JPH05309838A - Dot positional shift correction device in ink jet printer - Google Patents

Abstract

(57) [Abstract] [Purpose] To correct dot position deviation caused by each traveling direction accurately, easily and at low cost. [Structure] Print data for one round trip of a recording head before printing is input from a control unit 8 to a memory 1 in advance, and when actual printing is performed with a slight time delay, a position signal is output from a direction determination unit 2. It is input to the correction unit 3 and the traveling motor 4. In the correction unit 3, the position signal of the pulse signal is sequentially counted by the address counter 31 and corresponds to the regular address.
This regular address is an address corrector 32 depending on the traveling direction.
Is corrected by a predetermined address to become a corrected address. The print data in the memory 1 is read out according to the normal and correction addresses, and the drive circuit 33 is read based on the print data.
Each nozzle of the recording head 6 is driven via the to print.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing head driven by a motor between each dot which should be printed at the same running position through each nozzle in either forward or backward travel direction. The dot misalignment of the ink jet printer corrects the misalignment caused by each traveling direction mainly due to the misalignment factors due to the traveling direction, such as the play gap on the traveling transmission mechanism, and the correction is accurate and easy. The present invention relates to a correction device.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording head (hereinafter referred to as a recording head) mounted on an ink jet printer and driven and driven by a motor through a transmission mechanism such as a gear, a belt or a wire, has a nozzle through each nozzle. The dots should be printed at the same traveling position originally in both the forward and backward traveling directions. In reality, however, there is a misalignment between these dots due to the traveling direction, such as play on the traveling transmission mechanism. Positional deviations occur in each traveling direction due to factors.

As a method for correcting this displacement, as disclosed in Japanese Patent Laid-Open Nos. 56-148571 and 58-87064,
It has been proposed to provide a timing delay for correcting the positional deviation between the signal related to the traveling position of the recording head and the applied signal related to ink ejection. A method based on a delay circuit using a shift register is used for this timing delay.

[0004]

The conventional method requires a delay circuit for setting a correction amount related to print dot position deviation, and requires a clock signal faster than the ink ejection timing for fine correction. To do. Moreover, the delay circuit must be provided for each nozzle. Therefore, there is a possibility that the circuit and the operation become complicated, the cost increases, and the reliability decreases. If the delay circuit is configured in an analog manner, errors will occur due to changes in temperature and aging, making recorrection difficult and troublesome.

An object of the present invention is to solve the above problems of the prior art and to accurately and easily correct the dot position deviation caused by each traveling direction.
An object of the present invention is to provide a dot position deviation correction device for a printer.

[0006]

According to another aspect of the present invention, there is provided a dot misregistration correction device for an ink jet printer, wherein each nozzle is provided with a nozzle regardless of whether the ink jet recording head, which is driven by a motor, travels in either the forward or backward direction. Between each dot to be originally printed at the same running position through, a device for correcting the positional deviation caused by each running direction, dot printing when each nozzle is located at each running position, A memory for temporarily storing print data indicating whether or not to print at each of the nozzles at an address corresponding to each of the traveling positions before printing; from this memory at the time of printing, from each regular address for printing, The print data of the corrected address is selected by moving by a predetermined address determined according to the traveling direction related to the printing, and the ink jet recording is performed. It comprises; a correction unit to be transferred to the head.

According to a second aspect of the present invention, there is provided an ink jet printer dot position correction apparatus, wherein the correction section selects the print data of the correction address only when the correction unit is in a predetermined direction in each traveling direction. Forward.

[0008]

According to the dot position deviation correcting device for an ink jet printer according to the first or second aspect, the print data for each nozzle is temporarily stored in the memory at an address corresponding to each running position before printing. At the time of printing, the print data of the corrected address is selected from this memory by the correction unit by moving from each of the regular print addresses by a predetermined address that is determined according to the traveling direction of the print. And the dot position deviation is corrected.

Particularly, in the dot position deviation correcting device for an ink jet printer according to a second aspect, the correction unit selects and transfers the print data of the correction address only at one predetermined time in each traveling direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a dot position deviation correcting device for an ink jet printer according to the present invention will be described below with reference to the drawings. The configuration around the recording head will be described with reference to FIG. FIG. 4 is a perspective view of the periphery of the recording head common to the embodiment and the conventional example. In FIG. 4, a carriage 5 is guided by a guide shaft 16 and a guide rail 17 so as to be able to move straight in the traveling direction X, and is driven via a traveling motor, wires and the like (not shown). A recording head 6 is mounted on the carriage 5 via a frame 14. A plain paper serving as a recording medium 19 is fed in the Y direction by a cylindrical platen 18 in close proximity to a nozzle that opens on the surface on the other side of the recording head 6.

