JPH04286665A - Recording device - Google Patents

Abstract

PURPOSE:To make a joint between one recorded line and other recorded line in recorded image invisible by performing binary processes differently dependent on each horizontal scanning when input data is binarized so as to supply to a record head through a line buffer. CONSTITUTION:Line buffers 9-1 and 9-2 store inputted binary data once, and thereafter, transfer them to a record head 11 alternately. The data transferred from the first line buffer 9-1 is recorded in recording areas a-1 and a-2. The data transferred from the second line buffer 9-2 is recorded in recording areas b-1 and b-2, so as to be recorded in sequence of a-1, b-1, a-2, b-2. Accordingly, the recording areas are superposed because only a 1/2 line is sent in the vertical scanning direction with respect to one horizontal scanning, and white stripe or black stripe to be generated between one recorded line and other recorded line which easily occurs at ordinary record line feeding can be prevented.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a type of recording device such as an inkjet recording device or a thermal recording device that mainly records in dots.
The present invention relates to, for example, a serial type printing apparatus that performs printing with a width of multiple dots in the row direction).

0002

2. Description of the Related Art Conventionally, one of the well-known devices of this type is an inkjet recording device that performs recording by depositing ink on a recording surface.

[0003] These inkjet printing apparatuses ultimately perform printing based on binary information of printing or non-printing. In an inkjet printing device that performs printing based on such binary information, in order to express more gradations, the density data is converted into binary data using an error diffusion method, etc., and the print head is adjusted according to this binary information. Many of them use a method of driving and recording.

0004

[Problems to be Solved by the Invention] However, when recording is performed using the above-mentioned recording head and especially a serial type recording head, variations in the diameter of the platen roller that feeds the recording paper in the sub-scanning direction or Due to eccentricity of the platen roller, etc., the amount of paper feed varies, and white or black streaks may occur between recording lines, degrading the quality of the recorded image.

The present invention has been made in view of the above-mentioned conventional problems to be solved, and its object is to provide a recording apparatus in which the seams between recording lines in a recorded image are made inconspicuous. It is about providing.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention provides a recording head that records information on a recording material with a width of multiple dots in the sub-scanning direction in one main scan. ,
The amount of relative movement of the recording material and the recording head in the sub-scanning direction at one time is determined by dividing the width of the plurality of dots by an integer value of 2 or more, and the recording area in one main scanning is divided into other areas. a driving means for overlapping the recording area; a plurality of line buffers that are used individually and sequentially for each main scan and correspond to the integer values; The present invention is characterized by comprising a binarization means that performs different binarization processing corresponding to each main scan when being supplied to the recording head.

Further, as an aspect of the present invention, the recording head has an electrothermal transducer for applying thermal energy to cause film boiling on the ink, as an element for generating energy for ejecting the ink. It is characterized by

[0008]

[Operation] According to the above configuration, the present invention covers the joints between recording lines by the recording head by multiple recordings, and performs independent binarization processing corresponding to each recording. Therefore, the seams between the recorded lines in the recorded image can be made less noticeable.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a circuit configuration of an inkjet recording apparatus according to an embodiment of the present invention.

In this figure, 1 is a CPU (central processing unit) such as a microprocessor that controls the entire device.
The gradation data (image data) received from the interface (I/F) circuit 4 is stored in the input buffer 5, and the gradation data stored in the input buffer 5 is read out and stored in a look-up table (LUT) 6. Execute control processing such as transfer to. In addition, the CPU 1 is a binarization circuit 7.
The selection circuit 8 which switches the storage destination of the binarized data is switched and controlled, and the line buffers 9-1 and 9-
2 is transferred to the recording head 11, and a carriage drive circuit (CR) 12 and a paper feeding platen drive circuit (LF) 13 are driven to perform a recording operation. 2 is a ROM (read only memory) that stores a control program as shown in FIG. 5 for executing the control operations of this device, and 3 is a RAM (random access memory) that the CPU 1 uses as a work area.

