JP2012086443A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording device, which is configured to reduce deterioration of recording resolution resulting from elongation of paper by landed droplets.SOLUTION: The device includes a tray to be loaded with recording paper 2, a recording paper carrying means for carrying the recording paper 2 loaded in the tray, and a line head 6 having a plurality of nozzles for discharging ink toward the carried recording paper 2, which are linearly aligned, the alignment direction of the nozzles being orthogonal to the carrying direction of the recording paper 2. Thus, when the ink is discharged from the line head 6, the fiber direction of the recording paper 2 is conformed to the alignment direction of the nozzles of the line head 6.

Description

  The present invention relates to an image recording apparatus that performs high-resolution image recording in consideration of paper elongation when an image is recorded on a recording medium by a line-type recording head that ejects ink droplets.

  In general, there is known an ink jet printer that records an image on a transported recording medium using a full-line recording head having a recording area (nozzle array) having a plurality of nozzles arranged in a line and having a recording area (nozzle array) exceeding the width of the recording medium. It has been. In addition, a line type recording in which short recording heads each having a recording area equal to or smaller than the width of the recording medium are alternately arranged in a staggered manner so as to be equal to or larger than the width of the recording medium. There is a head.

  Ink jet printers using these recording heads are required to have higher resolution. However, in an inkjet printer that needs to arrange nozzles (recording elements) at the same pitch as the pixels that form an image, it is difficult to form the nozzles at the same pitch as the pixel pitch that is ultimately desired. . Therefore, as disclosed in Patent Document 1, nozzles are arranged at a pitch N times the pitch of the pixel to be finally obtained, and the line head is moved N times by 1 / N in the nozzle arrangement direction to form an image. By repeating the above, an image having a resolution N times the resolution of the nozzle is obtained.

JP 2000-94755 A

  However, when recording (printing) is performed in a plurality of times on the same recording area on the recording medium, paper elongation occurs due to the ink droplets of the previously recorded ink dots, and the ink dots to be recorded later are A positional deviation occurred without landing at a position having a desired relative relationship (that is, adjacent or overlapping) with respect to the position of the ink dot recorded previously. That is, when the recording process is performed separately by a plurality of line heads, a time difference occurs between the previous ink discharge and the subsequent ink discharge. The ink droplets ejected first and landed on the medium penetrate into the medium until the subsequent ink droplets land on the paper surface. Ink penetration causes paper elongation. Due to the elongation of the paper, there was a positional shift in the landing of the ink droplets. This misalignment is particularly noticeable when water-based ink is used.

As a recording medium corresponding to the water-based ink, a recording paper containing cellulose is often employed. Usually, when water is infiltrated into cellulose, swelling occurs and the size changes. Therefore, when water-based ink is used for recording paper, the paper elongation due to the penetration of droplets is large, and the degradation of recording resolution becomes noticeable.
Although it depends on the properties of the ink and the amount of liquid, the elongation of the recording paper when water is saturated is about 0.1 to 3.0%.

  When recording with a line-type recording head, the amount of elongation is on the order of several tens of micrometers because the amount of ink is generally small compared to the saturated water absorption of the recording paper. For example, since the dot interval (pixel interval) at a recording resolution of 600 dpi is about 25.4 mm / 600 = 42 μm, if there is a paper stretch of about several tens of μm while the medium passes through a plurality of heads, The dot spacing will be disturbed. As a result, the positions of the formed dots are shifted, and a background portion where ink dots are not formed is generated. That is, white lines (deterioration in printing resolution) due to the elongation of the recording paper become remarkable.

The positional deviation of the ink dots due to the paper elongation becomes relatively large as the recording resolution is increased, which becomes a significant problem. However, due to the deformation on the recording medium side, effective improvement cannot be achieved even if the processing accuracy of the nozzle is improved.
SUMMARY OF THE INVENTION An object of the present invention is to provide an image recording apparatus that performs image recording according to the properties of a recording medium and reduces deterioration in recording resolution caused by paper stretching due to landed droplets.

  In order to achieve the above object, an ink jet printer according to an embodiment of the present invention includes a tray on which recording paper is loaded, recording paper transporting means for transporting the recording paper loaded on the tray, and the transported A plurality of nozzles that eject ink toward the recording paper are linearly arranged, and the inkjet head is arranged so that the arrangement direction of the nozzles is orthogonal to the conveyance direction of the recording paper, and When the ink is ejected from the ink jet head toward the recording paper, the fiber direction of the recording paper is matched with the arrangement direction of the nozzles of the ink jet head.

As described above, according to the present invention, it is possible to provide an image recording apparatus that performs image recording according to the properties of a recording medium and reduces deterioration in recording resolution caused by paper stretching due to landed droplets.

