1. Field of the Invention
The present invention(s) relate to at least one apparatus and at least one method for recording.
2. Description of the Related Art
Nozzle arrays of general ink-jet printers are arranged at intervals, and thus, a difference in ink ejection timing due to the intervals is adjusted. In full-line ink-jet printers, a plurality of heads for different colors are arranged in a recording-medium conveying direction, so that the distance between the heads is large, thus causing a significant difference in ejection timing when a conveyance error has occurred. This causes image degradation, such as distortion of line images and a change in color tone. Japanese Patent Laid-Open No. 2005-138374 discloses a related technique for adjusting a recording position by detecting deviation of landing due to a conveyance error and by correcting ejection timing during recording. Japanese Patent Laid-Open No. 2008-175966 discloses a related technique for recording a pattern for detecting deviation of landing between images and determining the length of the detecting-pattern formed area in the conveying direction depending on the operating environment (temperature and cumulated operating time).
However, it is known that the conveyance error changes because of factors other than the operating environment. Specifically, the conveyance error may change depending on the moisture state, the kind, and the width of paper, and so on. These factors cause a change in the hardness of the paper and friction between conveying rollers and the paper to change the conveying speed. Therefore, merely determining the detection pattern on the basis of the cumulated operating time, as disclosed in Japanese Patent Laid-Open No. 2008-175966, leads to a concern about an excessive increase in the detecting-pattern formation area, thus increasing the consumption of the recording medium. Another concern is that a necessarily and sufficiently long detecting-pattern formation area cannot be ensured, which causes the detection pattern and recorded images to partially overlap, resulting in inaccurate detection of the recording position.
The present invention(s) provide at least one recording apparatus, and method(s) for recording with one or more recording apparatuses, capable of forming a detection pattern in a suitable area while reducing consumption of a recording medium.
The present invention(s) provide at least one recording apparatus including a plurality of ink ejecting nozzles, a recording control unit, an acquisition unit, and an adjusting unit. The ink ejecting nozzles may be arrayed in a first direction. The nozzles may have a first nozzle array and a second nozzle array disposed in a second direction perpendicular to the first direction. The recording apparatus may eject ink from the nozzles of the first nozzle array and the second nozzle array to record images on a recording medium while conveying the recording medium in the second direction. The recording control unit may control recording with the first and second nozzle arrays so that a plurality of alignment measuring patterns are recorded between recording areas of the images on the recording medium at predetermined intervals. The patterns may be used to obtain information on the amount of misalignment in the second direction on the recording medium between a position of recording with the first nozzle array and a position of recording with the second nozzle array. After the patterns are recorded, the plurality of images may be recorded upstream from the recording areas of the patterns in the second direction, respectively. The acquisition unit may obtain the information on the basis of the result of reading the patterns. In recording with the first nozzle array and the second nozzle array performed after the recording of a first pattern of the patterns, the adjusting unit may adjust the relative recording positions of the first nozzle array and the second nozzle array on the basis of the information obtained by the acquisition unit and the corresponding amount of misalignment. If the acquisition unit cannot obtain the information on the basis of the result of reading the first pattern, the adjusting unit may not perform the adjustment, and the next time, the recording control unit may control the recording so that a second pattern is recorded in a recording area longer in the second direction than the recording area of the first pattern. If the acquisition unit obtains the information on the basis of the result of reading the first pattern, the adjusting unit may adjust the recording positions for the first pattern, and the next time, the recording control unit controls the recording on the basis of the adjustment with the adjusting unit so that a second pattern is recorded in a recording area shorter in the second direction than the recording area of the first pattern. Additionally or alternatively, if the first pattern overlaps with the images, the recording control unit may control the recording so that a recording area of a second pattern in the second direction is longer than the recording area of the first pattern in the second direction. According to other aspects of the present invention(s), other apparatuses and methods are discussed herein.
Further features of the present invention(s) will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Embodiments of the present invention will now be described in detail with reference to the attached drawings. In the following description, a recording apparatus that adopts an ink-jet recording method will be described by way of example. Examples of the recording apparatus include a single-function printer having only a recording function and a multifunction printer having a plurality of functions, such as a recording function, a facsimile function, and a scanner function. Other examples are manufacturing apparatuses for manufacturing color filters, electronic devices, optical devices, microstructures, and so on.
In the following description, “recording” refers to forming significant information, such as characters and figures, and insignificant information. “Recording” further includes forming images, designs, patterns, structures, and so on on a recording medium so that humans can view, irrespective of whether or not it is an actualized matter, and processing a medium.
