JPH02153761A - Recording apparatus - Google Patents

Abstract

PURPOSE:To convert dot density without using specific application software by providing the first dot data receiving means, the second dot data forming means for forming interpolation dot data, the second dot data receiving means and the selection means of those data receiving means. CONSTITUTION:A frequency multiplying circuit 1 obtains an image clock VCLK' wherein the frequency of an image clock VCLK is converted doubly and an oscillation circuit 5 generates a clock LCLK having frequency of 4 times. A device control circuit 3 writes an image signal VDO in either one of line memories supplied alternatevely by a demultiplexer 2 on the basis of the clock VCLK' and reads an image signal from other two line memories on the basis of the clock VCLK. Two signals among the signals D1 - D3 read by data selectors 14, 15 are selected and a comparing and judge circuit 10 to which signals DS1, DS2 are inputted outputs an output signal Q to a line memory 9. Next, a data selector 16 selects a signal from signals D1 - D4 to output the same as a laser driving signal LD.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording device such as a laser beam printer.

[Prior Art] In recent years, laser beam printers have been widely used as output devices for computers. Especially low density (e.g. 30
0dpi) laser beam printers are rapidly becoming popular due to their advantages such as low cost and compact size.

For example, in a laser beam printer that prints at a printing density of 300 dpi, as shown in FIG. ,
The printer controller 52 receives code data sent from an external host computer 54, generates page information consisting of dot data based on the code data, and sequentially sends the dot data to the printer engine section 51.

Further, the host computer 54 loads one application software from a floppy disk 55 containing many types of application software and starts the program.For example, if the application software is for document creation, It functions as a word processor and allows the user to create and store a large number of data information.

On the other hand, the printer engine section 51 has a higher printing density and higher gradation in order to perform higher quality printing, and has a printer engine of 600 dpi or more, or a printer engine that handles multi-value data. Printer engines have also been announced in recent years.

[Problem to be solved by the invention] However, the above-mentioned high-density printer engine (600
Conventionally, the printer controller 52 connected to the print density (600 dpi) required an amount of data memory corresponding to each print density (600 dpi) (for example, in the case of 600 dpi, the memory was four times that of 300 dpi). .

In addition, application software had to be created specifically for high-density printers, and the numerous application software mentioned above could not be used as is for high-density printers.

For example, FIG. 2 is a diagram showing the dot configuration of the alphabet raJ at a printing density of 300 dpi.

If the dot configuration is used as it is and printed at a print density of 600 dpi, the character size will be reduced to 1/2 in both the vertical and horizontal directions.

Therefore, one data interpolation method is to simply double the dot configuration in both the vertical and horizontal directions to achieve 300 dpi (
7) There is a method of applying the dot configuration to 600 dpi, but as shown in Figure 3, if the dot configuration is converted, the image size does not become smaller, but
When printing at 0dpi and when printing at 600dpi, the outlines and jaggedness of the characters are not improved, and the disadvantage is that the print engine's ability (600dpi) cannot be used to achieve the beauty. Ta.

The present invention has been made in view of the above-mentioned drawbacks of the conventional technology, and enables recording at high recording densities by using many existing application software created for low recording densities as is. It is an object of the present invention to provide a recording device that converts expanded recording data into recording data with a high recording density using a minimum memory, and allows a user to select whether to perform high-quality recording at a high recording density.

[Means for Solving the Problem] In order to achieve the above object, the recording device of the present invention has the following configuration. That is, a first dot information receiving means for receiving dot information of a first recording dot density, a storage means for storing dot information from the first dot information receiving means, and a first dot information receiving means for storing dot information stored in the storage means. a second dot information generating means for generating interpolated dot information of a second recording dot density based on the second recording dot density; a second dot information receiving means for receiving the dot information of the second recording dot density; and the first dot information receiving means. and a selection means for selectively selecting the second dot information receiving means.