FIG. 1 is a diagram illustrating a configuration example of an ink jet printer as an image apparatus according to the first embodiment. 2 (a) and 2 (b) show the packing state of the recording paper, FIG. 2 (c) shows the concept of the grain of the vertical recording paper, and FIG. 2 (d) shows the paper of the horizontal recording paper. Shows the concept of the eye. 3A is a diagram showing a screen for instructing loading of recording paper, FIG. 3B is a diagram showing a setting screen for the model number of recording paper, and FIG. 3C is loading of longitudinal recording paper It is a figure which shows a confirmation screen. 4A shows a confirmation screen for loading the horizontal recording paper, FIG. 4B shows a start screen showing the set recording conditions, and FIG. 4C shows loading on the upper tray. FIG. 6 is a diagram illustrating a screen for instructing reloading of the recording paper that has been performed. FIG. 5 is a diagram illustrating an internal configuration of the upper tray as viewed from above. FIG. 6A is a diagram showing the orientation of the vertical recording paper loaded on the tray and the slider adjustment position, and FIG. 6B is a diagram showing the orientation of the horizontal recording paper loaded on the tray and the slider adjustment position. . FIG. 7 is a main flowchart for explaining the operation up to the start of recording in the printer of the first embodiment. FIG. 8 is a flowchart for explaining an upper tray confirmation subroutine. FIG. 9 is a flowchart for explaining a subroutine of paper detection processing. FIG. 10 is a flowchart for explaining a subroutine of the recording paper type setting process. FIG. 11 is a flowchart for explaining a subroutine of processing for the fiber direction and nozzle row direction of the recording paper. FIG. 12 is a flowchart for explaining a subroutine of notification processing. FIG. 13 is a block diagram illustrating a configuration of a control unit provided in the printer of the present embodiment. FIG. 14 is a diagram illustrating an example of a table for obtaining the paper elongation rate from the printing rate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the properties of the recording medium used in the image recording apparatus of this embodiment will be described. Cut paper used for recording paper (or copy recording paper) that is generally used as a recording medium has a grain (fiber (cellulose) orientation) generated due to the manufacturing process. As shown in FIG. 2C, when the longitudinal direction of the cut paper and the direction of the fibers are parallel at the time of manufacture, it is referred to as a longitudinal eye (T eye). On the other hand, when the longitudinal direction of the cut paper and the direction of the fibers are perpendicular, it is called a horizontal eye (Y eye).

  These recording papers, when absorbed, have a characteristic that they are not easily stretched in the direction of the fibers (in the direction of the arrows) and are easily stretched in the orthogonal direction. Although depending on the type of recording paper, paper thickness, etc., the expansion / contraction rate of the recording paper in the fiber direction is about 0.1 to 0.5% at the maximum, and about 2 to 3% in the direction orthogonal to the vertical direction. The elongation is different by 2 to 10 times between the eyes and the side eyes. However, these numerical values are maximum values (when completely applied), and in actual inkjet recording using water-based ink, the numerical values are not as they are. In the case of water-based ink printing by a line type recording head, the amount of ink that lands on the recording paper is small compared to the saturated water absorption amount of the recording paper, so the actual elongation is assumed to be on the order of several tens of μm. .

In the embodiment described below, when an image is recorded using water-based ink, attention is paid to the relationship between the nozzle arrangement direction in the image recording apparatus and the fiber direction (paper grain direction) of the recording paper. By aligning them so as to be parallel to each other, the nozzle row direction with respect to the recording paper is arranged so as to be parallel to prevent image deterioration due to paper elongation.
In the embodiment of the present invention described below, attention is paid to the relationship between the nozzle arrangement direction and the fiber direction (paper grain direction) of the recording paper, and by providing a positional relationship that is parallel to each other during image recording, An image recording apparatus that suppresses image degradation due to paper stretching in a direction parallel to the arrangement direction is proposed.

[First Embodiment]
The image recording apparatus according to the first embodiment will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of an ink jet printer (hereinafter referred to as a printer) equipped with a plurality of full line type recording heads (hereinafter referred to as line heads) as an example of the image apparatus according to the first embodiment. FIG. Further, a recording paper is taken as an example of the recording medium.

  The printer 1 of this embodiment includes a recording paper supply mechanism 3 that supplies the recording paper 2, a transport mechanism 4 that holds and transports the recording paper 2, and a storage mechanism that discharges and stores the recording paper 2 on which an image is recorded. 5, a recording head unit 6 provided with a plurality of line heads 6 (6C, 6K, 6M, 6Y) for recording an image on the recording paper 2, an input unit 7 for performing various settings and the like by user operations, The monitor unit 8 that displays the set information and the operation status of the apparatus, the ink supply unit 9 that supplies ink to the line type recording head 6, the control unit 10 that controls the entire apparatus, and the line head 6 are moved. And a head moving mechanism 20. These components are arranged in a device frame (not shown).

  In such a configuration, the supply mechanism 3 includes an upper tray 13 and a lower tray 14 that respectively store a plurality of recording papers, and a guide member 15 that guides the recording paper 2 taken out one by one to the transport mechanism 4. The The transport mechanism 4 includes a drum 16 that sucks and transports the recording paper 2, a recording paper detection sensor 17 that detects an end (leading end and rear end) of the recording paper 2 held on the drum 16, and a roller (not shown). Etc. The drum 16 is rotated about the rotation shaft 16a by a drive motor (not shown) driven and controlled by the control unit 10. Further, the rotary shaft 16a of the drum 16 is provided with an encoder 51 so as to be interlocked with the rotation. The encoder 51 outputs a signal (A phase, B phase) corresponding to the rotation angle of the drum 16 to the control unit 10. The control unit 10 can detect any of the rotation angle, the rotation speed, and the rotation direction by monitoring this signal.

