
Of the thermal printhead substrate 12 protrudes from the printed circuit board 16 and overlaps with the connection terminal 15.
The printed circuit board 16 also has holes 19, 18, 18, 19
Is provided. Also, on the lower surface of the printed circuit board 16,
Connectors 20, 20 for external connection are attached.

On the printed circuit board 16, the holding cover 2 is provided.
1 is attached. A pressing rubber 22 extending in the print scanning direction is provided on the lower surface of the holding cover 21.
4, 23, 23 and 24 are established. In this embodiment, two screws 25, 25 are respectively inserted into holes 23, 23,
The holding cover 21 and the printed circuit board 16 are fixed by being inserted through the holes 18 and 18 and screwed into the holes 7. At this time,
The pressure contact rubber 22 presses the front edge of the flexible board 17 against the connection terminal section 15, so that the printed circuit board 16 and the thermal print head board 12 are electrically connected.

The thermal print head substrate 12 and the printed circuit board 16 (the flexible substrate 17)
), And assembly of the holding cover 21 on the support plate 2 is performed as follows. First, as shown in FIG. 3, the pins 103 on the pallet 101 on the assembling apparatus are inserted into the pin holes 2d of the support plate 2, and the support plate 2 is set on the pallet 101. Next, the head substrate 12 is placed on the support plate 2. And
Through hole 2 e of support plate 2 and heating resistor 1 of head substrate 12
While looking at each other, the head substrate 12 is positioned with respect to the support plate 2 with a certain degree of accuracy. At this time, the through hole 2e
Since the positioning is performed while recognizing only both the heating resistor 13 and the heating resistor 13, the positional accuracy is improved in each step as compared with the related art.

Thereafter, the flexible substrate 17 on the circuit board 16 is electrically connected to and fixed to the head substrate 12 while maintaining appropriate positional accuracy with respect to the pins 103. After the holding cover 21 is set at a predetermined position on the circuit board 16, the screws 25 are tightened to press the flexible board 17 onto the head board 12 with the pressing rubber 22 of the holding cover 21, and the head board is placed on the support plate 2. 12. The circuit board 16 (including the flexible board 17) and the holding cover 21 are integrally fixed.

[0017]

As described above, the scanning head support plate of the present invention has one visual indicator near each guide of the platen rotating shaft provided at both ends of the support plate. It has the following effects. (1) When positioning the scanning head body made of ceramic with respect to the support plate, the positioning is performed while looking at the index. For example, when the scanning head body is brought into contact with the positioning pins on the support plate for positioning. In comparison with the above, the problem that the ceramic scanning head body is chipped or broken does not occur. (2) The positioning accuracy between the support plate and the heating resistor is remarkably improved. That is, the positional accuracy of the scanning head body with respect to the support plate can be sufficiently ensured in both the X direction (the extending direction of the heating resistor of the scanning head body) and the Y direction (the direction perpendicular to the extending direction). Also, the positional accuracy between the center of the guide and the heating resistor can be indirectly improved.

(3) Since the support plate is generally formed by die pressing using a sheet metal, the manufacturing cost of the support plate provided with the indicators does not increase and remains the same as before. (4) The structure of the pallet on the assembling apparatus used when assembling each part including the head substrate on the support plate is simplified, that is, not only is the conventional recognition mark unnecessary, but also
Strict positional accuracy between the recognition mark and the pin is not required, and the assembly device can be inexpensive.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a thermal printhead showing a support plate and components assembled on the support plate according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing a conventional general support plate.

FIG. 3 is a partially omitted perspective view showing a state in which a support plate is placed on a pallet of an assembling apparatus.

FIG. 4 is a side view of a thermal print head in which components are assembled on a support plate.

[Explanation of symbols]

 2 Support Plate 2e Through Hole (Indicator) 2d Pin Hole 10 Guide 12 Thermal Print Head Board 13 Heating Resistor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/32 B41J 2/44-2/45 B41J 25/34 H04N 1/028

Claims (2)

(57) [Claims] 1. A scanning head support plate on which a scanning head body made of ceramic is mounted and pressed against a platen, near the respective guides of a platen rotating shaft provided at both ends of the supporting plate, the scanning head with respect to the supporting plate. Body positioning
A support plate for a scanning head, wherein an index for visually performing the inspection is provided one by one . 2. The scanning head support plate according to claim 1, wherein said index is a through hole having a diameter of 1.0 mm or less.