JPH02215571A - Heater controller for recording head - Google Patents

Abstract

PURPOSE:To simplify a structure and to facilitate reduction in size by placing a plurality of heater driving circuits contained in a recording head and a plurality of timers for controlling the driving circuits on a carriage, and controlling the plurality of timers by one signal line. CONSTITUTION:A controller for a heater 1 is composed of a monostable multivibrator 11, a timing generating resistor 12, a capacitor 13, a D-shaped latch 14, a transistor 15, and a transistor base resistor 16. Similarly, a controller for a heater 2 is composed of a monostable multivibrator 21, a timing generating resistor 22, a capacitor 23, a D-shaped latch 24, a transistor 25, and a transistor base resistor 26. Driving circuits of a plurality of heaters 17, 27 contained in the head, and a plurality of timers for controlling the driving circuits are placed on the carriage, and the plurality of the timers are controlled by one signal line 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heater control circuit for temperature adjustment built into a recording head of a recording apparatus.

[Conventional technology]

Recording devices such as printers and facsimiles are configured to form dot patterns corresponding to image information on a recording medium (such as paper) by driving dot forming means of a recording head based on image information. Depending on the type of dot forming means, it can be divided into inkjet type, wire dot type, thermal type, laser beam type, etc.

In recent years, many recording devices have come into use in offices, and recording devices used in offices are required to have high speed printing, high resolution, high print quality, and low noise.

Therefore, an inkjet type recording apparatus is attracting attention as a recording apparatus that satisfies these strict conditions.

2. Description of the Related Art An inkjet recording apparatus uses an ejection energy generating means that ejects ink from an ejection port to form flying ink droplets in order to form a recorded image.

By the way, a suitable ejection energy generating means for the recording head uses and has a built-in electrothermal converter that generates thermal energy to cause a state change in the ink, so it is an element that is affected by temperature. Since the temperature is large, it is required to maintain the temperature within a predetermined range in order to maintain printing quality.

In particular, since inkjet recording heads use liquid ink, stricter temperature control is desired compared to other types of recording heads.

Temperature control of the print head is generally performed using a temperature adjustment heater together with a temperature sensor, and a large number of heaters are now being used to stabilize the temperature of the print head.

In particular, there is a strong tendency for multiple heaters to be installed when a plurality of print heads are used for color printing or when a large print head with 128 to 256 ejection ports is used.

[Technical problem to be solved by the invention]

However, in conventional recording head heater control means, as the number of heaters increases, the number of control wires that connect the recording head to the control system of the recording device also increases, making the control circuit complex. Therefore, miniaturization was difficult.

When a plurality of recording heads are used for color printing, the above technical problem becomes even more prominent.

The present invention was developed in view of these technical issues, and has a simple structure and is easy to downsize, and can be implemented even when the recording head is made larger or colored without complicating or increasing the size of the structure. An object of the present invention is to provide a heater control device for a recording head that is capable of controlling a recording head.

[Means for solving problems]

The present invention is characterized in that drive circuits for a plurality of heaters built into a recording head and a plurality of timer circuits for controlling each drive circuit are mounted on a carriage, and the plurality of timer circuits are controlled by a single signal. The above object is achieved by a heater control device for a recording head.

[Effect]

According to the above configuration, a driving means for driving the temperature raising heater in a time-sharing manner using a timer circuit is provided on the carriage on which the recording head is mounted, so that a plurality of heater driving means can be driven by a single signal line. It becomes possible to control accurately.

〔Example〕

The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of a recording head heater control device according to an embodiment of the present invention.

In FIG. 1, 11 is a monostable multipipe lake, 12 is a timing resistor, 13 is a timing capacitor, 14 is a D-type latch, 15 is a transistor that drives heater 1, and 16 is a base for transistor 15. The resistor 17 indicates the heater l.

The monostable multipipe rake 11 constitutes a timer circuit that controls the drive circuits 15 and 16 of the heater 1.

Similarly, in FIG. 1, 21 is a monostable multipipe rake that constitutes a timer circuit that controls the drive circuit of the heater 2, 22 is a timing resistor, 23 is a timing capacitor, and 24 is a D-type latch. , 25 is a transistor for driving the heater 2, 26 is a base resistor for the transistor 25, and 27 is the heater 2.

A drive circuit for the heater 2 includes a transistor 25 and a base resistor 26.

The above shows the circuit configuration of the two systems of receivers that control the heaters when the plurality of heaters built into the print head are the heater 1 and heater 2, that is, the circuit configuration on the carriage on which the print head is mounted. .

In the receiving section shown in FIG. 1, the control circuit for the heater 1 is composed of a monostable multipipulator 11, a timing generation resistor 12, a capacitor 13, a D-type latch 14, a transistor 15, and a transistor base resistor 16. There is.

