KR100205592B1 - Recording head driving circuit and method of inkjet printer having duplicate recording head - Google Patents

Abstract

1. Technical field to which the invention described in the claims belongs

The present invention relates to a circuit for driving a recording head in an ink jet printer equipped with two recording heads and a method thereof.

2. Technical Problems to be Solved by the Invention

The double recording head is driven by a simple structure.

3. The point of the solution of the invention

It is possible to select only one recording head corresponding to an image to be printed among the two recording heads to supply driving power and selectively enable driving signals of one driver correspondingly to an image to be printed, So that only the selected recording head is driven.

4. Important Uses of the Invention

It is used to drive the dual recording heads with only one driver.

Description

A recording head driving circuit of an ink jet printer having dual recording heads and a method thereof

FIG. 1 is a circuit diagram of a recording head driving circuit according to an embodiment of the present invention. FIG.

FIG. 2 is a processing flowchart according to an embodiment of the present invention; FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly, to a circuit and a method for driving a droplet head in an ink jet printer having a double recording head.

Recording methods such as a wite dot method, a thermal transfer method, an ink jet method, and the like are commonly used as recording methods for recording images on a recording medium such as paper or OHP (Overhead Project) A recording head is used. Among the above-described recording methods, the inkjet method is a method in which ink is jetted onto a recording medium to record an image. A recording head provided in a printer employing such an ink jet method has a plurality of nozzles each having a minute ejection hole for ejecting ink. The ink in the nozzles is heated and expanded by a heating element corresponding to each nozzle, and is ejected to the outside of the nozzle. The desired image can be recorded on the recording medium by selectively driving the heating elements while moving the recording head in the horizontal direction.

Generally, the recording head is integrally provided in an ink cartridge, so that when the ink in the ink cartridge is exhausted, the recording head is also discarded. The ink jet printer does not use one ink cartridge but uses various ink cartridges. For example, the ink jet printer is designed to be able to combine both monochrome printing and color printing, so that the ink cartridges are also compatible with mono ink cartridges filled with black ink and color inks filled with different colors of colcr ink Carriage is provided with copy.

Meanwhile, conventional ink jet printers were able to exchange mono ink cartridges and color ink cartridges. In such an ink jet printer, when a user wants to print monochrome ink, he or she has to print a monochrome ink cartridge and print a color ink cartridge when printing is desired. Therefore, each time the black and white print and the color print are changed, the ink cartridges must be changed accordingly. An ink jet printer having both a mono ink cartridge and a color ink cartridge has been developed in order to solve the above inconvenience. In such an ink jet printer, the recording head is also double-headed. That is, a recording head for monochrome printing provided in a mono ink cartridge, and a recording head for color printing provided in a color ink cartridge glazing.

However, when the dual recording heads are mounted in one ink jet printer, a driver for driving the recording heads is also required correspondingly to each recording head. In addition to this, the number of nozzles is also increased, so that the number of lines of the cable for connecting the recording head and the driver is further required. Accordingly, when a dual recording head is employed, the internal structure of the product is complicated as compared with an ink jet printer equipped with a single recording head, and the manufacturing cost is increased.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a driving circuit capable of driving a dual recording head by a simple structure and a method thereof.

It is another object of the present invention to provide a driving circuit capable of driving a dual recording head with only one driver and a method thereof.

According to an aspect of the present invention, there is provided an image forming apparatus including: a plurality of recording heads for selectively supplying only one recording head corresponding to an image to be printed among a plurality of recording heads to supply driving power; So that only the selected recording head is driven by applying one to each of the nozzles of the recording heads corresponding to each other.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and accompanying drawings, numerous specific details are set forth in order to provide a more thorough understanding of the present invention, such as specific circuit configurations, components, process flows, and logic state diagrams. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. Further, the detailed description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted.

FIG. 1 shows a recording head driving circuit according to an embodiment of the present invention, in which the mono recording head 100 and the color recording head 102 are double mounted. The mono recording head 100 and the color recording head 102 each have a plurality of nozzles (not shown) as described above. The mono recording head 100 and the color recording head 102 have a plurality of nozzles Are 56 nozzles, respectively. The driving signal input terminals N1 to N56 of 56 mono recording heads 100 and the color recording heads 102, respectively, correspond to the nozzles one by one. That is, the mono recording head 100 and the color recording head 102 are connected to the corresponding driving signal input terminals, one for each of the driving signal input terminals N1 to N56, with the driving power VPP applied to the common power terminals COM1 to COM4, The nozzles are driven by an applied driving signal input to inject the ink inside the recording medium.

