JP2006168197A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To record a high quality image regardless of the type of a recording medium. <P>SOLUTION: The type of a print sheet is judged and optimal sheet feed torque control is performed such that slip of sheet, or the like, does not take place for every type of sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus that includes a recording unit having a plurality of ejection openings and performs recording by ejecting ink onto a recording material. The present invention relates to an ink jet recording apparatus configured as described above.

  As an example, a main part related to recording of an ink jet color printer is configured as shown in FIG. When recording on the recording paper 105 on the platen 106, first, the motor 103 is driven, the main scanning carriage 102 is moved to the position of the home position sensor 108 by the driving belt 109, and then the forward movement is performed in the direction of arrow A, Image recording is performed by ejecting black Bk, cyan C, magenta M, and yellow Y ink from recording heads 120, 121, 122, and 123, respectively, from predetermined positions. When image recording for a predetermined length is completed, the main scanning carriage 102 is stopped, and on the contrary, the backward scanning is started in the direction of arrow B, and the main scanning carriage 102 is returned to the position of the home position sensor 108. During the backward scan, the paper feed for the length recorded by the recording heads 120 to 123 is performed in the direction of arrow C by driving the paper feed roller 101 by the paper feed motor 107. By repeating the above operation, color image recording is completed. Reference numeral 100 denotes a paper feed second roller, and 111 denotes a paper detection sensor.

In this type of ink jet recording system, the recording heads 120 to 123 are each equipped with several heaters in nozzles filled with ink. The ink is ejected at a bubble pressure generated thereby, and when normally used as an image forming apparatus, several nozzles are arranged to form one head to form an image.
The ejection timing of ink from the head is performed in synchronization with a signal from a linear encoder (not shown). This linear encoder has a sensor unit mounted on the main scanning carriage 102, and a signal is output as the main scanning carriage 102 moves, and the position of the main scanning carriage 102 can be detected by counting the signal.

  In recent years, the recording heads 120, 121, 122, and 123 are formed by integrating a plurality of recording elements, and a plurality of ink discharge ports and liquid paths are integrated to improve the recording speed.

  In addition, as a recording medium of an ink jet recording apparatus, there is a dedicated paper having a coating layer made in consideration of ink coloring property, fixing property, etc., but in recent years, a transparency film (Transparency film) for plain paper and OHP is used. The demand for a wide range of media such as film (hereinafter referred to as TP) is increasing. Along with this, the recording apparatus itself is required to be adapted to various media (high image quality). However, since the ink adaptability to each medium is various, using the same printing method for all the media has a number of adverse effects depending on the medium. In particular, TP has a slow ink absorption speed among various media, and the condensing power of ink droplets that have landed but have not been fully absorbed exceeds the absorbing power to the coating layer on TP. Accordingly, when two or more ink droplets exist at a distance in contact with each other as shown in FIG. 7, the ink droplets are attracted and combined with each other, and one large ink is located at a position shifted from the originally landed position. The phenomenon of forming droplets occurs. This is a phenomenon peculiar to a recording medium having a low ink absorption speed, such as TP, and is called beading.

  In the following patents, there is a technical disclosure of a method for dividing the recording in the same image region into a plurality of times to reduce the above-described adverse effects.

  In each scan, only a twill pattern (staggered, reverse staggered) pattern arranged alternately in the vertical and horizontal directions is printed, and a configuration is disclosed in which the image is completed by the forward and backward recording scans (Patent Document 1). In this case, the object is to prevent the adjacent dots from being printed continuously, thereby preventing the dot distortion caused by printing the adjacent dots before the printed dots are dried. Therefore, here, the thinning mask is limited to a cross-shaped pattern.

  Also, as a recording medium, a recording medium that emphasizes recording on a medium having a low ink absorption speed such as TP is disclosed (Patent Document 2).

  In this case, by performing complementary recording on pixels alternately positioned in the horizontal and vertical directions in the same recording area by the recording scanning divided into the first and second (or more), the recording on the medium such as TP In addition to preventing ink beading, color banding (color unevenness) can be prevented by reversing the ink placement order of mixed-color pixels between the first and second scans (reciprocal recording) when forming a color image. Describes the effects that can be. In this case, since the main purpose is to prevent beading between the pixels, it is characterized that the pixels recorded in one scan are alternately (not adjacent to each other) in the horizontal and vertical directions. Yes.