FIG. 1 is a block diagram of the embodiment. In the figure, a memory 1 temporarily stores print data for one round trip before printing, as will be described later in detail. The print data represents whether or not each nozzle prints dots at each running position, and is input from the control unit 8 based on a print command from the input unit 7. The direction determination unit 2 determines the traveling direction of the recording head 6 based on the position signal output from the control unit 8. As will be described later in detail, the correction unit 3 moves the corrected print data from the memory 1 by moving from the regular addresses for printing by a predetermined address determined according to the traveling direction of the printing from the memory 1. It is selected and transferred to the recording head 6. A position signal, which is a pulse signal, is sent to the traveling (pulse) motor 4 to drive the carriage 5 carrying the recording head 6 via a transmission mechanism such as a wire (not shown).

Returning to the correction section 3, its internal structure will be described. The address counter 31 counts the position signals of the pulse signals output from the control unit 8 and sequentially obtains corresponding addresses (see FIG. 3, which will be described later).
The signal is reset to zero by a reset signal output when each traveling on the return path is completed. The address corrector 32, which will be described in detail later, corrects the address when necessary based on the direction signal of the direction discriminator 2. The drive circuit 33 drives the piezoelectric element corresponding to each nozzle of the recording head 6, that is, applies a drive voltage to the piezoelectric element based on the data regarding the presence or absence of printing of each nozzle output from the memory 1.

As shown in the nozzle layout diagram of the recording head of FIG. 2, the respective nozzles of the recording head 6 are arranged side by side in a row, and the symbols A, B, C, ... H are attached in order from the top. The nozzles may be arranged in two rows in a zigzag manner, but here, in order to simplify the explanation, they are arranged in one row. FIG. 3 is a block diagram of the memory, in which a vertical column for reference to each nozzle and a horizontal column for an address corresponding to each traveling position are provided, and print data indicating the presence or absence of printing at vertical and horizontal intersections ( The code) is stored as, for example, existence = 1, existence = 0. Now, let us say that the left end of the travel range of the recording head 6 in FIG. 4 is the start point, the right end is the end point, the travel direction from the start point to the end point is the outbound path, and the opposite travel direction is the inbound path. .., i.DELTA., I.DELTA., N.DELTA. (.DELTA .: minute unit distance) taken from the starting point in the forward direction in correspondence with the traveling positions of addresses 1, 2, 3 ,. , ..., N are defined. Speaking of the order, the rotational position of the motor 4 is sequentially α, 2α, 3α, ..., Iα, ..., Nα from the origin by the position signal of the control unit 8.
(Α: minute unit angle), the running position of the recording head 6 sequentially moves to Δ, 2Δ, 3Δ, ..., iΔ, ..., nΔ, and in synchronization with this, the corresponding address in FIG. Sequentially proceed to 1, 2, 3, ..., I, ..., N, and print at each running position based on the print data at that address.
You can decide whether or not to do it. The address is advanced in the order of 1, 2, 3, ... In the forward path, and in the reverse order in the return path.

The operation of the embodiment will be described with reference to FIGS. In FIG. 1, based on a print command from the input unit 7, the control unit 8 inputs print data (broken line display) for one round trip of the recording head 6 before printing to the memory 1 in advance, and on the other hand, Then, when actually printing with a slight delay in time, the position signal of the solid line in the form of a pulse signal is the address counter 31 of the direction discriminating unit 2 and the correcting unit 3.
Are input to the traveling motor 4. The direction determining unit 2 determines the traveling direction of the recording head 6 based on the position signal. In the correction unit 3, by the address counter 31,
A pulse signal, which is a position signal, is counted, and this count value corresponds to the traveling position and determines the regular address of the print data to be called from the memory 1. The regular address is corrected by the address corrector 32 by a predetermined address according to the traveling direction, as described in detail below.

For example, suppose that the recording head 6 travels through the traveling motor 4 and prints at the traveling position i.DELTA. On the outward path, and when print data is input so as to print at the same traveling position i.DELTA. On the outward path, Actual print position is (i + 3)
It is assumed that Δ has occurred, and the positional deviation has occurred to the right by 3Δ from the printing position in the reference forward path. The motor 4 itself does not cause rotational displacement in the forward and backward passes, but the positional shift caused by the recording head 6 is caused by the play between the gears and the wire transmission mechanism between the motor 4 and the recording head 6 during the backward pass. It is caused by mechanical factors such as. To correct this to zero, on the return path, instead of the regular address i determined by the position signal output from the control unit 8,
The print data of the address (i + 3) corrected rightward by 3 may be sequentially selected and transferred to the recording head 6. In other words, on the return path, the print timing is delayed by the travel time of the travel distance 3Δ, that is, the movement time of the address correction amount 3, so that the print position is made to match the print position on the outward path.

