KR20070116456A - The image forming apparatus and image forming method of the same - Google Patents

Abstract

An image forming method of an image forming apparatus is provided to compensate for defects formed in a printing medium by continuously changing the location of defects of injection ink. In an image forming method of an image forming apparatus including chip arrays in the width direction of pages, where ink nozzle arrays(241,242,243,244) arranged in rows in the proceeding direction of pages, ink injection sequences of the ink nozzle arrays have different patterns.

Description

The image forming apparatus and image forming method of the same}

1 is a bottom view showing a part of an inkjet array head of a conventional image forming apparatus.

2A is a state diagram showing a state in which ink is ejected in the same pattern in an ink nozzle array of a conventional image forming apparatus.

FIG. 2B is a diagram showing a state where ink dots are not parallel to the print medium when the ink ejection sequence is performed in the same pattern in the ink nozzle array of the conventional image forming apparatus.

3 is a state diagram showing an example of an image formed on a print medium when an ink ejection sequence is made in the same pattern in an array head of a conventional image forming apparatus.

4 is a configuration diagram schematically showing a configuration of an image forming apparatus according to the present invention.

5 is a configuration diagram schematically illustrating an inkjet head of an image forming apparatus according to the present invention.

6 is a bottom view schematically showing the bottom of the inkjet head in the image forming apparatus according to the present invention.

7A and 7B are operation state diagrams illustrating an image forming method of the image forming apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

200: inkjet cartridge 210: ink storage tank

220: inkjet array head 231: chip array

241: ink nozzle array

The present invention relates to an image forming apparatus, and more particularly, to an image forming method of an image forming apparatus capable of minimizing image quality degradation.

In general, an image forming apparatus is an apparatus for forming an image on a print medium. The image forming apparatus includes an inkjet printer, a laser printer and a multifunction printer.

The inkjet printer sprays droplets of ink onto a print medium to form an image. The inkjet printer is classified into a shuttle printing method for printing while reciprocating the head and a page width printing method for printing with the head fixed.

1 is a bottom view showing a portion of an inkjet array head of a conventional image forming apparatus, and FIG. 2A is a state diagram showing a state in which ink is ejected in the same pattern in an ink nozzle array of a conventional image forming apparatus, and FIG. FIG. 3 is a diagram illustrating a state in which ink dots are not parallel to a print medium when an ink ejection sequence is performed in an ink nozzle array of an image forming apparatus, and FIG. 3 shows ink in the same pattern in an array head of a conventional image forming apparatus. It is a state diagram which shows an example of the image formed in the printing medium at the time of jetting sequence.

Referring to FIG. 1, the printer of the page width printing method includes an ink jet array head 10 having a length equal to a page width of a printing paper. A plurality of chips 11 are arranged in the inkjet array head 10 in parallel in the page width direction. In this case, the plurality of chips 11 are formed with ink nozzle arrays 12 and 13 formed by arranging a predetermined number of ink nozzle units in a page width direction. In FIG. 1, the black dots shown inside the chip 11 are ink nozzles.

Heaters (not shown) or piezoelectric plates (not shown) are respectively disposed in the ink nozzles to eject ink of the ink nozzles. At this time, when driving both the heater and the piezoelectric plate at the same time, the required power is significantly increased. Accordingly, the inkjet array head 10 operates the heater or the piezoelectric plate in a predetermined ink ejection sequence for each chip 11 on which a plurality of ink nozzles are formed. Here, the ink ejection sequence refers to a series of sequences in which ink nozzles of each chip 11 eject ink.

The above-described page width printing method printer prints printing paper in page width units in a state where the inkjet array head 10 is stopped.

However, since the inkjet array head ejects ink in the same ink ejection sequence for each chip, a relative difference between the conveying speed of the print medium and the ejection order of print nozzles for each section occurs. Thus, as shown in FIG. 2A, the print medium may have a line cutting phenomenon in which the print pattern 16 is not parallel but is broken by section. Here, the uppermost ink line 15 in FIG. 2A shows an ideal ink line 15 that is printed in parallel and continuously in the page width direction. In addition, the arrow in FIG. 2A shows the advancing direction of the page.

In addition, when the ejection speed and direction of the ink are abnormal at a predetermined ink nozzle among the ink nozzles in the page width direction, the predetermined ink droplets 17, 18, and 19 cannot eject the ink droplets at the correct ejection positions. do. Therefore, as shown in FIG. 2B, the print pattern is printed so as not to be parallel to the page width direction, thereby degrading the quality of the image. In FIG. 2B, the dashed-dotted line indicates the exact ejection position of the ink droplets, and the arrow shows the advancing direction of the page.

