JP2003312038A - Controller of print head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a controller of a print head for use in a printer wherein the volume of data being transmitted is reduced and print data can be processed efficiently. <P>SOLUTION: The controller of a print head comprises a shift register 22 receiving print data, and a plurality of registers 23 and 24 for latching data from the shift register 22 wherein data (HDATA) including a line of shift is latched in the plurality of registers, the data (HDATA) latched based on data of a preset shift is read out from the register 23 or 24 and then print processing having an inclination for correcting the shift is performed. With such an arrangement, the number of times for transferring the data to the register is decreased and efficient print processing is ensured. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, and more particularly to a print head controller.

[0002]

2. Description of the Related Art Today, personal computers have become widespread, and a personal computer is used as a host device to directly connect a printer or a LAN (local area.
Network) and the like, and a printer is connected to the network to perform print processing.

In such a printing apparatus, a so-called LED printer using an LED element for a print head is LE
The printing position may be displaced due to uneven arrangement of the LED chips on which the D element is formed. Such a print position shift adversely affects the print result.

Further, not only the arrangement unevenness of the LED chips but also the arrangement displacement of the image forming unit such as the developing unit and the drum unit causes the displacement of the printing position. Therefore, the printing position shift is conventionally adjusted by the following method. FIG. 10 is a block diagram of a conventional print head controller. In the figure, a conventional print head control device includes a shift register 50, a register 51, and a driver 5.
It is composed of two and many LED elements. Data (HDATA) is serially input to the shift register 50 in synchronization with the clock signal (HCLK), and the data is held. As will be described later, the shift register 5
The data held in 0 is 1 / N (line) data when one line of data is divided into N.

The 1 / N line data held in the shift register 50 is transferred to the register 51 in synchronization with the latch signal (RATCH). At this time, the register 51 has already been
The previous data latched by the LED is output to the driver 52 and synchronized with the strobe signal (STROB).
It is output to the element and drives the LED element.

In the above conventional circuit configuration, the print misregistration correction is performed as described with reference to FIG. The example shown in the figure is a correction example in the case where a print shift that is leftward and downward in the sub-scanning direction occurs due to a displacement of the LED chips and the like. In this case, in order to correct the printing deviation in the left-down direction, the printing data in the down-right direction shown in FIG.

That is, the data of the first 1/4 line of the first line shown in is the data of "line c-line b-line b-line b-line b-line a", and this data (HDATA ) Is the shift register 5 first
It is supplied to 0 and held. Next, the 2/4 line data “line c-line c-line b-line b-line b-line b” of the first line shown in is supplied to the shift register 50. At this time, the data held in the shift register 50 is transferred to the register 51.

Similarly, the data "line c-line c-line c-line b-" of the 3 / 4th line shown below is obtained.
When "line b-line b" is supplied, the data held in the shift register 50 is transferred to the register 51, and the data latched in the register 51 at this time is transferred to the driver 52.

Thereafter, similarly, the data shown in FIG. 11 is sequentially supplied to the shift register 50, and the LED elements are driven according to the data output from the driver 52. By performing the processing as described above, the LED element emits light, and the printing misalignment in the lower left direction can be corrected.

[0010]

However, in the above-mentioned conventional example, since printing for one line is performed by four times of light emission,
The number of times data is supplied to the print head (shift register 50) is four. That is, since the print data is shifted and printed every 1/4 line, the number of times of supplying data to the print head is required to be four. Therefore, in the example of 1 line divided into N, the number of times of supplying data to the print head is N since the printing for one line is performed by N times of light emission. Therefore, in the conventional print head control device, the number of times print data is transmitted increases, and high-speed printing processing cannot be performed.

Therefore, in order to solve the above problems, the present invention provides a print head control device that reduces the number of times of supplying data to be transmitted and corrects print misalignment by transmitting the data a smaller number of times.