The storage mechanism 5 is provided so as to be close to the drum 16, and includes a peeling claw 18 that peels off the recording paper 2 attached to the outer peripheral surface of the cylinder of the drum 16, and a discharge tray 19 that stores the removed recording paper 1. Consists of.
The line head 6 has a recording area (nozzle row length) having a length exceeding the recording paper width, and has a resolution of 300 dpi, for example. In the line head 6, the line heads 6C, 6K, 6M, and 6Y are attached to a frame (not shown) so that the nozzle surface 6a faces the outer surface of the drum 16 at a predetermined interval. Here, a configuration example using four line heads using four colors of ink is used, but the configuration is not limited, and the number can be increased or decreased according to the number of ink colors. These inks are supplied from an ink bottle of each color (not shown) through an ink supply path (not shown) provided independently for each ink color.

  The line head 6 is provided for each nozzle mainly communicating with an ink chamber to which ink is supplied from an ink supply path, a nozzle plate (nozzle surface) in which a plurality of nozzles are formed in a row, and the ink chamber. And a piezoelectric element. In this configuration, the piezoelectric element causes the ink supplied from the ink chamber to be ejected from the nozzle.

  The head moving mechanism 20 includes a plurality of line heads 6 formed in a row on the nozzle surface 6a in a direction (main scanning direction) orthogonal to the conveying direction of the recording paper 2 by the conveying mechanism 4 (rotational axis direction of the drum 16). A distance (42 μm) corresponding to ½ of the nozzle pitch (about 84 μm) between the nozzles 6 b is moved. The head moving mechanism 20 moves the line head 6 by a minute amount in the direction of the rotation axis of the drum 16 every time the drum 16 rotates (every image recording), thereby realizing an image recording with a resolution of 600 dpi.

  Moreover, the input part 7 consists of a touch panel, a key switch, etc., and is provided so that it may be exposed to the exterior part of an apparatus. The monitor unit 8 includes, for example, a liquid crystal display device, and displays the instruction content from the user by the input unit 7, device setting information, and operation status (including warning display). The touch panel is provided on the liquid crystal screen of the monitor unit 8. The user can select and set the model number of the recording paper to be used by touching the touch panel. Also, warnings such as out of ink and recording paper are notified to the user through the display on the liquid crystal screen.

  In the image recording apparatus of the present embodiment, the control unit 9 is further connected to an external device 12 such as a personal computer via a network 11 such as a LAN, and receives image information and the like (print information and print commands). The Image information or document information to be recorded by the user is transmitted from the external device 12 to the printer 1 through the network 11. After receiving these pieces of information, the recording paper stored in the tray is transported and charged and adsorbed on the drum, and water-based ink droplets of each color are ejected from the recording head onto the recording paper so that the printed matter can be taken out. .

Although details will be described later, the printer 1 has a high image quality mode as a function of correcting the above-described deterioration in image quality due to paper elongation. In the high image quality mode 1, there are ON (selected) and OFF (non-selected) states, which are selected and set by the input unit 7 of the printer 1, and the setting state of the high image quality mode is displayed on the monitor unit 8. .
When the high image quality mode is selected (ON), when the user loads a recording sheet according to a predetermined procedure to be described later, the sheet expansion correction is executed in the printer 1. On the other hand, when the high image quality mode 1 is not selected (OFF), the high image quality mode 2 is not selected.

Next, the operation of the printer of this embodiment will be described.
a. The user turns on the printer 1. When the power is turned on, the printer 1 performs initial settings, detects the presence / absence of the remaining amount of ink, the presence / absence of recording paper, etc., checks whether image recording is possible, and can start recording. Display a start screen that suggests. On the other hand, if the recording cannot be started, the current state of the printer 1 is displayed as a warning.

b. The procedure proceeds to the procedure for loading the recording paper 2.
[Check remaining amount of recording paper]
The printer 1 detects the remaining amount of the recording paper 2 loaded in the trays 13 and 14 by a recording paper remaining amount sensor (not shown). In this detection result, when there is no remaining recording paper 2 in the trays 13 and 14, a character or a mark for prompting the trays 13 and 14 to replenish the recording paper 2 is displayed on the screen of the monitor unit 8. FIG. 4A shows an example of a confirmation screen display for loading the horizontal recording paper.

[Recording paper loading and setting]
The user confirms the display of recording paper replenishment displayed on the monitor unit 8, and loads the recording paper 2 on the tray in which the recording paper 2 has run out. 2A and 2B, a designated recording paper package 31 used in the printer 1 of the present embodiment, and a printed exterior label 32 such as a recording paper size and a model number to be attached to the packaging 31, Two examples of 33 are shown. Among these, the model number is a unique character string for identifying the difference in sheet thickness, vertical / horizontal, coated paper / plain paper, and the like on the recording paper 2. 2C shows the concept of the vertical recording paper (T), and FIG. 2D shows the concept of the horizontal recording paper (Y). Among these, in the longitudinal recording paper (T), the longitudinal direction of the recording paper coincides with the fiber direction. In the horizontal recording paper (Y), the short side direction and the fiber direction of the recording paper coincide.