The interface circuit 4 is a circuit for receiving control commands, gradation recording data, etc. from the host device. The input buffer 5 is a memory for storing one raster of the gradation data received from the interface circuit 4, and the CPU 1 reads each gradation data stored in the buffer 5 twice, and reads each gradation data independently. Binarization processing is performed and the results are stored in line buffers 9-1 and 9-2, respectively. The LUT (look-up table) 6 is a memory for outputting pre-registered data corresponding to the gradation data transferred from the input buffer 5, and the registered data is updated every time the input buffer 5 is read. , can be changed by the CPU1.

The binarization circuit 7 is a circuit for obtaining binary data from the gradation data output by the LUT 6, and in this embodiment, as an example, the input gradation data is binarized by the error diffusion method. There is. The selection circuit 8 is the binarization circuit 7
This is a circuit for selecting and storing the binary data obtained in either the line buffer 9-1 or 9-2, and is controlled by the CPU 1.

The line buffers 9-1 and 9-2 temporarily store the input binary data, and then transfer the input binary data to the recording head 1.
Transfer alternately to 1. The recording head 11 is, for example, an inkjet recording head, and in this embodiment, as shown in FIG. 2, 64 ink ejection ports are arranged in the sub-scanning direction. The carriage drive circuit 12 is a circuit for driving the carriage in the main scanning direction, and the platen drive circuit 13 is a circuit for driving the platen to move the recording paper in the sub-scanning direction, both of which include drive motors. Controlled by CPU1.

FIG. 2 shows the appearance of the main parts of an inkjet recording apparatus according to an embodiment of the present invention. In this figure, reference numeral 14 denotes a carriage, on which the recording head 11 is mounted, and performs a recording operation while moving in the direction of arrow p (main scanning direction) in the figure along a guide shaft 14A. A platen roller 15 rotates to move the recording paper 16 in the direction of arrow q in the figure (
(sub-scanning direction) to change recording lines. In this embodiment, the amount of paper feed at one time is set to 32 nozzles, as an example, so that one location is recorded in two main scans.

FIG. 3 conceptually shows the positional relationship of recording areas in this embodiment. In this figure, a-1 and a
-2 indicates a recording area in which data transferred from the first line buffer 9-1 in FIG. 1 is recorded, b-1 and b-
2 indicates a recording area in which data transferred from the second line buffer 9-2 is recorded, and a-1, b-1, a
-2, b-2 are recorded in the order.

As is clear from this figure, since only 1/2 line is sent in the sub-scanning direction for one main scan, the recording areas overlap, which is likely to occur due to normal recording line changes. It is possible to prevent white streaks and black streaks that occur between recording lines.

Furthermore, since the recording areas indicated by a and b in this figure are binarized using independent error diffusion methods, unlike recording the same binary data twice, Since it becomes possible to record binary data in a more linear manner, it is possible to further make white streaks or black streaks less noticeable.

FIG. 4 shows an example of data contents written to the lookup table 6, in which the horizontal axis shows the input data value, the vertical axis shows the output data value, and the straight lines indicated by a and b are adopted for the data stored in line buffers 9-1 and 9-2, respectively. That is, the density of the input gradation data ranges from zero to intermediate value C.
Until then, output data increasing from zero according to the input data is written to the first line buffer 9-1, and when the density of the input gradation data is from C to the maximum value d, the maximum value is written to the first line buffer 9-1. Similarly, when the output data of the value is written, the output data increasing from zero according to the input data is written to the second
is written to the line buffer 9-2.

By adopting such a value, it becomes possible to print at the same density level as in normal printing operation. In addition, the binary data stored in line buffers 9-1 and 9-2 can be made different even though the input values are the same, and the same binary data can be divided into two times. This makes it possible to record dots more randomly than by recording dots. These table data values are stored in ROM2.
Alternatively, each time the multivalue data registered in RAM 3 and stored in input buffer 5 is transferred and stored in line buffers 9-1 and 9-2, it is written to LUT 6 according to the corresponding line buffer. .

