JPH09191397A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent output image by revising rules to thin picture elements depending on a form of the output image in the reduction mode. SOLUTION: An image buffer 502 stores image data sequentially. An thinning rule setting circuit 503 stores plural comparison patterns to be compared with an image pattern fed from the image buffer 502 and selects a thinning pattern to thin the image based on the comparison result. A thinning pattern generating circuit 504 generates the selected interleave pattern and provides an output of it. A video signal output circuit 506 replaces the image data outputted sequentially from the image buffer 502 with the thinned data outputted from the thinning pattern generating circuit 504 and provides an output of the result to a print section as a video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a material saving mode for saving an image forming material.

[0002]

2. Description of the Related Art Conventionally, in a toner saving mode of an electrophotographic printing apparatus or the like, a technique of regularly thinning out pixels in a region filled with black pixels is used, and this rule is fixed. It was a thing.

[0003]

However, in the above-mentioned conventional example, since the rule for thinning out the pixels in the area filled with the black pixels is fixed, for example, a printing apparatus with variable printing resolution is used. In this case, the thinning rule could not be changed according to the setting of the resolution. Therefore, when the resolution of the image data is changed by, for example, smoothing or degrading, the image quality is significantly deteriorated.

In the toner saving mode, although some deterioration in image quality must be recognized, it is not possible
Since there are a wide variety of forms of images to be handled such as pictures, documents, etc., it may naturally occur that the image quality is unacceptable depending on the images to be handled. Therefore, in order to obtain good image quality output for all forms of images, it is necessary to use the normal mode without using the toner-saving mode, but this defeats the significance of the toner-saving mode. Become.

The above-mentioned problems are not limited to the electrophotographic method using toner, but a mode for reducing the raw material for forming an image on a recording medium (hereinafter referred to as an image forming raw material), such as an ink ejection method, is used. Hereinafter, it is understood as a problem common to a printing apparatus, a copying machine, etc. having a saving mode).

The present invention has been made in view of the above problems, and it is an object of the present invention to obtain a good output image by changing the pixel thinning rule according to the form of the output image in the saving mode. .

[0007]

In order to solve the above problems, an image forming apparatus according to the present invention is an image forming apparatus having a raw material saving mode for saving raw materials for forming an image, and for thinning out image data. A thinning pattern generating means for generating a plurality of thinning patterns, a thinning pattern selecting means for selecting one of the plurality of thinning patterns, and a thinning means for thinning image data by the selected thinning pattern. And image recording means for recording an image by using the thinned-out image data.

According to a preferred embodiment of the present invention, for example, the thinning pattern generating means has a plurality of thinning pattern memories holding thinning patterns, and the thinning pattern selecting means has a plurality of thinning pattern memories. Select one of

Further, for example, the thinning pattern held in the thinning pattern memory can be rewritten.

Further, for example, the thinning pattern selecting means selects a thinning pattern based on a user's designation.

Further, for example, the thinning pattern selecting means selects the thinning pattern based on the image data.

Further, for example, the thinning pattern selecting means includes an image pattern memory holding a pattern of an image to be thinned, and a comparing means comparing the image data with the image pattern held in the image pattern memory. And a thinning pattern is selected based on the comparison result.

Further, for example, the image pattern memory holds patterns of a plurality of images to be thinned out.

Further, for example, the pattern of the image held in the image pattern memory can be rewritten.

Further, for example, the thinning pattern generating circuit changes the thinning density of the thinning pattern according to the resolution of the image to be formed.

Further, for example, the image recording means records an image by an electrophotographic method.

Further, for example, the image forming means records an image by an ink ejection method.

BEST MODE FOR CARRYING OUT THE INVENTION Before describing the thinning-out of pixels according to the present embodiment, the configurations of a laser beam printer and an inkjet printer suitable for applying the present invention will be described with reference to FIGS. To do. The printer to which the present invention is applied is not limited to the laser beam printer and the inkjet printer, and may be a printer of another printing method. Also, the present invention
It is obvious that the invention can be widely applied not only to printers but also to copying machines and the like to devices for forming images.

