JP2007144786A - Recording head tilt correction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively reduce a recording head tilt on a recording medium without requiring special mechanical tools or components, namely, while suppressing costs even when the recording head is mounted with a certain tilt to the direction vertical to a transfer direction of the recording medium. <P>SOLUTION: A data processing means is provided with a printing buffer capable of storing printing data equivalent to an amount of more than columns related to the recording head tilt, a data counter for a data amount read out from the buffer, an address management means for reading out corresponding data by comparing a count amount of the data counter with a data amount corresponding to the recording head tilt, a setting means for setting an amount to be corrected to the magnitude of the recording head tilt corresponding to the data amount, and a masking means for masking a part of the data read out from the buffer. An ink-jet recording device provided with the data processing means electrically corrects a tilt deviation of the recording head to a medium to be recorded. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that records an image on a recording medium such as paper using a recording head, and is used as information output means for a printer, a copying machine, a facsimile, or the like.

  For example, as an information output device in a word processor, personal computer, facsimile, or the like, there is a printer that records information such as desired characters and images on a sheet-like recording medium such as paper or film.

  Among printer recording methods, the inkjet method has attracted attention because of its low running cost, high image quality and non-impact method.

  The ink jet recording apparatus has a small carrier sliding load and high speed because the ink ejected from the recording head flies through the space between the recording head and the recording medium and then reaches the recording medium to perform desired recording. It is advantageous for realization.

  In the case of printing vertical ruled lines as shown in FIG. 6 in the serial printer, if the recording head is not accurately positioned on the carrier, and the ink ejection is not aligned correctly in the recording medium conveyance direction, There is a problem that a ruled line for each printed line causes a tilted ruled line shift. Moreover, in a recording apparatus that performs color printing by arranging a plurality of such recording heads in parallel and discharging ink of different colors with each recording head, even a slight deviation may cause uneven color and have a significant adverse effect on the image. Will be given.

  On the other hand, the ink jet recording apparatus is a recording method for forming an output image by landing a plurality of dots on a recording medium as described above. In such a recording method, when the speed is increased, the number of ink droplets ejected from the recording head toward the recording medium is increased, that is, the ink ejected from one nozzle by increasing the ink ejection frequency. This can be realized by increasing the number of droplets or increasing the absolute amount of ink droplets by increasing the number of recording nozzles.

  The plurality of nozzles increased in order to increase the speed of the recording operation are arranged extending in a direction parallel to the recording medium conveyance direction with respect to the previous nozzles.

  That is, it is possible to increase the recording speed by increasing the recording width in one scan when the recording head performs the recording operation by ejecting ink while moving in the direction perpendicular to the recording medium. In this case, the recording head is configured to be extended in parallel with the conveyance direction of the recording medium.

  When the recording nozzles are extended in parallel to the transport direction, the inclination angle between the recording head and the transport direction between the recording media affects the image quality more than when the number of recording nozzles is small. The recording head ejects ink droplets while moving in a direction perpendicular to the conveyance direction of the recording medium, and forms an image by repeating it a plurality of times according to the size of the recording medium. At this time, if the recording head performs recording with a certain inclination with respect to the recording medium conveyance direction, the above-described ruled line deviation or the like is caused. The correlation between the amount of deviation and the inclination of the recording head increases as the number of nozzles extends in the recording medium conveyance direction.

  As a conventional method for correcting the tilt of the recording head, there is a method of dividing the nozzles mounted on the recording head into a plurality of blocks and sequentially driving each block (see Patent Document 1). A block indicates a plurality of nozzles that discharge at the same timing. This conventional example is characterized by comprising setting means for variably setting the drive interval for each block in accordance with the magnitude of the inclination. According to this method, the recording head is divided into a plurality of blocks having the simultaneous ejection timing in the extending direction of the recording nozzles, and the ejection timing is changed for each block corresponding to the inclination of the recording head. It is possible to correct the inclination.

A print buffer for storing print data for a column corresponding to the print head tilt, an address management means for reading out data corresponding to the print head tilt from the print buffer, and the address management means There has also been proposed a method of changing the DMA address at the time of reading according to the inclination of the recording head, comprising setting means for setting the magnitude of the inclination of the recording head to be corrected (see Patent Document 2).
Japanese Unexamined Patent Publication No. 7-40551 JP 2004-9489 A

  However, in Conventional Example 1, the physical block division method of the recording head is limited. When there is an inclination in the mounting of the recording head, the nozzles that are ejected at the same timing must be present nearby. However, if the ejection frequency is increased when the nozzles ejected at the same timing are close, the ink refill may not be in time, causing problems such as scumming or concentration of nozzle temperature rising points. Could affect the image quality.