FIG. 5 shows the operational procedure of this embodiment. C.P.
In step S1, U1 clears a processing raster counter (not shown) in the work area of RAM2, which counts the raster currently being processed, to zero. Next, the process proceeds to step S2, where multi-value input data is received from the interface circuit 4, and one raster worth of data is stored in the input buffer 5. Furthermore, the process advances to step S3, and the first
The data corresponding to the line buffer 9-1 (that is, the data indicated by a in FIG. 4) is written. Then,
Proceeding to step S4, data is read from the input buffer 5, and the data binarized through the selection circuit 8 is stored in the first line buffer 9-1.

The process further proceeds to step S5, where data corresponding to the second line buffer 9-2 (ie, data indicated by b in FIG. 4) is written into the LUT 6. Next, the process proceeds to step S6, where data is read from the input buffer 5, and the binarized data is stored in the second line buffer 9-2 through the selection circuit 8.

At this point, since the binarization process of one raster's worth of multivalued data has been completed, the process advances to step S7, and the value of the processed raster counter (the number of processed rasters) is increased by +1. Next, the process advances to step S8, and it is checked whether the number of processed rasters is 32, which is the median value (1/2 line). If so, the process advances to step S9, where the binary data stored in the first line buffer 9-1 is transferred to the recording head 11, and the carriage drive circuit 12 and platen drive circuit 13 are driven to perform the recording operation. Go, step S
Return to 2.

On the other hand, if the number of rasters to be processed is not 32,
Proceeding to step S10, it is checked whether the number of processed rasters is 64, which is the maximum value (one line). If not, return to step S2, but if so,
Proceeding to step S11, the binary data stored in the second line buffer 9-2 is transferred to the recording head 11, and the carriage drive circuit 12 and platen drive circuit 13 are driven to perform a recording operation. Thereafter, the process returns to step S1 again and the above operations are repeated.

Note that the first 32 dots stored in the first line buffer 9-1 are stored in an area corresponding to the lower 32 nozzles of the recording head 11. Further, in one main scanning recording operation, the recording paper is set in advance so that it is fed by 1/2 line.

[0026] Through the above processing, it is possible to suppress the generation of white stripes or black stripes that conventionally occur between recording lines.

In this embodiment, a monochromatic printing apparatus having one printing head has been described, but it goes without saying that the present invention can be similarly applied to a color printing apparatus having a plurality of printing heads. Also, in this embodiment, one dot is recorded by two main scans, but the number of times (for example, three or four) is greater.
It is also possible to record one dot using this method. Further, the recording head of this embodiment is not limited to an inkjet recording head, but may be a thermal recording head, a photodiode recording head, a liquid crystal recording head, or the like.

(Others) The present invention particularly relates to means for generating thermal energy as energy used for ejecting ink in an inkjet recording system.
For example, the present invention provides excellent effects in recording heads and recording apparatuses that are equipped with an electrothermal converter, a laser beam, etc., and that use the thermal energy to cause a change in the state of ink. This is because such a system can achieve higher recording density and higher definition.

For its typical configuration and principle, see, for example, US Pat. Nos. 4,723,129 and 4,740.
Preferably, it is carried out using the basic principles disclosed in the '796 specification. This method is the so-called on-demand type.
It is applicable to both continuous types, but in particular, in the case of on-demand type, it is applicable to the electrothermal converter placed corresponding to the sheet holding the liquid (ink) or the liquid path. , by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise exceeding nucleate boiling, the electrothermal transducer generates thermal energy to produce film boiling on the thermally active surface of the recording head. liquid (ink) that corresponds one-to-one to this drive signal.
This is effective because it can form air bubbles inside. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one droplet. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, making it possible to eject liquid (ink) with particularly excellent responsiveness. This pulse-shaped drive signal is described in US Pat. No. 4,463,359 and US Pat.
345262 are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

[0030] In addition to the configuration of the recording head that is a combination of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44 disclose a configuration in which a heat acting part is arranged in a bending region.
A configuration using the specification of No. 59600 is also included in the present invention. In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal converters, and a hole that absorbs pressure waves of thermal energy is disclosed. The effects of the present invention are also effective even with a configuration based on Japanese Patent Application Laid-open No. 138461/1985 which discloses a configuration corresponding to the discharge section. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.

