JP2014043070A - Image forming apparatus, ink jet recording apparatus, and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent preliminary discharge from being performed at every fixed intervals at which discharge is performed to form an image even in the case of performing on-sheet preliminary discharge at fixed intervals.SOLUTION: An image forming apparatus provides ink drops discharged from a discharge port formed in a recording head to a recording medium to form an image. The device includes: image data generation means for generating image data for forming the image; preliminary discharge means for discharging ink drops, which do not form an image, from the discharge port to a region where the image of the recording medium is formed; and counting means for counting pixels for forming the image. When a count value of the counting means reaches a predetermined value, the image data of the pixels of the predetermined value is set as preliminary discharge data for performing preliminary discharge by the preliminary discharge means to reset the count value.

Description

  The present invention relates to an image forming apparatus, an ink jet recording apparatus, and an ink jet recording method, and more particularly to an image forming apparatus, an ink jet recording apparatus, and an ink jet recording method that perform preliminary ejection on a paper surface.

  In the serial printer system, a preliminary discharge receiving portion is provided at a place other than the recording area, and when preliminary discharge is performed, the preliminary discharge is performed by moving to that place. However, if the discharge port has a small diameter, more frequent preliminary discharge control must be performed. By reducing the diameter of the ejection port, the amount of ink ejected at one time becomes smaller. For this reason, dirt on the discharge port, ink sticking, an increase in ink viscosity, and the like affect the ink discharge more than conventional discharge port diameters.

  However, if the preliminary ejection is frequent, the recording head may not be able to move to the preliminary ejection location at the required preliminary ejection interval. Also, in line printers, more frequent preliminary discharge control is required, and the required preliminary discharge interval is reached while a single recorded image is being formed. In some cases, the preliminary discharge control is not performed in time.

  Therefore, Patent Document 1 discloses a technique for performing preliminary ejection (hereinafter also referred to as “paper preliminary ejection”) on a recording medium to an extent that cannot be judged with the naked eye. According to the technique disclosed in Patent Document 1, the recording data and the preliminary ejection data are synthesized to create data for actual recording. As the diameter of the dots is reduced, even if one dot of ink is ejected onto the surface of the paper on which nothing is recorded, the ink dot has a small diameter, and the ejected ink droplets are also extremely small. It cannot be recognized with the naked eye. For this reason, even if several dots are ejected in addition to the dots for forming a recorded image on the recording medium, the image finally formed is not affected.

JP 2004-98298 A

  However, when data to be actually recorded is created and recorded by the technique disclosed in Patent Document 1, the recording is performed at regular intervals regardless of whether or not the ejection port is used when an actual recorded image is formed. Pre-discharge on the paper. That is, in the technique disclosed in Patent Document 1, even if recording is performed during a predetermined interval after the preliminary ejection, the preliminary ejection is always performed. In other words, when a discharge is performed to form a recording image at a certain interval after a preliminary discharge is performed at a certain discharge port, it is necessary to perform the preliminary discharge until the predetermined interval has passed since the discharge. Absent. Therefore, by performing the preliminary ejection disclosed in Patent Document 1, ink consumption may be wasted.

  The present invention has been made in view of the above points. Even when preliminary paper ejection is performed at regular intervals, if there is ejection for forming an image during regular intervals, preliminary ejection is performed at regular intervals. An object of the present invention is to provide an image forming apparatus, an ink jet recording apparatus, and an ink jet recording method that do not perform ejection.

  Therefore, in the present invention, an image forming apparatus for forming an image by applying ink droplets ejected from ejection ports provided in a recording head to a recording medium, and generating an image data for forming the image A data generation unit, a preliminary ejection unit that ejects ink droplets that do not form an image in an area where an image is formed on the recording medium from the ejection port, and a counting unit that counts pixels for forming the image. When the count value of the counting means is a predetermined value, the image data of the pixel having the predetermined value is set as preliminary ejection data for performing preliminary ejection by the preliminary ejection means, and the count value is reset. .

  According to the above configuration, even when the paper surface preliminary ejection is performed at regular intervals, if there is ejection for forming an image during the regular intervals, the preliminary ejection is not performed at the regular intervals. Thereby, useless ink consumption can be suppressed.