Therefore, there is no correction when the vehicle is traveling forward, and the address output from the address corrector 32 remains (i) output from the address counter 31, and is corrected by (+3) addresses when returning. The correction address output from the address corrector 32 is (i + 3). The print data is read from the memory 1 based on the correction address output from the address corrector 32. The print data read from the memory 1 is converted into a voltage signal to be applied to the piezoelectric element corresponding to each nozzle of the recording head 6 via the drive circuit 33 and is sent to the recording head 6.
In synchronization with this voltage signal, the carriage 5 on which the recording head 6 is mounted is moved and positioned by the motor 4 which receives the position signal from the control unit 8. Therefore, the positional deviation of print dots based on the forward and backward travel directions is performed. Is corrected. When the printing for one reciprocation is completed in this way, the address counter 31 is reset by the reset signal from the control unit 8 so that it is ready for the next one reciprocation.

The operation of the above embodiment will be explained again by organizing it based on the following flow chart. FIG. 5 is a flowchart showing the former stage of the operation, and FIG. 6 is a flowchart showing the latter stage of the operation. In the following description, the reference numerals assigned to the respective names are the same as those in FIG. In FIG. 5, in step S1, print data for one round trip to be printed next is stored in the memory 1. Hereinafter, steps S2 to S7 correspond to the forward printing run. In step S2, the counter i is initialized. This counter i is a counter that represents the cumulative value of the pulse signals of the position signal, that is, the (rotational) position of the traveling motor 4, and is also the address of the print data in the memory 1. In step S3, the rotational position Θi of M (motor 4) is determined, and in synchronization with this, step S4
The reading of the print data at the address i from the memory 1 and the ink ejection from each nozzle, that is, the print Ji based on the print data in the next step S5 are performed. The procedure of the above steps S3 to S5 is repeated through the following steps S6 and S7 until i = n. Where n is i
Is the final value of (the final rotational position of the motor M).

The following steps S8 to S13 correspond to the printing run on the return path. In step S8, initialization i = n is performed, and in step S9, the rotational position Θi of the motor M is determined. In synchronism with this, the print data of the correction address (i + a) is read from the memory 1 in step S10, In the next step S11, ink ejection from each nozzle, that is, printing Ji is performed based on the print data. Here, a is the address correction amount, which is +3 in the above description. When (i + a) exceeds n in step S10, there is no print data at the corresponding address, so that printing Ji in step S11 is naturally not performed. The above steps S9 to S11 are repeated through steps S12 and S13 until i = 1. After that, based on the judgment of the end / continuation of printing in step S14, if the printing is completed, the operation is ended, and if the printing is continued, the process returns to step S1, and the print data for the next one round trip is stored in the memory 1. The same is repeated.

[0019]

According to the dot position deviation correction device for an ink jet printer of the first or second aspect, the print data for each nozzle is temporarily stored in the memory at an address corresponding to each running position before printing. At the time of printing, the printing data of the corrected address is selected from this memory by the correction unit by moving by a predetermined address determined from the regular printing address according to the traveling direction of the printing. It is transferred to the recording head and the dot position deviation is corrected. Therefore, compared to the case of the delay circuit using the shift register, the circuit and operation are simplified, and the printing quality is improved, the reliability is improved, and the cost is reduced.

Particularly, in the dot position deviation correction device for an ink jet printer according to the second aspect, the correction unit selects and transfers the print data of the correction address only at a predetermined one of the running directions. Therefore, in terms of circuit,
It is operationally simpler and supports improved reliability and lower costs.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment according to the present invention.

FIG. 2 is a nozzle layout diagram of the recording head in the embodiment.

FIG. 3 is a configuration diagram of a memory according to an embodiment.

FIG. 4 is a perspective view around a recording head common to an example and a conventional example.

FIG. 5 is a flowchart showing the first stage of the operation of the embodiment.

FIG. 6 is a flowchart showing the latter stage of the operation of the embodiment.

[Explanation of symbols]

 1 Memory 2 Direction Discrimination Unit 3 Correction Unit 4 Motor 5 Carriage 6 Recording Head 7 Input Unit 8 Control Unit 31 Address Counter 32 Address Corrector 33 Drive Circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41J 2/51 9012-2C B41J 3/04 104 G 9211-2C 3/10 101 J

Claims (2)

[Claims] 1. In each of the forward and backward traveling directions of an ink jet recording head driven by a motor, the respective traveling directions are provided between dots which should be printed at the originally same traveling position through each nozzle. A device that corrects the positional deviation caused by, wherein print data indicating whether or not to perform dot printing when each of the nozzles is located at each of the traveling positions is provided with an address corresponding to each of the traveling positions of each of the nozzles. And a memory that is temporarily stored before printing at the location of; from this memory when printing, an address corrected by moving from each regular address for printing by a predetermined address that is determined according to the traveling direction related to printing And a correction unit that selects the print data of the print data and transfers the print data to the inkjet printhead. Positional deviation correction device. 2. The dot position of an ink jet printer according to claim 1, wherein the correction section selects and transfers the print data of the correction address only at one predetermined time in each traveling direction. Deviation correction device.