JP2676147B2 - Facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a thermal recording type facsimile apparatus such as a thermal recording type or a thermal transfer recording type. (Prior Art) As is well known, for image signals used in facsimile communication, the main scanning direction is 8 dots / mm, while the sub-scanning direction is 7.7 lines / mm (or 3.85 lines / mm). Direction is 16 dots / mm, while sub-scanning direction is 15.4 lines / mm
, And 8 dots / mm in the main scanning direction.
Also, 15.4 lines / mm is used in the sub-scanning direction. Correspondingly, in the receiving / recording unit, the heating element is set to 8 dots / mm for an image signal of 8 dots / mm in the main scanning direction.
mm thermal recording heads are arranged side by side, and for image signals of 16 dots / mm, thermal recording heads in which heating elements are arranged side by side at 16 dots / mm are used. By the way, as a transmission image signal, 8 dots in the main scanning direction
/ mm, 7.7 lines / mm and 15.4 lines / mm in the sub-scanning direction 2
The reception record when two image signals are adopted is as follows. That is, as shown in FIG. 5, as a thermal recording head, heating elements 401 are arranged in parallel in the main scanning direction at 8 dots / mm, and the size of the heating elements 401 is about 100 μm in the main scanning direction.
On the other hand, the heating element 401 is formed with a width of about 190 μm, the common electrode 402 is connected to one end of the heating element 401 in the sub-scanning direction, and the individual lead electrode 403 is connected to the other end of the heating element 401. This is dealt with by controlling the electric power supplied to the heating element 401. More specifically, when power is supplied to the heat generating element 401 from the common electrode 402 and the lead electrode 403, heat generation starts from the central portion of the element. This is because the heat generated in the heating element 402 flows (escapes) to both electrodes in the vicinity of the electrodes 402 and 403 by heat conduction, so that the temperature becomes high in the central portion of the heating element 401 and becomes low in the electrodes 402, 403 side. Therefore, 8 dots / mm in the main scanning direction and 7.7 lines in the sub scanning direction.
The size of the heating element 401 of the heating head for recording an image signal of / mm is about 100 μm in the main scanning direction as shown in FIG. 5 (a).
On the other hand, in consideration of the heat escaping to the electrodes 402 and 403 in the sub-scanning direction, the size is about 190 μm, which is larger than 1 / 7.7 mm, and the size of the pixel recorded by this is about 1 / n in the sub-scanning direction.
It is designed to be 7.7 mm. In order to record an image signal of 8 dots / mm in the main scanning direction and 15.4 lines / mm in the sub-scanning direction with the heating head configured as described above, the fact that the heating element 401 starts to generate heat is used. The power supplied to is changed (reduced). That is, the temperature of the heating element 401 is reduced so that the recording pixel has a size corresponding to 1 / 15.4 mm in the sub-scanning direction, and the feeding of the recording paper in the sub-scanning direction is performed on the transmitting side. Corresponding to the signal, the pitch is 1 / 15.4mm. (Problems to be Solved by the Invention) However, the heating element 401 has a heat generation range sufficient to color or transfer the heat-sensitive recording paper or the ribbon for thermal transfer to the fifth area.
As shown in FIG. (A), the heat is spread from the central portion toward the end edge in sequence, and when the power supply is large, the heat generation C406 is changed to the heat generation B405 and the heat generation C404 as the power supply is reduced.