In general, since the ease of bending of the recording paper varies depending on the fiber direction, the finishing after recording (printing) and after bookbinding differs depending on the selection of the recording paper. In addition, the vertical and horizontal recording papers may have different purchase prices due to different processing steps and distribution amounts.
Accordingly, the user considers the finished print, the binding at the time of bookbinding (thread binding, wireless binding, mesh binding, flat binding), the purchase price of the recording paper, etc., and the vertical recording paper (T) and the horizontal recording paper. (Y) can be arbitrarily selected.

Hereinafter, an example in which the recording paper 2 is loaded on the upper tray 13 will be described.
FIG. 5 shows an internal configuration of the upper tray 13 as viewed from above. The same applies to the lower tray 14, and the description thereof is omitted.
In the upper tray 13, three sliders (regulatory plates) 41, 42, and 43 that slide in the central direction are provided so as to be interlocked so as to be surrounded from three sides around the periphery. When any one slider is slid between position Y and position T, the remaining two sliders are also slid simultaneously. By moving the positions of the sliders 41, 42, and 43, the position Y and the position T can be selected. Thereby, the direction and position of the recording paper 2 are regulated according to the size of the recording paper 2 to be loaded.

  Further, a display sticker 44 is affixed to the bottom surface of the upper tray 13, and an orientation guide display is attached so that the recording paper 2 is placed vertically or horizontally. The user loads the recording paper 2 by adjusting the positions (position T, position Y) of the sliders 41, 42, and 43 according to the type of recording paper 2 purchased (vertical recording paper or horizontal recording paper). . For example, as shown in FIG. 2A, in the case of using the vertical recording paper (T), as shown in FIG. After adjusting the sliders 41, 42, and 43 in the tray 13 to the position T, the recording paper 2 is loaded so that the longitudinal direction of the recording paper is the Y-axis direction.

  Further, as shown in FIG. 2B, when the horizontal recording paper (Y) is used, the upper tray is arranged as shown in FIG. 6B in accordance with the description on the exterior label 32 of the recording paper 2. After adjusting the sliders 41, 42, and 43 in position 13 to the position Y, the recording paper 2 is loaded so that the lateral direction of the recording paper is the X-axis direction. 5 and 6 (a) and 6 (b) show the nozzle row 6b formed on the nozzle surface 6a of the line head 6 in the printer for the purpose of later-described explanation.

  When the user loads the recording paper 2 into the upper tray 13 and stores the upper tray 13 in the main body of the printer 1, the upper tray 13 is opened and closed by a plurality of sensors (not shown) provided near the tray. The presence or absence of the remaining amount of the recording paper 2 and the positions (position T or position Y) of the sliders 41, 42, 43 are detected, and the printer 1 determines the orientation and size of the recording paper 2 loaded on the upper tray 13. . As a result, the monitor unit 8 shifts to the start screen shown in FIG. 4B, and setting information for confirming the type of the recording paper 2 loaded on the upper tray 13 is displayed.

[Setting the paper type]
FIG. 3B shows an example of a screen that displays setting information for prompting selection of the model number of the recording paper 2 displayed on the monitor unit 8 when the recording paper 2 is loaded in the upper tray 13 and the upper tray 13 is closed. Is shown. The model number of the recording paper 2 includes a unique character string corresponding to the type, size, and direction of the recording paper 2. After loading the recording paper 2, the user touches and inputs a button indicating the model number of the recording paper 2 on the input unit 7 including a transparent touch panel placed on the screen of the monitor unit 8, as shown in FIG. In this way, the confirmation screen corresponding to the model number of the recording paper 2 such as the vertical recording paper or the horizontal recording paper is displayed. This example shows a confirmation screen that is displayed when the user performs a touch input of the model number “XT4003” on the input unit 7. FIG. 3D shows a confirmation screen that is displayed when the user touches the model number “XY40004” on the input unit 8.

  Thereafter, as shown in FIGS. 3C and 3D, the user purchases the type (whether vertical or horizontal) of the recording paper 2 loaded in the upper tray 13 on the monitor unit 8. It is confirmed whether or not the display on the exterior label 32 of the recording paper 2 is correct. If it is correct, the “OK” button portion of the input unit 7 is touched to input. In accordance with this input, the printer 1 is set in a state where recording can be started and the high image quality mode is set (ON). If the loaded recording paper 2 is not specified and the user does not know the vertical / horizontal eyes, the “cancel” button shown in FIG. 3A is selected. Also in this case, the printer 1 is set in a state where recording can be started, but the print mode is set not in the high image quality mode but in the normal image quality mode.

  When the user sets the type of the recording sheet 2 by touch input by the input unit 7 on the screen shown in FIG. 3B displayed on the monitor unit 8, the printer 1 selects the type of the selected recording sheet 2. Is accessed to a non-volatile memory (not shown) provided in the control unit 10. That is, according to the selected model number, the table corresponding to the type of the recording paper 2 recorded in advance in the nonvolatile memory is referred to, and in the image recording operation, the size of the recording paper, the vertical recording paper or the horizontal recording paper Read and maintain the type. The information on the type of the recording paper 2 is used for determining the high image quality mode, as will be described in detail later.

  In the present embodiment, the setting is made by manual input by the user, but the present invention is not limited to this. For example, bar code input is used. That is, it can be realized by incorporating a barcode reading device into the input unit 7 and writing the same information as the character / symbol information written on the exterior label as a barcode. By using bar code input, it is possible to prevent a user from making an input error and to simplify the time and effort required for input.

