JPH05183697A - Picture processing unit - Google Patents

Abstract

PURPOSE:To realize a picture of 600dpi without use of a high speed, peripheral device and to reduce the memory capacity by implementing normally dot information at 300dpi and selecting a 600dpi smoothing mode in an engine in which dot information expanded to 300dpi is selected to 300dpi/600dpi. CONSTITUTION:In a printer engine 100 connecting to a printer controller 200 and using a drum 11 driven to form a visual picture, a PCPU 66 receives one resolution among plural sets of different resolutions (300dpi/600dpi) from the printer controller 200 via a connection cable 38 or from a changeover circuit 69 via a data line 68 to discriminate the resolution. In the case of 600dpi according to the discriminated resolution, a drive speed of a drum motor control circuit 62 is set so that the speed at the 600dpi is a half the drive speed at 300dpi and the smoothing processing corresponding to the resolution is implemented according to a prescribed algorithm after the setting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing device, and more particularly to an image processing device applicable to a recording device such as a laser beam printer.

[0002]

2. Description of the Related Art Conventionally, laser beam printers have been widely used as output devices for computers. Especially 3
A small machine with a resolution of 00 dpi to 600 dpi is generalized due to the advantages of low cost and compactness,
It is spreading rapidly.

FIG. 13 is a diagram showing an example of the configuration of a laser beam printer, and a description will be added below with reference to FIG.

In FIG. 13, reference numeral 1 is a sheet as a recording medium, and 2 is a sheet cassette for holding the sheet 1. 3 is a paper feed which separates only the topmost one of the papers 1 placed on the paper cassette 2 and conveys the leading end of the paper separated by the driving means (not shown) to the paper feed rollers 4, 4'position. The cam rotates intermittently for each paper feed.

Reference numeral 18 denotes a reflection type photo sensor, and the reflection type photo sensor 18 detects the absence of paper by detecting the reflected light of the sheet 1 through a hole 19 provided at the bottom of the sheet cassette 2.

The paper feed rollers 4, 4 ′ have a paper feed cam 3 for the paper 1.
When the sheet 1 is conveyed to the gap, the sheet 1 is rotated while being lightly pressed, and the sheet 1 is conveyed. When the sheet 1 is conveyed and the leading edge reaches the position of the registration shutter 5, the conveyance of the sheet 1 is stopped by the registration shutter 5, and the paper feed rollers 4 and 4 ′ rotate while generating a conveyance torque while slipping on the sheet 1. Keep doing. In this case, by driving the registration solenoid 6 to release the registration shutter 5 upward, the sheet 1 is sent to the transport rollers 7, 7 '. The registration shutter 5 is driven at a constant timing with the image formed by the laser beam 20 being focused on the photosensitive drum 11. 2
Reference numeral 1 denotes a photo sensor, which detects whether or not it is located at the position of the resist shutter 5.

Reference numeral 52 is a rotary polygon mirror. The rotary polygon mirror 52 is driven by a polygon mirror motor 53, and the beam 20 from the semiconductor laser 51 is guided onto the photosensitive drum 11 via a reflection mirror 54 to be exposed. A recorded image is formed on the drum 11. Further, the beam detector 55 arranged at the scanning start position of the beam 20 detects the beam 20 and is the image writing timing B in the main scanning direction.
Output the D signal.

After that, the paper 1 is fed to the photosensitive drum 11 by obtaining the carrying torque by the carrying rollers 7, 7'instead of the paper feeding rollers 4, 4 '. Here, the image exposed on the photosensitive drum 11 is the cleaner 12, the charger 13, the developing device 1.
4, the image is transferred onto the sheet 1 by the cooperation of the transfer charger 15. The paper 1 on which the image is transferred is then fixed to the fixing roller 8,
The sheet is fixed by 8'and discharged onto the stacker 10 by the discharge rollers 9 and 9 '.

In the figure, A is a guide for regulating the conveying direction of the sheet 1.

Reference numeral 16 denotes a paper feed table, which allows not only paper feed from the paper cassette 2 but also manual paper feed from the paper feed tray 16 one by one. The paper that has been fed into the gap between the manual feed roller 17 and the manual feed roller 17 on the paper feed table 16 is lightly pressed by the manual feed roller 17 and, like the paper feed rollers 4 and 4 ', the leading edge of the paper. Is conveyed until it reaches the registration shutter 5, and slips there. The subsequent transport sequence is exactly the same as when cassette feeding.