It becomes smaller in both the main scanning direction and the sub scanning direction. When an image signal of 8 dots / mm in the main scanning direction and 15.4 lines / mm in the sub-scanning direction transmitted from the transmitting side is recorded using such a thermal recording head, as shown in FIG. The size of the recording pixel 407 in the scanning direction is much smaller than 1/8 mm, and a gap occurs between the recording pixels, and the recorded image becomes unnatural. If the power supply is increased to eliminate this gap, the recording pixel 407 in the sub-scanning direction Since the recording pixel size becomes large, overlap occurs, and there is a problem that a resolution of 15.4 lines / mm cannot be obtained. It is an object of the present invention to provide a facsimile apparatus capable of recording an image signal having a large pixel density in the sub-scanning direction with respect to the main scanning direction more naturally and without deteriorating the resolution. [Structure of the Invention] (Means for Solving the Problems) In the present invention, a heating element in which the size of the recording pixel in the heating element is approximately 1/2 of the width in the sub-scanning direction is arranged in parallel. By setting the received image signal to a pixel signal corresponding to the width of the recording pixel in the sub-scanning direction, and conveying the recording paper at a pitch corresponding to the width of the recording pixel in the sub-scanning direction, the above object is achieved. To achieve. (Function) The size of the heating element in one pixel of the thermal recording head is set so that the width of the recording pixel in the sub-scanning direction is larger than the width in the main scanning direction.
Since it is configured to be 1/2, and the feed of the recording paper is sent in correspondence with the width of the print pixels in the sub-scanning direction, the received image signal is 8 dots / mm in the main scanning direction and in the sub-scanning direction.
If it corresponds to a pitch of 7.7 lines / mm, a pixel signal is formed so that this received image signal records the same data for two lines in the sub-scanning direction. If the data is 3.85 lines / mm in the sub-scanning direction, the same data is recorded on 4 lines. As a result, data of 15.4 lines / mm in the sub-scanning direction can be recorded without any difficulty, and the size of the recording pixel is the same in any case. (Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, in which a control unit 1, a pixel density conversion unit 2, a head drive unit 3, a motor drive unit 4, a motor unit 5, a thermal recording head 6 are provided. ,
It has a thermosensitive recording paper 7 and a platen roller 8. When the control unit 1 receives the image signal PIX, it determines the type of the image signal PIX (density in the main and sub scanning directions), and when the density in the sub scanning direction is smaller than the density in the main scanning direction, the pixel density conversion unit 2, the plurality of lines corresponding to the width in the sub-scanning direction of the heating elements of the thermal recording head 6 are converted into pixel signals for recording. The pixel density conversion unit 2 sends the converted image signal to the thermal recording head 6 via the head drive unit 3, and selectively drives a plurality of heating elements in the thermal recording head 6 with a pixel pattern corresponding to the image signal. On the other hand, the control unit 1 sends a drive signal to the motor unit 5 via the motor drive unit 4 to rotate the motor unit 5 at a speed corresponding to the width of the recording pixel in the sub-scanning direction by the heat generating element, so that the thermosensitive recording paper can be obtained. 7 is conveyed in the sub-scanning direction at a pitch corresponding to the speed. Here, as shown in FIG. 2A, the thermal recording head 6 is composed of a heating element unit 60 and an integrated circuit unit 61 for driving the heating element of each pixel. Hereinafter, it is assumed that the thermal recording heads are arranged side by side at 8 dots / mm in the main scanning direction. In this case, the heating element 62 of one pixel in the heating element unit 60 has a width in the sub-scanning direction of about 90 μm and a width in the main scanning direction of about 100 μm, as shown in the enlarged view of FIG. A lead electrode 63 for guiding the drive voltage from the common electrode 64 is connected to the heating element 62. The heating elements 62 are set as described above because the pitch is 1/8 mm, that is, 125 when the dots are arranged in parallel in the main scanning direction at 8 dots / mm.
μm, and the width in the main scanning direction must be smaller than this. However, if this value is made too small, recording omission will occur in the main scanning direction, and if the value is close to 125 μm, the manufacturing will be extremely difficult, so it is generally set between 90 and 110 μm. Regarding the length (width) in the sub-scanning direction, the width in the main scanning direction is 100 μm,
When the sub-scanning pitch is 1 / 15.4 mm (≈65 μm), the relationship between the relative energy for producing a recording density of 1 [OD] and the length of the heating element in the sub-scanning direction is as shown in Fig. 4. However, it is confirmed by an experiment and, empirically, there is a similarity rule for the width in the main scanning direction. Therefore, as is apparent from FIG. 4, although the length in the sub-scanning direction is set to 90 μm as described above, it is possible to obtain a value of 50 to 100 μm.