  As another input method, a model is printed on the end of the recording paper with a transparent ink that can be read by ultraviolet light, and a sensor that reads the written information is arranged by irradiating ultraviolet light above the tray in the printer 1. To do. With this configuration, the recording paper model number is read into the printer 1 and set by simply loading the recording paper into the tray pulled out by the user and returning the tray. That is, it is possible to shift to the confirmation screen shown in FIG. 3C or FIG. 3D just by loading the recording paper. Therefore, even if compared with the handling of the conventional printer, there is no effort required by the user other than reloading when a recording paper loading error occurs.

  Next, when the recording paper 2 is loaded and the setting by the user is completed, as will be described later, the high image quality mode is turned on and recording is possible. When the high image quality mode is ON, the print screen of the external device 12 is displayed through the network 11, and the “high image quality mode” is displayed on the screen of the monitor unit 8 as shown in FIG. Is displayed. Thereafter, if the high image quality mode is set, when a print job (image data and recording command) is transmitted from the external device 12 to the printer 1 via the network 11, the printer 1 is in the high image quality mode and the image is recorded on the recording paper 2. Perform recording. That is, the function for correcting the influence of the paper elongation described above works and the user can obtain a desired printed matter.

[Reset recording paper type]
For example, when the user does not set the recording paper type, when the recording paper type is unknown, when the direction of the slider in the tray is wrong, the recording paper type is input and the slider is set (actually loaded). When the recording paper size and orientation do not match, the high image quality mode is not turned on. Therefore, by re-inputting information such as an appropriate model number of the recording paper 2 to the input unit 7, the “high image quality mode” can be turned on, and recording in the high image quality mode becomes possible. In this case, the input unit 7 is provided with a reset button.

Next, the recording operation in the printer according to the first embodiment will be described in more detail. FIG. 7 is a flowchart for explaining the overall image recording operation by the printer 1.
First, the user turns on the printer 1 (step S1). With this input, each component in the printer is activated, and initialization of the memory and output of various sensors are confirmed, and initial setting is performed (step S2). If there is an ink shortage or the like at the time of the initial setting, the monitor unit 8 is displayed to replenish the ink, and prompts the user to perform an appropriate operation.

  Next, the remaining amount of the recording paper 2 in the upper tray 13 and the lower tray 14 is confirmed (step S3, step S4). If it is not determined that the remaining amount is insufficient, the recording can be started (step S5), and start. Display the screen.

  Next, a subroutine in the operation of the upper tray 13 shown in FIG. 7 will be described with reference to the flowchart shown in FIG. The operation in the lower tray 14 is the same as that in the upper tray 13, and the description thereof is omitted. In FIG. 7 and FIG. 8, error processing is omitted. For example, when an abnormal operation occurs such as not closing the opened tray for a certain time or more, the routine exits these routines and displays a predetermined error screen on the monitor unit 8 for warning. Prompt the user for appropriate processing.

  When the confirmation step for the upper tray 13 shown in FIG. 7 is entered, parameters are first set as shown in FIG. 8 (step S11). That is, parameters such as the size of the recording paper 2 stored in the upper tray 13 and the loading direction (TY1, TY2) are initialized (TY1 = 0, TY2 = 0 and MODE1 = 0).

  Next, a recording paper detection process is performed (step S12). That is, when the opening / closing of the tray is detected and it is confirmed that the tray is closed, the printer detects the recording paper size and the loading direction. Thereafter, a recording paper type setting process is performed (step S13). That is, the user is prompted to input the model number of the recording paper, and the recording paper sheet is referred to by referring to a table provided in the non-volatile memory mounted on the control unit 10 based on the model number of the recording paper 2 input by the user. The direction of the eyes (fibers) is recognized, and it is set whether the loaded recording paper 2 is the vertical recording paper or the horizontal recording paper.

  Next, a fiber direction / nozzle row direction determination process is performed (step S14). That is, the fiber direction of the loaded recording paper 2 is recognized from the recording paper detection process and the input information of the model number. If this fiber direction matches the Y-axis direction (nozzle row arrangement direction) (YES), a return value of “1 (match)” is obtained as MODE1, and the high image quality mode is set to ON (step In step S16, the process returns to the main routine (step S17).

  On the other hand, if they do not match (NO), a return value of “0 (does not match)” is obtained as MODE1, and a notification process (step S15) is performed. This notification process acquires the user's input, and when the input from the user is canceled (0), the process proceeds to step S17 and returns. On the other hand, if the input from the user is the resetting of the recording paper type (1), the process returns to step S13 to perform the recording paper type setting process. Further, when the user selects reloading of recording paper (2), the process returns to step S12 to perform recording paper detection processing.

  Next, with reference to the flowchart shown in FIG. 9, a subroutine in the operation of the recording paper detection process in step S12 shown in FIG. 8 will be described. Here, the upper tray 13 is described as an example, and the description of the lower tray 14 that performs the same operation is omitted.

  First, the open / close state of the upper tray 13 is detected (step S21). If the upper tray 13 remains open, the user waits until the upper tray 13 is closed by the user. Next, when the upper tray 13 is closed, the remaining amount of the recording paper 2 and the position information of the sliders 41, 42, 43 are acquired (step S22). From these pieces of information, the size of the recording paper 2 and the orientation of the loaded recording paper are detected.