Similarly, the control circuit for the heater 2 includes a monostable multipipe rake 21, a timing generation resistor 22, a capacitor 23, a D-type latch 24, a transistor 25, and a transistor base resistor 26.

That is, the configurations of the control circuits of heater 1 and heater 2 are the same.

On the other hand, the main body of the control system of the recording apparatus is provided with a transmitting section as shown on the left side of FIG. It is connected.

The transmitter has a circuit configuration corresponding to the number of recording heads, and in the illustrated example, a first control signal transmitter including a monostaple multivibrator 31, a timing generation resistor 32, and a timing capacitor 33. ,and,
It is composed of a second control signal section consisting of a monostaple multi-byte break 41, a timing resistor 42, and a timing capacitor 43.

Thus, the recording head heater control device according to the present invention,
That is, a plurality of heaters 17.2 built into the recording head
7 drive circuits and a plurality of timer circuits that control each drive circuit are mounted on a carriage, and the plurality of timer circuits are mounted on a carriage.
A recording head heater control device is constructed which is characterized in that it is controlled by a real signal line 10.

Fig. 2 is a timing chart when only heater 1 is controlled by the heater control device shown in Fig. 1, and Fig. 3 is a timing chart when heater 1 and heater 2 are controlled simultaneously by the heater control device shown in Fig. 1. FIG. 4 is a timing chart when the heater control device shown in FIG. 1 controls only heater 1 and controls both heater 1 and heater 2.

The operation of the recording head heater control device described above will be described below with reference to FIGS. 1 to 4.

First, control in a standby state in which both heater 1 and heater 2 are turned off will be described.

In the standby state, the control signal sent from the transmitting section in FIG. 1 to the receiving section through the signal line 10 is outputted at a constant cycle with a pulse width TM3, as shown by TO to T6 in FIG.

At this time, at the rising edge of the HTCK pulse of the transmitter, a monostable multivibrator (hereinafter abbreviated as MM) is activated.
11.21 starts operating, MM outputs a pulse width TMI, and MM21 outputs a pulse width TM2.

In period To in FIG. 2, the control signal is "L" at the rising edge of pulse TMI, so the D-type latch 14
When the D input of the D-type latch 14 is 1L, the C input rises, and the output Q of the D-type latch 14 remains at "L".

Therefore, the transistor 15 is 0FFj, and the heater 1 is turned off.

Similarly, in period TO in FIG. 2, the WIi control signal is 'L' at the rising edge of pulse TM2, so when the D input of the D-type latch 24 is 'L', the C input rises, causing the D The output Q of the type latch 24 remains at "L".

Therefore, the transistor 25 is turned off, and the heater 2 is turned off. Next, turn heater 1 ON/OFF
Control will be explained.

To turn on heater 1, press H on the transmitter in Figure 1.
Set the TIE signal to “H”.

Then, the HT shown by the period T2 in FIG.
The MM31 starts operating at the rising edge of the CK signal.

At this time, the length of the output pulse of MM31 is indicated by 7M4. This pulse TM4 is transmitted to the receiving section through the signal line 10 and triggers the MMII. Therefore, the control signal at the fall of the pulse width TMI in the timer 1 becomes "H", and the latch 14 sets the output Q to "H" to turn on the transistor 15, so that the heater 1 is turned on.

Conversely, in order to turn off the heater 1, the HTIB signal of the transmitter in FIG. 1 is set to "L".

Then, the state becomes the same as the standby state described above, and the heater 1 is turned off.

The ON/OFF control of the heater 1 is performed as described above.

Next, ON/OFF control of heater 1 and heater 2 will be explained.

In order to turn on the heaters 1 and 2, the HT2B signal from the transmitter shown in FIG. 1 is set to "H".

Then, H as indicated by period T2 in FIG.
The MM41 starts operating at the rising edge of the TCK signal.

The length of the output pulse of MM41 at this time is 7M5.

This pulse TM5 is transmitted through the control signal line 10 and triggers MMII and MM21 in the receiving section.

Since the control signal is H'' at the falling edge of the pulse widths TMl and 7M2 in timers 1 and 2, the output Q of latch 14 and latch 24 becomes H', and the respective transistors 15 and 25 are turned on. , heater 1
Both the heater 2 and the heater 2 are turned on.

Here, the ON/OFF timing of the heater 2 is determined by MM21 of the receiving section in Fig. 1, and as shown in Fig. 2, depending on the case of MMII, the direction of the output time to the timer 2 is longer. It is set. Due to this time difference,
Control of heater 1 and control of heater 2 are distinguished.