The fixing roller 8 contains a fixing heater 24, and the surface temperature of the fixing roller 8 is controlled to a predetermined temperature on the basis of the temperature detected by the thermistor 23 that makes a slip contact with the roller surface to record the paper 1. Heat fix the image. Reference numeral 22 denotes a photo sensor, which is a fixing roller 8,
It is detected whether or not there is a sheet at the position 8 '.

Such a printer is connected to a controller by an interface means, and receives a print command and an image signal from the controller to perform a print sequence. The signals transmitted and received by this interface means will be briefly described below.

FIG. 14 is a diagram showing interface signals between the printer engine section and the controller for generating image data. Each of the interface signals shown in the figure will be described below.

The PPRDY signal is a signal sent from the printer to the controller, and is a signal notifying that the power of the printer is turned on and the printer is in an operable state. The CPRDY signal is a signal sent from the controller to the printer and is a signal notifying that the controller is powered on and the controller is in an operable state. The RDY signal is a signal sent from the printer to the controller, and indicates that the printer is ready to start the printing operation or can continue the printing operation whenever it receives the PRNT signal described later. For example, when the paper cassette 2 is out of paper and the print operation cannot be executed, the signal is "false".

The PRNT signal is a signal sent from the controller to the printer, and is a signal for instructing the start of the printing operation or the continuation of the printing operation. Upon receiving the signal, the printer starts the printing operation. V
The SREQ signal is a signal sent from the printer to the controller, and when the RDY signal sent from the printer is in the "true" state, the controller sets the PRNT signal to "true" to instruct to start the print operation. Is a signal indicating that the printer is ready to receive image data after being sent. In this state,
It becomes possible to receive the VSYNC signal described later.
The VSYNC signal is a signal sent from the controller to the printer, and is a signal for synchronizing the sending timing of image data in the sub-scanning direction. Due to this synchronization, the toner image formed on the drum is transferred onto the paper in synchronization with the paper in the sub-scanning direction.

The BD signal is a signal sent from the printer to the controller, and is a signal for synchronizing the sending timing of image data in the main scanning direction. Due to this synchronization, the toner image formed on the drum is transferred onto the paper in synchronization with the paper in the sub-scanning direction.
The signal indicates that the scanning laser beam is at the starting point of main scanning. The VDO signal is a signal sent from the controller to the printer and is a signal for transmitting image data to be printed. This signal is transmitted in synchronization with the VCLK signal described later. The controller receives code data such as a PCL code transmitted from the host device, generates a character bit signal generated from a character generator corresponding to the code data, or a vector such as a Postscript code transmitted from the host device. Receives a code, generates graphic bit data according to the code,
Alternatively, bit image data read from the image scanner is generated and the data is transmitted to the printer as a VDO signal. The printer prints a black image when the signal is "true" and a white image when the signal is "false".

The VCLK signal is a signal sent from the controller to the printer and is a synchronizing signal for transmitting and receiving the VDO signal.

The SC signal is a bidirectional serial signal for bidirectionally transmitting and receiving a "command" which is a signal sent from the controller to the printer and a "status" which is a signal sent from the printer to the controller. .. An SCLK signal, which will be described later, is used as a synchronization signal when transmitting or receiving the signal. Further, as a signal for controlling the transmission direction of the bidirectional signal, an SBSY signal and C
And the BSY signal. Here, the "command" does not have an 8-bit serial signal, and the controller indicates to the printer whether, for example, the paper feeding mode is the mode of feeding from the cassette or the mode of feeding from the manual feed port. This is command information for giving an instruction to the user. "Status" is a serial signal consisting of 8 bits,
For example, the printer notifies the controller of various states of the printer such as a wait state in which the temperature of the fixing device of the printer has not reached a printable temperature, a paper jam state, and a paper cassette empty state. This is information to do.

The SCLK signal is used by the printer to take in "commands" or by the controller in "status".
Is a synchronizing pulse signal for taking in.

The CBSY signal is a signal for occupying the SC signal and the SCLK signal before the controller transmits the "command". The SBSY signal is sent by the SC signal and the S signal before the printer sends the "status".
This is a signal for occupying the CLK signal.

The operation of such an interface will be described below.

When the power switch of the printer is turned on and the power switch of the controller is turned on, the printer initializes the internal state of the printer and then sets the PPRDY signal to "true" to the controller. On the other hand, the controller similarly initializes the internal state of the controller and then sets the CPRDY signal to "true" for the printer. With this, the printer and the controller confirm that the respective power supplies have been turned on.