The configuration common to the above two patents is to complete the recording of the pixel group in the same image area by a plurality of recording scans. Such a configuration is an effective means for a recording medium having a low ink absorption speed such as TP, because an image can be completed while being gradually evaporated and absorbed in each scan. In particular, if dots are arranged in a staggered manner in each scan, the dots printed in the same recording scan are absorbed in the true pixel position over time without attracting each other on the medium. It is also possible to prevent specific beading harmful effects. In addition, since a large amount of ink does not overflow into the recording area at one time, it is possible to prevent bleeding at a different color boundary.
As described above, conventionally, the divisional recording method has been used to obtain an image that prevents bleeding or beading on a different color boundary on a recording medium having a low ink absorption speed such as TP.
Japanese Patent Laid-Open No. 55-113573 USP 4748453

  However, the divided recording method divided into two recording scans as described above is not necessarily sufficient depending on the absorption speed of the recording paper, and the divided recording of about two passes does not really overcome the problem.

  Depending on the recording medium, the number of scans for completing an image is further increased, and processing of about 8 or 12 passes is required at present.

  This multi-pass eliminates the problem of beading on recording paper and enables high-quality printing without blurring as an image. It occurs as a factor. This is because the recording paper conveyance control in the current inkjet recording apparatus performs only fixed conveyance control. Conventionally, the conveyance control of the recording device has been performed so that the gift amount can be finely adjusted for each recording paper, but this only corrects the difference in the feeding amount due to the difference in the thickness of the recording paper. However, sufficient consideration has not been given to correction of paper slip and conveyance unevenness that occur according to the waist and surface characteristics of the recording paper.

  In addition, the process of simply increasing the number of passes and suppressing the occurrence of beading increases the time that the recording surface of the recording paper stays under the scanning carriage and increases the number of scans of the scanning carriage. There has also been a problem that the frequency of occurrence of defects in contact with paper increases.

  The present invention has been made in view of the above drawbacks, and an object thereof is to provide an ink jet recording method capable of recording a high-quality image regardless of the type of the recording medium.

  For this reason, the present invention performs main scanning by moving a recording head in which a plurality of recording elements for ejecting ink are arranged in a direction different from the arrangement direction of the recording elements, and the recording head in a direction different from the main scanning. In an ink jet recording method in which recording is completed while moving relative to a recording medium and performing sub-scanning, a printing operation is performed by variably setting the conveyance speed of the recording medium according to the type of recording paper to be printed. It can be performed.

  As a result, it is possible to eliminate the occurrence of feed amount unevenness due to the slippage of the recording paper due to the stiffness and surface characteristics of the recording paper, and to perform high-quality printing without occurrence of band unevenness. For recording paper with a slow absorption speed, by feeding the paper at a speed matching the absorption speed, it is possible to obtain a good image that prevents beading caused by ink overflow on the recording paper. It is what I did.

  As described above, in the apparatus according to the invention relating to the present application, the recording paper conveyance speed can be changed according to the type of the recording paper to be printed, thereby enabling the printing operation to be performed. It is possible to remove the occurrence of feed amount unevenness due to paper slip caused by waist and surface characteristics, and to perform high-quality printing without causing band unevenness. For recording paper with a slow absorption speed, by feeding the paper at a speed matching the absorption speed, it is possible to obtain a good image that prevents beading caused by ink overflow on the recording paper. It is what I did.

(First embodiment)
The configuration of the print engine unit according to the ink jet recording apparatus of the first embodiment of the present invention is the same as that of the conventional example shown in FIG. 2, and a printing operation sequence for recording an image by ejecting ink from each recording head. Is performed in the same manner as described in the conventional example.

  FIG. 1 is a block diagram showing the configuration of an ink jet recording apparatus showing a first embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a control unit that controls the entire recording apparatus. Reference numeral 14 denotes an I / F (interface) unit. The I / F unit 14 and a host computer (not shown) are connected to each other, and commands and recording data for printing (recording) are sent from the host computer. The ink jet recording apparatus operates to record the recording data onto the recording paper. In general, Centronics and USB interfaces are often used as the I / F unit 14. An image processing unit 11 performs γ correction, color processing, enlargement / reduction processing, binarization, etc. on the recording data (multi-valued image data) sent from the I / F unit 14. It is composed of DSP, RISC chip and the like. The configuration and functions of this image processing unit are often configured to be processed by a host-side driver or RIP (Raster Image Processor) in order to reduce the main body cost.