Although the mono recording head 100 and the color recording head 102 conventionally require two drivers one by one, the mono recording head 100 and the color recording head 102 are driven by only one driver 104 according to the present invention. The driver 104 uses the conventional driver as it is, and 56 drive signal output terminals Y1 to Y56 for outputting different drive signals one by one correspond to each other of the mono recording head 100 and the color recording head 102 Are commonly connected one by one to the nozzles. That is, the drive signal output terminal Y1 of the driver 104 is commonly connected to the drive signal input terminal N1 of each of the mono recording head 100 and the color recording head 102, and the other drive signal output terminals Y2-Y56 And are respectively connected to the driving signal input terminals N2-N56 one by one in the same manner. The driver 104 selectively generates driving signals by a selection signal SEL and an output enable signal OE applied from the CPU 106 and generates driving signals Y1 through Y56 through corresponding driving signal output terminals Y1 through Y56 Output. The selection signal SEL is a signal to select necessary nozzles among the nozzles N1 to N56 of the mono recording head 100 or the color recording head 102 and the output enable signal OE is a signal for enabling the output of the driving signal Lt; / RTI > The selection signal SEL output enable signal OE is generated in the same manner as in the conventional art. Here, the CPU 106 executes a program according to a flowchart of FIG. 2, which will be described later, on a CPU provided for overall control of the ink jet printer.

At this time, although the mono recording head 100 and the color recording head 102 are commonly connected to one driver 104, since the driving power Vpp is selectively supplied by the first and second switching units 108 and 110, Only one of them is driven. The first and second switching units 108 and 110 are connected to each other between the driving power supply Vpp and the mono recording 100 and the color recording head 102 to supply the driving power Vpp for the corresponding recording head to the CPU 106, In accordance with the control. The CPU 106 generates the logic states of the first and second switching signals S1 and S2 differently corresponding to the image to be printed, that is, monochrome or color, so that only one of the first and second switching units 108 and 110 is turned & .

The first switching unit 108 includes a transistor Q1 switched by inputting the first switching signal S1 to the base terminal and a pull-up resistor Q1 connected between the power supply voltage Vcc and the base terminal of the transistor Q1. Resistors R7 to R10 connected to the common power terminals COM1 to COM4 of the mono recording head 100 and emitter terminals and collector terminals respectively connected to the driving power supply Vpp and a base terminal connected to the resistors R3 A transistor Q2 connected between the emitter terminal of the transistor Q2 and the collector terminal of the transistor Q1 and connected to the collector terminal of the transistor Q1 through the switch Q1, (R2). The resistors R2 and R3 are resistances for controlling the bias and base currents.

If the first switching signal S1 is applied "high ", the transistor Q1 is turned on and the transistor Q2 is turned on so that the driving power Vpp is supplied to the mono recording head 100. [ In contrast, when the first switching signal S1 is applied at a low level, the transistor Q1 is turned off and the transistor Q2 is thus turned off, so that the driving power Vpp is not supplied to the mono recording head 100 .

The second switching unit 110 includes a transistor Q3 which is switched by inputting the second switching signal S2 to the base terminal, a pull-up resistor r4 connected between the power supply voltage Vcc and the base terminal of the transistor Q3, Resistors R11 to R13 connected to the common power terminals COM1 to COM4 of the color recording head 102 and the emitter terminal and the collector terminal are connected to the driving power supply Vpp respectively and the base terminal is connected to the transistor R6 through the resistor R6, And a resistor R5 connected between the emitter terminal of the transistor Q4 and the collector terminal of the transistor Q3 connected to the collector terminal of the transistor Q3 and switched in response to the switching of the transistor Q3 do. The resistors R5 and R6 are resistors for controlling the bias ALDC base current. If the second switching signal S2 is applied "high ", the transistor Q3 is turned on and the transistor Q4 is turned on, thereby supplying the driving power Vpp to the color recording head 102. [ On the other hand, when the second switching signal S2 is applied at a low level, the transistor Q3 is turned off and the transistor Q3 is turned off so that the driving power Vpp is not supplied to the color recording head 102 .

Therefore, the CPU 106 can selectively drive or not drive the mono recording head 100 and the color recording head 102 to the first and second switching signals S1 and S2.

Therefore, the CPU 106 enables only one recording head among the mono recording head 100 and the color recording head 102 to be selected and driven by the first and second switching units 108 and 110, The driver 104 can be driven to drive the dual recording head with only one driver 104. At this time, of course, the CPU 106 operates the driver 104 corresponding to the image to be printed in the same manner as usual, and operates differently depending on the case of black-and-white printing and the case of color printing.

An operation example as described above will be described in more detail with reference to FIG. 2, which shows a processing flowchart of the CPU 106 according to the embodiment of the present invention.

