JPH07137325A - Method of printing recording apparatus - Google Patents

Abstract

PURPOSE:To drastically enhance the image quality of a medium contrast printing mode in a case equipped with a function selecting a binarizing printing mode and an intermediate tone printing. CONSTITUTION:When one line printing time of a binarizing printing mode performing printing on the basis of simple binarized data is set to Tps and one line printing time of an intermediate tone printing mode performing printing on the basis of pseudointermediate tone data is set to Tpm, the relation of Tps<Tpm is preset and, at the time of printing, one line printing times of the respective printing modes are differentiated to perform printing. When the wait time between respective line printings of the binarizing printing mode is set to Tsw and the wait time of the intermediate tone printing mode is set to Twm, the relation of Tws<Twm is preset and, at the time of printing, the wait times between line printings are differentiated to perform printing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method of a recording apparatus suitable for use in a magnifying copying machine for magnifying and printing image data read from an original.

[0002]

2. Description of the Related Art Conventionally, there is known a magnifying copying machine which reads an original of A4 size or the like by an image sensor, processes the read image data, and enlarges and prints it in a large size such as A1 or A0 size. .

This type of enlargement copying machine is equipped with a serial type print head (thermal head) in which a large number of print elements are arranged, and at the time of printing, recording paper (thermosensitive recording paper) is intermittently transferred and the print head is used for recording. Scanning is performed in a direction perpendicular to the paper transport direction, and printing is performed line by line on the recording paper. A plurality of print heads are arranged at regular intervals in the line direction, and each print head prints a length obtained by dividing the total line length by the number of print heads.

[0004]

The enlargement copying machine described above selects a binarized print mode for printing based on simple binarized data and a halftone print mode for printing based on pseudo halftone data. However, there is a problem that the following problems occur when a printable function is provided.

That is, when printing is performed based on the pseudo halftone data, the print density (for example, 64 gradations) is represented by the density of the dot pixels to be printed, and the dot pixels are set for a predetermined time Ts. Only the printing element (see FIG. 2) is energized to print. Therefore, as shown in FIG. 4, the print width of the dot pixel I becomes relatively narrow as shown in FIG. 4A when the scanning speed of the print head is low, and as shown in FIG. 4B when it is high. So that it becomes landscape.

On the other hand, the printing speed of the recording apparatus is required to be high. At high speeds, the binary print mode, which is mainly used for printing text documents, is represented in black and white.
Even if the dot pixels become horizontally long, the print image quality is hardly affected, but in the halftone print mode that is mainly used for printing photographs, etc., the density of dot pixels differs depending on the density of the density. This greatly affects the black-and-white area ratio in the high portion, leading to deterioration in halftone density accuracy and further in print image quality.

On the other hand, the print head returns to the print start position after printing one line, but the return speed at this time is usually set to a high speed. Therefore, mechanical vibration is generated in the cabinet or the like due to the impact when the print head returns, and this vibration affects the initial stage in the next one-line printing. Also in this case, the print quality is hardly affected in the binarized print mode because there are many white areas, but in the halftone print mode, printing is started (especially when printing is started from the image middle part in the case of multiple heads). Since the halftone image is printed more immediately, the print image quality is directly affected, and for example, vertical stripes may occur in the print image at the beginning of printing due to uneven density.

The present invention solves the problems existing in the prior art as described above. Even when the present invention has a function of selectively printing the binarized printing mode and the halftone printing mode, the halftone printing is particularly effective. An object of the present invention is to provide a printing method for a recording apparatus that can dramatically improve the image quality of modes.

[0009]

According to the present invention, a serial type print head Ha, in which a recording paper P is intermittently transferred and a large number of printing elements are arranged, is arranged in a direction perpendicular to the transfer direction of the recording paper P. A printing method of a recording device capable of performing printing by scanning and selecting a binary print mode for printing based on simple binary data and a halftone print mode for printing based on pseudo halftone data In particular, when the one-line printing time of the binarization printing mode is Tps and the one-line printing time of the halftone printing mode is Tpm, T
By setting the relationship of ps <Tpm,
The feature is that each line is printed with different one-line printing time.

In the printing method according to another embodiment of the present invention, the wait time between line prints in the binarized print mode is Tws, and the wait time between line prints in the halftone print mode is Twm. By setting the relationship of Tws <Twm in advance, the wait time between each line printing is made different at the time of printing.