[Operation] In the above configuration, dot information with the first recording dot density or dot information with the second recording dot density is selectively received, and if the dot information with the first recording dot density is received,
It stores the received dot information and operates to generate interpolated dot information of a second recording dot density based on the stored dot information.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Description of Device> FIG. 4A is a block configuration diagram showing a first embodiment of the present invention. As shown in the figure, the circuit of this embodiment is a data conversion circuit inserted between the printer controller 52 and the printer engine section 51 as shown in FIG. In addition, the printer controller 52 sends out 300 dpi dot data, and the printer engine unit 51 sends out 600 dpi dot data. The printer engine section 51 shown as an example of a conversion circuit is, as is well known, comprised of a laser driver for modulating a laser beam, a scanner for scanning the beam, a photosensitive drum, etc. based on an image signal (dot information).

The printer controller 52 responds to the horizontal synchronization signal HSYNC output by the horizontal synchronization signal generation circuit 4
The image signal VDO of 0 dpi and the image clock VCLK are sent to the printer engine 51. The horizontal synchronization signal generation circuit 4 is a circuit that sends out a horizontal synchronization signal based on a well-known beam detect signal BD, which is a synchronization signal in the main scanning direction.

On the other hand, the printer engine 51 prints a laser drive signal LD which is converted to 600 dpi from the 300 dpi image signal DO and the image clock CLK by a data conversion circuit which will be described in detail later. It is something.

Description of Interpolation> Next, the above data conversion circuit will be described in more detail with reference to FIG. 4A.

Reference numeral 1 denotes a frequency multiplier circuit that multiplies the frequency of the image clock VCLK to obtain a clock VCLK' whose frequency is doubled. 5 is an oscillation circuit, and the image clock VCLK
A clock LCLK having a frequency four times that of the clock LCLK is generated. 11
, 12 and 13 are switching circuits which select the clock VCLK' or LCLK and supply it as a write clock or a read clock to each line memory 6 to 8.

A demultiplexer 2 has a function of selectively supplying the image signal VDO to each of the line memories 6 to 8. 4 is a beam detect signal (hereinafter, BD double signal is counted,
One horizontal synchronization signal HSY every time two BD double signals are input
Output NC.

Reference numeral 3 denotes a device control circuit, which controls the demultiplexer 2, each switching circuit 11 to 13, and each data selector 14 to 16, which will be described later, to write or read each line based on the BD double signal.

This device control circuit 3 controls each line memory 6 to 8.
The image signal VDO is written into one of the line memories using the clock VCLK', and the image signal is read from the other two line memories based on the clock LCLK.

This operation is performed sequentially; when writing to line memory 6, line memory 7 and line memory 8 perform a read operation, and at the next timing, line memory 7 performs a write operation, and line memories 6 and 8 perform a read operation. . Similarly, at the next timing, the line memory 8 performs the old read operation, the line memories 6 and 7 perform the read operation, and the above-described control is repeated.

Note that each line memory 6 to 8 has a memory capacity twice as large as the data in the main scanning direction of 300 dpi, that is, 600 dpi
data memory capacity in the main scanning direction. Then, the image signals read from each line memory 6 to 8 are input to DI, D2. This will be explained below as D3.

14 and 15 are data selectors 1.2, which receive read signals D1, D2, . Of D3, two signals during a read operation are selected. For example, when line memory 6 is in a write operation, line memory 7
．． 8 is in a read operation, the data selector 14 selects the read data D2 of the line memory 7 and outputs a DSL signal to the comparison/discrimination circuit 10. Further, the data selector 15 selects the read data D3 of the line memory 8,
The DS2 signal is output to the comparison/discrimination circuit 10. And D
The comparison/discrimination circuit 10 inputting the SL signal and the DS2 signal is
Compare each data and output signal Q according to the result
is output to the line memory 9.