  Also, in Conventional Example 2, if the data to be aligned by DMA is large, such as a burst unit, and the data unit acquired by DMA is large, the correction unit becomes large only by address management at the read head position, and the correction amount for the tilt angle is limited. The problem of being done occurs. If the number of recording nozzles increases and the amount of data to be processed increases, it is necessary to shorten the time for reading stored data as much as possible, and it is necessary to read a large amount of data at a time. For example, reading in burst units is required. When 640 bits of data for one column of a certain recording head are aligned and the burst unit of DMA is 256 bits, only 2.5 columns or 1.25 columns can be used for electrical correction according to Conventional Example 2 in the address management only for the burst head position. It cannot be corrected.

  Although a method for mechanically suppressing the tilt of the recording head is conceivable as a completely different means, it is not an effective method in terms of cost in consideration of a fine tilt adjustment.

  To solve the above problem, the method according to the present invention proposes an electrical tilt correction method that can read data in burst units and does not limit the block division method of the recording head.

  The configuration is shown below.

  A print buffer capable of storing print data for more than the column required for the print head tilt, a data counter for counting the number of bits of data read from the buffer, and a data amount corresponding to the count amount of the data counter and the print head tilt An address management means for reading out the corresponding data by comparison, a setting means for setting the amount to be corrected corresponding to the amount of data with respect to the magnitude of the inclination of the recording head, and the data read from the buffer And mask means for masking a part.

  As described above, according to the method of the present invention, even when the recording head is mounted with a certain inclination with respect to the direction perpendicular to the conveyance direction of the recording medium, a special mechanical tool is used. In other words, the tilt of the recording head on the recording medium can be effectively reduced while suppressing costs.

Example 1
In this specification, “recording” (sometimes referred to as “printing”) is not only for forming significant information such as characters and graphics, but also for human beings, regardless of whether it is significant or not. Regardless of whether or not it has been manifested, it also represents a case where an image, a pattern, a pattern or the like is widely formed on a recording medium or the medium is processed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Furthermore, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly in the same way as the definition of “r recording (printing)” above. It represents a liquid that can be used to form a pattern or the like, process the recording medium, or process the ink (for example, solidification or insolubilization of the colorant in the ink applied to the recording medium).

<Outline of the device>
FIG. 1 is a block diagram showing an electrical configuration of main parts of a recording apparatus described in an embodiment of the present invention.

  The ink jet recording apparatus of the present embodiment includes a carriage 2 equipped with a recording head (not shown) in which a plurality of nozzle rows are arranged for each of BK (black), C (cyan), M (magenta), and Y (yellow). Has a structure movable with respect to the guide shaft 3 extending in a direction perpendicular to the conveyance direction of the recording medium. The carriage 2 is connected to a part of a carriage drive motor 48 (not shown) via the drive belt 4, and the carriage 2 reciprocates over the entire width of the recording medium by the drive force of the carriage drive motor 48.

  Next, recording sheet conveyance control in the recording apparatus configured as described above will be described. When performing the recording operation, the CPU 34 first drives the LF motor 6 via the LF drive circuit 46.

  As a result, the recording sheets set in the paper feed cassette 7 are fed out, and then separated one by one by a separating means (not shown) and fed in the direction of the conveying roller. When the recording sheet conveyed by a conveyance roller (not shown) reaches the recording position, the recording head drive control is performed while driving the carriage motor 48 via the CR drive circuit 47 and scanning the carriage 2 in the direction intersecting the sheet feeding direction. The recording head 1 is driven via the circuit 45, and the first line is recorded on the recording sheet. The scale 5 is a scale for referring to the absolute position of the carriage.

  When the recording of the first line is completed, the LF motor 6 is driven to move the recording sheet to the next recording position by a conveyance roller (not shown), and the carriage motor 48 and the recording head 1 are driven again to record the next line. I do. By repeating this operation for one page of data, recording on the recording sheet is completed. When the LF motor 6 is further driven after the recording is completed, the trailing edge of the recording sheet is supported only by a discharge roller and a spur roller (not shown) and is conveyed by the rotation operation of the discharge roller. When the discharge roller is further driven, the rear end of the recording sheet passes through the discharge roller, and the recording sheet is discharged out of the recording apparatus.