FIG. 1 is a sectional view showing the arrangement of a laser beam printer which is an example of an output device to which the present invention can be applied. In the figure, reference numeral 1500 denotes a laser beam printer main body, which inputs and stores print information (character codes, etc.) or form information, macro commands, etc. supplied from an externally connected host computer or the like. A corresponding character pattern or form pattern is created according to the information, and an image is formed on a recording medium such as recording paper.

Reference numeral 1501 denotes a switch and LE for operation.
An operation panel on which a D display device and the like are arranged, and 1000 is a printer control unit that controls the entire printer main body 1500 and analyzes character information and the like supplied from a host computer. The printer control unit 1000 mainly converts character information into a video signal having a corresponding character pattern and outputs the video signal to the laser driver 1502. Laser driver 1
Reference numeral 502 denotes a circuit for driving the semiconductor laser 1503, which corresponds to the semiconductor laser 1 depending on an input video signal.
A laser beam 1504 emitted from 503 is switched on and off.

The laser beam 1504 is a rotating polygon mirror 1505.
Then, the electrostatic drum 1506 is swung in the left-right direction to perform scanning exposure on the electrostatic drum 1506. As a result, a character pattern electrostatic latent image is formed on the electrostatic drum 1506. This latent image is stored in a developing unit 150 disposed around the electrostatic drum 1506.
After being developed by 7, the image is transferred to recording paper. This recording paper uses a cut sheet, and the cut sheet recording paper is LB
The sheet is stored in the sheet cassette 1508 attached to P1500, and is taken into the apparatus by the sheet feeding roller 1509, the conveying roller 1510, and the conveying roller 1511 and is supplied to the electrostatic drum 1506.

Further, the printer main body 1500 is provided with at least one or more card slots (not shown) so that an optional font card and a control card (emulation card) having a different language can be connected in addition to the built-in font. .

FIG. 2 is an external view showing a configuration example of an ink jet recording apparatus which is an example of an output apparatus to which the present invention can be applied. In the figure, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in conjunction with the forward and reverse rotation of the drive motor 5013 has a pin (not shown). Then, it is reciprocated in the directions of arrows a and b. An ink jet cartridge IJC is mounted on the carriage HC.

A paper pressing plate 5002 presses the recording paper against the platen 5000 in the moving direction of the carriage. Reference numerals 5007 and 5008 denote photocouplers, which function as home position detecting means for switching the rotation direction of the motor 5013 after confirming that the lever 5006 of the carriage is present at a predetermined position.

Reference numeral 5016 is a member for supporting a cap member 5022 for capping the entire surface of the recording head, and 5015 is a suction means for sucking the inside of the cap, which is an opening 50 in the cap.
The suction recovery of the recording head is performed via 23. A cleaning blade 5017 is movable in the front-rear direction by the member 5019. 5018 is a main body support plate,
The above 5017 and 5019 are supported. Reference numeral 5012 denotes a lever for starting suction for suction recovery, which moves in accordance with the movement of the cam 5020 that engages with the carriage, and the driving force from the drive motor is movement-controlled by a known transmission means such as clutch switching. .

The capping, cleaning, and suction recovery are configured so that the desired processing can be performed at their corresponding positions by the action of the lead screw 5005 when the carriage reaches the home position side area. It may be configured so as to perform a desired operation at a timing.

FIG. 3 is a block diagram illustrating the control configuration of the ink jet recording apparatus shown in FIG. In the figure, 1700 is an interface for inputting print information,
Reference numeral 1701 denotes an MPU, 1702 denotes an R storing a control program executed by the MPU 1701 and host print information.
The OM 1703 is a DRAM, and stores various data (the above-mentioned print information, recording data supplied to the head, etc.).

