JPH01271251A - Serial recording method - Google Patents

Abstract

PURPOSE:To enhance the throughput of a recording apparatus, by detecting the state of dots printed by a head lowermost stage raster and the head uppermost stage raster of the next line to determine one-pass printing or two-pass printing. CONSTITUTION:The JK flip-flop 21 parallel to an I/F controller 3 inputs the data and clock from a host system 10 and transfers a detection signal showing the presence of a printing dot in each raster (two-pass printing is necessary) to an MCU and receives a reset signal from the MCU at each time to initialize the same. When there is no printing dot (one data) in the received lowermost stage raster, usual one-pass printing is performed. When there is a printing dot, one-pass printing is performed in the same way if there is no one data in the uppermost stage raster and two-pass printing is executed if there is one data. By this method, control performing two-pass printing only at a necessary time becomes possible and the throughput of a recording apparatus can be enhanced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention uses a head in which a plurality of dot forming elements are arranged in the sheet I/feeding direction, and the head is not main scanned in the direction of the sheet. This invention relates to a serial recording method in which each line is recorded, the sheet is advanced, and the next line is recorded.

[Conventional technology]

Recording devices such as printers and facsimiles are configured to drive dot-forming elements in the head based on print data, and to form characters and images consisting of dot patterns while feeding the sheet (sub-scanning). The recording method can be classified into wire dot method, thermal method, inkjet method, laser method, LCD method, etc.

In addition, due to the scanning method, a head mounted on a carriage performs main scanning in the middle direction of the sheet, and also feeds the sheet line by line (
The method can also be divided into a serial recording method that performs sub-scanning) and a line recording method that performs recording only by sheet feeding (sub-scanning) using a head having a dot forming element equivalent to the size of the sheet.

In the above-mentioned recording apparatuses, dot densities are becoming higher in order to improve image quality.

As density increases, serial recording devices are required to have higher precision in both the head movement direction (main scanning direction) and sheet feeding direction (sub scanning direction).

By the way, in the serial type, main scanning is performed by moving the head, so accuracy can be ensured relatively easily, but in the sheet feeding method, mechanical errors in various parts of the sheet feeding mechanism such as gears and rollers and elongation of the sheet accumulate. Therefore, even if the rotation angle (step angle) of the motor is accurately controlled,
It has been difficult to increase the accuracy of the sheet feed amount.

If the sheet feeding accuracy is low, there will be variations in the dot/knot spacing between rows, and especially in image printing, if the spacing is too large, white streaks will occur, and if the spacing is too small, black streaks will occur, resulting in uneven printing. As a result, image quality deteriorates.

Therefore, conventionally, as a method to make the above-mentioned printing unevenness less noticeable, there is a method in which each raster at the bottom of the lid and each raster at the top of the head of the next line are printed by wrapping them in a staggered manner, for example, in a row. A method is adopted in which the lines at the boundaries between the lines and the lines are printed in two passes.

[Problem that the invention seeks to solve]

However, in the conventional two-pass printing method, no matter what kind of dot pattern the image at the boundary between lines has, it is difficult to print two
Since pass printing (double printing) was performed, there was a problem that 2-pass printing was performed uniformly even if 2-pass printing was unstable because even 1-pass printing would make printing unevenness noticeable, resulting in a decrease in throughput. Ta.

In particular, if the amount of overlap is large (for example, half the head) and the number of lines to be printed in two passes increases, the loss time will increase and the printing speed will be significantly reduced (for example, by half).

SUMMARY OF THE INVENTION An object of the present invention is to provide a serial recording method that can solve the above-mentioned problems of the prior art and can minimize the decrease in throughput when eliminating white lines in images due to errors in sheet feeding amount. That's true.

[Means for solving problems]

The present invention achieves the above object by detecting the state of dots printed on the bottom raster of the head and the top raster of the next row of heads, and determining whether to perform one-pass printing or two-pass printing based on the detection results. It is something to be achieved.

[Effect]

If the distribution of dots printed between the bottom raster of the head and the top raster of the next head is sparse, printing irregularities such as white stripes and black stripes may be hardly noticeable even if there is a sheet feed error.

The present invention was completed by focusing on this point.

〔Example〕

The present invention will be specifically described below with reference to the drawings.