After that, the printer energizes the fixing heater 24 housed inside the fixing rollers 8 and 8 ', and sets the RDY signal to "true" when the surface temperature of the fixing roller reaches a temperature at which fixing is possible. After confirming that the RDY signal is "true", if the controller has data to be printed,
The PRNT signal is made "true" to the printer. When the printer confirms that the PRNT signal is "true", the photosensitive drum 11 is rotated to uniformly initialize the potential on the surface of the photosensitive drum, and at the same time, in the cassette sheet feeding mode, the sheet feeding cam 3 is driven and the leading edge of the sheet is fed. Is conveyed to the position of the registration shutter 5. In the manual paper feed mode, the paper manually fed from the paper feed tray 16 by the manual paper feed roller 17 is conveyed to the position of the registration shutter 15. Then, when the printer becomes ready to accept the VDO signal, the VSREQ signal is set to "true". After the controller confirms that the VSREQ signal is "true",
At the same time that the YNC signal is set to "true", the VDO signal is sequentially transmitted in synchronization with the BD signal. When the printer confirms that the VSYNC signal has become "true", the printer drives the registration solenoid 6 in synchronization with this and releases the registration shutter 5. As a result, the sheet 1 is conveyed to the photosensitive drum 11. In response to the VDO signal, the printer transfers a laser beam when an image should be printed black and turns off the laser beam when an image should be printed white to form a latent image on the photosensitive drum 11. , Developing unit 14
The toner is attached to the latent image and developed to form a toner image. Next, the toner image on the drum is transferred onto the sheet 1 by the transfer charger 15, fixed by the fixing rollers 8 and 8 ', and then discharged onto the sheet discharge tray.

In recent years, high precision printing output has become an essential condition, and various methods have been implemented to realize this.

For example, there is a method of increasing the print density.
This has a resolution of 600 dpi in the main scanning direction and the sub scanning direction.
It is a method to make high resolution. In that case, printing / non-printing of the dots in one pixel divided based on the logical expression based on the pixel information of the pixel of interest and the pixel around the pixel of interest is determined. By doing so, smoothing is achieved for diagonal lines and curves.

[0026]

However, the high precision in the above conventional example has the following drawbacks. That is, (1) When the resolution is changed from 300 dpi to 600 dpi, the image memory capacity required for the printer controller is four times 300 dpi, which is very expensive. (2) When the resolution is changed from 300 dpi to 600 dpi and the throughput is the same, the image clock has to be quadrupled, and peripheral devices required for image processing have high speed and strength capable of withstanding high speed. It has to be done, which is very expensive.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and the object thereof is 300
Dot information expanded to dpi is 300 dpi / 600
In a switchable dpi engine, typically 300
Although the processing is performed at the dpi, it is an object to provide an image processing apparatus that can realize the memory reduction when switching to the 600 dpi smoothing mode and can realize the 600 dpi image without using a high-speed peripheral device.

[0028]

[Means for Solving the Problems]
To achieve the object, an image processing apparatus according to the present invention is an image processing apparatus that is connected between a recording control section and a recording mechanism section having a photosensitive member that is rotationally driven and that controls the recording mechanism section. The input means for inputting one resolution among a plurality of different resolutions, the determination means for determining the resolution input by the input means, and the resolution determined by the determination means,
Control means for controlling the rotation speed of the photoconductor so that the resolution handled by the recording mechanism section corresponds, resolution conversion means for converting the resolution of the input pixel data according to the resolution determined by the determination means, and the resolution Output means for outputting the result converted by the converting means to the recording mechanism section.

[0029]

According to this structure, the input means inputs one resolution among a plurality of different resolutions, the determination means determines the resolution input by the input means, and the control means compares the resolution determined by the determination means. , The rotation speed of the photoconductor is controlled so that the resolution handled by the recording mechanism unit corresponds, the resolution conversion unit converts the resolution of the input pixel data according to the resolution determined by the determination unit, and the output unit uses the resolution conversion unit. The converted result is output to the recording mechanism unit.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1A and 1B are block diagrams showing the configuration of a laser beam printer according to a first embodiment of the present invention. The mechanical portion of this embodiment is substantially the same as that of FIG. 13, and the same components as those of FIG. 13 are designated by the same reference numerals and the description thereof will be omitted.

In FIGS. 1A and 1B, 100 is a printer engine, and 200 is a printer controller for outputting output information to the printer engine 100 and controlling dot density to be output by the printer engine 100, which will be described later.