“Recording medium” refers to not only paper for use in general recording apparatuses but also fabrics, plastic film, metal plates, glass, ceramics, resin, wood, leather, and other materials that accept ink.
“Ink” should be broadly interpreted as in the definition of “recording” described above. Specifically, “ink” refers to liquid applied onto a recording medium to be used in forming images, designs, or patterns, processing the recording medium, or processing ink (for example, solidifying or insolubilizing coloring materials in the ink).
The recording apparatus 20 accommodates a sheet feeding unit 1, a decurling unit 2, a skew correcting unit 3, a recording unit 4, a checking unit 5, a cutter unit 6, an information recording unit 7, a drying unit 8, a sheet take-up unit 9, and a discharge conveying unit 10. The recording apparatus 20 further accommodates a sorter unit 11, an output tray 12, and a control section 13.
A recording medium (in this case, a sheet) is conveyed along a sheet conveying path (indicated by the solid line in
The sheet feeding unit 1 accommodates a rolled continuous sheet 51 and feeds it. The sheet feeding unit 1 can accommodate two rolls R and selectively draws the continuous sheet 51 for feeding. The number of rolls to be accommodated may not necessarily be two; one or three or more rolls may be accommodated.
The decurling unit 2 reduces the curl (warp) of the sheet 51 fed from the sheet feeding unit 1. The decurling unit 2 curves the sheet 51 with two pinch rollers for each driving roller so as to give a reverse warp. This can reduce the curl of the sheet 51.
The skew correcting unit 3 corrects the skew (an inclination with respect to an initial advancing direction) of the sheet 51 that has passed through the decurling unit 2. The skew correcting unit 3 corrects the skew of the sheet 51 by pressing a reference end of the sheet 51 against a guide member.
The recording unit 4 forms an image on the conveyed sheet 51 for recording. The recording unit 4 includes a plurality of sheet conveying rollers and a plurality of ink-jet recording heads (hereinafter simply referred to as recording heads) 14. The recording heads 14 are full-line recording heads each having a recording width corresponding to the maximum width of a sheet to be used or longer than that so as to cover the maximum width of the sheet.
The recording heads 14 are arranged in parallel along the conveying direction. In this embodiment, four recording heads 14 corresponding to four colors, black (K), cyan (C), magenta (M), and yellow (Y), are disposed. The recording heads 14 are disposed in order of K, C, M, and Y from the upstream side in the sheet conveying direction, with their recording widths aligned along the sheet conveying direction. The number of colors and the number of recording heads may not necessarily be four and may be changed as necessary. Examples of the ink-jet system include a system using a heater element, a system using a piezoelectric element, a system using an electrostatic element, and a system using a microelectromechanical system (MEMS) element. The individual color inks are supplied from ink tanks to the recording heads 14 through ink tubes.
The checking unit 5 checks on reading of images with an optical sensor, for example, a CCD line sensor 17. An example of the CCD line sensor 17 is a two-dimensional image sensor, in which a plurality of reading elements are arranged in a direction perpendicular or substantially perpendicular to the sheet conveying direction (in the nozzle array direction). The checking unit 5 further includes a light-emitting element and so on. With such a configuration, the checking unit 5 optically reads patterns and images recorded on the sheet 51 by the recording unit 4 to check the state of the nozzles of the recording heads 14, the state of conveyance of the sheet 51, the position of the images, and so on.
The cutter unit 6 is a mechanism for cutting the sheet 51 on which images are recorded into a predetermined length of sheets 51 with a cutter C. The cutter unit 6 has a plurality of conveying rollers for feeding the sheets 51 to the next process.
The information recording unit 7 records a serial number, date, and other information on the back of the cut sheets 51. The drying unit 8 heats the sheet on which images are recorded by the recording unit 4 to dry the applied ink (in a short time). The drying unit 8 has a conveying belt for feeding the sheets 51 to the next process and conveying rollers.
The sheet take-up unit 9 temporarily takes up the continuous sheet 51 whose front surface has been printed at double-sided recording. The sheet take-up unit 9 includes a take-up drum that rotates to take up the sheet 51. After completion of recording on the front surface of the sheet 51, the continuous sheet 51 that is not cut by the cutter unit 6 is temporarily taken up by the take-up drum. After completion of the taking-up operation, the taken-up sheet 51 is fed to the recording unit 4 via the decurling unit 2. Since the sheet 51 is reversed inside out, the recording unit 4 can perform recording on the back of the sheet 51. A specific operation for double-sided recording will be described later.