Conversely, in order to turn off both heater 1 and heater 2, the HT2E signal of the transmitter shown in FIG.
25 is turned off, and both heaters 1 and 2 are turned off.

The timing when controlling only the heater 1 and controlling the heaters 1 and 2 is as shown in FIG.

The conditions for the above timing (pulse width) TMI to TM5 are as follows.

7M3<TMI<7M4<7M2<7M5 These timings are preferably set to appropriate values depending on the circuit elements used.

Furthermore, when increasing the number of heaters in the above embodiment, it is sufficient to increase the number of MMs on the transmitting side and the receiving side and control them at the same timing.

According to the embodiment described above, when controlling the plurality of heaters built into the recording head on the carriage, it is possible to control the plurality of heaters with the - control signal line 10, and when printing in color. It has become possible to easily and accurately control multiple heaters for temperature adjustment of multiple recording heads.

Furthermore, it has become possible to easily and accurately control the use of a plurality of heaters for temperature adjustment when the print head is enlarged.

Furthermore, since there is only one signal line 10 for controlling the recording head, it is possible to downsize the cable.

FIG. 5 is a circuit diagram showing the configuration of heater control for a recording head according to another embodiment of the present invention.

In FIG. 5, the control circuit of the heater 1 (numbered 17) in the reception section on the carriage side consists of a monostable multipipulator (hereinafter abbreviated as MM) 11, a timing generation resistor 12, a capacitor 13, and a D-type latch 14
, a monostaple multivibrator (hereinafter abbreviated as MM) 51 for heater protection, and a resistor 52 for timing generation.
, a capacitor 53, a transistor 55, and a transistor base resistor 56.

Similarly, the control circuit for the other heater 2 (numbered 27) in the receiving section includes an MM21, a timing generation resistor 22, a capacitor 23, a D-type latch 24, and a heater protection MM6.
1, a timing generation resistor 62, a capacitor 63, a transistor 65, and a transistor base resistor 66.

The configurations of the control circuits of the heater (17) and the heater (27) are substantially the same.

In this embodiment, the control circuit for each heater 1.2, which is the same as in the case of FIG.
A protection circuit (
It has a configuration with an additional overheating prevention circuit).

In other words, the circuit configuration of this embodiment differs from the circuit shown in FIG. 1 only in the above-mentioned parts, but the other parts are the same, and corresponding parts are indicated by the same numbers, and their details are Explanation will be omitted.

Therefore, the operations of the heater control device shown in FIG. 5 are substantially the same as those of the heater control device shown in FIG. O of heater 1 and heater 2
Control operations such as N, OFF control, control for only heater 1, and control for heaters 1 and 2 are all the same as those described with reference to FIGS. 2 to 4.

According to the embodiment shown in FIG. 5, the same effects as those of the above-mentioned embodiments explained in FIGS. A protection circuit has been added to prevent this from happening, making it possible to prevent print quality from deteriorating due to overheating of the recording head. Particularly excellent effects were obtained when the method was applied to an inkjet recording head that is susceptible to overheating.

〔Effect of the invention〕

According to the recording head heater control device of the present invention described above, a plurality of heater drive circuits built into the recording head and a plurality of timer circuits for controlling each drive circuit are mounted on the carriage, and the plurality of timer circuits are mounted on the carriage. Since the circuit is configured to control one signal line, it is possible to easily and accurately control multiple heaters with -1 heater control signal, and the temperature of multiple recording heads when printing in color can be controlled easily and accurately. It is possible to control multiple heaters for temperature adjustment, or multiple heaters when mounting temperature adjustment heaters in multiple locations when the print head becomes larger, and moreover, it is possible to control multiple heaters for temperature adjustment using a single signal line for the print head. By doing so, it is possible to obtain a recording heater control device that allows for miniaturization of the cable.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a heater control circuit for a recording head according to an embodiment of the present invention, FIG. 2 is a timing chart when only one heater is controlled by the circuit in FIG. 1, and FIG. Fig. 4 is a timing chart when controlling both heaters simultaneously using the circuit shown in Fig. 1. Fig. 4 is a timing chart when controlling only one heater and controlling both heaters using the circuit shown in Fig. 1. Fig. 5. FIG. 2 is a circuit diagram showing the configuration of a recording head heater control device according to another embodiment of the present invention. 10. Control signal line, 11.21.31.41
Monostable multivi break, 14.24
D-type latch, 15.25.55.65 Transistor, 17.27---Heater, TMI~T
M5...-----One timing pulse.

Claims (1)

[Claims] (1) Drive circuits for a plurality of heaters built into the recording head and a plurality of timer circuits for controlling each drive circuit are mounted on a carriage, and the plurality of timer circuits are controlled by a single signal line. A heater control device for a recording head.