[0012]

According to the first aspect of the present invention, the above-mentioned problem is solved by the first aspect of holding the print data of the first line.
Holding means for holding the print data of the second line following the print data of the first line,
Based on the information of the print deviation amount, the print data is read from the first holding unit or the second holding unit for each pixel, and a print data selecting unit that outputs the print data is selected and output by the selecting unit. This can be achieved by providing a control device for a print head having a light emitting element that irradiates a photosensitive surface with light according to the print data.

Here, the first holding means and the second holding means are registers, for example, which convert the print data output from the host device into bitmap data and transfer the converted data to the shift register. After that, for example, they are sequentially held in the registers. Further, the print data held in the register is selectively output to the exposure element by a selector, which is a selector, for example. Here, the selection unit is information corresponding to the information of the print deviation amount, and the print data corresponding to the deviation amount is selected from the first holding unit or the second holding unit according to this information.

With such a configuration, the print data selected and output by the selection unit is emitted by the light emitting element, and the light emitting process for correcting the print deviation amount is performed on the photosensitive surface to correct the print deviation. You can According to a second aspect, in the invention according to the first aspect, the information on the print deviation amount is stored in advance in the storage means, and the selection processing of the selection means is performed according to the information on the print deviation amount stored in the storage means. Is a configuration for executing.

Here, the information on the above-mentioned print deviation amount is measured in advance by, for example, test printing, and stored in the storage means. With this configuration, the print misregistration can be corrected more efficiently. According to a third aspect, in the first or second aspect, the print data is, for example, bitmap data.

Further, the description of claim 4 is based on the above-mentioned claim 1,
In the description of 2 or 3, the print data is print data for one line divided into N. Therefore, 1 line 2
Division, 1 line 4 divisions, 1 line 8 divisions, etc., and each division number corresponds to the gradation value of the print data.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a schematic configuration diagram of a color printer including a print head controller according to the present embodiment. In FIG. 1, the printer device 1 is a so-called tandem type color printer, and includes a paper supply / conveyance mechanism 2, an image forming unit 3, and a control unit 4. The sheet supply / conveyance mechanism 2 includes a sheet feed cassette 5 in which sheets are stacked and stored, a standby roll pair 6, a sheet conveyance belt 7, a drive roll 8 and a driven roll 9, and the like, and is discharged from the sheet feed cassette 5. The sheet is guided to the conveyance path and reaches the standby roll pair 6.
The sheet that has reached the pair of standby rolls 6 is further conveyed onto the conveyance belt 7 at the timing when the transfer position matches the toner image.

The paper carried out to the paper carrying belt 7 is the image forming units 10, 11, 1 constituting the image forming unit 3.
An image forming process is performed by 2 and 13, and a heat fixing process is performed by the fixing device 14. The image forming unit 3 is arranged in the order of magenta (M), cyan (C), yellow (Y), and black (K), and transfers the toner of the corresponding color onto the paper. Further, magenta (M), cyan (C), and yellow (Y) are image forming units that perform color printing by subtractive color mixing, and the black (K) image forming unit 1
3 is used for monochrome printing.

Further, each of the above image forming units 10 to 13
Have the same configuration except for the toner (of which color) is stored in the developing container.
The head, the developing device, and the transfer device are sequentially arranged. For example, when the above configuration is described using the black (K) image forming unit 13, the peripheral surface of the photosensitive drum 15 is made of, for example, an organic photoconductive material, and the peripheral surface of the photosensitive drum 15 is close to the peripheral surface. Is a charger 16, an LED head 17,
A developing device 18 (developing roll 18 ') and a transfer device 19 are sequentially arranged.

The photoconductor drum 15 rotates in the direction of the arrow, and first the charge is applied from the charger 16 to cause the photoconductor drum 15 to move.
The peripheral surface of is uniformly charged. Next, an electrostatic latent image is formed on the peripheral surface of the photoconductor drum 15 by optical writing based on the print information from the print head 17, and a toner image is formed by the developing process by the developing roll 18 '. At this time, the toner image formed on the peripheral surface of the photosensitive drum 15 is formed by the black (K) toner contained in the developing container 18. The toner image thus formed on the peripheral surface of the photoconductor drum 15 reaches the transfer position with the rotation of the photoconductor drum 15 in the direction of the arrow as described above, and is transferred onto the conveyor belt 7 by the transfer device 19. It is transported and transferred to paper.

