JPH0382559A - Image recorder - Google Patents

Abstract

PURPOSE:To record an image with arbitrary two types of linear densities using one thermal head by a method wherein two trains of heating elements of different gaps are adjacently disposed on one substrate of a thermal head, and a sheet of thermal recording paper is pressed down against each of the two trains by a platen roller. CONSTITUTION:On a heat resistant layer 106 of a thermal head 1, a train of heating resistors 1021a with a gap corresponding to 300 dpi and a train of heating resistors 1021b with a gap corresponding to 400 dpi are adjacently arranged. Recording paper 2 is pressed down against each of the heating resistors 1021a and 1021b by a platen roller 3. The heating resistors 1021a and 1021b are electrically conducted in a selective manner. In this manner, using the single thermal head 1, an image recording can be carried out with two types of linear densities 300 dip and 400 dip. Because the heating resistors 1021a and 1021b are allowed to be formed with a gap of a recording linear density, the production of a thermal head is facilitated. In addition, the heating resistors 1021a and 1021b are formed with a gap corresponding to 300 dpi and 400 dpi in this invention, but it is needless to say that each of them can be formed with an arbitrary gap.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal recording type image recording apparatus using a thermal head.

[Prior Art] In recent years, in the G4R rating recommended by the CCITT, the line density of main scanning lines when transmitting images is 200 dpi (dot per
1nch), 240dpi, 300dp
i, 400 dpi are specified as options.

Therefore, in this G4 standard facsimile machine, any one of the four types of linear densities mentioned above is fixedly set.
Alternatively, image transmission is performed at one linear density arbitrarily selected by the operator.

Incidentally, in facsimile machines, image recording apparatuses of a thermal recording type using a thermal head are often used, but there are cases where it is desired to switch the linear density of the recorded image during image recording.

[Problems to be Solved by the Invention] Conventionally, for example, when recording images of 200 dpi and 400 dpi, a 400 dpi thermal head is used to record images of 200 dpi and 400 dpi.
While 40 Gdpi images were recorded as usual, 200 dpi images were also recorded by using two heating elements corresponding to each pixel as one dot pixel.

However, with this method, recording control for the thermal head is relatively simple, but the linear density ratio that can be switched is
If N is a natural number, it must be 1:N, and there is a problem in that it cannot be set to an arbitrary linear density ratio.

On the other hand, for example, 200dpi and 300dpi.

1: If not N, then 1, which corresponds to the least common multiple of both.
Using a 200 dpi thermal head, one dot of a 300 dpi image is printed on two heating elements each corresponding to a pixel.

Alternatively, a method is known in which images are recorded at the two types of linear densities by using three dots each as L dots for a 400 dpi image.

However, this method has the problem that it is difficult to manufacture the thermal head because the heating elements must be arranged at a high density corresponding to the least common multiple of the two linear densities to be switched, such as 1200 dpi in the above case. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image recording device that solves the above problems, is easy to manufacture, and can record images at any two types of linear densities using one thermal head.

[Means for Solving the Problems] To this end, the present invention provides two adjacent rows of heating elements arranged at different intervals on one substrate of a thermal head, and one sheet of heating elements for each of the two rows of heating elements. By pressing the thermal recording paper with one platen roller and selectively energizing the heating elements in each row, images are recorded on the thermal recording paper at each linear density corresponding to two types of spacing. It is characterized by:

[Function] Since the heating elements in each row need only be arranged at intervals corresponding to the linear density to be recorded, it is easy to manufacture the thermal head, and the heating elements in each row can be arranged in accordance with the g-density of the desired recorded image. By arranging the
It becomes possible to record images with different linear densities.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a cross-sectional view of an image recording section of an image recording apparatus according to an embodiment of the present invention. In FIG.
are pressed together. The thermal head 1 includes a substrate 102 and two printed circuit boards 103 arranged on an aluminum heat sink 101, and a protective cover 104 on top of the substrate 102 and two printed circuit boards 103.
is arranged and formed.

Two rows of heating resistors 1021a and 1021b are formed on the upper part of the substrate 102 at the contact portion with the platen roller 3, each corresponding to one line of pixels.

The printed circuit board 103 includes a shift register and a latch circuit for temporarily storing image information, and a heating resistor 102.
An integrated circuit such as a drive circuit that supplies electricity to 1a and 1021b is formed.