The discharge conveying unit 10 conveys the sheets 51, which are cut by the cutter unit 6 and are dried by the drying unit 8, to the sorter unit 11. The sorter unit 11 discharges the sheets 51 on which images are recorded to the output tray 12. The sorter unit 11 may sort the sheets 51 to different output trays 12.
The control section 13 controls the components of the recording apparatus 20. The control section 13 includes a controller 15 having a CPU, a memory, various I/O interfaces, and so on, and a power source. The operation of the recording apparatus 20 is controlled by the controller 15 or in accordance with an instruction from an external device 16 (for example, a host computer) connected to the controller 15 via an I/O interface.
Referring next to
When the sheet 51 is fed from the sheet feeding unit 1, the sheet 51 is processed by the decurling unit 2 and the skew correcting unit 3. Thereafter, images are recorded on the surface of the sheet 51 by the recording unit 4. The sheet 51 on which images are recorded passes through the checking unit 5 and is cut into a predetermined length of sheets 51 by the cutter unit 6. The back of the cut sheets 51 is printed with information, such as date, by the recording unit 7 as necessary. Subsequently, the sheets 51 are dried by the drying unit 8 one by one and are then discharged onto the output tray 12 of the sorter unit 11 through the discharge conveying unit 10.
The operations from the sheet feeding unit 1 to the checking unit 5 are the same as those for single-sided recording described using
After completion of the recording sequence for the front surface of the sheet 51, the recording sequence for the back surface is started. When this sequence is started, the take-up drum rotates in the opposite direction to the direction during the taking-up operation (in
The sheet 51 is then conveyed to the skew correcting unit 3 and to the recording unit 4, where images are recorded on the back surface of the sheet 51. The sheet 51 on which images are recorded passes through the checking unit 5 and is cut into a predetermined length of sheets 51 by the cutter unit 6. Since images are recorded on both sides of the cut sheets 51, the information recording unit 7 does not record information, such as date. The sheets 51 then pass through the drying unit 8 and the discharge conveying unit 10 and are discharged to the output tray 12 of the sorter unit 11.
The CPU 201 is a central processing unit with a microprocessor (microcomputer) configuration and is included in the control section 13 shown in
The operating portion 206 includes hard keys or a touch panel for a user to perform various operations and a display unit (not shown) for presenting (notifying) various items of information to the user. The operating portion 206 corresponds to the controller 15 in
The image processing portion 207 develops (converts) print data that the recording apparatus 20 deals with (for example, data expressed in a page description language) to image data (a bitmapped image) and performs image processing. The image processing portion 207 converts the color space (for example, YCbCr) of image data included in input print data to a standard RGB color space (for example, sRGB). Furthermore, the image processing portion 207 performs various image processing operations, such as conversion of resolution to an effective number of pixels (that the recording apparatus 20 can provide), image analysis, and image correction, on the image data as necessary. Image data obtained by such image processing operations is stored in the RAM 203 or the HDD 204.
The engine control portion 208 functions as a recording control unit that controls the process of printing an image based on print data on a sheet in response to a control command received from the CPU 201 or the like. The engine control portion 208 gives an instruction to eject ink to the recording heads 14 for individual colors, sets ejection timing to adjust dot positions (ink landing positions) on a recording medium, and makes an adjustment based on the driving state of the heads. The engine control portion 208 controls driving of the recording heads 14 in accordance with print data to eject ink from the recording heads 14, thereby forming an image on the sheet 51. The engine control portion 208 controls paper feed rollers and conveying rollers, such as giving an instruction to drivepaper feed rollers and an instruction to drive conveying rollers, and obtaining the rotation states of the conveying rollers, to convey the sheet 51 at an appropriate speed through an appropriate path or stops the sheet 51.
The scanner control portion 209 controls an image sensor in accordance with a control command received from the CPU 201 or the like to read images on the sheet 51 to acquire analog luminance data on red (R), green (G), and blue (B), and converts the analog luminance data to digital data. Examples of the image sensor include a CCD image sensor and a CMOS image sensor. The image sensor may be either a linear image sensor or an area image sensor. The scanner control portion 209 gives an instruction to operate the image sensor, obtains the state of the image sensor based on the operation, and analyzes the luminance data obtained from the image sensor to detect an ejection failure of ink ejected from the recording heads 14 and sheet cut positions. Sheets 51 that are determined to be accurately printed with images by the scanner control portion 209 are subjected to the process of drying ink on the sheets 51 and are then discharged onto a tray 12 of the sorter unit 11.