  Next, it is determined in which direction the loaded recording paper 2 is disposed, that is, whether the longitudinal recording paper is disposed (step S23). If it is determined in this determination that the longitudinal recording paper is placed (YES), the flag is set to TY1 = 1 (step S25), and the process returns to the main routine. On the other hand, if it is not the longitudinal recording paper layout (NO), the flag is set to TY1 = 2 (step S24), and the process returns.

Next, a subroutine in the operation of the recording paper type setting process in step S13 shown in FIG. 8 will be described with reference to the flowchart shown in FIG.
In the recording paper type setting process, first, a model number input screen as shown in FIG. 3B is displayed (step S31). This input screen is displayed and input by the user is awaited (step S32).

  When the user's input is completed, referring to the table of the non-volatile memory based on the input recording paper model number, whether the loaded recording paper 2 is the vertical recording paper or the horizontal recording paper based on the information stored in advance. Is discriminated (step S33). Thereafter, a recording paper confirmation screen is displayed (step S34). In the above determination, for example, when the vertical recording paper is loaded on the upper tray 13 and the vertical recording paper is input as the model number by the input unit 7, a confirmation screen shown in FIG. Is done. That is, a confirmation screen as shown in FIG. 3C or FIG. 3D is displayed according to the type of vertical recording paper or horizontal recording paper confirmed in step S33, and the input by the user is awaited. .

  Thereafter, when the user presses the OK button for confirmation, the input is normal and the process returns to the main routine under the condition for setting the high image quality mode. On the other hand, if it is not recognized and the OK button is not pressed and a predetermined time has elapsed, recording in the high image quality mode is stopped and the routine returns to the main routine under the conditions set in the normal mode.

Next, a subroutine in the determination operation of the fiber direction / nozzle row direction determination processing in step S14 shown in FIG. 8 will be described with reference to the flowchart shown in FIG.
In this determination, it is determined whether or not the above-described flags TY1 and TY2 are appropriately input (TY1> 0, TY2> 0) and the two match (step S41). In this determination, if TY1> 0 and TY1 = TY2, that is, if an input is made by the user, and the grain of the recording paper 2 matches the nozzle row direction of the line head 6 (YES). Then, the process proceeds to step S16 in FIG. 8, where the value 1 is set to MODE1, and the high image quality mode is set to ON. In other cases (NO), the process proceeds to step S15 in FIG. 8, a value 0 is set in MODE1, and a notification process is executed.

Next, with reference to the flowchart shown in FIG. 12, the subroutine in the determination operation of the notification process in step S15 shown in FIG. 8 will be described.
In this notification process, first, a notification screen as shown in FIG. 4C is displayed (step S51). That is, the user can input the correspondence on the notification screen shown in FIG.

    Next, a user input is detected (step S52). When there is a user input, the selected setting is retained. That is, when “cancel” is selected on the screen, the value 0 is set in the flag, and the process returns to step S17 (step S54). If “Re-enter model number” is selected, a value of 1 is set in the flag, and the process returns to the recording sheet type setting process (step S13) (step S55).

  If “Reload recording paper” is selected, a value of 2 is set in the flag, and a countermeasure, for example, “Incorrect loading direction of recording paper” is displayed. The user pulls out the corresponding tray, changes the loading direction of the recording paper so as to be reversed, and returns the tray 13 to the original. After the replacement work is completed, the process returns to step S12 and returns to the recording sheet detection process. Thereby, as shown in FIG. 8, when the fiber direction and the nozzle row direction do not coincide with each other, the user is notified and the recording paper model number is reset or the recording paper is reloaded.

FIG. 13 is a block diagram illustrating a configuration of the control unit 10 provided in the printer 1 of the present embodiment.
The control unit 10 includes an image memory 53, an image signal generation circuit 54, a head drive circuit 55, a head movement circuit 56, and a paper stretch correction circuit 57. Further, a recording paper detection sensor 17 is provided which is disposed in the vicinity of the drum on the upstream side in the conveyance direction of the line head 16 and detects the end portions (leading edge and trailing edge) of the recording paper. Further, an interface 52 for transmitting and receiving signals (image data and the like) between the external device 12 and the control unit 10 via the network 11 is provided. The image memory 53 is configured by a semiconductor memory such as a rewritable flash memory or RAM, for example. The image memory 53 stores image data input via the interface 52.

  The image signal generation circuit 54 generates an image signal for driving the line head 6 from the image data read from the image memory 53. Specifically, the image signal generation circuit 54 includes a non-volatile memory, and a table for obtaining the amount of paper expansion is provided for each type of recording paper pre-recorded in the non-volatile memory as shown in FIG. Yes. With reference to this table, the printing rate to be used (ink ejection amount per page) is obtained from the luminance value information of the image memory of each page to be recorded. Further, a corresponding paper elongation amount (β1) is obtained from the printing rate and transmitted to the paper elongation correction circuit 57. For example, when the printing rate α1 is 20%, the table for obtaining the paper elongation amount shown in FIG. 14 refers to the table from the top and determines that the paper elongation amount β1 in the transport direction is 0.2%.