FIG. 2(a) is a plan view of the substrate 102, and FIG. 2(b) is a plan view of the substrate 102.
A side sectional view thereof is shown. In these figures, the top surface of the ceramic connecting plate 1022 has a layer of several tens of μm.
A heat resistance layer 1023 made of a thick glass material is formed. On top of that, there is a heating resistor 1021 shown by hatching in the figure.
6 heating resistors 1 formed in two rows of a and 1021b
The arrangement interval Da of each heating resistor 1021a is 1/300 inch, and the arrangement interval Db of the heating resistor 1021b is 1/4
00 inches. Further, on the thermal resistance layer 1023, common electrodes 1024a and 1024b are commonly connected to one end of each of the heating resistors 1021a and 1021b, and individual electrodes 1025a are individually connected to the other end of each of the heating resistors 1021a and 1021b.
1025b is formed.

The above common electrodes 1024a, 1024b and individual electrode 1
025a and 1025b are connected to the drive circuit on the printed circuit board 103 side by bonding wires 105.

The heating resistors 1021a and 1021b, the common electrodes 1024a and 1024b, and the individual electrodes 1025a and 102
5b has a thickness of 0.1 to several μm, and is formed into a predetermined pattern by etching after forming a thin film of each material by vapor deposition or sputtering. Furthermore, a wear-resistant layer 1026 made of Ta, O, etc. with a thickness of approximately 10 μm is formed on these.

FIG. 3 shows a block diagram of this image recording apparatus. In the thermal head 1, the shift register 106 stores 300 dpi or 400 dpi image information for one line per hour.
Image information for one line of dpi is output to the latch circuit 107a, and image information for one line of 400 dpi is output to the latch circuit 107b.

The driver 108a energizes each of the heating resistors 1021a, and is composed of four circuits.The heating resistor 1021a is divided into four blocks, and each circuit controls each block. Further, the driver 108b is configured to energize each of the heating resistors 1021b, and is composed of five circuits.
1b is divided into four blocks, and each block is controlled by each circuit.

The thermistor 115 measures the temperature of the thermal head 1.

FIFO memory 4 is FIFO (First I
It has a function (FirstOut) and temporarily stores image information of a certain number of lines. 1. Image information is inputted from a device not shown in the figure, and the stored image information is outputted to the shift register 106 as recording data SD. There is.

The stepping motor 5 opens the platen roller 3 and conveys the recording paper 2, and the motor drive circuit 6 has the following functions:
It controls the opening of the stepping motor 5.

The clock circuit 7 outputs clock pulses for various operation timings, and the recording control section 8 inputs the clock pulses and the detection signal from the thermistor 115 to control the various sections described above.

In order to control the thermal head l, the recording control unit 8 supplies strobe pulses 5Ba1 to SBa to the driver 108a side, which indicate the timing of energizing one heat generating resistor 1021a.
Similarly, the driver 108b outputs strobe pulses 5Bbi to SBb indicating the timing of energization to the heating resistor tozib. In addition, a latch pulse S indicating the latch timing of one line of image information
A latch pulse La is output to the latch circuit 107a, and a latch pulse SLb is output to the latch circuit 107b.

With the above configuration, the image recording device of this embodiment has a 300 dp
It has the function of recording images with two types of S density: 1 and 400 dPi. When recording an image, predetermined image information is transferred from another device (not shown), and
Recording control unit 8 is activated.

Now, if we are to record an image at 300 dpi,
The 300 dpi image information is sequentially transferred and temporarily stored in the FIFO memory 4, while the recording control unit 8 starts recording control.

That is, FIG. 4 shows each signal during this recording control. First, as shown in FIG. 4(a), one line of image information SD is read out from the FIFO memory 4, and the image information is SD is stored in shift register 106 as 0, then
As shown in the figure, latch pulse SLa is applied to latch circuit 1
07a, and the one line of image information SD is set in the latch circuit 1c. Thereafter, as shown in FIG. 2C, each strobe pulse 5Ba1 to 5Ba4 is sequentially input to the driver 108a. At this time, the temperature of the thermal head l is detected by the thermistor 115, and the pulses l1l of the strobe pulses SBayu to SBa are
Iv is adjusted so that it is narrow when the detected temperature is high and wide when the detected temperature is low.