FIG. 3 is a block diagram illustrating a data flow of the recording apparatus according to the first embodiment. It is a conceptual diagram which shows the multi-value data expansion | deployment process of 1st Embodiment. It is a schematic diagram for demonstrating the process of the paper surface preliminary discharge production | generation part of 1st Embodiment. It is explanatory drawing which shows typically the example of the arrangement | sequence of the multi-value data of 1st Embodiment. It is a flowchart which shows the flow of the image processing of 1st Embodiment. It is explanatory drawing which shows typically the example of the arrangement | sequence of the multi-value data after performing image processing. It is a schematic diagram for demonstrating the nozzle chip connection part of 2nd Embodiment. It is a conceptual diagram which shows the process with respect to the nozzle tip connection part of 2nd Embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a data flow of the ink jet recording apparatus of the present embodiment. The ink jet recording apparatus of this embodiment forms a recorded image by applying ink droplets ejected from the ejection ports to a recording medium conveyed perpendicularly to the ejection port array arranged in the scanning direction of the recording head. Recording is performed according to the method. This embodiment can be applied to a serial printer or a line printer.

  Multi-valued data in RGB format (for example, 8-bit data) input from the host computer 301 is temporarily stored in a recording buffer 303 in the recording device 302. Multi-value data is input from the recording buffer 303 to the image processing unit 304 and converted into a color space that can be output by the recording apparatus. Thereafter, color separation processing is performed into seven colors of cyan (C), magenta (M), yellow (Y), black (K), light cyan (LC), light magenta (LM), and gray (G). Thereafter, in the present embodiment, quantization processing is performed on 2-bit multi-value data for each color, and the result is output to the paper surface preliminary ejection data generation unit 304.

  If the image data from the host computer has already been subjected to the above-described image processing by a driver or the like in the host computer, the quantized bit multi-value data is directly sent from the image processing unit to the paper preliminary ejection generation unit. You may input into 304. In the paper preliminary ejection data generation unit 305, data for preliminary paper ejection is added according to the recording data input from the image processing unit 304 and input to the print engine unit 305.

  The multi-value data output from the paper preliminary ejection data generation unit 305 is developed into binary data by the multi-value data conversion unit 307 via the chip connection mask unit 306 in the print engine unit 309. The operations of the paper preliminary ejection data generation unit 305 and the chip connection mask unit 306 will be described later.

  FIG. 2 is a conceptual diagram showing the multi-value data expansion processing of this embodiment. Multi-value data expansion processing (hereinafter also referred to as index expansion processing) is performed in the multi-value data conversion unit 307.

  In FIG. 2, each color pixel has an information amount of 2 bits, and the gradation that can be expressed is four values, and this value is called an index value. Then, with respect to the input multi-value data, the number of dots to be ejected and the dot arrangement in a predetermined area (in this embodiment, four frames of 1200 dpi × 1200 dpi in this embodiment) are determined as index expansion for predetermined index expansion. Determine based on the table. In this case, it is a 2 × 2 matrix, and the dot arrangement of the corresponding two ejection ports is determined.

  For example, when the index value is “01”, there are four dot arrangements 401 to 404 as shown in FIG. Then, which dot arrangement is to be determined is determined from the index development table. In this way, 2-bit multi-value data is converted to binary data.

  The binary data output from the multi-value data conversion unit 307 is transmitted to the recording head 308, and a recording operation is performed by the recording head 308 according to the input data.

  Details of the operation of the paper preliminary ejection data generation unit 305 will be described below.

  The paper preliminary ejection control performs ejection that does not regularly form an image on a recording medium. As a result of no ink being ejected from a specific ejection port for a certain period of time, when ink does not eject or dust or dirt adheres to the ejection port and ink droplets cannot land at the intended position, or the ink at the ejection port evaporates. This is done in order not to cause density unevenness due to an increase in ink density. However, with regard to the ejection port for which ejection control is performed in order to form an actual recorded image, as long as it is performed within a desired ejection interval, the preliminary ejection on the paper surface is purposely performed with respect to the ejection port. There is no need for control. In other words, whether it is for forming a recorded image or preliminary ejection control, if ejection control of each ejection port is performed at a desired interval, the ejection port is not ejected by the ejection port. No ejection or the like will not occur.

  Therefore, regardless of whether or not the ejection control for forming the image data is performed, if the paper preliminary ejection control is performed at a required interval, a situation of performing the paper preliminary ejection control which is not necessary originally occurs. As a result, useless ink is consumed. Therefore, in the embodiment, the paper preliminary ejection data generation unit 305 controls the paper preliminary ejection only for the ejection ports that are not used for forming a fixed interval recording image with respect to the image data of the image processing unit 304. It has a data conversion function that can perform

  FIG. 3 is a schematic diagram for explaining processing of the paper preliminary ejection generation unit 305 for multi-value data input to the image processing unit 304 of the present embodiment. In this figure, the number of pixels is shown in the X direction, and the ejection ports 501 to 510 on the recording head are shown in the Y direction. In the present embodiment, it is assumed that the resolution is 1200 dpi × 1200 dpi.