The print data developed into a dot pattern at the final stage of processing in the image processing unit 11 is temporarily stored in the memory unit 16. This memory unit 16 is composed of a memory for one or more bands necessary for a recording head (not shown) to perform recording by scanning once in the main scanning direction, and if the number of nozzles in the sub-scanning direction of the recording head is 128 nozzles If the maximum number of dots that can be recorded in one scan in the main scanning direction is 8k dots,
128 (nozzles) * 8k (dots) * 4 (color) = 4MBit
It will have a memory capacity of. Further, writing / reading of print data to / from the memory unit 16 is performed by the memory controller 15 under the control of the DSP or RISC chip of the image processing unit 11, and an address signal and a write / read timing signal are sent to the memory unit 16. Generated. The print data read from the memory unit 16 is output to the head controller 17 in synchronization with the read signal from the head controller 17. The head controller 17 generates an ink discharge timing signal and a heat pulse from the head unit 18 based on the control of the control unit 10 based on a signal from a linear scale (not shown). A head unit 18 includes recording heads corresponding to the respective color inks. The controller unit 10 and the head controller 17 heat the heater unit to eject ink, thereby recording an image on the paper surface. The head unit 18 is actually mounted on the carriage of the mechanical drive unit 13.

  The mechanical drive unit 13 has substantially the same configuration as that in FIG. 2 used in the description of the conventional example, and includes a carriage unit and a carriage drive unit for moving a recording head (not shown) in the main scanning direction, a recording paper feeding unit, The paper transport unit, the paper discharge unit, and the recovery unit for recovering from ink clogging of the recording head. Reference numeral 12 denotes an operation panel including switches for feeding, discharging, and selecting menus and a display device for displaying the status of the inkjet recording apparatus and displaying menus. And the status / menu display is performed. In this embodiment, the control of the entire inkjet recording apparatus is controlled by the image processing unit 11 and the control unit 10, and the command processing and recording data input from the I / F unit 14 are mainly processed. The processing from the processing to the storage in the memory unit 16 is performed by the image processing unit 11, and then the head controller 17 and the mechanical driving unit 13 are controlled to perform the printing operation and the control of the operation panel 12 is performed by the control unit 10. It is supposed to be done with. Therefore, the image processing unit 11 and the control unit 10 are configured to regularly communicate and exchange control information.

Next, the details of the system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a flowchart showing an embodiment of the present invention. In FIG.
Step 301 First, the processing of the present invention is started. This may be the timing when the printer power is turned on or the timing when the recording paper is replaced.

  Step 302 First, the paper type is designated from the operation panel 12. This is normally specified when a roll paper is fed. In addition, regarding a model in which a multi-stage sheet cassette is mounted, a sheet type is designated for each cassette.

  This operation may be configured to be designated by the host via the I / F unit 14 as a command. Further, in a configuration having a plurality of paper feed cassettes, all the paper types set in each cassette may be designated at a time, or may be designated only for a cassette whose paper types are exchanged.

  Step 303 Then, it waits for a print instruction from the host. When a print instruction is received from the host, the process proceeds to step 304.

Step 304: Determine the paper conveyance speed during printing from the paper type designated for printing. An example showing the relationship between the paper type and the paper conveyance speed is shown in FIG. If the paper conveyance speed in FIG. 4 depends only on the ink absorption speed of each paper, the ink absorption speed of each paper in FIG. 4 is paper A> paper B> paper C> paper D.
It has become a relationship.

However, we are not only presenting a method for solving only the ink absorption speed of the paper, but also considering the correction of the feed characteristics in the paper feeding / conveying system for printing paper. It is also possible to correct characteristics such as paper slip in the transport system. In the conventional paper transport process, the paper is transported at a constant speed regardless of the paper, and depending on the paper characteristics, the transport amount increases or decreases from the desired transport amount, which appears on the image as feed unevenness and causes image quality degradation. . In the method of the present invention, for this correction, the conveyance speed for realizing the optimum sheet conveyance for each sheet is measured in advance, and an optimum sheet conveyance speed table as shown in FIG. 4 is provided in the apparatus. 305 The paper is transported for each band, which is performed for each scan at the paper transport speed determined in step 304, and the printing operation is performed. Similarly, in the paper feed and paper discharge operations, it is needless to say that control is performed so as not to cause a transport deviation due to a paper slip or the like by selecting an optimal paper transport speed according to the designated paper type.