Reference numeral 1704 is a gate array for controlling the supply of output data to the recording head 1708, which includes an interface 1700, an MPU 1701 and a DRAM 170.
It also controls the transfer of data between the three. Reference numeral 1710 denotes a carrier motor for carrying the recording head 1708, 170
Reference numeral 9 is a conveyance motor for conveying recording paper, 1705 is a head driver for driving the recording head, 1706 is a motor driver for driving the conveyance motor 1709, 170
A motor driver 7 drives the carrier motor 1710.

In the recording apparatus thus configured, when print information is input from the host computer or the like via the interface 1700, the gate array 17
The input information is converted between the 04 and the MPU 1701 to output information for printing. Then, the motor driver 170
6, 1707 are driven, and the head driver 17
The recording head is driven according to the output information sent to 05, and printing is executed.

FIG. 4 is a block diagram showing an example of a control configuration of a printer system including the above laser beam printer and a host computer. The present invention can be applied to a printer system, whether it is a system including a plurality of devices or a system in which processing is performed via a network such as a LAN.

In the figure, reference numeral 3000 denotes a host computer, which executes document processing in which graphics, images, characters, tables (including spreadsheets, etc.) are mixed based on a document processing program stored in the program ROM 3b. A CPU 1 is provided, and the CPU 1 generally controls each device connected to the system device 4.

The program ROM 3b stores a control program for the CPU 1 and the like, the font ROM 3a stores font data and the like to be referred to during document processing, and the data ROM 3c stores various data used when performing document processing and the like. Is stored. The RAM 2 functions as a main memory, a work area, and the like for the CPU 1. A keyboard controller (KBC) 5 controls key inputs from the keyboard 9 and a pointing device (not shown). The CRT controller (CRTC) 6 is a CRT display (CRT).
RT) 10 display control. A disk controller (DKC) 7 controls access to an external memory 11 such as a hard disk for storing a boot program, various applications, font data, user files, printer driver software, editing files and the like.

The printer controller (PRTC) 8 is
Printer 150 via bidirectional interface 21
0 to execute communication control processing with the printer 1500. The CPU 1 executes outline font rasterization processing in a display information area arranged on the RAM 2, for example, and performs WY on the CRT 10.
SIWYG is possible. Further, the CPU 1
Various registered windows are opened based on commands designated by a mouse cursor (not shown) on T10, and various data processes are executed.

Next, in the printer 1500, the CPU
Reference numeral 12 generally controls access to each device connected to the system bus 15 on the basis of a control program stored in the program ROM 13b or a control program stored in the external memory 14, and the printer interface 16 An image signal as output information is output to a printing unit (printer engine) 17 connected via the above.

The program ROM 13b includes the CPU 12
The control program and the like are stored. Font ROM
13a stores font data used when generating output information, and the data ROM 13c stores information used on the host computer when the external memory 14 such as a hard disk is not provided. Is stored.

The CPU 12 is capable of performing communication processing with the host computer 3000 via the input unit 18, and outputs information in the printer and the like to the host computer 3000.
Is configured to be notified. RAM 19 is the CPU 1
The second RA is a memory that functions as a main memory, a work area, etc., and is connected to an expansion port (not shown)
The memory capacity can be expanded by M. The RAM 19 is an output information expansion area,
It is used as an environment data storage area, NVRAM, and the like.

Access to the external memory 14 such as a hard disk or an IC card is controlled by a disk controller (DKC) 20. Access to the external memory 14 is controlled by a disk controller (DKC) 20. The external memory 14 is connected as an option and stores font data, an emulation program, form data, and the like. Further, the operation panel 18 is provided with switches for operation, an LED display, and the like.

As the external memory 14 described above, a plurality of external memories storing an optional font card and a program for interpreting printer control languages of different languages may be connected in addition to the built-in font.
Further, the operation panel 150 includes an NVRAM (not shown).
The printer mode setting information from No. 1 may be stored.

In the printer system having the above configuration,
The print information output from the host computer 3000 is first temporarily stored in the input unit 18. CPU 12
Decodes the input information with reference to the ROM 13, and temporarily stores the decoded content in the RAM 19. R
The AM 19 may store, for example, an intermediate form having a width of 16, 32, or 48 bits, or the content decoded as bitmap data.