The fixing device 14 is composed of a heat roll 14a and a pressure contact roll 14b. While the paper is nipped and conveyed between the heat roll 14a and the pressure contact roll 14b, for example, color toners of plural colors transferred to the paper are melted. And heat-fix on the paper,
It is carried out of the aircraft. On the other hand, the control unit 4 is composed of an interface (I / F) controller, a printer controller, etc., and is a personal computer (P
C) The print data output from 20 is supplied. The print data output from the personal computer (PC) is converted into bitmap data corresponding to the designated character font by the I / F controller (control unit 4) and output to the head controller 21. Then, the print data output to the head controller 21 is
It is supplied to the print heads 17 arranged in the corresponding image forming units 10 to 13.

FIG. 2 is a structural example of the print head 17. The print head 17 includes a shift register 22 and a register 2
3a, 23b, a selector 25, and a driver 26. Data supplied from the control unit 4 (HDATA)
Is input to the shift register 22 in synchronization with the clock signal (HCLK). The shift register 22 is a serial-in / parallel-out type shift register,
The inside of the shift register 22 is sequentially shifted from the left side to the right side of the drawing, and one line of data (H
DATA) is retained.

The registers 23a and 23b are two-stage registers and are synchronized with the latch signal (RATCH).
First, the data (HDAT) held in the shift register 22
A) is latched in the register 23b. The data (HDATA) latched in the register 23b is transferred to the register 23a and latched in synchronization with the next latch signal (RATCH). That is, continuous data for driving the same LED element is sequentially latched in the registers 23a and 23b.

The data (HDATA) latched in the registers 23a and 23b is output to the selector 25, and one of the data is selected by the selector 25. FIG. 3A is a diagram for explaining the configuration of the selector 25, and FIG. 3B is a truth table thereof. Selector 25
Is composed of a line selection unit 25a and a data selection unit 25b. Information on the print deviation amount is supplied from the register Rs to the line selection unit 25a and registered. The information about the print misregistration amount registered in the register Rs is data registered in advance according to a control signal (not shown).

The output of the line selection unit 25a changes according to the timing of the print head, and LSL0 to LSL3 are output at the timing shown in FIG. The data selection unit 25b selects the output of the register 23a or the output of the register 23b in accordance with the print deviation amount data registered in advance in the register Rs.

For example, when "0" is set in the register Rs as the shift amount as shown in the truth table of FIG. 6B, the data selecting section 25b causes the data selecting section 25b to have 1/4 lines to 4/4 lines.
In any of the four lines, the output (B) of the register 23b is selected. Further, for example, when “1” is set as the shift amount in the register Rs, the data selection unit 25
b selects the output (A) of the register 23a in the 1/4 line, and in the 2/4 line to 4/4 line,
The output (B) of the register 23b is selected.

If "2" is set as the shift amount in the register Rs, the data selection unit 25b sets 1
The output (A) of the register 23a is selected on the / 4 line and the 2/4 line, and the output (B) of the register 23b is selected on the 3/4 line and the 4/4 line.

Further, when "3" is set in the register Rs as the shift amount, the data selecting section 25b selects the output (A) of the register 23a in the 1/4 line to the 3/4 line to select 4 / Register 23 in 4 lines
Select the output (B) of b. The data selected by the selector 25 is output to the driver 26 and output to the corresponding LED element in synchronization with the strobe signal (STROB). Further, the data supplied to the LED element is the data converted into the bitmap data by the control unit 4 described above, and is 1: 1 with respect to the print position on the paper.
The light emitted from the LED element is applied to the photosensitive surface of the photoconductor drum 15 and is printed on the paper by transfer and fixing processing according to the above-described process.

