JPH1086352A - Printer - Google Patents

Abstract

(57) Abstract: To reduce the access load to a drive data table that stores drive data for driving a drive element, and to reduce the cost of a printing apparatus. SOLUTION: A correction data register 2 for storing correction data set in advance for each driving element is provided, and correction data for each driving element is input to an addition circuit 3 together with image data. The drive data table 4 stores drive data corresponding to the addition result of the adder circuit 3. When the addition result is input to the data selector 5, the drive data corresponding to the addition result is selectively output. The drive circuit 8 is driven based on the drive data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printing apparatus such as an ink jet printer, and more particularly to a printing apparatus having a function of correcting variations in characteristics of driving elements for printing.

[0002]

2. Description of the Related Art Conventionally, in an ink-jet printer or the like, variations in driving characteristics (for example, variations in the volume of ejected ink droplets) occur in the driving elements of an ink chamber arranged corresponding to a plurality of orifices. Is generated, and there is a problem that the print quality is degraded if there is this variation. On the other hand, conventionally, there has been proposed an apparatus for performing printing by correcting variations in drive characteristics of drive elements. As a correction method, the print image data is corrected by drive data reflecting the drive characteristics of the drive elements, and it is necessary to provide a table for storing the drive data in the apparatus. The drive data includes data for correcting a variation in drive characteristics for each drive element and data for correcting a variation in drive characteristics for each group by grouping an appropriate number of drive elements.

[0003]

However, in the above-described conventional apparatus, it is necessary to provide a table for storing drive data for correcting print image data for each drive element or for each group of drive elements. There has been a problem that the cost increases and the access load is large as an apparatus system.

[0004]

In order to solve the above-mentioned problems, a printing apparatus according to the present invention is a printing apparatus that performs image printing by correcting image data in accordance with characteristics of a plurality of driving elements that perform image printing. A correction data register that holds correction data set according to the characteristics of the driving elements for each driving element, and calculates the correction data output from the correction data register and the image data to correspond to each driving element. An arithmetic circuit for outputting a selection signal and a drive data table for storing drive data according to the content of the selection signal in advance are provided.

According to the present invention having the above configuration, the image data is input to the arithmetic circuit together with the correction data output from the correction data register. The arithmetic circuit calculates image data and correction data and outputs a selection signal corresponding to each drive element. A selection signal corresponding to each drive element is input to a drive data table, and drive data corresponding to the selection signal is output from the drive data table. The drive element is driven by the drive data. By doing as described above, it is not necessary to provide a plurality of tables for storing drive data according to drive characteristic variations of the drive elements.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. Elements common to the drawings are assigned the same reference numerals. FIG. 1 is a block diagram showing an ink jet printer according to a first embodiment of the present invention. First
In the embodiment, an ink jet printer will be described as an example of a printing apparatus.

In FIG. 1, an ink jet printer 1
A correction data register 2 for storing driving correction data unique to each driving element set in accordance with a variation in driving characteristics of a driving element described later, and correction data from the correction data register 2 and image input data. An adder circuit 3 for inputting and adding, a driving data table 4 for storing driving data described later in advance, and a data selector 5 for outputting any one driving data to each driving element
Is provided. Further, a drive circuit 8 for driving each of the drive elements 7-1 to 7-n of the print head 6 by the output of the data selector 5 is provided.

FIG. 2 is a block diagram showing a data flow in the first embodiment, and shows a correction data register 2, an addition circuit 3, and an image input data buffer 9 for storing image input data. 2, the image input data buffer 9 stores image data sent from a higher-level device (not shown). As shown in FIG. 3, the image data is stored for each drive element 7, and is stored as 4-bit data "0" to "15". FIG. 3 is an explanatory diagram showing an image input data buffer. The correction data stored in the correction data register 2 is stored for each drive element, and the content is gray-scale data, as shown in FIG. 4, and is stored as 2-bit data "0" to "3". Is done. FIG. 4 is an explanatory diagram showing a correction data register.

The image data of the image input data buffer 9 and the correction data of the correction data register 2 are input to the addition circuit 3 for each driving element. The addition circuit 3 outputs the addition result as the first drive element drive TBLPTR to the n-th drive element drive TBLPTR for each drive element.