  As shown in the figure, the image processing unit 304 first outputs 2-bit multi-value data 511, 512, 513,... Corresponding to the ejection ports 501 and 502 in this order. After all the data in the X direction are output, multivalued data corresponding to the discharge ports 503 and 504 are output in the X direction in the same manner. The process ends when this process is output to all the discharge ports in the Y direction. The 2-bit multi-value data is index-developed by the multi-value data development unit 307 in the subsequent stage to determine the actual dot arrangement. For example, the multi-value data 511, 512, 513 is index-developed so that the discharge ports 501 and 502 Driving data is generated.

  FIG. 4 is an explanatory diagram schematically illustrating an example of the arrangement of multi-value data according to the present embodiment.

  First, attention is focused on Y = 0, that is, 2-bit multi-value data corresponding to the ejection ports 501 and 502. Assume that the data shown in FIG. 4 is input from the image processing unit 304 as multi-value data corresponding to these ejection ports. That is, with respect to the X direction shown in FIG. 3, “11” → “01” → “00” → “10” → “01”... → “10” → “10” Are sequentially input.

  Here, the purpose of the paper preliminary ejection data generation unit 305 is to convert the multi-value data from the image processing unit 304 into paper preliminary ejection data as much as necessary. That is, when ejection control is performed for actual image formation at a desired preliminary ejection interval, conversion to paper preliminary ejection control data is not performed. When ejection control for actual image formation is not performed at a desired preliminary ejection interval, the image data at that timing is converted into multivalued paper preliminary ejection data. At this time, it can be determined that the paper surface preliminary ejection control need not be performed on the multi-value data from the image processing unit 304. After the multi-value data is indexed, This is only when the dot arrangement is such that the outlet is controlled to discharge. That is, in this case, these discharge ports discharge for image formation.

  Therefore, what kind of multi-value data is such that two corresponding discharge ports are reliably discharged after the index expansion will be described with reference to FIG.

  First, consider the case where the multi-value data in FIG. 2 is “00” and “01”. In the multi-value data “00”, ink is not ejected from either of the ejection ports 501 and 502, and in the multi-value data “01”, ink is ejected from only one ejection port. For this reason, there are ejection ports that do not eject ink, and multi-value data that does not reliably perform ejection control after index development is obtained. Next, when the input multi-value data is “10”, there is a possibility that any of the dot arrangements 405 to 410 shown in FIG. As described above, the actual dot arrangement is determined after the index is developed by the multi-value data development unit 307 in the subsequent stage, and is unknown at the stage of input to the paper preliminary ejection generation unit 305. Therefore, when the multi-value data is “10”, if the dot arrangement after the index expansion is any one of 405, 407, 408, and 410, ink is ejected from both of the two ejection ports. . However, if a dot arrangement such as 406 or 409 is obtained after the index development, only one ejection port is controlled and ink is not ejected from the other ejection port, so there are ejection ports that are not used. It will be. Therefore, it is not multi-value data that is reliably discharged after index development.

  Therefore, only when the multi-value data is “11”, both the discharge ports are surely discharged. Therefore, if the input 2-bit multi-valued data is “11”, it is determined that it is not necessary to perform the paper preliminary ejection control. If the data is other than that, it is necessary to perform the paper preliminary ejection control. Judge as some data. At the timing when the multi-value data “11” is not input at a pixel interval that requires paper preliminary ejection, all the ejection ports are surely used as data for paper preliminary ejection as image data from the image processing unit 304. It is converted into multi-valued data “11” to be struck. As a result, all the ejection openings are reliably controlled at the required intervals, and the paper preliminary ejection control is performed only when necessary, so that ink is not wasted. In order to perform this control, the paper preliminary ejection data generation unit 305 is provided with a counter for counting the number of data and determining whether the desired preliminary ejection interval (count value is a predetermined value) has been reached.

  FIG. 5 is a flowchart showing the flow of image processing according to this embodiment. First, the first image data from the image processing unit 304 is “11” data that does not need to be subjected to paper preliminary ejection control (data that is the same as the paper preliminary ejection performed by ejection control for recording image formation). Whether or not (step S701). If the image data is not “11”, the processing of step S704 is performed without performing the processing of steps S702 and S703. On the other hand, if the image data is not “11”, it is converted into multi-value data “11” for performing preliminary paper ejection (step S702), and the counter is reset (step S703).