FIG. 7 is a schematic perspective view of a serial recording device suitable for carrying out the method of the present invention, in which 1 is a sheet feeding roller that also serves as a platen, 2 is a sheet feeding roller that supports the sheet feeding roller, and a sheet feeding device (not shown). The roller shaft transmits the rotational force from the motor (LF motor), 3 is a sheet as a recording medium such as paper or a thin plastic plate, and 4 is a plurality of sheets arranged in the pupil (
a head having 5 dot-forming elements, e.g. 64 dot-forming elements;
6 is a carriage carrying a head 4 and reciprocating from side to side;
1 and 2 respectively indicate guide shafts that guide and support the carriage.

FIG. 8 is a block diagram showing the configuration of a control system of the recording apparatus shown in FIG. 7.

In FIG. 8, 10 is a recording device 11 for recording image data.
A host system 12 is a microcomputer unit (hereinafter abbreviated as MCU) consisting of a microprocessor, ROMSRAM, timer, Ilo, etc.;
3 is the host system 10 and the recording device i! An interface controller (hereinafter abbreviated as 1/F controller) performs communication between 11 and 11, an image RAM 14 stores image data transferred from the host system, and 15 reads and writes to the image RAM 14 and generates addresses. A RAM controller 16 is controlled by the commands of the MCU 12, which has bits equal to the number of head elements (dot forming elements), and an image RA;
A shift register temporarily holds the data read from M14, 17 is a head driver that drives the head element and prints based on the data in the shift 1 register, and 18 is a stevening motor that moves the carriage on which the head is mounted left and right. Carriage motor driver to drive, l
Reference numeral 9 indicates a sheet feed motor driver that drives a stepping motor that feeds the sheet 3.

In the above configuration, the host system 10 is the recording device 1
When the print preparation command is transferred to MCU1
2, after the sheet feed motor driver 19 moves the sheet 3 to the print start position, the RAM controller 5 initializes the image data storage position and transfers one line (raster) worth of image data via the I/F controller 13. Make a request.

When the host system 10 receives this transfer request signal, it starts transmitting the image data.

The transmitted data is written to the image RAM 14,
Further, a number of line data corresponding to the number of dot forming elements (head elements) are stored in the image RAM 1 in the same way.
4, the MCU 12 sets in advance in the RAM controller 15 the read start address where the data that should be located at the upper left corner of the screen is stored, the number of data bits for one line (raster), and the data read focus number. (.

Therefore, carriage driver 18 starts carriage scan (main scan).

Each time the head on the carriage reaches the printing position, the MCU
12 gives a read command to the RAM controller 15, the RAM controller automatically generates addresses for each dot position corresponding to the number of dot forming elements, and transfers the data to the shift register 16.

When the transfer is completed, the MCU 12 sends a drive signal (pulse) for a fixed period of time to the head driver 17.

The head driver 17 receives the drive signal and the shift register 1.
The driver group has the same number of dot forming elements as inputs and receives an AND signal of each of the six outputs, and a printing operation is performed by driving one column of dot forming elements (head elements) in the vertical direction.

When printing for one line is completed by repeating the above sequence for each digit position (left and right dot spacing positions), the MCU 12 stops the carriage 5 and prints the number of sheets corresponding to the number of dot forming elements. Perform sending.

This sheet feeding is performed by driving a sheet feeding motor by a sheet feeding motor driver 19.

Furthermore, the MCU 12 receives the next data from the host system 10, moves the carriage 5 to the printing start position, prints the next line in the same manner, and then receives data from the next and subsequent lines. While doing so, repeat the above operations to print one page.

FIG. 9 is an explanatory diagram showing an example of two-pass printing, where the black part shows the dot arrangement driven and controlled in the first pass, and the marked part shows the dot arrangement driven in the second pass (next line). Indicates an array.

Between the first pass and the second pass, there is one rasku (line) in which black dots (first pass) and mark dots (second pass) are arranged alternately. This raster is used for two-pass printing.

That is, FIG. 9 shows two-pass printing in which the lowermost raster of the head and the uppermost raster of the next row of heads are wrapped so as to be printed in a staggered manner (alternately).

Embodiments of the serial recording method according to the present invention will be described below.