A specific example will be described below with reference to FIGS. First, as described above, the print deviation amount data is registered in the register Rs using a control signal (not shown). The data of the print misregistration amount is, for example, a value measured in advance by test printing or the like, and the data registered in this way is "0", "1",
These are “2”, “3”, “0”, and “1”.

The shift register 22 and the registers 23a and 23b have the same data (HDA) as shown in FIG.
TA) is held or latched. For example, the shift register 22 holds data of "line d-line d-line d-line d-line c-line c", and the register 23b holds "line c-line c-line c-line c-line". b-line b "data is latched,
The register 23a stores "line b-line b-line b-
The data of "line b-line a-line a" are latched.

Shift register 22 and register 23a,
When the above setting is made in 23b, the line selection unit 25
The line is designated from a. That is, the line selection unit 25a outputs a line selection signal and outputs LSL0 to LSL3. In this case, the selector 25 to which the shift amount "0" is set selects the data in the register 23b as described above. Therefore, in this case, the output (B) of the register 23b, that is, the data of the line c is selected from FIG.
The data of the line c is continuously output from 1/4 line to 4/4 line (shown in (b) of the same figure).

On the other hand, in the selector 25 in which the shift amount "1" is set, the register 23 is set for the first 1/4 line.
The output (A) of a is selected, and the output (B) of the register 23b is selected for the next 2/4 line to 4/4 line.
Therefore, in this case, for the corresponding LED element, as shown in (b) of the same figure, the data of the line b is output in the first 1/4 line, and the next 2/4 to 4/4 lines are output. , The data of line c is output ((b) of the same figure)
Shown in).

In the selector 25 to which the shift amount "2" is set, the output (A) of the register 23a is selected for the first 1/4 line and the 2/4 line, and the next 3/4 line is selected.
The output (B) of the register 23b is selected for the line and the 4/4 line. Therefore, in this case, the data of the line b is output for the first 1/4 line and the 2/4 line to the corresponding LED element, and the data of the line c is output for the next 3/4 line and the 4/4 line. Is output (shown in (b) of the same figure).

The same applies to the following items (1) to (4) of FIG. 4, and the selector 25 performs the selection process corresponding to the information of the print deviation amount and outputs the data of the register 23a or 23b. By processing as described above, the print data for one line is output to the LED element for each 1/4 line, and the data (HDA
TA) is data sequentially selected by the selector 25. That is, the data latched in the register 23a or 23b by the selector 25 is selected and output without the new data (HDATA) being supplied to the shift register 22.

That is, 1 for the shift register 22.
/ 4 without using the data transferred every line
Selects the data latched by the selector 25, and
It is possible to control the light emission of the ED element. Meanwhile, the new one
When performing line printing processing, the shift register 22
Then, the data (HDATA) of the next line is input. The example shown in FIG. 5 is this example. As shown in FIG. 5A, new data (HDAT) is stored in the shift register 22.
A) is input and held as "line e-line e-line e-line e-line d-line d".

The register 23b stores the data "line d-line d-" held in the shift register 22.
"Line d-line d-line c-line c" is latched, and the data "line c-line c-line c-line c" held in the register 23b is stored in the register 23a.
-Line b-Line b "is latched.

Therefore, in this state, the selector 25 is driven in the same manner as described above to perform the printing process according to the information on the print misregistration amount. FIG. 18B shows this result. For example, in the selector 25 in which the shift amount “0” is set, the data in the register 23b is selected as described above, and the register 23b is selected.
The data of the line d latched in the line is continuously output (shown in FIG. 7B). Further, the selector 25 to which the shift amount “1” is set outputs the data of the line c for the first 1/4 line and the data of the line d for the 2/4 line to 4/4 line.

The same applies to the following, and outputs the data (1) to (4) shown in the same figure to the corresponding LED element. By the above processing, light emission / non-light emission data is output to the LED element for each 1/4 line for the second line as well, but during this period, the data output to the LED element is the data sequentially selected by the selector 25 and the shift is performed. Register 22
The print misregistration can be corrected without supplying the data for each 1/4 line. Therefore, during this period, new data (H
DATA) transfer processing is not performed.