  Next, it is determined whether processing for the number of image data in the X direction has been completed (step S704). If not completed, it is determined whether or not the image data from the image processing unit 304 is “11” data (step S705). If the image data is “11”, the counter is reset (step S709) and the process returns to step S704 again because the corresponding discharge port is reliably controlled to discharge. On the other hand, if the image data is not “11”, the counter that counts the number of data is incremented by “+1” (step S706). Then, it is determined whether or not the counter has reached a predetermined value (within the predetermined data), that is, the pixel interval at which the paper surface preliminary ejection is to be performed (step S707). If the counter value has reached a predetermined value at this time, the image data from the image processing unit 304 is converted into multi-value data “11” for preliminary ejection on the paper (step S708). Then, after resetting the counter (step S709), the process returns to step S701. On the other hand, when it is determined that the counter has not reached the predetermined value (step S707), the process returns to step S704 again, and the processes from step S704 to S707 until the data “11” or the counter reaches the predetermined value. repeat. By performing these controls on all image data in the X direction, data processing for one column in the Y direction is completed.

  Next, with respect to the multivalued data for Y = 0 shown in FIG. 4, the above-described flow is performed assuming that the pixel interval to be preliminarily ejected on the paper is 1200 dpi, 10 pixel intervals, that is, 10 pixel intervals in the X direction. The case where it went is demonstrated.

  FIG. 6 is an explanatory diagram schematically showing an example of the arrangement of multi-value data after the image processing shown in FIG. 5 is performed. Since the first multi-value data 801 is “11”, it is data that is reliably controlled for ejection, and the counter is reset at this timing. Since the next multi-value data 802 is “01”, the count is started again and the counter is incremented by “+1”. Similarly, the subsequent multi-value data 803, 804, and 805 are not "11" data, so the counter is incremented by "+1". At the stage when 806 is input, there is no “11” data within the desired preliminary ejection interval (within the 10-pixel interval from 802 to 805). Therefore, the multi-value data 806 input from the image processing unit, which is the last image data of a predetermined value, is converted to “11” so that the paper preliminary ejection process can be performed at this timing.

  In the same manner, the counter is reset because the image data is “11” in the image data 807 and 808. In other cases, the counter is incremented by “+1”, and the multi-value is obtained when the counter reaches the desired preliminary discharge interval. The data 809 and 810 are converted into “11”, and the processing in the X direction ends.

  In addition, when the next one row of data is processed after completing all the processing in the X direction, if one row starts to be counted at the same timing, all the columns are converted into the paper preliminary ejection data “11”. there is a possibility. Therefore, there is a possibility that the line becomes dark every time and a good image cannot be obtained. Therefore, when processing the next row after processing the data for one row, the count start timing is shifted by one pixel. In this way, the same single row is not converted into paper preliminary ejection data, so that the output image is not affected. When the shifted value reaches the desired preliminary discharge interval, the row may start counting from X = 0.

  According to the present embodiment described above, it is possible to suppress unnecessary ink consumption by not performing unnecessary preliminary ejection control, and it is possible to cope with multi-value data. As a result, it can be realized with a simple and high throughput image reading apparatus.

  In this embodiment, the host computer is provided separately from the recording device. However, in the present invention, the processing performed by the host computer may be performed by the recording device. In this embodiment, the image processing is performed by the recording apparatus. However, in the present invention, up to multi-value data or binary data may be generated by the image forming apparatus and sent to the recording apparatus.

  In this embodiment, four-level recording data is described as an example. However, the present invention may be multi-level data having four or more values.

(Second Embodiment)
In the present embodiment, a case of a line printer in which a plurality of discharge port chips are arranged in a staggered manner will be described.

  First, the processing of the connecting portion of the nozzle tips of the recording head will be described.

  FIG. 7 is a schematic diagram for explaining a nozzle chip connecting portion of the recording head of the present embodiment. When using a long recording head, a plurality of nozzle chips may be connected to form one recording head as shown in FIG. That is, a line head for one color is realized by connecting a plurality of nozzle chips 201 and 202. At this time, in the region 203 in the chip 201 and the region 204 in the chip 202, a region where the discharge ports overlap is generated.

  If an input image is formed without taking this overlapping portion into consideration, the same data is ejected from the ejection openings of the region 203 and the region 204, and the density becomes high at the joint portion, and a good image can be obtained. become unable. Therefore, processing is performed in which the region of the connecting portion of the chips is recognized in advance, and the discharge control at the discharge port of either chip is masked in that portion.

  In other words, a specific mask pattern is prepared, the discharge port of the region 204 is masked at a certain timing, the discharge is performed only by the discharge port of the region 203, and the discharge port of the region 203 is masked at a certain timing. Mask processing is performed so that ejection is performed only at the outlet.