In any of these printing methods, it is desirable to use a plurality of print heads Ha, Hb, Hc arranged at regular intervals in the line direction. It is also possible to combine and implement these printing methods.

[0012]

According to the printing method of the recording apparatus of the present invention, the recording apparatus first transfers the recording paper P intermittently and has a serial print head Ha in which a large number of printing elements are arranged as a prerequisite function. Is provided with a function of performing scanning by printing in a direction perpendicular to the transport direction of the recording paper P, and printing based on a binary printing mode for printing based on simple binary data and pseudo halftone data. It has the function of printing by selecting the halftone print mode.

Assuming these functions, the time condition for the printing process is that the one-line printing time of the binary printing mode is Tps and the one-line printing time of the halftone printing mode is Tpm. , Tps <Tpm. That is, the scanning speed (printing speed) of the print heads Ha in the halftone printing mode is set to be slower than the scanning speed in the binarized printing mode. Therefore, the shape of the printed dot pixels is about the same in width from horizontal to vertical,
The accuracy of halftone density is improved.

On the other hand, if the wait time between line prints in the binarized print mode is Tws and the wait time between line prints in the halftone print mode is Twm, then Tw is set in advance.
The relation of s <Twm is set. Accordingly, the wait time Twm between the line prints in the halftone print mode is the wait time Tws between the line prints in the binarized print mode.
Longer than that of the print head Ha ...
The influence of mechanical vibration of the cabinet or the like that occurs when returning to the print start position is eliminated, and vertical stripes are prevented from occurring in the print image at the initial stage of print start. In particular, when a plurality of print heads Ha, which are arranged at regular intervals in the line direction, are used, deterioration of image quality at the seam in one line printed by each print head Ha ... Is prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, an outline of an enlargement copying machine equipped with a recording apparatus capable of carrying out the printing method according to the present invention will be described with reference to FIG.

FIG. 1 shows a block system diagram of the enlargement copying machine. The magnifying copying machine 1 is roughly divided into a reading processing system A, an operating system B, a control processing system C and a printing processing system D. In particular, the operating system B, the control processing system C and the printing processing system D are the printing according to the present invention. Configure a recording device 2 that can carry out the method.

The reading processing system A includes a reading unit 3 having an image sensor, a reduction processing unit 4 for performing reduction processing, a pseudo halftone processing unit 5 for converting into pseudo halftone data, and a simple binary value for converting into simple binary data. The conversion processing unit 6 and the expansion processing unit 7 that performs the expansion process are included. As a result, the reading unit 3 reads the original with the image sensor and outputs the image data through necessary processing such as A / D conversion, and the image data is reduced by the reduction processing unit 4, the pseudo halftone processing unit 5, or the like. It is given to the control processing system C via the simple binarization processing unit 6 and the expansion processing unit 7.

In this case, if the same magnification is selected by the magnification selection key 10 to be described later, the image data passes through the reduction processing section 4 and the enlargement processing section 7 as it is. On the other hand, if an integer multiple enlargement ratio is selected, the image data is reduced by the reduction processing unit 4.
If the non-integer magnification ratio is selected, the image data is once reduced by the reduction processing unit 4 and then enlarged by the enlargement processing unit 7. Processed to obtain a constant magnification. Further, if the binarized print mode is selected by the print mode selection key 8 described later, the image data is converted into black and white binarized data via the simple binarization processing unit 6 and the halftone printing is performed. If the mode is selected, the image data is converted into pseudo halftone data via the pseudo halftone processing unit 5. An error diffusion method is used for conversion into pseudo-halftone data, and the pseudo-halftone processing unit 5 performs data processing (binarization) on image data so that halftone density of 64 gradations is represented by the density of dot pixels. ) Is done.

The operation system B includes a print mode selection key 8 for selecting the binarized print mode and the halftone print mode, a recording paper selection key 9 for selecting the type of recording paper, and a magnification selection key 10 for selecting the enlargement ratio. A numeric keypad (not shown) and various function keys are provided. Then, the selection information is given to the control processing system C.

The control processing system C includes a central control unit 11 including a CPU, a ROM 12 for storing a control program, a RAM 13 for storing various data including image data,
It controls the entire enlargement copying machine 1 and executes various calculations.