The host computer 16 (the external device, described above) is a device connected outside the recording apparatus 20 and serving as an image-data supply source for the recording apparatus 20 to perform printing and issues various print job orders. The host computer 16 may be a general-purpose personal computer (PC) or another type of data supply device. An example of the other type of data supply device is an image capture device that captures images and generates image data. Examples of the image capture device include a reader (scanner) that reads images on a document to create image data and a film scanner that reads a negative film or a positive film to create image data. Other examples of the image capture device include a digital camera that acquires a still image to create digital image data and a digital video camera that acquires a moving image to create moving image data. Alternatively, a photo storage on a network or a socket into which a portable removable memory inserted may be provided to allow an image file stored in the photo storage or the portable memory to be read into image data for printing. Instead of the general PC, various kinds of data supply device, such as a terminal specifically for recording apparatuses, may be provided. These data supply devices may be included in the recording apparatus 20 or may be another device connected outside the recording apparatus 20. If the host computer 16 is a PC, the PC stores an OS, application software for creating image data, and a printer driver for the recording apparatus 20 in a storage. The printer driver controls the recording apparatus 20 and converts image data supplied from the application software to a format that the recording apparatus 20 can deal with to create print data. It is also possible that after print data is converted to image data by the host computer 16, the image data is supplied to the recording apparatus 20. Not all of the above processes need to be implemented by software; part or all of them may be implemented by hardware. Image data, commands, and status signals supplied from the host computer 16 can be transmitted to or received from the recording apparatus 20 via the external I/F 205. The external I/F 205 may be either a local I/F or a network I/F. The external I/F 205 may adopt either wired connection or wireless connection.
The above components in the recording apparatus 20 are connected to communicate with one another through the system bus 210. While in the above examples, one CPU 201 controls all the components in the recording apparatus 20 shown in
Referring to
The engine control portion 208 includes, as a functional configuration, a pattern-formation control section 21, a read-pattern acquisition section 22, a misalignment calculating section 23, and a correcting section 24.
The pattern-formation control section 21 functions as a recording control unit for controlling recording of misalignment measuring patterns for measuring the amounts of misalignment of the landing positions (attachment positions) of ink ejected from the individual nozzle arrays of the recording heads 14. The details of the misalignment measuring patterns will be described later with reference to
The read-pattern acquisition section 22 obtains misalignment measuring patterns recorded on a recording medium (sheet). The misalignment measuring pattern is read using a reading device, such as a CCD line sensor 17, provided in the checking unit 5.
The misalignment calculating section 23 calculates the amounts of misalignment in the recording heads 14 and among the recording heads 14, which is caused by a production error, an installation error, or the like, on the basis of the result of reading the recording-position-misalignment measuring pattern. In other words, the misalignment calculating section 23 calculates the amounts of misalignment of actual landing positions of ink relative to ideal ink landing positions.
The correcting section 24 functions as an adjusting unit that adjusts the recording positions of the nozzle arrays of the individual recording heads 14 by correcting misalignment of the landing positions of ink ejected from the nozzles of the individual recording heads 14 on the basis of the amounts of misalignment calculated by the misalignment calculating section 23. The correction performed by the correcting section 24 is applied also to recording of a recording-position-misalignment measuring pattern performed after the correction. The correcting section 24 includes an ejection-timing control section 25 that controls the ejection timing of ink from the individual nozzles and a shift processing section 26 that shifts the areas of the nozzles for use in recording. This is a description of an example of the functional configuration implemented by the control section 13.
Referring next to
The recording head 14 includes eight chips 31 to 38. The chips 31 to 38 each have a nozzle member layered on, for example, a silicon substrate, and have an effective ejection width of 1 meter in the Y-direction in
The individual chips 31 to 38 each have a plurality of nozzle arrays in which nozzles for ejecting ink are arrayed in a predetermined direction (in this case, in the Y-direction) in the X-direction perpendicular to the Y-direction. More specifically, eight nozzle arrays (a nozzle array A, a nozzle array B, a nozzle array C, a nozzle array D, a nozzle array E, a nozzle array F, a nozzle array G, and a nozzle array H) are disposed in parallel. The chips 31 to 38 overlap with each other by a predetermined number of nozzles. More specifically, part of the nozzles of the nozzle arrays A to H of adjacent chips overlap with each other in the Y-direction (in the nozzle array direction).