  On the other hand, even in the connecting portion, non-ejection or the like may occur at the ejection ports of the respective nozzle chips unless preliminary ejection is controlled at a predetermined preliminary ejection interval. However, in the joint portion, the mask control is performed with respect to the overlapping discharge ports. For this reason, as described above, multi-value data that is not simply “11” is counted, and the process of converting the multi-value data to “11” when the counter reaches the desired preliminary discharge interval is also performed at the connecting portion. Thus, preliminary ejection on the paper surface is performed at twice the interval at the joint portion.

  Therefore, only the connection portion is counted up to half the number of data of the desired interval, and the image data is converted to “11” when the counter reaches the half value. In this way, if the counter converts the data at half the timing, even if one of the discharge ports is masked at the connecting portion, as a result, each discharge port of the connecting portion can be surely printed at the desired interval. Preliminary discharge control is performed.

  FIG. 8 is a conceptual diagram for explaining the processing for the nozzle tip connecting portion of the present embodiment. The multi-value data 923 to 927 are preliminarily stored on the paper surface when “11” data is not input to the discharge ports 901 and 902 at a desired preliminary discharge interval (10 pixels in this embodiment). This is a place where data is converted into “11” data for ejection. Similarly, the multi-value data 928 to 931 are “11” for preliminary ejection on the paper surface when data “11” is not input to the ejection ports 903 and 904 at a desired preliminary ejection interval. This represents the location to be converted to data. As described above, 928 is shifted by one data in the X direction so that it is not converted to the paper preliminary ejection data “11” at the same timing in the row direction.

  On the other hand, paying attention to the connecting portion, the data is converted into “11” data for preliminary ejection on the paper surface at half the desired interval as in the multi-value data 932 to 940. At this time, the multi-value data 932 is controlled so as to be data for driving the discharge ports 909 and 910 (in this case, the discharge ports 911 and 912 are masked). The multi-value data 933 is controlled so as to be data for driving the discharge ports 911 and 912 (in this case, 909 and 910 are masked). As a result, the discharge ports 909 to 912 in the connecting portion are surely discharged at a desired preliminary discharge interval.

  In the chip connection mask unit 306 shown in FIG. 1, a mask that can mask the input multi-value data as described above alternately and obtain a good image without increasing the density while controlling ejection at a desired interval. It has a function. The data generated in this way is converted into binary data by the multi-value data conversion unit 307 and transmitted to the recording head 308 to form a recording image.

  As described above, in the present embodiment, the preliminary discharge is performed at an appropriate interval and without wasting ink while obtaining a good image in consideration of a connecting portion in a line head formed by connecting a plurality of chips. Control can be performed.

301 Host Computer 305 Paper Preliminary Discharge Data Generation Unit 308 Recording Head

Claims (5)

An image forming apparatus for forming an image by applying ink droplets ejected from ejection ports provided in a recording head to a recording medium,
Image data generating means for generating image data for forming the image;
Preliminary ejection means for ejecting ink droplets that do not form an image in an area where an image is formed on the recording medium from the ejection port;
Counting means for counting pixels for forming the image,
When the count value of the counting means is a predetermined value, the image data of the pixel of the predetermined value is set as preliminary ejection data for performing preliminary ejection by the preliminary ejection means, and the count value is reset Forming equipment.   When there is data to be ejected from the ejection port in the image data between the start of counting and the count value reaching a predetermined value, the count value is reset and counting is started again. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the image data is multi-value data of four or more values. An ink jet recording apparatus that forms an image by applying ink droplets ejected from ejection ports provided in a recording head to a recording medium,
Image data generating means for generating image data for forming the image;
Preliminary ejection means for ejecting ink droplets that do not form an image in an area where an image is formed on the recording medium from the ejection port;
Counting means for counting pixels for forming the image,
When the count value of the counting means is a predetermined value, the image data of the pixel having the predetermined value is set as preliminary ejection data for performing preliminary ejection by the preliminary ejection means, and the count value is reset. Recording device. An ink jet recording method for forming an image by applying ink droplets ejected from ejection ports provided in a recording head to a recording medium,
An image data generation step for generating image data for forming the image;
A preliminary ejection step of ejecting ink droplets that do not form an image in an area where an image is formed on the recording medium from the ejection port;
A counting step of counting pixels for forming the image,
When the count value in the counting step is a predetermined value, the image data of the pixel having the predetermined value is set as preliminary ejection data for performing preliminary ejection in the preliminary ejection step, and the count value is reset. Recording method.

Images