The print processing system D includes a print processing unit 14 including a RAM for temporarily storing image data for one line (print data) and three print heads Ha, Hb, Hc. Thereby, the image data to be printed is printed by the print processing unit 14
Is applied to each print head Ha through the. in this case,
A serial thermal head in which a large number (for example, 124 dots) of printing elements (heating elements) are arranged can be used as each printing head Ha. Further, the print heads Ha ... Are arranged at regular intervals in the line direction, and the print heads Ha.
Is printed. Therefore, the scanning distance of the print heads Ha is also X / 3. The print heads Ha ... Perform scanning by scanning in a direction perpendicular to the arrangement direction of the print elements. This direction is the main scanning direction Em. On the other hand, the recording paper P is intermittently fed in a direction perpendicular to the main scanning direction, and by this, one line L _n-1 , L _n ... Is sequentially printed. Then, this direction becomes the sub-scanning direction Es.

The print processing system D includes a motor controller 15,
A head moving motor 16 and a transfer roller driving motor 17 are provided. The head moving motor 16 moves (scans) the print heads Ha ..., and the transfer roller driving motor 17 drives a transfer roller (not shown) to intermittently transfer the recording paper P. The motors 16 and 17 are centrally controlled. It is controlled by the motor control unit 15 based on a control command from the unit 11 side.

Next, the printing method according to the present invention and the function of each related portion in the enlargement copying machine 1 will be described with reference to FIGS.
Will be described with reference to.

First, when the one-line printing time of the binarized printing mode is Tps and the one-line printing time of the halftone printing mode is Tpm, the printing time during the printing process is Tps <Tpm according to the present invention. So that the scanning speed (one-line printing time) of the print heads Ha in each print mode is set. In this case, the optimum result is obtained by setting Tpm to about 1.2 to 1.8 times Tps.

When the wait time in the binarized print mode is set to Tws and the wait time in the halftone print mode is set to Twm, the wait time between line prints in the printing process is Tws <Twm according to the present invention. The wait time (stop time) of the print heads Ha in each print mode is set so as to be related to each other. In this case, the optimum result is obtained by setting Twm to about 11 to 19 times Tws.

As a result, as shown in FIGS. 1A and 1B, the scanning speed of the print heads Ha in the halftone printing mode becomes slower than the scanning speed in the binarization printing mode, and the halftone printing is performed. The one-line printing time Tpm in the mode is longer than the one-line printing time Tps in the binary printing mode. As a result, the printed dot pixels have the same horizontal to vertical widths (see FIG. 4A), and the accuracy of the halftone density is improved, so that the print image quality is improved. Further, the wait time Twm between the line prints in the halftone print mode becomes longer than the wait time Tws between the line prints in the binarized print mode, and the print heads Ha ... The influence of mechanical vibration of the cabinet or the like that occurs when returning is eliminated, and the occurrence of vertical stripes in the printed image at the beginning of printing is prevented. In particular, when a plurality of print heads Ha, Hb, Hc arranged at regular intervals in the line direction are used, each print head H
The deterioration of the image quality at the seam in one line printed by a ... Is prevented, and the print image quality is further improved.

In FIGS. 1 (a) and 1 (b), T
r represents the return time of the print heads Ha ... The return time Tr is set to be the same in both the binarization print mode and the halftone print mode. 2 shows the print strobe signal Ss. In the figure, Ts is an energization time during which an electric current is applied to the printing elements (heat generating elements) of the print head Ha, and this energization time Ts is set to be the same in both the binarized printing mode and the halftone printing mode.

Therefore, when the binarized print mode is selected by the print mode selection key 8, the image data converted into the binarized data by the simple binarization processing unit 4 is transferred to the respective binarization processing units via the print processing unit 14. It is sent to the print head Ha, and is printed on a recording paper (thermal recording paper) P. At this time, the central control unit 1
1 gives a control command to the motor control unit 15 to control the head moving motor 16, and the scanning speed (printing time Tps) and return speed of the print heads Ha ... along the characteristic line shown in FIG. (Return time Tr) and stop time (wait time Tws) are controlled.

On the other hand, when the halftone print mode is selected by the print mode selection key 8, the image data converted into the pseudo halftone data by the pseudo halftone processing unit 5 is sent to each print head via the print processing unit 14. It is sent to Ha ... and printed on the recording paper P. At this time, the central control unit 11 controls the head moving motor 16 by giving a control command to the motor control unit 15, and controls the scanning speed (printing speed) of the print heads Ha ... along the characteristic line shown in FIG. Time Tpm), return speed (return time Tr), stop time (wait time Tw)
m) is controlled.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment.
For example, although the case where three print heads are used is illustrated, one or two print heads or four or more print heads may be used. Although the print head is a thermal head as an example, it does not prevent the use of a print head based on another principle. Furthermore, although the case where it is applied to the enlargement copying machine is illustrated, it can be applied to any recording device for other purposes. In addition, the detailed configuration, method, and the like can be arbitrarily changed without departing from the scope of the present invention.