Further, in the printer engine 100, 56 is a drum motor for rotating the photosensitive drum 11, and 60 is a PC.
The semiconductor laser 5 is controlled by the PU 66 via the data line 63 and accordingly the control line 57.
1 is a laser drive circuit for driving 1; 61 is a polygon mirror motor control circuit for controlling a polygon mirror motor 53, which is controlled by a PCPU 66 via a data line 64, and accordingly rotates a rotary polygon mirror 52 via a control line 58; 6
2 is a drum motor control circuit for controlling the drum motor 56, and the drum motor control circuit 62 also has a data line 65.
Is controlled by the PCPU 66 via the control line 59.
The rotation of the drum motor 56 is controlled via.

Here, the drum motor 56 is also used as a drive source for transporting the paper via a gear (not shown).

Here, the image signal from the printer controller 200 is directly input to the laser drive circuit 60 via the input / output interface 30 instead of being sent to the laser drive circuit 60 from the data line 63 via the PCPU 66. You may control. Further, 66 is a microprocessor (PC) which controls the entire printer engine 100.
PU), the PCPU 66 is a ROM memory 66a for storing a control program, and an R for storing various control data.
It has an AM memory 66b and an I / O port (not shown) that controls input and output.

The PCPU 66 controls the entire drive system of the printer engine 100, for example, a drive system for carrying and unloading recording paper, and a system for executing an electrophotographic process via I / O ports. Of these, only the drive system for the recording paper and the connection and control between the sensor and the optical system provided in the drive system are shown, and the others are omitted. It goes without saying that the other parts are controlled by a known method.

On the other hand, the printer controller 200 for controlling the printer engine includes an input / output interface 32 for performing serial communication and image communication with the printer engine 100. The printer controller 200
Reference numeral 67 denotes a CPU that executes various types of information processing.

The printer engine 100 and the printer controller 200 mutually input / output interfaces 30, 3
2, the connection cable 38, and the I / O buses 34 and 36 of each other. Input / output signals from the connection cable 38 have the same configuration as that shown in FIG. It is shown in FIG. Here, the VDO signal processing unit 10 converts the input VDO signal by signal processing described below and inputs it as a converted signal VDOM to the laser drive circuit 60 of FIG. 1 to drive the semiconductor laser 51 to blink.

A switching circuit 69 is constituted by a rotary switch or the like, and the PCPU 66 can read the set value of the switching circuit 69 through the data line 68 when necessary. This switching circuit 69 is used for switching whether or not smoothing is performed in this embodiment. 300 dpi or 6 depending on the setting position of the switching circuit 69.
00 dpi smoothing is determined.

Reference numeral 99 is a BD for converting the photodetection signal from the beam detector 55 into a digital signal and outputting it.
It is a signal processing circuit.

FIG. 3 is a diagram showing the configuration of the drum motor control circuit according to the first embodiment.

In FIG. 3, reference numeral 81 is a crystal oscillating circuit, which counts the FMHz clock oscillated by the crystal oscillating circuit 81 into a counter 8
Output to 2. Reference numeral 82 is a counter that counts down the clock from the crystal oscillation circuit 81 to a predetermined value (1 / M). Reference numeral 83 is a preset counter that counts down to "1 / N" according to the data "N" set by the latch circuit 84, and the output clock fo from the preset counter 83 serves as a reference signal for the PLL circuit 85.

That is, fo = FMHz × (1 / M) × (1 /
There is a relationship of N).

Reference numeral 84 is a latch circuit. The latch circuit 84 is set with an arbitrary value (an arbitrary value among "1" to "256") sent from the PCPU 66 via the data line 88. An 8-bit data line is output from the latch circuit 84 to the preset counter 83, and the preset counter 83 determines the countdown value (1 / N) according to the set value of the latch circuit 84.

Reference numeral 85 is a PLL circuit, and the PLL circuit 85
Along with the rotation of the drum motor 56
The signal fc obtained from the rotation pulse signal generator 87 for generating one pulse per one rotation of
The error signal is detected so as to be equal to, and the rotation of the drum motor 56 is controlled via the amplifier 86 based on the error signal. In this case, the PLL circuit 85 receives the motor ON signal 89 from the PCPU 66 and starts rotation, and when the rotation speed of the drum motor 56 reaches the specified rotation speed and the rotation is constant, the ready signal 90 is transformed into the PCPU 66. To do.

Reference numeral 87 is a rotary pulse generator which generates a pulse signal corresponding to the rotation of the drum motor 56. 8
Reference numeral 9 is an ON signal for the drum motor 56, and 90 is a ready signal similar to the ready signal 80 in FIG.

Also in the drum motor control circuit 62, smoothing ON / OFF corresponding to the set value of the switching circuit 69.
According to the above, the feed speed of the drum motor 56 can be controlled to a predetermined speed.

FIG. 12A is a flow chart for explaining the operation according to the first embodiment.