A recorded image of 15.4 lines / mm can be obtained with dots / mm. That is, as shown in FIG. 3 (a), the recording by the recording head shown in FIGS. 2 (a) and (b) is an image signal of 8 dots / mm in the main scanning direction and 7.7 lines / mm in the sub-scanning direction. When receiving the image signal, the pixel density conversion unit 2 outputs the same image signal to two lines in the sub-scanning direction of the received image signal, or outputs the image signal of the preceding and following lines to the sub-scanning direction.
It is drawn with one recording pixel. Further, as shown in FIG. 3B, the main scanning direction is 8 dots / mm and the sub scanning direction is 3.85 lines / mm.
When the value is mm, four recording pixels are drawn in the sub-scanning direction. Of course, the motor drive unit 4 drives the motor unit 5 so that the sub-scanning line density is 15.4 lines / mm, and conveys the thermal recording paper 7 in the sub-scanning direction at a pitch of 1 / 15.4 mm. The main scanning direction is 8 dots / mm and the sub scanning direction is 15.
When recording 4 lines / mm image signal, it is recorded as it is. As described above, for any of the above image signals, the size of the recording pixel corresponds to the size of the heating element 62, and the size thereof is about 1/8 mm in the sub-scanning direction. Since the width is about 1 / 15.4 mm (that is, about 1/2 in the sub-scanning direction with respect to the main scanning direction), uniform recording is achieved. In the above embodiment, 8 dots / mm in the main scanning direction
When recording an image signal of 7.7 lines / mm or 3.85 lines / mm in the sub-scanning direction, the same image signal was recorded twice or four times in the sub-scanning direction. Pixels to be recorded may be formed from the information by the pixel density conversion unit 2. In this way, the recorded image can be made more natural. In the above embodiment, the case of 8 dots / mm in the main scanning direction has been described, but the present invention is not limited to this. (Effects of the Invention) As described above, according to the present invention, the size of the heating element is set to be approximately 1 / the width of the recording pixel in the sub-scanning direction in the main scanning direction.
Since it is set to 2, it is possible to record a good image without causing a gap in the main scanning direction as in the conventional case.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a block diagram of a thermal recording head used in the present invention,
FIG. 5 is an explanatory diagram of an image recorded by converting the pixel density according to the present invention, and FIG. 4 is a diagram showing a relationship between a heating element size required to obtain a density of 1 [OD] and relative input energy, and FIG. FIG. 7 is an explanatory diagram of a recorded image in a conventional facsimile apparatus. 1 ... control unit, 2 ... pixel density conversion unit, 3 ... head drive unit, 4 ... motor drive unit, 5 ... motor unit, 6
...... Thermal recording head, 7 Thermal recording paper, 60 Heating element unit, 62 Heating element.

Claims (1)

(57) [Claims] In a thermal recording type facsimile apparatus for recording a received image signal by using heating elements arranged side by side in a row, the heating element determines the size of a recording pixel by the heating element with respect to the width in the main scanning direction. It is formed to have a width of about half in the sub-scanning direction, converts the received image signal into a pixel signal corresponding to the width of the recording pixel in the sub-scanning direction, and records the recording paper by the heating element. A facsimile apparatus, which conveys at a pitch corresponding to the width of pixels in the sub-scanning direction. 2. The heating elements have a width in the main scanning direction of 90 to 110 μm and are arranged in parallel in the main scanning direction at 8 pieces / mm, and have a width of 50 to 1 in the sub scanning direction.
It is formed with 00 μm, and the feed pitch of the recording paper in the sub-scanning direction
The facsimile apparatus according to claim (1), characterized in that the size is 1 / 15.4 mm.