The RAM 19 stores character data and image data.
When storing in, for example, the RAM 19 used as one memory until now is divided into two memories,
You may divide and define one as a character area and the other as an image area. In this case, the form in which the character information is expanded and the form in which the image information is expanded are stored in separate areas in the respective areas. In this storage method, when the intermediate object is generated, the character data and the image data are identified based on the header information included in each and expanded into the corresponding area. Since the RAM 19 generally has a memory area for one page, it is not necessary to add memory by dividing the character area and the image area. If so, you need to add memory.

FIG. 5 is a block diagram showing a detailed configuration example of the printing unit interface 16. In the figure, a bus interface circuit 501 is a circuit for connecting to the system bus 15, and the CPU 12 can control the printing unit interface 16 via the bus interface circuit 501. The image buffer 502 is
This is a buffer that temporarily holds image data (bitmap data) supplied via the bus interface circuit 501. The capacity of this image buffer 502 is CP
It may be determined in consideration of the operating speed of U12, the operating speed of the printing unit 17, and the like. The image data held in the image buffer 502 is output to the video signal output circuit 506 in synchronization with the video clock supplied from the video clock generation circuit 505. When a thinning-out pattern is generated based on the image held in the image buffer 502, an image of a predetermined size (m rows × n columns) is thinned out by the thinning rule setting circuit 5.
03 is output.

The thinning rule setting circuit 503 is a circuit for setting whether or not a mode (saving mode) for thinning out a region of black pixels in the image held in the image buffer 502 and a thinning rule. For example, the CPU 12 can set whether or not the mode is the saving mode by writing in the thinning rule setting circuit 503. When thinning out images, a rule of thinning out can be set. The thinning rule may be set by the CPU 12 or based on the image stored in the image buffer 502.

The CPU 12 is operated by the user, for example, on the operation unit 1.
It is possible to select an appropriate thinning rule based on the mode set in 501, the set resolution, the type of image to be output (eg, document, image, etc.) and set it in the thinning rule selection circuit 503. it can. This information is
Since both are recognized by the CPU 12, it is effective to set them directly from the CPU 12 if the thinning rule setting circuit 503 dares to make the process complicated.

Further, the thinning rule setting circuit 503 compares the image held in the image buffer 502 with a plurality of preset patterns, and if there is a matching pattern, it corresponds to the matching pattern. You can also set rules to do.

The thinning pattern generation circuit 504 generates a thinning pattern corresponding to the rule set by the thinning rule setting circuit 503 and supplies it to the video signal output circuit 506. In this configuration example, the image buffer 502
By substituting the thinning pattern for the image data supplied in synchronization with the video clock, the thinning according to the set rule is performed.

The video clock generation circuit 505 generates a video clock of an appropriate frequency based on a signal supplied from an oscillator or a vibrator (not shown).

The specific operation will be described below. FIG. 6 is a diagram showing an example of image data corresponding to an image.
In the figure, the image data when the image 601 including the character "A" is scanned in the arrow direction is indicated by 601 in the figure. That is, in the present embodiment, the image data of black pixels is low level, and the image data of white pixels is high level. Therefore, when thinning out the black pixels, the period in which the image data is at the low level is thinned out.

FIG. 7 is a diagram for explaining an operation example of thinning out an image. In this example, the image data changes in synchronization with the rising edge of the video clock. Further, as described above, the image data of black pixels is at low level, and the image data of white pixels is at high level. In the figure, thinning pattern 1
The thinning pattern 3 is generated in the thinning pattern generation circuit 504 in synchronization with the video clock. The thinning pattern generation circuit 504 includes, for example, a counter that counts in synchronization with a video clock, and a count value conversion circuit that generates a thinning pattern based on the count value of the counter.
~ The thinning pattern 3 can be generated.