First, the operation of this embodiment is initialized (S10).
After 1), the switching routine (S102) and the main routine (S103) are repeated.

The main operation of this embodiment in the entire flow chart will be described below.

FIG. 12B is a flow chart for explaining the switching routine according to the first embodiment.

The PCPU 66 reads the set value of the switching circuit 69 (S201) and turns on 600 dpi smoothing.
When the instruction of is confirmed (S202), 3 is input to the latch circuit 84.
A value twice as large as that at 00 dpi (twice as large as 300 dpi) is set (S203). As a result, 1 / N preset 8
In No. 3, the reference frequency of 1/2 at 300 dpi is input to the PLL circuit 85, and the feeding speed of the drum motor 56 can be reduced to 1/2 at 300 dpi by the PLL operation described above. Then, smoothing processing is performed according to a predetermined algorithm (S204). Also S202
When 300 dpi is confirmed in step S205, normal operation is performed in step S205.

Here, the smoothing process of S204 will be briefly described.

FIG. 2 is a diagram showing interface signals between the printer engine section and the controller according to the first embodiment.
FIG. 4 is a diagram showing a matrix memory of the first embodiment, FIGS. 5A and 5B are diagrams showing a block configuration of the present embodiment, and FIG. 6 is a change area of a target pixel applied in the first embodiment. FIG.

The smoothing process is performed by the VDO signal processing unit 101 shown in FIG. The operation will be described in detail below.

Pixel A to be printed as shown in FIG.
With respect to (hereinafter, this pixel is referred to as a target pixel), a peripheral area surrounding the target pixel (main scanning 11 pixels × sub scanning 9 pixels)
The feature of the pixel data is checked, and the target pixel is changed according to the result. In the first embodiment, the pixel of interest is 300 dpi in the main scanning direction 1 as shown in FIG.
It is located in the center of a dot matrix memory consisting of 1 dot × 9 dots in the sub-scanning direction, and is a set of sub-sections (x ₁ , x ₂ , y with a print density that is double in the main scanning direction and double in the sub-scanning direction)
It is intended to print by changing to image data determined by ₁ , y ₂ ).

In this embodiment, the peripheral area surrounding the pixel of interest (main scanning 1
The feature of the image data of 1 pixel × sub-scanning 9 pixels) is examined, and the target pixel is changed according to the result.

At the stage of printing by such a method, the main scanning is equivalently 600 dpi × the sub scanning 600 dpi.
It is printed at the print density of.

In FIGS. 5A and 5B, a VDO signal processing unit 10 for smoothing processing installed in the input unit of a 600 dpi printer engine for both main scanning and sub-scanning.
The function of each device in 1 will be described.

SW1 to SW9 are switch circuits, which switch the positions of α and β in the figure to switch the signals input to the line memories 125 to 133. The switch circuit is controlled in its switching position by a control signal SWC issued by a control circuit 147 issued by a control circuit 147 described later. Control circuit 147 is 600 dp
BD compatible with 600 dpi sub-scanning for printing i
, And a control signal SWC which is inverted in synchronization with the BD signal is generated every time the synchronizing signal BD is input. In the smoothing processing mode, the rotation speed of the drum is halved, so the synchronization signal is equal to the synchronization signal BS for interfacing with the printer controller 200. First, the switch circuits SW1 to SW9 are set to the “α” position. The printer controller 200 transmits the image data VDO of 300 dpi in synchronization with the BD signal. Line memory 1
9 to 9 store the image signal VDO of 300 dpi while sequentially shifting in synchronization with the clock signal VCLK, and each line memory stores dot information of the main scanning length for the page to be printed. Each line memory is connected in order of a line memory 1, a line memory 2, a line memory 3, ..., A line memory 9, and stores dot information of a main scanning length for 9 lines in the sub scanning direction.

Thereafter, the switch circuits SW1 to SW9 are switched to the position "β" side by the control signal SWC issued from the control circuit 147. Reference numerals 134 to 142 denote shift registers, and the shift registers 1 to 9 correspond to the line memories 1 to 9 and the data output from the line memories in synchronization with the clock signal VCKN is transmitted through the switch circuits SW1 to SW9. Will be re-entered.

Each shift register is composed of 11 bits, and as shown in the figure, 1a to 1k, 2a to 2
A dot matrix memory of 11 dots in the main scanning direction × 9 lines in the sub-scanning direction of k, 3a to 3k, ... Of the matrix memory, the central dot 5
Define f as the dot of interest. Reference numeral 143 denotes a processing circuit that detects the characteristics of the data stored in the dot matrix memory for smoothing and changes the pixel of interest 5f as necessary, and each bit (1a-9k) of the shift registers 1-9. Of a total of 99 bits) is input, and the changed parallel signal MDT (x ₁ , x ₂ ) is output. The parallel signal MDT (x ₁ , x ₂ ) is input to the parallel / serial conversion circuit 144.