As a result, the heating resistor 1021a is
Each of them is energized, and one line of image is recorded on the recording paper 2. Further, by adjusting the pulse @V, the recording density can be adjusted to an appropriate level.

Next, the stepping motor 5 is opened and the recording paper 2 is conveyed by one line pitch, and the recording control of the thermal head 1 is executed again. This operation has a constant period Tp
This process is repeated and images are recorded one line at a time.

On the other hand, when recording an image at 400 dpi,
dpi image information is temporarily stored in the FIFO memory 4, and as in the case described above, the image information sD of the l line is read out and stored in the shift register 106.Next, the latch pulse SLb is sent to the latch circuit 107b. The one line of image information SD is input to the latch circuit 107b. After this, strobe pulse SBb ~ SBb,
are sequentially input to the driver 108b, and an image of 1 line is recorded.

After this, the recording paper 2 is conveyed by one line pitch.

The recording control operation of the thermal head 1 is repeatedly executed at a constant period, so that images are recorded sequentially one line at a time.

As described above, in this embodiment, two rows of heating resistors 1021a with a spacing corresponding to 300 dpi and heating resistors 1021b with a spacing corresponding to 400 dpi are arranged adjacently on the thermal resistance layer 106 of the thermal head 1. , heating resistor 10
The recording paper 2 is pressed against each of the heating resistors 1021a and 1021b by the platen roller 3, and the heating resistors 1021a and 102
1b is selectively energized.

Thereby, one thermal head 1 can perform image recording at two types of linear densities, 300 dpi and 400 dpi. Furthermore, since the first heating resistors 1021a and 1021b need only be formed at intervals corresponding to the recording linear density, the thermal head can be manufactured easily.

In addition, in the above embodiment, the heating resistor 1021a and the heating resistor 1021b are 300 dpi and 400 dpi.
Although they are formed at intervals corresponding to the above, it goes without saying that they can be formed at arbitrary intervals.

Further, although the case where an image is recorded on the recording paper 2 has been described, it is known that thermal transfer carbon paper or plain paper can be used instead of the recording paper 2.

[Effects of the Invention] As described above, according to the present invention, two rows of heating elements are arranged adjacently at two types of spacing on one substrate of a thermal head, and one heat-sensitive sheet is attached to each heating element in each row. By pressing the recording paper against a single platen roller and selectively energizing the heating elements in each row, images can be recorded on the thermal recording paper at two different linear densities. Since it is only necessary to form the heating elements at intervals, manufacturing of the thermal head becomes easier, and by forming the heating elements in each row at the desired linear density, one thermal head can have any two types of IIA densities. It becomes possible to record images.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an image recording section of an image recording device according to an embodiment of the present invention, FIG. 2(a) is a plan view of an insulating substrate of a thermal head, and FIG. 2(b) is a side sectional view thereof. , FIG. 3 is a block diagram of the image recording apparatus, and FIG. 4 is a time chart of each signal showing the recording operation. DESCRIPTION OF SYMBOLS 1... Thermal head, 2... Recording paper, 3... Platen roller, 4... FIFO memory, 5... Stepping motor, 6... Motor drive circuit, 7... Clock circuit , 8... Recording control unit, 102... Substrate,
103...Printed circuit board. 104... Protective cover, 105... Bonding wire, 106... Shift register, 107a, 10
7b... Latch circuit, 108a, 108b-driver, 115-... Thermistor, 1021a, 1021b-
...heating resistor, 123...thermal resistance layer, 1024a,
1024b... common electrode, 1025a, 1025b...
...Individual electrode. Figure 4

Claims (1)

[Claims] In an image recording apparatus that includes a thermal head in which heating elements are arranged linearly on a substrate at regular intervals, and a platen roller that presses a thermal recording paper against the heating elements, thermal heads are arranged adjacently on the substrate at different intervals. two rows of heating resistors arranged in a row, and one platen roller that presses one sheet of thermal recording paper against each of the two rows of heating elements;
and recording control means for recording images on the thermal recording paper at respective linear densities corresponding to the two types of intervals by selectively energizing each of the two rows of heating elements. Features of the image recording device.