As described above, according to the present invention, a new data (HD
It is possible to perform correction processing for print misalignment by the selection processing of the selector 25 without supplying (ATA).
The number of data transfers can be reduced.

Therefore, in the present embodiment, the plurality of registers 23a and 23b are used, and the selector 25 selects the output of the register 23a or 23b based on the preset deviation amount and supplies it to the LED element. It is possible to provide a print head control device capable of reducing the number of times of data transfer to the print head and correcting print deviation. <Second Embodiment> Next, a second embodiment of the present invention will be described.

This example is an invention for correcting a print position deviation due to a variation in the arrangement interval of LED chips. For example, LED chips in which a large number of LED elements (for example, 256 LED elements) are arranged are formed on a substrate at regular intervals. However, as shown in FIG.
There may be a deviation in the arrangement interval of the D chips.

For example, FIG. 3A shows the LED chip 30.
This is a case where the arrangement intervals of 31 and 31 are narrow, and FIG.
This is the case where the disposition interval between the D chips 32 and 33 is wide. In the case of FIG. 3A, since the arrangement interval of the LED chips 30 and 31 is narrow, the LED element 30-n formed at the end of the LED chip 30 and the LED formed at the end of the LED chip 31.
The pitch (P) with the element 31-1 is a predetermined pitch interval p.
It becomes narrower, for example, P-. On the other hand, in the case of FIG. 2B, since the LED chips 32 and 33 are arranged at large intervals,
LED element 32-n formed at the outermost end of the D chip 32 and LED element 33-formed at the outermost end of the LED chip 33-
The pitch (P) with 1 is wider than the predetermined pitch interval p,
For example, P +.

Therefore, in the case of FIG. 7A, when the LED elements are driven and the LED elements 30-n and 31-1 emit light, the pitch interval between both LED elements is narrow, and therefore both LED elements emit light. A receiving area occurs along the sub-scanning direction, and a black streak is formed as shown in FIG. On the other hand, in the case of FIG. 6B, since the pitch interval between both LED elements is wide, a region where light emitted from both LED elements is not received occurs along the sub-scanning direction, and white stripes are generated as shown in FIG. Is formed. As described above, the formation of the black stripes and the white stripes causes deterioration of the image quality in any case. Therefore, in this example, the LED elements are divided and formed in the main scanning direction to perform print control. The details will be described below.

FIG. 7 shows an example of using the LED element of this example. In this example, the LED element is divided into two in the main scanning direction, and 40a
And 40b. In this case, the LED elements 40a, 40
When the same data is supplied to b to emit light, the received light amounts become the received light amounts 41a and 41b shown in FIG.
The total amount of received light is the amount of received light 41 shown in FIG. In this case, the amount of light received exceeding the threshold value T contributes to image formation.

On the other hand, FIG. 8 shows the case where the amount of light emitted from the divided LED elements is set to be weak, and weak light is emitted from one of the divided LED elements 42a and the other LED element is formed.
Strong light is emitted from the element 42b. By controlling the light emission in this way, the amount of light received on the photosensitive surface becomes the amount of light received 43a, 43b shown in FIG. In this case, the total amount of light received on the photosensitive surface is the amount of light received 43 shown in FIG. 8B, and the balance of the amount of light received can be shifted to the right with respect to the paper surface of FIG.

Therefore, such control is performed by the above-mentioned LE.
By performing the operation between the D elements 30-n and 31-1, it is possible to prevent the occurrence of the above-described black stripes and white stripes. For example, FIG. 9 shows an example in which the above processing is performed to prevent the generation of black stripes and white stripes. For example, in the case of FIG. 7C, this is an example in which the print position is shifted to the right as shown in FIG. On the other hand, in the case of FIG. 6D, in order to prevent the occurrence of white stripes, the print position is moved to the left as shown in FIG.