[0032]

As described above, according to the present invention, a recording sheet is intermittently transferred, and a serial type print head in which a large number of printing elements are arranged scans in a direction perpendicular to the transfer direction of the recording sheet for printing. In addition to the above, the binarization printing mode for printing based on simple binarization data and the halftone printing mode for printing based on pseudo halftone data When the one-line printing time of the printing mode is Tps and the one-line printing time of the halftone printing mode is Tpm, the one-line printing time of each printing mode is set at the time of printing by setting the relationship of Tps <Tpm in advance. Since the printing is performed differently, the shape of the dot pixel is optimized to improve the accuracy of halftone density, especially in the halftone printing mode, thereby significantly improving the print image quality. A marked effect of being able to.

Further, in the present invention, when the wait time between each line print in the binarized print mode is Tws and the wait time between each line print in the halftone print mode is Twm, the relationship of Tws <Twm is established in advance. By setting the settings, the wait time between each line printing is changed so that it is possible to prevent the occurrence of vertical stripes in the printed image at the beginning of printing and to prevent image quality deterioration at the seams within one line. And a remarkable effect that it can contribute to further improvement of print image quality.

Moreover, by combining these printing methods, the overall printing image quality can be dramatically improved.

[Brief description of drawings]

FIG. 1 is a time chart showing a position of a print head for explaining a printing method according to the present invention,

FIG. 2 is a waveform diagram of a print strobe signal,

FIG. 3 is a block system diagram of an enlargement copying machine equipped with a recording device capable of implementing the same printing method;

FIG. 4 is a shape pattern diagram of printed dot pixels,

[Explanation of symbols]

2 Recording device Ha ... Print head P Recording paper Tps One-line printing time of binarizing printing mode Tpm One-line printing time of halftone printing mode Tws Wait time between each line printing of binarizing printing mode Twm Halftone printing mode Wait time between each line printing

Claims (6)

[Claims] 1. A serial type print head, which transfers recording paper intermittently and in which a large number of printing elements are arranged, scans in a direction perpendicular to the transfer direction of the recording paper to perform printing, and a simple binary value. In the printing method of the recording device that can print by selecting the binarized print mode for printing based on the digitized data and the halftone print mode for printing based on the pseudo halftone data, one line printing time of the binarized print mode Tps,
When the one-line printing time of the halftone printing mode is Tpm, the relationship of Tps <Tpm is set in advance so that the one-line printing time of each printing mode is different at the time of printing. Printing method of recording device. 2. The printing method for a recording apparatus according to claim 1, wherein a plurality of print heads arranged at regular intervals in the line direction are used. 3. A serial type print head, which transfers recording paper intermittently and in which a large number of printing elements are arranged, scans in a direction perpendicular to the transfer direction of the recording paper to perform printing, and a simple binary method. In the printing method of a recording device capable of printing by selecting the binarized print mode that prints based on the digitized data and the halftone print mode that prints based on the pseudo halftone data, between the line prints in the binarized print mode. When the wait time for each line is Tws and the wait time between each line printing in the halftone print mode is Twm, the wait time between each line printing is made different at the time of printing by setting the relationship of Tws <Twm in advance. A printing method for a recording device, wherein the printing is performed by printing. 4. The printing method for a recording apparatus according to claim 3, wherein a plurality of print heads arranged at regular intervals in the line direction are used. 5. A serial type print head, which transfers recording paper intermittently and in which a large number of printing elements are arranged, scans in a direction perpendicular to the transfer direction of the recording paper to perform printing, and a simple binary method. In the printing method of the recording device that can print by selecting the binarized print mode for printing based on the digitized data and the halftone print mode for printing based on the pseudo halftone data, one line printing time of the binarized print mode Tps,
One line printing time of halftone printing mode is Tpm, wait time between each line printing of binarization printing mode is Tws,
Wait time between each line printing in halftone printing mode is T
If wm, Tps <Tpm and Tws <T in advance
A printing method for a recording apparatus, wherein by setting a relationship of wm, one line printing time in each printing mode and a wait time between each line printing are made different at the time of printing. 6. The printing method for a recording apparatus according to claim 5, wherein a plurality of print heads arranged at regular intervals in the line direction are used.