FIG. 1 is a block diagram of a main part of a control system that implements the method of the first embodiment, and FIG. 2 is a flowchart showing the procedure of the method of the first embodiment.

This embodiment detects the data contents of the bottom raster of the head and the top raster of the head in the next row, and executes two-pass printing when both rasters have at least one printing dot. If there are no printing dots on both rasters, normal one-pass printing is performed.

The control system in Figure 1 is based on the control system in Figure 8, and
/JK flip-flop 2 in parallel with F controller 13
1 is connected.

This JK flip-flop is connected to the data and clock from the host system 10, and transmits a detection signal to the MCLJ 12 indicating that there is a printing dot in each raster (requires 2-pass printing), and also sends a detection signal to the MCLJ 12 each time. M.C.
It is configured to be initialized upon receiving a reset signal from U12.

In FIG. 2, when E9 lower raster data is received in step 101, the process proceeds to step 102, where it is determined whether or not there is a printed dot (1 data) in the lowermost raster. Proceed to step 103 and reset the print dot detection register (,2. In step 104, normal one-pass printing is executed.

If there is a printed dot (1 data) in step 102, the process advances to step 105, and after 11-resetting the evening detection i/-sister, the next row topmost Leicester data is received in step 106, and the next row data is received in step 107. It is determined whether there is 1 data in the topmost raster.

If there is no 1 data, proceed to step 103.10 as described above.
4-.Proceed and perform 1-pass printing.

■If there is data, proceed to step 10B, reset the 1 data detection register, and execute 2-pass printing in step 109. In this embodiment, the bottom raster and the next row's top raster are There is no dot printing on either side and 2 passes are p.
If it is not necessary, it automatically determines this and performs normal one-pass printing, which makes it possible to improve throughput and increase printing speed.

FIG. 3 is a block diagram of the main parts of the control system for carrying out the second embodiment of the method of the present invention, and FIG. 4 is a flowchart showing the operating procedure of the second embodiment.

In this embodiment, two-pass printing is performed only when the number of printed dots in the bottom raster of the RAD and the top raster of the next row of heads are both greater than the specified value, and one or both of the rasters are If the number of printed dots is less than a specified value, normal one-pass printing is performed.

This embodiment was designed in consideration of the fact that white stripes and black stripes are not noticeable unless the printed dots at the boundaries between rows are continuous over a certain number. For example, if the number of dots in one line is 2400, In this case, it is determined that two-pass printing is performed when the number of printed dots for both rasters is 100 or more.

The control system in Figure 3 is basically the same as the control system in Figure 8.
A dot counter 22 is connected in parallel with the I/F controller 13 and is configured to count the number of printed dots F (the number of 1 data) in each raster disk.

An ant gate 23 which receives data and a clock from the host system 10 as input signals is connected to the input side of the Doff counter 22.

Further, the dot counter 22 converts the counter output into MC.
It is connected so that it is transmitted to U12 and initialized by receiving a reset signal from MCLJ X 2 each time.

In FIG. 4, when the bottom raster data is received in step 201, the process proceeds to step 202-, where it is determined whether or not there are more than a specified number of printed dots (1 d~) in the bottom raster, and if the number is less than or equal to the specified number. If so, proceed to step 203 to reset the print dot counter, and then proceed to step 20.4.
Execute normal 1-pass printing in step 2057 if the number exceeds the specified number in step 202.
After proceeding to reset the print dot (1 data) counter, the next row's top sister is received in step 206, and in step 207 it is determined whether the number of print dots in the top raster is greater than or equal to a specified number.

If the number is less than the specified number, the process proceeds to steps 203 and 204 described above and normal one-pass printing is executed.

If the number is equal to or greater than the specified number, the process advances to step 208 to reset the print dot counter, and in step 209 two-pass printing is executed.

In this way, in this embodiment, if the number of printed dots on either the bottom raster or the next top raster is equal to or less than a certain number, 2
If pass printing is not required, this is automatically detected and one-pass printing for commuting is performed, so that the throughput can be further improved than in the first embodiment and the printing speed can be improved. was completed.

FIG. 5 is a block diagram of the main parts of the control system for carrying out the third embodiment of the method of the present invention, and FIG. 6 is a flowchart showing the operating procedure of the third embodiment.