The chips 31 to 38 each have a temperature sensor (not shown) for measuring the temperature of the chips 31 to 38. The nozzles (ejection ports) each have a recording element (a heater) formed of, for example, a heating resistor. The recording elements foam ink by electric heating to cause the ink to be ejected through the ejection ports with their motion energy.
The recording heads 14 have an effective ejection width of about 8 inches, which covers the short side of an A4 recording medium, thus allowing recording of images to be completed by one scanning.
Referring next to
Referring next to
In
In
If a recording-position-misalignment measuring pattern recorded after the recording-position-misalignment measuring pattern 66 is as shown in
The first analysis pattern may be an error because it is not corrected using the previous analysis. In other words, the first analysis pattern cannot be correctly analyzed because the lengths X1 and X2 of the portions 101 and 102 of the recording-position-misalignment measuring pattern 64 are short. Therefore, for the first analysis pattern, the lengths X1 and X2 may be set large in advance, as shown in
A method for determining the lengths X1 and X2 will be described. The conveying speed changes depending on the moisture state, the kind, and the width of paper, and so on. These factors change the hardness of the paper and friction between conveying rollers and the paper to change the conveying speed. Therefore, the lengths X1 and X2 are set in consideration of these errors and a change in conveying speed from the start of recording to the recording-position-misalignment measuring pattern 64.
A specific method for determining the lengths X1 and X2 is based on a conveying speed at the start of printing estimated from the kind and width of paper.
Although this is a typical embodiment of the present invention, the present invention should not be limited to the above and can be appropriately modified without departing from the spirit and scope of the present invention. For example, although the above embodiment shows an example in which the checking unit 5 is a CCD line sensor, it may be a CMOS sensor.
Although the recording-position-misalignment measuring patterns are recorded in non-image portions at fixed intervals, they may not necessarily be recorded at fixed intervals. The recording-position-misalignment measuring patterns may be recorded either in all of a plurality of non-image portions or in every several (for example, three) non-image portions. The number of the several non-image portions in which no recording-position-misalignment measuring pattern is recorded may be varied.
Although the measurement of the amounts of misalignment of a recording position during recording is based on an analysis of the amounts of misalignment among recording heads, the present invention should not be limited thereto; the measurement may be based on an analysis of the amounts of misalignment in recording heads, for example, the amounts of misalignment among nozzle arrays or chips.
Although a random tile pattern is given as an example, the present invention is not limited thereto. Although the tile pattern is recorded with reference to the nozzle array H, any other nozzle arrays may be used as reference. Although the amounts of misalignment among recording heads are analyzed with reference to the recording head for black (K), any other recording heads may be used as reference.
Although a method for determining the lengths X1 and X2 depending on the kind and width of paper is given, the present invention is not limited thereto. The lengths X1 and X2 may be determined by storing the history of an analysis of landing-misalignment analysis patterns in the ROM 202 and estimating the conveying speed from the history of the past analysis before the recording-position-misalignment measuring pattern 64 is recorded.
Since the conveying speed changes depending on the conveying distance between images, the lengths X1 and X2 may be determined depending on the length of an image before a recording-position-misalignment measuring pattern is recording.
A unit for measuring the conveying speed of the recording medium may be provided to determine the lengths X1 and X2 from the measured conveying speed.
The recording heads may not necessarily have the above configuration (see
The basic configuration of the apparatus and control in the second embodiment are the same as those in the first embodiment. In this embodiment, recording areas for recording-position-misalignment measuring patterns in non-image areas will be described.
Next, a cut mark will be described. The cutter unit 6 of the ink-jet recording apparatus 20 shown in
The width of the blank area W1 shown in
The recording-position-misalignment measuring pattern 115 in
This embodiment allows measurement of misalignment of recording positions without providing additional recording areas only for recording-position-misalignment measuring patterns by recording the recording-position-misalignment measuring patterns in cut-mark pattern areas, as described above.
Although this embodiment shows an example in which the recording-position-misalignment measuring patterns are recorded in cut-mark pattern areas, the present invention is not limited thereto; they may be recorded part of non-image patterns having another function. For example, they may be patterns for recovering ejection performance or patterns for determining the state of ejection.
The present invention can provide a recording position at which a detection pattern can be formed in an appropriate area with lower consumption of a recording medium.
Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present invention, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2013-257154, filed Dec. 12, 2013, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2013-257154 | Dec 2013 | JP | national |