The parallel / serial conversion circuit 144 converts the input parallel signal MDT (x ₁ , x ₂ ) into a serial signal VDOM, and then drives the semiconductor laser 55 by the laser driver 50. Similarly, processing for one main scanning line is sequentially performed.

Thereafter, the switch circuits SW1 to SW9 are switched to the position "α" side. Then, in synchronization with the synchronization signal BD input at the next timing, the data is similarly transferred to the next line memory by reading from the line memories 1 to 9 and the data is output to the shift registers 1 to 9. The processing circuit 143 detects the characteristics of the data stored in the dot matrix memory of 11 dots in the main scanning direction × 9 dots in the sub scanning direction output from the shift register, and changes the target pixel 5f as necessary,
The parallel signal MDT (y ₁ , y ₂ ) is output. The parallel / serial conversion circuit 144 converts the input parallel signal MDT (y ₁ , y ₂ ) into a serial signal VDOM, and then drives the semiconductor laser 55 by the laser driver 50. Similarly, the processing for one main scanning line is sequentially performed.

Thereafter, the switch circuits SW1 to SW9 are switched to the position "α" side. Then, the image signal VDO of the next sub-scanning line of 300 dpi transmitted from the controller is input.

In the present embodiment, the parallel signal is 2 bits as described above, but the first MDT signal (x ₁ , x ₂ ) and the second MDT signal (y ₁ ,
y ₂ ) and are alternately output. Reference numeral 45 denotes a clock generation circuit, which inputs a BD signal which is a main scanning synchronization signal and generates a clock signal VCK synchronized with the BD signal.

The clock signal VCK has twice the clock frequency f _ck required for recording at 300 dpi in the main scanning direction.

The serial is synchronized with the clock VCK.
Signal VDOM (x₁ , X₂ Or y ₁ , Y₂ ) Is sent sequentially
Will be issued. 146 is a frequency dividing circuit,
Input VCK, divide by 2 and frequency f_ckClock signal
Generate VCKN. The clock signal VCKN is
Dot matrix processing circuit 14 for processing dot data
It is used as a synchronous clock when it is taken into 3.

FIG. 7A, FIG. 7B and FIG. 8 show that in the first embodiment, the characteristics of the dot pattern are extracted from the matrix area of dots in the main scanning direction × 9 dots in the sub scanning in the entire matrix area, It is a figure explaining the algorithm for checking whether it is a dot pattern which should be smoothed.

The same figure will be described below. FIG. 7A is a diagram showing a reference area of dots in the main scanning direction × 9 dots in the sub-scanning direction, showing a, b, c, d, e, f, g, h, in the main scanning direction.
i, j, k, 1, 2, 3, 4, 5, with respect to the sub-scanning direction
A matrix of 6, 7, 8, and 9 represents each of 99 pixels.
For example, the central pixel is represented by 5f. The central pixel is selected as the pixel to be changed for smoothing. FIG. 7B shows
The reference areas of FIG. 7A are designated as X1 to X8, Y1 to Y8, and 5f.
It is divided into 17 areas. Where region X
1 is 3d, 3e, 3f, 4d, 4e, 4f, region X2 is 3f, 3g, 3h, 4f, 4g, 4h, region X3 is 6
d, 6e, 6f, 7d, 7e, 7f, the region 4 is 6f, 6
g, 6h, 7f, 7g, 7h, the region X5 is 3d, 3e,
4d, 4e, 5d, 5e, the region X6 is 5d, 5e, 6
d, 6e, 7d, 7e, the region X7 is 3g, 3h, 4g,
4h, 5g, 5h, region X8 is 5g, 5h, 6g, 6
It is composed of 6 dots each of h, 7g, and 7h. The area Y1 includes 1a, 1b, 1c, 2a, 2b, 2c, 3a, 3
b, 3c, the region Y3 is 1i, 1j, 1k, 2i, 2j,
2k, 3i, 3j, 3k, the region Y4 is 4i, 4j, 4
k, 5i, 5j, 5k, 6i, 6j, 6k, the region Y5 is 7i, 7j, 7k, 8i, 8j, 8k, 9i, 9j, 9
k, the region Y7 is 7a, 7b, 7c, 8a, 8b, 8c,
9a, 9b, 9c and the region Y8 are 4a, 4b, 4c, 5
It is composed of 9 dots each of a, 5b, 5c, 6a, 6b and 6c. The area Y2 includes 1d, 1e, 1f, 1g, 1
h, 2d, 2e, 2f, 2g, 2h, the region Y6 is 8d,
8e, 8f, 8g, 8h, 9d, 9e, 9f, 9g, 9
Each is composed of 10 dots of h. In this way, the above-mentioned area is composed of 8 areas (X1 to X8) consisting of 6 dots and 6 areas (Y1, Y3, Y4, Y5, Y7,
Y8) and two areas consisting of 10 dots (Y2, Y6)
And the central pixel 5f can be divided.