  Step 306 This is the end of the process of the present invention. Thereafter, steps 303 to 305 are repeated unless the recording sheet is changed. If there is a paper change, step 302 is performed.

  By the above processing from 301 to 306, by changing the paper conveyance speed at the time of printing according to the recording paper, it is possible to suppress the occurrence of uneven paper feeding and to perform the printing operation according to the ink absorption speed of the recording paper. become.

(Second Embodiment)
In the first embodiment, the configuration in which the user designates the recording paper type when the recording paper is replaced has been described. However, in the second embodiment, the paper feeding operation is performed when the recording paper is replaced or before printing is started. And automatically determining the type of recording paper.

  FIG. 5 shows a block diagram of the second embodiment. In FIG. 5, the same processes as those in FIG. In FIG. 5, the difference from FIG. 1 showing the first embodiment is only the sheet determination unit 19. In the present invention, the sheet determination unit 19 performs sheet feeding operation at the time of sheet replacement or before starting printing, and sequentially emits a light emitting unit having a plurality of color filters on the sheet to receive reflected light on the sheet. The paper type is determined from the received light level. It is possible to distinguish between a plurality of paper types such as coated paper, glossy paper, and OHP film from the combination of the received light levels by switching between the color filters to emit light.

  FIG. 6 is a flowchart showing an example of processing of the second embodiment.

  In each process of FIG. 6, the same number is attached | subjected regarding the same process as the flowchart of FIG. 3 used by description of the 1st Example. The flowchart of FIG. 6 shows the processing when the type of printing paper is always determined at the start of printing. However, the present invention is not limited to this, and the paper type determination operation is performed once when the paper is replaced. It may be configured to perform only.

  Step 301 As in the first embodiment, the process of the present invention is first started. This may be the timing when the printer power is turned on or the timing when the paper is replaced.

  Step 303 Then, it waits for a print instruction from the host. When a print instruction is received from the host, the process proceeds to step 601.

  Step 601 First, a paper feeding operation for printing paper is performed, and after the paper feeding, a paper type identification sensor is moved onto the paper surface to determine the paper type. The specific configuration is as described in the description of the sheet determination unit 19 in FIG.

  Step 304 The paper conveyance speed at the time of printing is determined from the paper type determined in Step 601. This configuration is as described in the first embodiment.

  Step 305 The printing operation is performed at the paper conveyance speed determined in Step 304. In this case, the optimum sheet conveyance speed is applied to the sheet type designated for all sheet feeding operations, sheet feeding operations, and sheet ejection operations performed for each scan.

  Step 306 First is the end of the process indicating the process of the present invention. Thereafter, steps 303 to 305 are repeated unless the paper is changed. If there is a paper change, step 302 is performed.

  Through the above processes 301 to 306, the printing operation according to the ink absorption speed of the printing paper can be performed by changing the paper conveyance speed during printing according to the printing paper.

1 is a block diagram illustrating a configuration of an ink jet printer apparatus according to a first embodiment of the present invention. The principal part perspective view of the scanning carriage for demonstrating a prior art example. The flowchart which shows the process of the 1st Example of this invention. FIG. 4 is a diagram illustrating a relationship between a paper type and a carriage speed as an example of the present invention. FIG. 5 is a block diagram illustrating a configuration of an ink jet printer apparatus according to a second embodiment of the present invention. The flowchart which shows the process of the 2nd Example of this invention. The figure which shows a mode that it couple | bonds on the surface of two ink droplet paper for demonstrating a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control part 11 Image processing part 12 Operation panel 13 Mechanical drive part 14 I / F part 15 Memory controller 16 Memory part 17 Head controller 18 Head part

Claims (2)

  In an ink jet recording apparatus that uses a recording head having a plurality of ejection openings and performs recording by discharging ink from the recording head to a recording medium, a recording medium designating unit that designates the type of the recording medium, and the recording medium An ink jet recording apparatus comprising: a conveyance speed variable unit capable of variably switching a conveyance time of the recording medium according to a recording medium type designated by a designation unit.   In an inkjet recording apparatus that uses a recording head having a plurality of ejection openings and performs recording by ejecting ink from the recording head to a recording medium, a recording medium determination unit that automatically determines the type of the recording medium; An ink jet recording apparatus comprising: a conveyance speed variable unit capable of variably switching a conveyance time of the recording medium according to a recording medium type determined by a recording medium determination unit.

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