FIG. 5 is a block diagram showing a data flow in the first embodiment, and shows a drive data table 4, a data selector 5, a drive circuit 8, and a print head 6.
In FIG. 5, the driving data table 4 stores driving data corresponding to all possible addition results of the image data and the correction data in advance. FIG. 6 is an explanatory diagram showing a drive data table. As shown in FIG. 6, 19 types of values (INDEX) are used as drive data in the first embodiment.
, And two types of timing data (denoted by TIM1 and TIM2) are stored in accordance with the respective values.

The first drive element drive TBLPTR to the n-th drive element drive TBLPTR output from the adder circuit 3 are input to the data selector 5. The data selector 5 selects one of the first to nineteenth drive data output from the drive data table 4 based on the first drive element drive TBLPTR to the n-th drive element drive TBLPTR, and for each drive element. Output as drive data. Drive circuit 8
Drives the drive elements 7-1 to 7-n of the print head 6 based on the drive data input from the data selector 5.

Next, the operation of the first embodiment will be described.
In FIG. 2, when image data is transferred from a host device (not shown), the image data is temporarily stored in the image input data buffer 9 for each driving element. The image data corresponding to all the driving elements is input to the adding circuit 3 together with the correction data of the correction data register 2. The addition circuit 3 adds the image data and the correction data corresponding to each drive element. For example, taking the case of the third drive element as an example, as shown in FIGS. 3 and 4, the image data is “15” and the correction data is “3”, so the addition result is “18”.
As described above, the addition circuit 3 calculates the addition result as shown in FIG. 7 corresponding to all the driving elements, and outputs the result to the data selector 5 as the first driving element driving TBLPTR to the n-th driving element driving TBLPTR. FIG. 7 is an explanatory diagram showing an output result of the adding circuit 3. The addition circuit 3 is configured so that when the image data is “0” (do not print), the addition result is also “0”.

The data selector 5 calculates the sum of the driving elements (first driving element driving TBLPTR to n-th driving element driving T
Drive data is selected from the drive data table 4 for each drive element based on (BLPTR). For example, taking the case of the third drive element as an example, since the addition result of the third drive element is “18”, the corresponding timing data is TIM1 = “3” and TIM2 as shown in FIG. =
“6”. The data selector 5 outputs drive data (data of TIM1 and TIM2) of each selected drive element to the drive circuit 8. FIG. 8 shows an output result of the data selector 5.

The drive circuit 8 drives each of the drive elements 7-1 to 7-n based on the data of TIM1 and TIM2. That is, the value of the internal timer (not shown), which counts up with the internal clock (not shown), becomes high level at the next rise of the internal clock that matches the value of TIM1, and the value of the internal timer matches the value of TIM2 It goes low at the rise of the next internal clock. Taking the third drive element as an example, the timing data of the third drive element is TIM1 = “3” and TIM2 = “6”
Therefore, the drive level becomes high at the rise of the internal clock following the internal timer of "3", and becomes low at the rise of the internal clock following the internal timer of "6". This state is shown in FIG. FIG. 9 shows the first
10 is a time chart illustrating a drive timing of a third drive element according to the embodiment.

As described above, according to the first embodiment,
Since only one series of drive data tables corresponding to image data to be printed need be provided, it is possible to correct a variation in drive characteristics of each drive element without increasing an access load as an apparatus system. .

Next, a second embodiment of the present invention will be described. FIG. 10 is a block diagram showing a data flow in the second embodiment. In the second embodiment, a multiplying circuit is provided as an arithmetic circuit instead of the adding circuit of the first embodiment.

In FIG. 10, an image input data buffer 9 and a correction data register 2 are connected to a multiplying circuit 10, and image data of each drive element of the image input data buffer 9 and correction of each drive element of the correction data register 2 are provided. The data is input to the multiplication circuits 10, respectively. The multiplication circuit 10 multiplies the image data and the correction data for each driving element, and outputs the result as a first driving element driving TBLPTR to an n-th driving element driving TBLPTR for each driving element. Other configurations are the same as those of the first embodiment. That is, the image input data buffer 9 stores 4-bit data "0" to "1" for each drive element.
5 ", and the correction data is stored in the correction data register 2 as 2-bit data" 0 "to" 3 "for each drive element.
Is stored as Further, the drive data table 4 of the second embodiment stores drive data corresponding to all kinds of values (INDEX0 to INDEX19) of the multiplication result of the multiplication circuit 10 as shown in FIG. FIG. 11 is an explanatory diagram showing a driving data table.