  Reference numeral 8 denotes a scale indicating the absolute position in the rotation direction of the transport roller and a discharge roller (not shown). The transport roller is driven and rotated by the pulley 6 to the LF motor. Reference numeral 9 denotes a discharge tray for storing discharged sheets.

  FIG. 2 is a block diagram showing a control configuration of the recording apparatus of the present embodiment. In the figure, 33 is an interface (1 / F) for receiving recording data sent from the host device and sending / receiving various control signals, 34 is a CPU for controlling the entire apparatus, and 35 is a ROM for storing control programs and various data , 36 is a RAM used as a work area for recording data processing and data processing, 37 is an EEPROM for storing a part of programs and various data, and is rewritten from the outside as needed, 39 is a key switch 40 Reference numeral 41 denotes an input control circuit that controls a user operation part such as LED. Reference numeral 41 denotes an output control circuit that controls a display part such as the LED 42. 43 is a data processing timing generation circuit, and 44 is a recording data processing circuit. Reference numeral 45 denotes a recording head drive control circuit that generates a drive signal for the recording head unit 1, 46 denotes an LF motor drive circuit that drives the LF motor 6, and 47 denotes a CR motor drive circuit that drives the CR motor 48.

  FIG. 3 is a block diagram showing the control configuration of the recording apparatus of the present embodiment, which takes out 640-bit data, which is data for one column of the recording head, from the print buffer by DMA and corrects the deviation due to the inclination of the recording head. Have a circuit. The configuration consists of a request control unit 50 for transmitting a data request to the BUS or RAM 49, a reception control unit 52 for receiving data from the BUS / RAM 49, and storing the received data in a predetermined location of the 640-bit data latch 55. It comprises a selector 51 and a register unit 54 that controls the DMA address from the inclination of the recording head. Details are shown below. The request control unit 50 receives the DMA address from the register 54 and transmits a request to the BUS / RAM 49. The register 54 can set the address and the print head inclination amount from the outside, or the division amount (see 56 in FIG. 4) for dividing the data according to the inclination amount. When the request control unit 50 receives an external start trigger, the request control unit 50 transmits a request destination address request signal to the register unit. When the address to be referred to by the BUS / RAM 49 is returned from the register unit, the request control unit 50 returns to the BUS / RAM 49. A data request request is executed for the request. The request control unit 50 counts the data acquisition amount 56 corresponding to the tilt amount of the recording head simultaneously with the data request. The request control unit 50 has a counter function that counts data bits acquired by DMA. When the first request is completed, the request control unit 50 determines from the data count value whether the next reference address acquires data of the adjacent column / acquires data of the same column, and notifies the register unit. At the same time, it generates a mask for masking unnecessary data other than the necessary data bits from the data count value for the burst data, and generates mask data for the mask execution part 53 in the read control unit 52. give. The reception control unit 52 masks the data received from the BUS / RAM 49 based on the mask information from the read control unit 52. Based on the selector signal generated by the read control unit 50, the data after masking is selected by the selector 51 as to which bit position of the 640-bit latch 55 the data read out is latched. Is latched on. The request control unit 50 repeats the above-described operation until all the 640 bits of data in one column are collected. That is, the request control unit 50 receives the request address from the register unit 54, issues a request to the BUS / RAM 49, and the read control unit 52 reads out from the mask information received from the request control unit 50 in the mask execution unit 53. Mask processing is performed on the data, and the masked data is stored in a predetermined position of the 640-bit latch 51 by the selector 51. The mask processed by the mask processing unit 53 is a mask in which the overlapped data becomes valid when the next data overlaps in the 640-bit latch, and if the storage method stored in the 640-bit latch is “or”, If the mask is “0” and the storage method is “and”, the mask is “1”. When 640 bits of recording data are collected by a series of execution operations, the request control unit 50 transmits a ready signal that urges that the recording data is prepared to the subsequent block.