In addition, even in the case of a serial type as in the above example, the recording head is fixed to the main body of the apparatus, or by being attached to the main body of the apparatus, electrical connection with the main body of the apparatus and ink flow from the main body of the apparatus are possible. The present invention is also effective when using a replaceable chip-type recording head that can be supplied with ink or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself.

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, etc. to the configuration of the recording apparatus of the present invention, since this further stabilizes the effects of the present invention. Specifically, these include heating the recording head using a capping means, a cleaning means, a pressure or suction means, an electrothermal transducer, a separate heating element, or a combination thereof. For example, there may be mentioned a pre-heating means for performing the ejection, and a pre-ejection means for ejecting other than recording.

Furthermore, regarding the type and number of recording heads to be mounted, for example, in addition to a single head that corresponds to a single color ink, there are also systems that correspond to a plurality of inks of different recording colors and densities. A plurality of them may be provided. That is, for example, the recording mode of the recording apparatus is not limited to a recording mode for only a mainstream color such as black, but may also be a recording mode in which the recording head is configured integrally or in a combination of multiple colors, Alternatively, the present invention is extremely effective for an apparatus equipped with at least one of the full-color recording modes using color mixing.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid, but an ink that solidifies at room temperature or lower, and that softens or liquefies at room temperature, may also be used. Generally speaking, in inkjet systems, the temperature of the ink itself is adjusted within the range of 30°C or higher and 70°C or lower to keep the viscosity of the ink within a stable ejection range. Sometimes, ink in liquid form may be used. In addition, in order to actively prevent temperature rise due to thermal energy by using the energy to change the state of the ink from a solid state to a liquid state, or to prevent ink from evaporating, it is possible to solidify and heat the ink when left standing. An ink that is liquefied by water may also be used. In any case, by applying thermal energy in accordance with the recording signal, the ink is liquefied and the liquid ink is ejected, or the ink has already begun to solidify by the time it reaches the recording medium. The present invention is also applicable when using ink that is liquefied for the first time. Ink in such cases is disclosed in Japanese Patent Application Laid-open No. 54-56847 or Japanese Patent Application Laid-open No. 60-71.
In a state where it is held as a liquid or solid in the porous sheet recesses or through holes, as described in Japanese Patent No. 260,
It may also be configured to face the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

In addition, the ink jet recording apparatus of the present invention can be used as an image output terminal for information processing equipment such as a computer, a copying machine combined with a reader, etc., and a facsimile machine having a transmitting/receiving function. It may also take a form.

[0036]

[Effects of the Invention] As explained above, according to the present invention,
A high-quality recorded image can be obtained in which white streaks or black streaks that occur between recorded lines are suppressed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the circuit configuration of a recording apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the appearance of a main part of a recording device according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing the positional relationship of recording areas in one embodiment of the present invention.

FIG. 4 is a graph showing an example of the contents of data stored in a lookup table in an embodiment of the present invention.

FIG. 5 is a flowchart showing a control procedure according to an embodiment of the present invention.

[Explanation of symbols]

1 CPU 2 ROM 3 RAM 4 Interface circuit 5 Input buffer 6 LUT (lookup table) 7 Binarization circuit (binarization means) 8 Selection circuit (selection means) 9-1, 9-2 Line buffer 11 Recording head 12 Carriage drive circuit (drive means) 13 Platen drive circuit (drive means) 14 Carriage 15 Platen roller 16 Recording paper

Claims (2)

[Claims] 1. A recording head that records information on a recording material with a width of a plurality of dots in the sub-scanning direction in one main scan; a driving means for overlapping a recording area in one main scan with another recording area by setting the relative movement amount of the plurality of dots to a value obtained by dividing the width of the plurality of dots by an integer value of 2 or more; A plurality of line buffers that are used individually in order and correspond to the integer values, and a plurality of line buffers that correspond to each main scan when input data is binarized and supplied to the recording head via the line buffers. 1. A recording device comprising: binarization means for performing different binarization processes. 2. The recording head includes an electrothermal transducer for applying thermal energy to cause film boiling on the ink, as an element that generates energy for ejecting the ink. 1. The recording device according to 1.