In addition, if the line cutting phenomenon and / or abnormal ink jetting are continuously performed at the same position in the vertical direction while the print medium is being printed, the image of the print medium may include a band (in the page advance direction (vertical direction) as shown in FIG. 3. 20 band appears. At this time, a white band in which ink droplets are not ejected at all, or a black band in which ink of all colors are mixed may appear. In FIG. 3, the arrow shows the advancing direction of the page.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an image forming method of an image forming apparatus capable of minimizing deterioration of an image.

Another object of the present invention is to provide an image forming method of an image forming apparatus which can prevent a band from being generated in an image.

In order to achieve the above object, according to an aspect of the present invention, an image forming apparatus comprising an inkjet array head in which a page width ink nozzle array is arranged in parallel along a traveling direction of a page, the ink of the ink nozzle arrays The jetting sequence provides an image forming method of an image forming apparatus, wherein each of the jetting sequences is changed into different patterns.

Further, according to another aspect of the present invention, an image forming apparatus comprising an inkjet array head in which at least two or more rows of the same color ink nozzle arrays are arranged in parallel along a traveling direction of a page, wherein the same color ink nozzle arrays are provided. Provided are an image forming method of an image forming apparatus, wherein the ink ejection sequences are changed in different patterns.

The ink ejection sequence may be periodically changed to another pattern.

In addition, ink nozzle arrays of different colors may be changed in the same pattern as the ink ejection sequence.

In addition, each of the ink nozzle arrays may have the same or different ink ejection sequences for each predetermined number of nozzle units.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

A specific embodiment of the image forming apparatus according to the present invention, which can achieve the above object, will be described.

4 is a configuration diagram schematically showing a configuration of an image forming apparatus according to the present invention.

Referring to FIG. 4, the image forming apparatus includes a main body 100 having a transport path 110 formed therein, and a paper feeding unit 120 installed on the main body 100. The paper feeding unit 120 is stored in a state in which the print medium P is inclined.

Pick-up roller assembly 130 is disposed on the paper feeder 120 to provide the stored print medium P to the transfer path 110 one by one. The pickup roller assembly 130 includes a shaft 131 rotated by a driving device (not shown), and a pickup roller 132 rotated by the power transmitted from the shaft 131. The pickup roller 132 is installed to contact while pressing the print medium (P). The pickup roller 132 is rotated to transfer the print medium P one by one to the conveying path 110.

The friction buckle 140 is disposed on the lower surface of the paper feeder 120. The friction buckle 140 is made of rubber or synthetic resin to rub against the lower end of the print medium (P). The friction buckle 140 prevents the lower end of the print medium P from sliding while supporting the lower end of the print medium P.

The feed path 110 is disposed to rotate while the feed roller 151 and the friction roller 152 are in contact with each other. The friction roller 152 is rotatably installed at the end of the lever 153. The lever 153 is connected to a spring 154, the spring 154 is fixed to a separate structure (not shown). At this time, the spring 154 pulls the lever 153 so that the friction roller 152 of the lever 153 presses the feed roller 151.

The inkjet cartridge 200 is disposed in the main body 100 to form an image on the print medium P transferred from the feed roller 151. The inkjet cartridge 200 will be described in detail below.

A platen 160 is disposed below the inkjet cartridge 200 to support and guide the lower portion of the transferred print medium.

In addition, a discharge roller 171 and a discharge wheel 172 are disposed on the transfer path 110 to discharge the print medium P printed by the inkjet cartridge 200 to the outside. The discharge roller 171 and the discharge wheel 172 is installed to rotate while contacting each other.

5 is a schematic view showing the inkjet head of the image forming apparatus according to the present invention, and FIG. 6 is a bottom view schematically showing the bottom surface of the inkjet head in the image forming apparatus according to the present invention.

5 and 6, the inkjet cartridge 200 includes an ink storage tank 210 in which ink is stored, and an inkjet array head 220 for spraying ink from the ink storage tank 210 onto a print medium. do.

The inkjet cartridge 200 may be a black-and-white type, a color type, a black and white / color mixed type cartridge. Here, in the case of the black and white type, only one ink storage tank for storing black ink is disposed. Also, in the case of the color type, three ink storage tanks for independently storing magenta, cyan and yellow inks are disposed. In addition, in the case of the black-and-white color mixing type, four ink storage tanks are arranged to independently store black, magenta, cyan and yellow colors of ink. Hereinafter, a color / monochrome mixed type inkjet cartridge will be described.

Four ink storage tanks 210 are arranged in the inkjet cartridge 200 along the length direction. This ink storage tank 210 is in communication with the inkjet array head 220.