  The head drive circuit 55 drives the line head 6 based on the image signal, and ejects ink droplets corresponding to the image data onto the recording paper 2 to record an image. The head moving circuit 56 performs drive control of the head moving mechanism 20 and finely moves the line head 6 by a distance equal to or less than the nozzle pitch during a recording operation during which no ink is ejected from the nozzles. That is, a high-resolution image equivalent to 600 dpi is recorded using the line head 6 with a nozzle pitch equivalent to 300 dpi by moving the nozzle pitch a plurality of times, for example, once (2 passes) of 1/2 pitch. can do. The output (encoder signal) obtained by the encoder 51 is transmitted to the head drive circuit 55 via the paper stretch correction circuit 57.

  When the high image quality mode is ON, the paper stretch correction circuit 57 delays the timing of the encoder signal and outputs it as a timing signal as described below. When the high image quality mode is OFF, the encoder signal is transmitted as it is to the head drive circuit 55 as a timing signal.

  When the recording paper 2 is conveyed to the outer peripheral surface of the drum 16 shown in FIG. 1, the leading edge of the recording paper 2 is detected by the recording paper detection sensor 17. Then, as shown in FIG. 10, a recording paper detection signal (timing at which the recording paper 2 is conveyed onto the drum 16 and the leading end position of the recording paper 2) is input to the paper stretch correction circuit 57.

  Further, the encoder signal output from the encoder 51 is input to the paper stretch correction circuit 57. Since the parameters based on the mechanical dimensions such as the radius of the drum 16 shown in FIG. 3 are known in advance from the apparatus design, the paper stretch correction circuit 57 sucks and holds the drum surface on the drum surface from the encoder signal and the timing of loading the recording paper. The position of the recording paper 2 is obtained.

The paper stretch correction circuit 57 transmits the encoder signal as it is as a timing signal to the head drive circuit 55 while the recording paper 2 goes around the drum after the recording paper 2 is transported onto the drum 16.
When the recording paper 2 is transported by the rotation of the drum 16 in the second round, the head moving mechanism 20 causes the line head 6 to move 1/2 pitch in the drum rotation axis direction according to an instruction from the head moving circuit 56. At the same time, the paper stretch correction circuit 57 outputs the encoder signal with a time delay equivalent to the paper stretch. For example, in FIG. 14, when it is determined that the paper elongation amount β1 is 0.2%, the head drive circuit 55 uses the signal obtained by delaying the pulse width by 0.2% as a timing signal from the image signal generation circuit 54 described above. To communicate.

  The head drive circuit 55 reads image data for one line corresponding to the recording paper width from the image memory 53 in accordance with the delay timing signal, and sends a drive signal (image signal) to the line head 6. The line head 6 includes a nozzle plate formed with a plurality of nozzles and a piezoelectric element processed so as to correspond to the nozzle holes. Ink is supplied in the vicinity of the piezoelectric element. When a voltage signal corresponding to image data for one row is applied to the head, the piezoelectric element portion corresponding to the corresponding nozzle position is deformed. As a result, ink droplets are ejected from each nozzle unit corresponding to the image data corresponding to one row.

As described above, by increasing the period of the timing signal in the second round as compared with the first round, the image length on the second recording surface becomes longer in accordance with the ratio of paper elongation. Accordingly, the influence of the recording paper length swollen by the landing of the first round is corrected by the paper stretch correction circuit 57, and the resolution in the transport direction is improved by increasing the image length in the second round. .
In the second round, as described above, the line head is shifted by 1/2 nozzle interval in the nozzle row direction. Accordingly, a resolution of 600 dpi is obtained in the nozzle row direction.

[Description of recording paper used in this embodiment]
The recording paper used in this embodiment will be described in detail. Here, A4 size recording paper is taken as an example.
In general, as a characteristic of recording paper, the elongation of the recording paper when swollen is small in the grain direction and large in the vertical direction. When compared with the amount of elongation in the fiber direction and in the vertical direction, the value is about 1: 2 to 1:10. Accordingly, the maximum elongation of the recording paper is dominant in the direction perpendicular to the paper grain.

  As shown in FIGS. 6A and 6B, according to the first embodiment, when the high image quality mode is ON, the grain of the recording paper 2 is in the nozzle row direction of the line head, that is, the Y axis. It is set to be parallel to the direction. Therefore, with this setting, the main elongation of the recording paper 2 is the recording paper conveyance direction. Deterioration of image quality due to the influence of the elongation of the recording paper in the transport direction can be corrected by adjusting the recording timing by the paper elongation correction circuit.

In the nozzle row direction, the amount of paper elongation is 1/2 to 1/10, which is a small value compared to the nozzle interval, and the occurrence of white streaks can be substantially eliminated. Therefore, by setting the direction of the recording paper in the tray based on the grain size, the influence of the recording paper elongation in the nozzle row direction is remarkably improved.
The recording paper 2 is an example of ink jet printer recording paper, but even plain paper or the like can be used satisfactorily because image quality deterioration due to paper elongation is improved. Further, it may be a thin mouth recording paper, a thick mouth recording paper or the like. In this case, since the amount of elongation of the medium is different, it is more preferable to set it on the selection screen based on the model number.