Note that the memory capacity of the line memory 9 that stores this output signal is the same as that of each of the line memories 6 to 8 described above. LCLK is used as a clock for writing and reading from this line memory 9. Also,
Writing to each line memory 6 to 8 and line memory 9,
Control of the read operation and selection control of the data selectors 14 and 15 are executed by the device control circuit 3.

Next, the data selector 16 selects each signal D1 to D3 read from each line memory 6 to 8 and the line memory 9
One of the signals D4 read from the signal D4 is selected and outputted as the laser drive signal LD. The selection control is similarly performed by the device control circuit 3.

Next, an example of the comparison/discrimination circuit 1O mentioned above will be explained below with reference to the configuration diagram shown in FIG.

As shown, input signals DSI and DS2 are each input to 7-bit shift registers 17 and 18. Shift output A of each shift register.

B, C, D, E, D, G, and a, b, c, d.

e, f, and g are input to the logic circuit 19. The output signal Q is set for the pixel of interest (see FIG. 6) according to the following logical formula.

Q= (B+F)bcdef + (b+f)BCDEF + (C1E)cde + (c+e)CDE +Dd +ABCDEFG +abcdefg There is a logic circuit as shown in Fig. 7 that realizes the above logical formula, and its output A laser drive signal LD is generated using the signal Q.

Note that 31 to 35 shown in FIG. 7 are OR circuits, and 36 to 46 are AND circuits.

FIG. 8 is a diagram showing the results of printing according to the method of this embodiment. As can be seen from the diagram, the jagged portion of the alphabet raJ has been improved compared to FIG. 3.

Incidentally, FIG. 4B is a timing chart of the data conversion circuit in this embodiment.

As explained above, according to this embodiment, it is possible to use the application software as is, and
Enables high-density printing with minimum memory capacity.

Description of Selection Means Next, an example in which a print density selection means is added to the data conversion circuit described above and the print density is switched according to command information from the print controller 52 will be described below with reference to FIG.

Components with the same reference numerals as the data conversion circuit shown in FIG. 4A have the same functions.

In FIG. 9, 21 is a CPU, which controls the device of the printer engine 51 of the laser beam printer, for example, controls the rotation stop of the photosensitive drum motor, and controls the printing process operation by an input/output board (not shown). In addition, it has a function of reading the setting state of the switch 22, a function of receiving commands through serial communication with the printer controller, and a function of switching the switching circuits 23 and 24.
It has a function of controlling the device control circuit 3.

The ROM also stores each control program (the first one) of the CPU 21.
(Flowchart shown in Figure 1) is stored in the RAM, and the CP
This is a memory serving as various tables and a work area when U21 performs various controls.

Note that the switch 22 is normally set to the "b" terminal side. Immediately after the power is turned on, the CPU 21 connects the switching circuit 23 and the switching circuit 24 to the "a" terminal side. That is, in this state, it performs the same function as the circuit shown in FIG. 4A, and
It is in a state where it can receive image data from the printer controller 52 of Pi, and as described above, it interpolates the 300 dpi image data and performs 600 dpi printing.

On the other hand, when the CPU 21 receives a mode switching command from the print controller 52 via the serial communication line, the
The PU21 switches the switching circuit 23 and the switching circuit 24 to the "b" terminal side, and outputs 600 dpi to the device control circuit 3.
Outputs image data input instructions. Then, the image clock VCLK is input as is, and the horizontal synchronization signal HSY
The NC also outputs the BD signal as it is. Further, the device control circuit 3 controls the line memories 6 and 7 as double buffer memories. That is, when receiving the n-th main scanning direction data, the demultiplexer 2
Instructs to write the 0dp i image signal VDO into the line memory 6, simultaneously instructs the data selector 16 to select the output D2 of the line memory 7, and at the same time instructs the switching circuit 12 to select LCLK as the read clock. and controls the data selector 16 to output the data read from the line memory 7 as the laser drive signal LD.