The inkjet array head 220 includes a plurality of ink nozzle arrays 241, 242, 243, and 244 arranged in parallel in the page width direction. The plurality of ink nozzle arrays 241 are arranged in parallel along the advancing direction of the page.

For example, the inkjet array head 220 is arranged with eight arrays of chip arrays 231 and 232 in which a plurality of chips are arranged in the page width direction. Each of the chip arrays 231 and 232 is provided with ink nozzle arrays 241, 242, 243 and 244 in which four ink nozzles are arranged in two rows in the page width direction. In this case, four rows of ink nozzle arrays 241, 242, 243, and 244 are arranged in parallel in the advancing direction of the page in the ink array head 220.

In FIG. 6, the ink nozzle arrays 241, 242, 243 and 244 of black, magenta, cyan and yellow colors are sequentially arranged in the page advance direction. 6, the chip is shown as a rectangle, and black dots inside the rectangle represent ink nozzles. The ink nozzle array for each color may be changed in various orders. In addition, although four ink nozzle arrays 241, 242, 243, and 244 are arranged in the inkjet array head 220 for each color, the number of arrays of ink nozzle arrays for each color may be increased or decreased according to the resolution of the printer.

In addition, ink ejection means (not shown) is disposed in each of the ink nozzles. As the ink ejection means (not shown), a heater or a piezoelectric plate may be selectively applied. Each ink ejecting means is electrically connected to a controller (not shown). Hereinafter, a description will be given based on an example in which a heater is applied as the ink ejection means.

In addition, the control unit (not shown) stores a table relating to an ink ejection sequence of the ink nozzle array in advance. Here, the ink ejection sequence refers to a series of sequences in which ink nozzles eject ink in each ink nozzle array.

An image forming method and an operation of the image forming apparatus according to the present invention configured as described above will be described.

4 is a configuration diagram schematically showing a configuration of an image forming apparatus according to the present invention.

Referring to FIG. 4, when the user selects the color print, the pickup roller 132 is rotated to transfer the print medium. At this time, the print medium is conveyed one by one between the feed roller 151 and the friction roller 152 by the frictional force of the friction buckle 140. In addition, when two or more print media are supplied to the feed roller 151, the friction roller 152 prevents the upper print media from being transferred by the frictional force. Therefore, the print media of each sheet is transferred to the inkjet array head 220.

At this time, the control unit sequentially supplies power to the heater according to the ink ejection sequence for any ink nozzle array preset in the table. The control unit periodically changes the ink ejection sequence of the nozzle arrays to different patterns periodically.

7A is an operation state diagram illustrating an image forming method of an image forming apparatus according to the present invention.

A pattern change of the ink jetting sequence will be described with reference to FIG. 7A.

Arrows in FIG. 7A indicate the page advance direction. In addition, t1, t2, and t3 represent periodic time. In addition, the electrothermal ink nozzles in each chip are arranged in the order of N1, N2, N3, N4 on the left side. In each chip, the ink nozzles in the rear row are arranged in the order of N5, N6, N7, N8 on the left side. The number at the top of each chip shows the ink ejection sequence of the nozzle.

When time t1 is reached, the controller supplies power to the heaters in the order of the nozzles N1, N8, N2, N7, N3, N6, N4, and N5 in the front two rows 241 and 242 of the magenta ink nozzle array. In addition, the rear two rows 243 and 244 of the magenta ink nozzle array sequentially supply power to the heaters in the order of the nozzles N5, N4, N6, N3, N7, N2, N8, and N1. Thus, the magenta ink nozzle arrays 241, 242, 243, and 244 discharge ink according to the above-described ink ejection sequence.

When time t2 is reached, the front two rows 241 and 242 of the magenta ink nozzle array supply power to the heaters in the order of nozzles N5, N4, N6, N3, N7, N2, N8, and N1. In addition, the rear two rows 243 and 244 of the magenta ink nozzle array sequentially supply power to the heaters in the order of nozzles N1, N8, N2, N7, N3, N6, N4, and N5.

When the time t3 is reached, the power supply order of the front two rows and the rear two columns 241, 242, 243 and 244 of the magenta ink nozzle array is changed to be equal to the t1 time.

In this way, an image may be formed on the print medium while the ink ejection sequences of the front two rows and the rear two columns 241, 242, 243 and 244 are alternately changed.

7B is an operational state diagram showing another embodiment of the image forming method of the image forming apparatus according to the present invention.

A pattern change of the ink ejection sequence will be described with reference to FIG. 7B.

In FIG. 7B, the arrow indicates the page progress direction. And t1, t2, and t3 represent time. In addition, the electrothermal ink nozzles in each chip are arranged in the order of N1, N2, N3, N4 on the left side. In each chip, the ink nozzles in the rear row are arranged in the order of N5, N6, N7, N8 on the left side. The number at the top of each chip shows the ink ejection sequence of the nozzle.