Although three types of thinning patterns are shown here for the sake of convenience of description, in reality, any one thinning pattern specified by the thinning rule setting circuit 503 is generated to generate a video signal. It is supplied to the output circuit 506. Further, the type of thinning pattern is not limited to this example, and may be another pattern or three types.

The video signal output circuit 506 replaces the image data output from the image buffer 503 in synchronization with the video clock with the thinning pattern and outputs the image data.
In the example of FIG. 7, this output is like video signal 1 to video signal 3 (logically the same as the corresponding thinning pattern). In this example, for example, the image buffer 5
A thinned video signal can be generated by taking the logical sum of the image data output from 02 and the thinning pattern.

FIG. 8 shows a thinning pattern generation circuit 504.
FIG. 3 is a block diagram showing an example in which is constituted by a memory storing a thinning pattern. In the figure, pattern memories 801 to 803 have thinning patterns (for example,
Memory for storing the thinning pattern shown in FIG. 7),
The stored thinning patterns are sequentially output in synchronization with the video clock supplied from the video clock generation circuit 505. The contents of the pattern memories 801 to 803 are the CPU
It is desirable to be rewritable from 12 via the bus interface circuit 501, and thereby, the thinning pattern can be freely set according to, for example, the user's preference, the change with time of the device, and the like.

The selector 804 is the thinning rule setting circuit 5
A selector for selecting and outputting either the pattern memories 801 to 803 or the high level (terminal 3) according to the thinning rule set by 03. In this case, the normal mode (non-saving mode) can be selected by selecting the high level.

FIG. 9 is a block diagram showing a configuration example of the thinning rule setting circuit 503. In the figure, comparison pattern memories 901 to 903 are memories that store patterns of images to be thinned out (for example, m rows × n columns). The contents of the comparison pattern memories 901 to 903 are
It is desirable to be rewritable from the CPU 12 via the bus interface circuit 501. This allows the thinning rule to be freely set according to, for example, the user's preference, changes in the device over time, and the like.

The comparator 904 is a comparison pattern memory 90.
Comparing the image patterns stored in 1 to 03 with the image (for example, m rows × n columns) supplied from the image buffer,
When the pattern of the matching image exists, information indicating which comparison pattern memory the pattern is stored in is output to the output circuit 905.

The output circuit 905 determines the thinning rule based on the information supplied from the comparator 904 and the information supplied from the bus interface circuit 501, and outputs the information to the thinning pattern generation circuit 504. The output circuit 905 can directly output the thinning rule specified by the CPU 12 via the bus interface circuit 501, or can determine and output the thinning rule based on the information supplied from the comparator 904. . For example, when determining the thinning rule based on the information supplied from the comparator 904, for example, when the image data matches the comparison pattern stored in the comparison pattern memory 901, the pattern memory 801 is selected.

In the thinning rule setting circuit 503, the thinning rule is set on the basis of the pattern comparison unit including the comparison pattern memories 901 to 903 and the comparator 904, and the CPU 1 via the bus interface circuit 501.
Although it is desirable to have both the configurations for setting the thinning rule specified by 2, it is possible to have only one configuration.

Next, an example in which the present embodiment is applied to an image forming apparatus capable of changing the image resolution will be described. For example, when the resolution of the image to be output is changed based on the user's designation or the like, the CPU 12 changes the setting of the thinning rule setting circuit 503 based on the change. For example, when the resolution of an image is changed (degraded) from 600 dpi to 300 dpi, the number of video clocks is halved in the normal mode, but 60 in the saving mode.
By controlling the video clock generation circuit 505 so as to output a video clock for 0 dpi and making the thinning density by the thinning pattern the same as in the case of 600 dpi, an image is output in the saving mode while maintaining the quality of the output image. Can be formed. Also, for example, 300 dp
In an image forming apparatus that can be used by selecting a resolution of i, 600 dpi, or 1200 dpi, the resolution is 300 dpi.
When the original image of i is output at a resolution of 600 dpi by the smoothing technique, 1 is set in the saving mode.
By controlling the video clock generation circuit 505 so as to output the video clock for 200 dpi, it is possible to form an image in the saving mode while maintaining the quality of the image to be output as described above.