Here, the characteristic of each region is X_n Y_n As a table
I will decide. When the dots in each area are the same as all dots
(All pixels are white pixels or all pixels are black pixels
(X _n , Y_n ) Is set to "0". Also, the dots within each area
Different from each other (white and black pixels are mixed
Features of each area (X_n , Y_n ) Is set to "1". This
Main scan 1 using a dot pattern feature extraction method such as
Processing circuit 14 based on 99 pixel information of 1 pixel × 9 pixels in sub-scanning
Smoothing processing is performed within 3.

9A, 9B, 9C, 9D, 9
E, FIG. 9F and FIG. 9G show the processing circuit 14 according to the first embodiment.
It is a figure explaining an example of the algorithm of the smoothing process in 3.

Condition 1 is applied to 99 pixels including the target pixel.
Is that the pixel configuration pattern including the pixel of interest shows the pattern shown in FIG. 9B.

Condition 2 is that X5 = X6 in the classification of pixel regions shown in FIG. 9C. In the classification of pixel regions shown in FIG. 9C, at least one region among Y1 to Y8, X7, X8, and X4 is “0”.

When the above two conditions are satisfied, FIG.
As shown in D, the pixel of interest (5f) is divided into subsections (X ₁ ,
_{X 2, Y 1, Y 2} ) of, and X _2, Y ₂ subsections print area.

The dot configuration pattern of 99 pixels shown in FIG. 9A is applied to the condition of such smoothing processing.

Actually, the pattern shown in the condition of the smoothing process has the feature extraction of the pattern in which the right and left sides of the pixel of interest are replaced. For example, the left and right sides of the feature extraction for FIGS. 9B, 9C, and 9D are replaced with those shown in FIGS. 9E, 9F, and 9G. The pixel configuration including the target pixel is the pattern of FIG. 9D, which is the condition 1 ′. X7 = X8, Y1 to Y8, X5, X
The condition 2'is defined when at least one of X6 and X3 is "0", which is shown in FIG. 9E. When the conditions 1'and 2'are satisfied, the target pixel 5f has the subdivision area configuration shown in FIG. 9F. By making the feature extraction algorithm symmetrical in this way, for example, "0", "U",
Smoothing for characters such as "V" and "W" is performed by a symmetric algorithm to make the characters look natural.

The above embodiment is 300 dpi / 600 dpi.
Regarding the printer engine capable of i-switching, when the smoothing mode is set and the controller sends image data of 300 dpi, the throughput of the printer engine is halved to perform 600 dpi smoothing. Is not limited to 300 dpi / 600 dpi printers,
240 dpi / 480 dpi or 400 dpi / 800
This is also possible in printers such as dpi.

The equivalent print density in the main scanning direction need not be limited to twice the sub-scanning direction, but may be three times, four times, five times, or six times.
It may be doubled, 7 times, 8 times, ...

As described above, according to the first embodiment, in the printer capable of switching 300 dpi / 600 dpi, the throughput is halved and the smoothing process is performed to reduce the memory and the peripheral device cost. There is an effect that it can be realized and a high quality image of 600 dpi can be printed.

(Second Embodiment) FIGS. 10A and 10B are block diagrams showing the structure of a laser beam printer according to a second embodiment of the present invention. In FIGS. 10A and 10B, the same components as those in FIGS. 1A and 1B are designated by the same reference numerals, and the description thereof will be omitted.

In the first embodiment, the switching circuit for switching to the 600 dpi smoothing mode is the switching device on the main body of the printer engine 100 as shown in FIGS. 1A and 1B. As described above, switching by the switching circuit 69 on the printer controller 200 is also possible.

The printer controller 200 includes the switching circuit 4
2 receives the designation of smoothing ON, S on Fig. 2
C (command / status) communication or the like is used to transmit smoothing ON to the printer engine 100, and when the printer engine 100 receives the smoothing ON, it controls the drum motor and the like as in the first embodiment.