As described above, according to this embodiment, when there is an error in the arrangement interval of the LED chips on which the LED elements are mounted, the LED elements are divided and the emission intensity is controlled to eliminate black stripes and black stripes. It is possible to prevent the occurrence of white lines.
The number of divisions of the LED element is not limited to two, but three, four, and so on.
It can be set to N divisions such as division, and in more detail LE
It is possible to adjust the dislocation of the D chip.

[0048]

As described above, according to the present invention, a plurality of holding means are used, print data for each line is latched in each holding means, and a light emission signal based on the print data is output to the LED element. At this time, the printing deviation can be corrected by selecting the output of the holding means by the selecting means and outputting it to the LED element.

Further, by registering the information of the print deviation amount in the storage means in advance, the print deviation can be corrected more efficiently.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a color printer including a print head control device according to an embodiment.

FIG. 2 is a configuration diagram of a print head.

FIG. 3A is a diagram illustrating a configuration of a selector,
(B) is a truth table of the selector.

4A and 4B are diagrams illustrating an operation example of the first embodiment.

5A and 5B are diagrams illustrating an operation example of the first embodiment.

6 (a) and 6 (b) are diagrams for explaining the arrangement configuration of the LED chips, and FIG. 6 (c) is a diagram for explaining a problem in the arrangement state of the LED chips in FIG. 6 (a). , (D)
FIG. 6 is a diagram for explaining a problem in the arrangement state of the LED chips in FIG.

FIG. 7A is a diagram for explaining the amount of light received when the LED element is divided and FIG. 7B is a diagram for explaining the combined amount of light received when the LED element is divided.

FIG. 8A is a diagram for explaining the amount of light received when the LED element is divided, and FIG. 8B is a diagram for explaining the combined amount of light received when the LED element is divided.

9 (a) and 9 (b) are views for explaining the arrangement configuration of the LED chip of this example, and FIG. 9 (c) is an LE of FIG. 9 (a).
It is a figure explaining that a problem is improved by the arrangement state of a D chip, and (d) is a figure explaining that a problem is improved by the arrangement state of an LED chip of the figure (b). .

FIG. 10 is a circuit block diagram of a conventional print head controller.

FIG. 11 is a diagram illustrating an operation example when a conventional print head controller is used.

[Explanation of symbols]

1 Printer device 2 Paper supply / transport mechanism 3 Image forming section 4 control unit 5 paper cassettes 6 Standby roll pairs 7 Paper transport belt 8 drive rolls 9 Follower roll 10 to 13 image forming unit 14 Fixing device 14a heat roll 14b Pressure contact roll 15 Photosensitive drum 16 charger 17 LED head 18 Developer 19 Transfer device 20 Personal computer (PC) 21 head controller 22 shift register 23 and 24 registers 25 selector 25a Line selection section 25b Data selection section 26 drivers 30, 31, 30-n, 31-1 LED element 32, 33, 32-n, 33-1 LED element 40a, 40b LED element 41a, 41b Amount of light received 41 Combined received light amount 43a, 43b Amount of light received 43 Synthetic light receiving amount

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiaki Yajima             2-229 Sakuragaoka, Higashiyamato-shi, Tokyo             Casio Computer Co., Ltd. Tokyo office F-term (reference) 2C162 AE12 AE28 AE47 AF14 AF22                       AF60 FA04 FA17                 5C051 AA02 CA08 DA03 DB02 DB12                       DB29 DC03 DE03

Claims (4)

[Claims] 1. A first holding unit for holding print data of a first line, a second holding unit for holding print data of a second line following the print data of the first line, and printing. Based on the information on the shift amount, the print data is read from the first holding unit or the second holding unit for each pixel, and the print data selecting unit that outputs the print data, and the selection unit selects and outputs the print data. A print head control device comprising: a light emitting element that irradiates a photosensitive surface with light according to print data. 2. The print deviation amount information is stored in advance in a storage unit, and the selection process of the selection unit is executed in accordance with the print deviation amount information stored in the storage unit. 1. The print head control device according to 1. 3. The print head control device according to claim 1, wherein the print data is bitmap data. 4. The print data is print data for one line divided into N lines.
The control device for the print head described.