In this embodiment, the bottom raster of the head and the top raster of the next row of the head are each divided into a plurality of areas, and the number of printed dots (1 data) is counted and output for each area, and the number of printed dots is specified in any area. 2 if more than
The configuration for performing pass printing further improves throughput.

The control system shown in Fig. 5 is based on the control system shown in Fig. 8.
A printed dot number detection circuit for each area is connected in parallel to the 7F controller 13.

This printed dot number detection circuit includes a column counter 24 that counts the number of dots in each raster, a decoder 25 that divides the dots in the raster into each area (A and BflJi areas in the illustrated example), and a decoder 25 that divides the dots in each raster into each area (A and BflJi areas in the illustrated example). It is composed of a dot counter 26 and a dot counter 27 that count the number of printed dots (one data).

The input side of each dot counter 26, 27 is connected to an AND gate 28, 29 which receives data and a clock from the host system 10 as input signals.

Further, each of the dot counters 26 and 27 transmits the counter output to the MCU 12, and also transmits the counter output to the MCU 12 each time.
It is connected so that it is initialized by receiving a reset signal from.

The column counter 24 is connected to count the number of dots for each rask by receiving a clock signal from the host system 10 and a reset signal from the MCU 12.

In FIG. 6, when the bottom raster data is received in step 301, the process proceeds to step 302 and each area A, B is
It is determined whether the printed dot counter number of either of the dot counters 26.2 and 7 has reached a specified number or more.

If both areas are below the specified number, step 303
Proceed to column counter 24 and dot counter 26.
．． 27 is reset, and normal one-pass printing is executed in step 304.

If in step 302 any area contains more than the specified number of printed dots (1 data), step 30
5, the top raster data of the next row is received, and in step 30'6, it is determined whether the number of printed dots in each area A, B is equal to or greater than a specified number.

If both areas are below the specified number, step 303
．． The process advances to step 304 to execute normal one-pass printing.

If there are more than a specified number of printed dots in any area, the process proceeds to step 307, where the column counter 24 and each dot counter 26, 27 are reset, and in step 308, two-pass printing is executed.

In this way, according to this embodiment, the bottom raster and the next top raster are each divided into a plurality of areas (two or more), and when the number of printed dots in either area of both rasters is greater than or equal to the specified number, 2-pass printing is performed only when the printing unevenness is not noticeable, and normal 1-pass printing is performed when other printing irregularities are not noticeable.
Furthermore, it was possible to improve throughput and printing speed.

〔Effect of the invention〕

As is clear from the above explanation, according to the serial recording method of the present invention, the state of the dots printed on the bottom raster of the head and the top raster of the next head is detected, and one-pass printing is performed based on the detection results. Since it is possible to perform control to perform two-pass printing only when necessary, it is possible to improve the throughput of the recording apparatus.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing main parts of a control system suitable for carrying out the first embodiment of the method of the present invention, FIG. 2 is a flowchart of the operation of the control system of FIG. 1, and FIG. Method 2
Block diagram of main parts of a control system suitable for implementing the embodiment, No. 4
The figure is a flowchart of the operation of the control system in Figure 3, Figure 5 is a block diagram of the main parts of a control system suitable for implementing the third embodiment of the method of the present invention, and Figure 6 is a flowchart of the operation of the control system in Figure 5. FIG. 7 is a schematic perspective view of a recording device suitable for implementing the method of the present invention, and FIG. 8 shows the basic configuration of a control system of a serial recording device suitable for implementing the present invention. The block diagram shown in FIG. 9 is a dot arrangement diagram illustrating two-pass printing.
・-Seat, 4...--Head, 5...
--- Carriage, 11--- Recording device, 12-----M CU, 13---1/
F controller, 21-----~--JK flip-flop, 22.26.27--Don't counter, 24-----1.-column counter, 25--
−−−−・−Decoder.

Claims (1)

[Claims] (1) In a serial recording method that performs dot matrix printing using a head in which multiple dot forming elements are arranged in the sheet feeding direction, the dots printed on the bottom raster of the head and the top raster of the next row of heads are A serial recording method characterized by detecting a state and determining whether to perform one-pass printing or two-pass printing based on the detection result.