First, the CPU 106 checks in step (200) whether or not the current printing should be executed. At this time, if the print is not to be executed, it is determined in step 228 that the corresponding processing is presently required, and the process is finished. If the print is executed in step 202, it is checked whether the color recording head 102 needs to be driven or turned on. At this time, if it is necessary to print with the color recording head 102, the CPU 106 outputs the second switching signal S2 as "high" in step 204 to turn the color recording head 102 on. Next, the CPU 106 checks in step (206) whether the mono recording head 100 needs to be driven, i.e., "turned on. &Quot; At this time, when the monochrome recording head 100 is to be printed, the CPU 106 outputs the first switching signal S1 as "High" in step 208 to turn the mono recording head 100 on.

The CPU 106 outputs the first switching signal S1 as "low" in steps 210 to 212 to turn on the monochrome recording head 100 Quot; off " On the other hand, when the mono recording head 100 is turned on by the above process, the CPU 106 outputs the second switching signal S2 as " low "in steps 214 to 216, 102).

Accordingly, only one necessary recording head corresponding to the image to be printed among the mono recording head 100 and the color recording head 102 becomes drivable.

Next, the CPU 106 performs the printing in step 218, and then checks in step 220 whether the printing of one line has been completed. At this time, if the printing of one line has not been completed, the CPU 106 prepares the next print in step 222 and then repeats the above step (200). If the printing of one line is finished, the CPU 106 prepares the next print in step 222, It is confirmed whether or not printing has been completed. At this time, if the printing has not been completed, the CPU 106 prepares the next line to be printed in step 226, and then repeats the above step (200).

By the above-described process, the CPU 106 selects only one necessary recording head to be printed between the mono recording head 100 and the color recording head 102 at the time of each recording head drive .

Therefore, even if only one driver is used, the double recording head can be driven to perform normal printing, so that the number of drivers and cables can be reduced as compared with the conventional one.

Although in the example of FIG. 2 described above, the CPU 106 selects one recording head among the mono recording head 100 and the color recording head 102 each time the recording head is driven, It may be selected. For example, if there is no need to print black and white and color mixed on one line, select each line.

Although the numbers of the nozzles of the mono recording head 100 and the color recording head 102 are the same in the example of FIG. 1, the numbers of the mono recording head and the color recording head are generally different from each other. That is, the number of nozzles of the mono recording head is larger than that of the color recording head. However, in this case, since the driving signal output terminal of the driver corresponding to the nozzles not included in the color recording head is not connected, no problem occurs in the operation of the present invention.

As described above, the present invention is advantageous in that the number of drivers and cables can be reduced by driving the dual recording heads with only one driver, thereby simplifying the configuration and reducing manufacturing costs.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Particularly, in the embodiment of the present invention, the ink jet printer is applied to a case where the mono recording head and the color recording head are provided in duplicate, but the same applies to the case where a larger number of recording heads are provided in multiple. In this case, the driving signal output terminal of the driver may be connected to the recording head to be added in common, and a switching unit may be additionally connected, and the program of the other CPU may be changed corresponding to the flow chart of FIG. Accordingly, the scope of the invention is not to be determined by the embodiments described, but should be determined by the scope of the appended claims and equivalents of the claims.

Claims (9)

A recording head driving circuit of an ink jet printer having nozzles for ejecting ink on a recording medium, the nozzles being driven by a corresponding driving signal input, each of the nozzles having a dual recording head, A driver for generating drive signals by selectively enabling the drive signals by a predetermined control, the drive signal output terminals being commonly connected to the corresponding nozzles of the print heads one by one, Switching means for interrupting supply of driving power to a corresponding recording head, and switching means for selectively driving only one recording head corresponding to an image to be printed among the recording heads through the switching means And drives the drive in correspondence with the selected recording head A recording head driving circuit comprising: a control means for start. 2. The recording head driving circuit according to claim 1, wherein the switching means intermittently controls driving power supply to the corresponding recording head among the recording heads by control of the control means. 3. The recording head driving circuit according to claim 2, wherein the control means selects one of the recording heads each time the recording head is driven. 3. The recording head driving circuit according to claim 2, wherein the control means selects among the recording heads for every line. The recording head driving circuit according to claim 3 or 4, wherein the double recording head comprises a recording head for monochrome printing and a recording head for color printing. A method of driving a recording head of an ink jet printer having a dual recording head and a single driver, comprising the steps of: selecting only one recording head corresponding to an image to be printed among the recording heads to supply driving power; And selectively driving the drive signals of the driver to correspond to an image to be printed and applying the common signals one by one to nozzles corresponding to the recording heads to drive only the selected recording head. Driving method. The recording head driving method according to claim 6, wherein the selection of the recording head is performed each time the recording head is driven. The recording head driving method according to claim 6, wherein the selection of the recording head is performed for every line. The recording head driving method according to claim 7, wherein the double recording head comprises a recording head for monochrome printing and a recording head for color printing.