Next, the operation of the second embodiment will be described with reference to the drawings of the first embodiment. In FIG. 2, when image data is transferred from a host device (not shown), the image data is temporarily stored in the image input data buffer 9 for each driving element. The image data corresponding to all the driving elements is input to the multiplication circuit 10 together with the correction data of the correction data register 2. The multiplication circuit 10 multiplies the image data and the correction data corresponding to each drive element. Here, the multiplication circuit 10 performs an operation represented by the following equation, where A is the image data and B is the correction data. That is, INT {(A) × (1+ (B) / 10)} (1) Note that INT represents an operation of rounding down decimal places.

For example, taking the case of the third drive element as an example, as shown in FIGS. 3 and 4, the image data is "15" and the correction data is "3". The multiplication result is “19”. FIG. 12 is an explanatory diagram showing an output result of the multiplication circuit. As described above, the multiplication circuit 10 calculates the multiplication results shown in FIG. 12 corresponding to all the driving elements, and outputs the results to the data selector 5 as the first driving element driving TBLPTR to the n-th driving element driving TBLPTR.

The data selector 5 calculates the addition result of each drive element (first drive element drive TBLPTR to n-th drive element drive T
Drive data is selected from the drive data table 4 for each drive element based on (BLPTR). Taking the case of the third drive element as an example, since the addition result of the third drive element is “19”, the corresponding timing data is TIM1 = “3” and TIM2 as shown in FIG.
= “6”. The data selector 5 outputs drive data (data of TIM1 and TIM2) of each selected drive element to the drive circuit 8. The output result of the data selector 5 is the same as that of the first embodiment shown in FIG.

The drive circuit 8 drives each of the drive elements 7-1 to 7-n based on the data of TIM1 and TIM2. As in the first embodiment, the value of an internal timer (not shown) that counts up with an internal clock (not shown) is:
At the next rise of the internal clock that matches the value of TIM1, the drive circuit 8 goes high, and the value of the internal timer becomes TI.
It goes low at the next rise of the internal clock that matches the value of M2. Taking the third drive element as an example,
The timing data of the third drive element is TIM1 = “3”
Since TIM2 = “6”, as shown in FIG.
The drive level becomes high at the rise of the internal clock following the internal timer of "3", and becomes low at the rise of the internal clock following the internal timer of "6".

As described above, according to the second embodiment,
Even if a multiplying circuit is used as the arithmetic circuit, the same effect as in the first embodiment using the adding circuit can be obtained.

In each of the above embodiments, an ink jet printer has been described as an example of a printing apparatus. However, the present invention is not limited to an ink jet printer. For example, an electrophotographic printer using an LED (light emitting diode) as a head may be used. It is also applicable to thermal printers.

[0024]

As described in detail above, according to the present invention, only one drive data table for storing drive data is provided, image data and correction data are calculated, and the drive data table is calculated based on the result. Since the corresponding drive data is selected, the access load to the drive data table is reduced, and the cost of the apparatus is expected to be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an inkjet printer according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a flow of data according to the first embodiment.

FIG. 3 is an explanatory diagram showing an image input data buffer.

FIG. 4 is an explanatory diagram showing a correction data register.

FIG. 5 is a block diagram showing a data flow in the first embodiment.

FIG. 6 is an explanatory diagram showing a driving data table.

FIG. 7 is an explanatory diagram showing an output result of an adding circuit.

FIG. 8 is an explanatory diagram showing an output result of a data selector.

FIG. 9 is a time chart showing drive timing in the first embodiment.

FIG. 10 is a block diagram illustrating a data flow according to the second embodiment.

FIG. 11 is an explanatory diagram showing a driving data table.

FIG. 12 is an explanatory diagram showing an output result of the multiplication circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet printer 2 Correction data register 3 Addition circuit 4 Drive data table 5 Data selector 7 Drive element

Claims (4)

[Claims] 1. A printing apparatus for performing image printing by correcting image data according to characteristics of a plurality of driving elements for performing image printing, wherein correction data set according to the characteristics of the driving elements is applied to each driving element. A correction data register to be held; a calculation circuit that calculates the correction data output from the correction data register and the image data to output a selection signal corresponding to each drive element; A driving data table for storing the driving data in advance. 2. The printing apparatus according to claim 1, wherein the arithmetic circuit is an addition circuit that adds the correction data and the image data. 3. The printing apparatus according to claim 1, wherein the arithmetic circuit includes a multiplication circuit that multiplies the correction data and the image data. 4. The printing apparatus according to claim 1, wherein said image data is gradation data.