Next, when receiving the (n+1)th main scanning direction data, similarly, the demultiplexer 2 guides VDO to the line memory 7, selects VCLK as the write clock of the line memory 7, and writes the data to the line memory 7. A data write instruction is given, and at the same time, an instruction is given to the data selector 3 to select the output Dl of the line memory 6, and the switching circuit 11 is made to select LCLK as the read clock, so that the read data from the line memory 6 is It is controlled to be output as a laser drive signal LD. Then, when receiving the (n+2)th main scanning direction data, the same operation as the nth data is performed, and the same operation is repeated thereafter.

As explained above, after the power is turned on, if no command is input from the printer controller, the printer operates as a printer that receives 300 dpi image data, and when a command is input from the printer controller, it operates as a printer that receives 600 dpi image data.
operates as a printer that receives image data. Therefore, a conventional 300dpi printer controller,
New 600 dpi printer controllers that will be developed in the future can be connected as is. Immediately after the power is turned on, it is possible to operate the printer engine as a 600 dpi printer engine simply by sending a command to the printer engine.

Also, if the switch 22 is set to the "a" terminal side, the 6
It is also possible to function as a printer that receives an image signal of 00 dpi.

FIG. 11 is a flowchart showing the control of the CPU 21 explained above.

Next, another embodiment of the above-mentioned printing density selection means will be described as a 10th embodiment.
This will be explained below with reference to the figures.

Components with the same reference numerals as those in FIG. 9 indicate the same functions.

As shown in FIG. 1O, 31 is a frequency discrimination circuit;
Determine the frequency of the input image clock VCLK, and
It is determined whether the image clock is for 0dpi or 600dpi.

The determination here uses the fact that the frequency of the image clock for 600 dpi is four times the frequency of the image clock for 300 dpi. Similar to the CPU 21 described above, the frequency discrimination circuit 31 switches the switching circuit 23 .
24 and the device control circuit 3 to control the 300dp
If the image clock of i is input, 300dp i
If a 600 dpi image clock is input, the 600 dpi image signal is received and printed.

In the above-mentioned embodiment, recording densities of 300 dpi and 600 dpi were explained, but recording densities of 400 dpi and 800 dpi
It may be a combination of i.

[Effects of the Invention] As explained above, according to the present invention, dot density conversion can be selectively performed without using special application software.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the system of a laser beam printer, Figure 2 is a diagram showing a dot configuration in a conventional example, Figure 3 is a diagram showing an example of dot conversion, and Figure 4A is a diagram of this embodiment. 4B is a diagram showing a timing chart of the circuit shown in FIG. 4A, FIG. 5 is a diagram showing a detailed circuit of the comparison/discrimination circuit 10 in this embodiment, and FIG. 7 is a diagram showing the relationship between the pixel of interest and the bit in this example, FIG. 7 is a diagram showing an example of the configuration of a logic circuit in this example, FIG. 8 is a diagram showing the dot configuration obtained from FIG. 4A, FIG. 9 is a diagram showing the selection means in this embodiment, FIG. 10 is a diagram showing the selection means in another configuration, and FIG. 11 is a flowchart showing the processing procedure in this embodiment. In the figure, 1... Frequency multiplier circuit, 2... Demultiplexer, 3... Device control circuit, 4... Horizontal synchronization signal generation circuit, 5... Oscillation circuit, 6-8.9...・Line memory, 14-16...Data selector, 10...
・Comparison/discrimination circuit, 11 to 13, 23.24...Switching circuit, 21...CPU, 22...Switch, 31...
・It is a frequency discrimination circuit. 2 Figure 11

Claims (1)

[Scope of Claims] First dot information receiving means for receiving dot information of a first recording dot density; storage means for storing dot information from the first dot information receiving means; and dot information stored in the storage means. a second dot information generating means for generating interpolated dot information of a second recording dot density based on the dot information of the second recording dot density; a second dot information receiving means for receiving the dot information of the second recording dot density; 1. A recording apparatus comprising a selection means for selectively selecting between a dot information receiving means and a second dot information receiving means.