As described above, by making it possible to change the thinning pattern, it is possible to form an image while performing appropriate thinning according to the image to be output. Therefore, when forming an image in the saving mode, The image forming raw material can be saved while maintaining the image quality of the output image.

By comparing the image pattern with a plurality of preset patterns and selecting the thinning pattern based on the result, it is possible to perform thinning according to the pattern of the output image.

Further, when the resolution of the image to be output is changed, it is possible to suppress the deterioration of the image quality due to the thinning by changing the thinning pattern according to the resolution.

Further, by making the pattern memory for generating the thinning pattern and the comparison pattern memory rewritable, the thinning rule can be changed according to the user's preference and the change over time, and the thinning can be performed without changing the design. You can also change the rules.

Further, the present invention may be applied to a system composed of a plurality of devices such as a host computer, an interface and a printer, or to an apparatus composed of a single device such as a copying machine. Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to the system or device, the system or device operates in a predetermined manner.

[0062]

As described above, according to the present invention, by making it possible to change the thinning pattern, it is possible to form an image while performing appropriate thinning according to the image to be output. When forming an image in (1), it is possible to save the image forming raw material while maintaining the image quality of the output image.

[0063]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a laser beam printer which is an example of an output device to which the present invention can be applied.

FIG. 2 is an external view showing a configuration example of an inkjet recording apparatus which is an example of an output apparatus to which the present invention can be applied.

3 is a block diagram illustrating a control configuration of the inkjet recording apparatus shown in FIG.

FIG. 4 is a block diagram showing an example of a control configuration of a printer system including a laser beam printer and a host computer.

FIG. 5 is a block diagram showing a detailed configuration example of a printing unit interface 16.

FIG. 6 is a diagram showing an example of image data corresponding to an image.

FIG. 7 is a diagram illustrating an operation example of thinning out images.

FIG. 8 is a block diagram showing an example in which a thinning pattern generation circuit is configured by a memory that stores thinning patterns.

FIG. 9 is a block diagram showing a configuration example of a thinning rule setting circuit.

Claims (11)

[Claims] 1. An image forming apparatus having a raw material saving mode for saving raw materials for forming an image, the thinning pattern generating unit generating a plurality of thinning patterns for thinning image data, and a plurality of thinning patterns. A thinning pattern selecting means for selecting any thinning pattern, thinning means for thinning out image data by the selected thinning pattern, and image recording means for recording an image using the thinned image data. An image forming apparatus characterized by. 2. The thinning pattern generating means has a plurality of thinning pattern memories holding thinning patterns, and the thinning pattern selecting means selects one of the plurality of thinning pattern memories. The image forming apparatus according to claim 1. 3. The image forming apparatus according to claim 2, wherein the thinning pattern held in the thinning pattern memory is rewritable. 4. The image forming apparatus according to claim 1, wherein the thinning pattern selection unit selects a thinning pattern based on a user's designation. 5. The image forming apparatus according to claim 1, wherein the thinning pattern selection unit selects a thinning pattern based on image data. 6. The thinning pattern selecting means includes an image pattern memory for holding a pattern of an image to be thinned, and a comparing means for comparing the image data with the image pattern held in the image pattern memory. The image forming apparatus according to claim 5, wherein the thinning pattern is selected based on the comparison result. 7. The image forming apparatus according to claim 6, wherein the image pattern memory holds patterns of a plurality of images to be thinned out. 8. The pattern of the image held in the image pattern memory is rewritable.
Alternatively, the image forming apparatus according to claim 7. 9. The image forming apparatus according to claim 1, wherein the thinning pattern generation circuit changes the thinning density of the thinning pattern according to the resolution of the image to be formed. 10. The image forming apparatus according to claim 1, wherein the image recording unit records an image by an electrophotographic method. 11. The image forming apparatus according to claim 1, wherein the image forming unit records an image by an ink ejection method.