When the time t1 is reached, the controller supplies power to the heaters in the order of the nozzles N3, N6, N4, N5, N2, N8, N2, and N7 in the front two rows 241 and 242 of the magenta ink nozzle array. In addition, the rear two rows 243 and 244 of the magenta ink nozzle array sequentially supply power to the heaters in the order of the nozzles N5, N1, N8, N2, N7, N3, N6, and N4.

When the time t2 is reached, the front two rows 241 and 242 of the magenta ink nozzle array supply power to the corresponding heaters in the order of the nozzles N7, N3, N6, N8, N2, N1, N5, and N4. In addition, the rear two rows 243 and 244 of the magenta ink nozzle array sequentially supply power to the heaters in the order of the nozzles N1, N8, N2, N7, N5, N4, N6, and N3.

When the time t3 is reached, the front two rows 241 and 242 of the magenta ink nozzle array supply power to the heaters in the order of the nozzles N4, N5, N2, N7, N1, N8, N3, and N6. In addition, the rear two rows 243 and 244 of the magenta ink nozzle array sequentially supply power to the heaters in the order of the nozzles N8, N2, N3, N6, N4, N5, N7, and N1.

In this way, an image may be formed on the print medium while the ink ejection sequences of the front two rows and the rear two columns 241, 242, 243 and 244 are changed at random. In this case, the ink ejection sequence may be periodically changed to another pattern.

As described above, since each of the ink nozzle arrays 241, 242, 243, 244 is continuously changed to different ink ejection sequences, different print patterns are continuously printed at predetermined positions in the page width direction. In this way, since the printing pattern is randomly changed at a predetermined position in the page width direction, the defect position of the ink is continuously changed even if a defect is continuously generated in the predetermined ink nozzle. As a result, the image becomes natural even when ink jetting becomes abnormal at a predetermined ink nozzle.

As shown in FIGS. 7A and 7B, the ink nozzle arrays 241, 242, 243, and 244 may have the same ink ejection sequence for each predetermined number of nozzle units. In FIG. 7A and FIG. 7B, nozzle units are configured for each chip, but nozzle units may be configured for each predetermined number of chips.

In this case, the ink jetting sequence for each nozzle unit may be set differently, and the ink jetting sequence for each nozzle unit may be continuously exchanged with each other.

 In addition, the ink nozzle arrays 241, 242, 243, and 244 of the same color may each change the ink ejection sequence in different patterns. For example, as shown in FIG. 7B, the ink ejection sequence of the magenta ink nozzle arrays 241, 242, 243, and 244 may be continuously changed randomly every t1, t2, t3 time.

In addition, the ink nozzle arrays of different colors allow the ink ejection sequences to be changed in the same pattern. For example, the ink jetting sequence of magenta ink nozzle arrays 241, 242, 243, 244 can be changed to be identical to the ink jetting sequence of cyan and yellow ink nozzle arrays. Therefore, since the ink of the different color is ejected at the ejection position of the magenta ink droplet, color can be realized.

On the other hand, when black and white printing is selected, the black ink array nozzles eject ink in the same ink ejection sequence as the magenta ink nozzle arrays 241, 242, 243 and 244. Since the black-and-white print is the same as the color print, the description thereof will be omitted below.

Further, the present invention can be applied to both an inkjet printer to which a monochrome type, a color type, and a monochrome and color mixing type cartridge are applied.

As described above, according to the embodiment of the present invention, since the ink ejection sequence of the ink nozzle arrays is continuously changed to different patterns, the printing pattern printed on the print medium is continuously changed. Therefore, even if abnormal ink ejection is continuously made at a predetermined ink nozzle, the defect position of the ejected ink is continuously changed, so that defects formed in the print medium are compensated for, resulting in a more natural image and improved image quality.

Claims (5)

An image forming apparatus comprising an inkjet array head having a page width ink nozzle array arranged in parallel along a traveling direction of a page, And an ink ejection sequence of the ink nozzle arrays is changed in a different pattern, respectively. An image forming apparatus comprising an inkjet array head having at least two rows of the same color ink nozzle arrays arranged in parallel along a direction of travel of a page, And the ink ejection sequences of the same color ink nozzle arrays are changed in different patterns. The method of claim 2, And the ink ejection sequence is periodically changed to another pattern. The method of claim 2, An image forming method of an image forming apparatus, wherein ink nozzle arrays of different colors are changed in the same pattern. The method of claim 2, Wherein each of the ink nozzle arrays has the same or different ink ejection sequences for each predetermined number of nozzle units.

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