  As described above, according to the recording paper 2 loaded by the user, the recording in the high image quality mode according to the present embodiment avoids the influence of paper elongation during recording, particularly in the nozzle row direction, and generates a high quality image. Can be recorded. That is, the main paper elongation due to the penetration of the water-based ink is the recording paper conveyance direction, and the paper elongation in the nozzle row direction which is difficult to be corrected can be suppressed, so that a high-quality full-color image can be obtained. Further, when the high image quality mode is set (ON), the printer 1 corrects the timing signal from the recording mechanism 2 to the line head 6 according to the size, orientation, and type of the recording sheet 2. In addition, it is possible to suppress deterioration in image quality due to paper elongation in the conveyance direction of the recording paper caused by the penetration of water-based ink, and a high-quality full-color image can be obtained. When the high image quality mode is not set (OFF), the timing signal is not corrected. Therefore, according to the present embodiment, it is possible to provide a printer that performs image recording without deterioration in recording (printing) resolution of white streaks or the like in both the nozzle row direction and the transport direction.

A modification of the first embodiment will be described.
Even in the nozzle row direction of the line head 6, it is more useful to finely adjust the image length according to the number of rotations of the drum 16, that is, the elapsed time from the first image recording. In other words, the nozzle spacing of the line head is determined at the time of nozzle processing, and therefore cannot be finely adjusted at the time of image recording. For example, as in the paper elongation amount β1 shown in FIG. 14, the elongation amount of the recording paper can be determined also in the nozzle row direction. Even in the nozzle row direction, if the image data of the recorded image is finely adjusted, the resolution cannot be improved, but the influence of the color shift can be improved in appearance, which is even better.

  In the present embodiment, the setting of the grain direction when loading the recording sheet is performed by the user. However, an area sensor may be attached near the inside of the tray to automatically detect the paper direction. Furthermore, although the ink color has been described with an example of four colors of black, cyan, magenta, and yellow, it is not necessarily limited. For example, white, light cyan, light magenta, and the like may be further added. .

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 2 ... Recording paper, 3 ... Recording paper supply mechanism, 4 ... Conveyance mechanism, 5 ... Accommodating mechanism, 6, 6C, 6K, 6M, 6Y ... Line head, 6a ... Nozzle surface, 7 ... Input part, DESCRIPTION OF SYMBOLS 8 ... Monitor part, 9 ... Ink supply part, 10 ... Control part, 11 ... Network, 12 ... External apparatus, 13 ... Upper tray, 14 ... Lower tray, 15 ... Guide member, 16 ... Drum, 16a ... Rotating shaft, 17 ... Recording paper detection sensor, 18 ... Peeling claw, 19 ... Discharge tray, 20 ... Head moving mechanism, 31 ... Packing, 32,33 ... Exterior label, 41,42,43 ... Slider (regulating plate), 51 ... Encoder, 52 ... Interface 53. Image memory 54 Image signal generation circuit 55 Head drive circuit 56 Head movement circuit 57 Paper expansion correction circuit

Claims (7)

A tray loaded with recording paper,
Recording paper conveying means for conveying the recording paper loaded in the tray;
A plurality of nozzles that eject ink toward the recording paper to be conveyed are linearly arranged, and an inkjet head arranged so that the arrangement direction of the nozzles is orthogonal to the conveyance direction of the recording paper;
Comprising
An ink jet printer, wherein when the ink is ejected from the ink jet head toward the recording paper, a fiber direction of the recording paper coincides with an arrangement direction of the nozzles of the ink jet head. In the inkjet printer,
Loading of the recording paper into the tray such that the fiber direction of the recording paper coincides with the arrangement direction of the nozzles of the ink-jet head when the ink is ejected from the ink-jet head toward the recording paper The ink jet printer according to claim 1, further comprising an informing unit for guiding the user. An input unit for operating and inputting recording sheet type information unique to the recording sheet;
A recording paper orientation detection unit for detecting the orientation of the recording paper loaded in the tray;
The recording paper in the tray is transported from the recording paper type information input from the input operation unit and the recording paper orientation information in the tray from the recording paper orientation detection unit, and the inkjet head is directed toward the recording paper. Determining means for determining whether or not the fiber direction of the recording paper input as the recording paper type information matches the nozzle arrangement direction of the inkjet head when ejecting ink from the recording paper;
Further comprising
The notification means prompts the direction of the recording paper in the tray to be changed if the determination means determines that the fiber direction of the recording paper does not coincide with the nozzle arrangement direction of the inkjet head. The ink jet printer according to claim 2. In addition, it is slidable and applied to an end of the recording paper loaded in the tray, and includes a regulation plate that defines the orientation of the recording paper in the tray,
The ink jet printer according to claim 3, wherein the recording paper orientation detection unit detects the orientation of the recording paper in the tray by detecting an installation position of the restriction plate.   And a controller that changes an ink discharge timing from the inkjet head so that an image length of an image to be recorded on the recording paper is increased in accordance with a signal output from the recording paper orientation detection unit. The inkjet printer according to claim 3.   The inkjet printer according to claim 2, wherein the notification unit includes a first display unit that informs a direction of the recording paper loaded in the tray.   The informing means includes a second display unit that informs an installation position of a regulating plate that defines the orientation of the recording paper in the tray by being applied to an end of the recording paper loaded in the tray. The inkjet printer according to claim 2.

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