  FIG. 4 is a diagram showing data stored in the RAM and a method for retrieving the data according to the method of the present invention. Data is arranged on the RAM as shown in FIG. The request control unit 50 issues an acquisition request for one burst from the address 000h for the data in the burst area including the read start position. The read control unit receives data for one burst including the read start position from the BUS / RAM 49. The request control 50 generates a mask in which the data from the read start position to the data boundary for inclination correction is left in the requested one burst data. By processing this mask on the burst data received by the read control unit 52, the read data becomes 57 in FIG. Next, the data to be extracted is one burst from 500h because there is a tilt correction boundary in the data obtained by the first acquisition request. An acquisition request is issued by the request control unit, and the data received and masked by the read control unit is as shown at 58. Since the unmasked portion of data acquired in 58 is smaller than the data bit amount to be acquired up to the next slope boundary, an acquisition request is next issued for one burst data at an address of 500h + 100h. The data after the mask process is 59. Finally, the request control 50 requests 57 to 62 data, and the data received by the read control 52 generates recording data 63 stored in the 640-bit latch 55. The recording data 63 is generated from data over four columns as compared to the recording data 64 generated from normal 000h, 100h, and 200h requests.

  FIG. 5 shows the case where the data generated by the conventional method 64 without correction for tilt 65 when the DMA data is changed according to the print head tilt by the method according to the present invention and attached to the print head having the tilt. The state recorded on the recording medium is shown. The portion indicated by the black square in the figure is a comparison when a black straight line is recorded. The straight line 64 recorded by the conventional method has a ruled line shift having a distance of L1 at the scan boundary, but in the straight line 65 according to the method of the present invention, the ruled line shift amount at the scan boundary is L2. The ruled line deviation is effectively reduced as compared with the conventional method.

  As described above, according to the method of the present invention, even when the recording head is mounted with a certain inclination with respect to the direction perpendicular to the conveyance direction of the recording medium, a special mechanical tool is used. In other words, the tilt of the recording head on the recording medium can be effectively reduced while suppressing costs.

[Industrial applicability]
Although the embodiment described above has been described by taking a serial type ink jet printer as an example, the present invention can be widely applied to other types of recording apparatuses such as a thermal transfer type and a dot impact type. Furthermore, it is a very effective method even when the nozzle mounted on the recording head is extended in the direction perpendicular to the scanning direction in order to increase the speed in the future.

The perspective view of the recording device in the Example by this invention The block diagram of schematic structure of the recording device in the Example by this invention The block diagram of the recording data processing circuit in the Example by this invention The figure which shows the mode of recording data storage in the Example by this invention, and the extraction method FIG. 3 is a development view of recording data on a recording medium in an embodiment according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 2 Carriage 3 Guide shaft 4 Drive belt 5 Linear scale 6 LF motor 7 Cassette 8 Rotary scale 33 Interface circuit 34 CPU
35 ROM
36 RAM
37 EEPROM
39 Input control device 40 KEY
41 Output control circuit 42 LED
43 Data processing timing generation circuit 44 Recording data processing circuit 45 Recording head drive control circuit 46 LF motor drive circuit 47 CR motor drive circuit 48 CR motor 49 BUS or RAM
50 Request Control Unit 51 Selector Circuit 52 Read Control Unit 53 Mask Processing Unit 54 Address Management Register Unit 55 640 Bit Latch 56 Data Boundary for Correcting Recording Head Tilt 57 Data after Mask Processing of First DMA Acquisition Data 58 Second Time Data after mask processing of the third DMA acquisition data 59 Data after mask processing of the third DMA acquisition data 60 Data after mask processing of the fourth DMA acquisition data 61 Data after mask processing of the fifth DMA acquisition data 62 Sixth DMA Data after masking of acquired data 63 Data obtained by combining all DMA acquired data 64 Recorded data by conventional method 65 Recorded data after tilt correction according to the present invention

Claims (2)

  In an ink jet recording apparatus that uses a recording head that has a plurality of discharge rollers and discharges ink from the plurality of discharge rollers and discharges ink from the recording head to a recording medium. Compares the print buffer that can store more than the print data for the column, the data counter that counts the number of bits of the data read from the print buffer, and the data amount corresponding to the count of the data counter and the inclination of the recording head. Address management means for reading out corresponding data, setting means for setting an amount to be corrected corresponding to the data amount with respect to the magnitude of the inclination of the recording head, and part of the data read from the buffer Data processing means comprising mask means for masking.   2. An ink jet recording apparatus comprising a plurality of the recording heads arranged in parallel in the scanning direction, and each recording head having the data processing means and the variable setting means shown in claim 1.

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