(Third Embodiment) FIGS. 11A and 11B are block diagrams showing the structure of a laser beam printer according to a third embodiment of the present invention. In FIGS. 11A and 11B, the same components as those in FIGS. 1A and 1B are designated by the same reference numerals and the description thereof will be omitted.

In the first and second embodiments, the switching circuit is provided inside the printer engine 100 or the printer controller 200. However, as shown in FIG. 11B, it is possible to use a communication signal from an external device such as the host computer 300. May be.

When smoothing ON is designated by the host computer 300, I / F 4 such as RS-232C is selected.
Smoothing ON is transmitted to the printer controller 200 by communicating with the printer controller 200 through 0 and 41. After that, the same operation as in the second embodiment is performed.

(Fourth Embodiment) The I / F of the host computer 300 and the printer controller 200 described in the third embodiment may be a dedicated line for smoothing ON determination.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0088]

As described above, according to the present invention,
It is possible to reduce memory and cost of peripheral devices, and to print high-quality images with high density.

[Brief description of drawings]

FIG. 1A

FIG. 1B is a block diagram showing the configuration of the laser beam printer according to the first embodiment of the present invention.

FIG. 2 is a diagram showing interface signals between a printer engine unit and a controller according to the first embodiment.

FIG. 3 is a diagram showing a configuration of a drum motor control circuit according to the first embodiment.

FIG. 4 is a diagram showing a matrix memory of the first embodiment.

FIG. 5A

FIG. 5B is a diagram showing a block configuration of the first exemplary embodiment.

FIG. 6 is a diagram showing a changed image section of a target pixel applied in the first embodiment.

FIG. 7A

FIG. 7B

FIG. 8 is a dot pattern for which smoothing is performed by extracting the characteristics of the dot pattern from the matrix area of dots in the main scanning direction × 9 dots in the sub scanning in the entire matrix area in the first embodiment. It is a figure explaining the algorithm for checking whether or not.

FIG. 9A

FIG. 9B

FIG. 9C

FIG. 9D

[FIG. 9E]

[FIG. 9F]

FIG. 9G is a diagram illustrating an example of an algorithm of smoothing processing in the processing circuit 143 according to the first embodiment.

FIG. 10A

FIG. 10B is a block diagram showing the configuration of the laser beam printer according to the second embodiment of the present invention.

FIG. 11A

FIG. 11B is a block diagram showing the configuration of the laser beam printer according to the third embodiment of the present invention.

FIG. 12A is a flowchart for explaining the operation according to the first embodiment.

FIG. 12B is a flowchart illustrating a switching routine according to the first embodiment.

FIG. 13 is a diagram showing a mechanism of a conventional laser beam printer.

FIG. 14 is a diagram showing interface signals between a general laser beam printer and a controller.

[Explanation of symbols]

 1 paper 2 paper feed cassette 3 paper feed cam 4 paper feed roller 5 registration shutter 6 registration solenoid 7 transport roller 8 fixing roller 9 paper ejection roller 11 photosensitive drum 30, 32 interface 51 semiconductor laser 52 rotary polygon mirror 53 polygon mirror motor 55 beam Detector 56 Drum motor 60 Semiconductor laser drive circuit 61 Polygon mirror motor control circuit 63 Drum motor control circuit 69 Switching circuit 81 Oscillation circuit 82 Counter 83 Preset counter 84 Latch circuit 85 PLL circuit 200 Printer controller 100 Printer engine 101 VDO signal processing unit 125- 133 line memories 134 to 142 shift register 143 processing circuit 144 parallel-serial conversion circuit 145 clock generation circuit 146 frequency dividing circuit

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Claims (4)

[Claims] 1. An image processing apparatus for controlling the recording mechanism section, which is connected between a recording control section and a recording mechanism section having a photosensitive member that is rotationally driven, wherein one of a plurality of different resolutions is used. An input unit for inputting, a determining unit for determining the resolution input by the input unit, and a rotation speed of the photoconductor so that the resolution handled by the recording mechanism unit corresponds to the resolution determined by the determining unit. Control means for controlling, resolution conversion means for converting the resolution of the input pixel data according to the resolution determined by the determination means, and output means for outputting the result of conversion by the resolution conversion means to the recording mechanism section. An image processing device characterized by. 2. The image processing apparatus according to claim 1, wherein the input means is a switch by hardware. 3. The input means includes a receiving means for receiving a resolution from the recording control section.
The image processing device described. 4. The image processing apparatus according to claim 1, wherein the resolution conversion means includes smoothing means for performing smoothing processing.