JPH02295766A - Imaging system - Google Patents

Abstract

PURPOSE:To enable formation of a single high quality image from a multi-level image and a binary image such as a character by controlling resolution selectively from multi-level image information and image information to be merged. CONSTITUTION:Binary pattern data BK1 are converted through a multiplexer 907 into serial binary signals synchronized with a pixel output then the serial binary signals are converted through a buffer 908 into multi-level data. Inked data BK2 and the multi-level data (OOH or FFH) are ORed at a multi-level data OR gate 909. Black data BK3 at a portion where the logic 1 of character pattern data is merged in a natural picture based on R, G, B data are converted into FFH and images are merged. The natural picture is printed out as it is at a portion where the character pattern data have logic 0 and the black data BK3 selected by means of a CPU 2110 are outputted from a selector 910.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and particularly to an image forming apparatus that forms images at a plurality of resolutions.

[Prior Art] Conventionally, in this type of device, the resolutions of a natural image and a character image in one image output have been made different according to an image area separation method or instructions from a CPU. By the way, there are cases where it is desired to combine a natural image and a text image that exist independently.

[Problems to be Solved by the Invention] However, according to the conventional method, images that have been synthesized in advance on the host side are separated into image areas on the printer side, which is wasteful.

The present invention eliminates the drawbacks of the prior art described above, and its purpose is to provide an image forming apparatus (or a novel interface ).

[Means for Solving the Problems] In order to achieve the above object, the image forming apparatus of the present invention has the following features:
a first input means for inputting multivalued image information; a second input means for inputting second image information to be combined with the multivalued image information; an image forming means for forming an image of image information at a first resolution or a second resolution different from the first resolution; The outline of the apparatus includes a control means for selectively controlling the first and second resolutions.

Further, in order to achieve the above object, the image forming apparatus of the present invention includes a first memory that stores multivalued image information, a second memory that stores binary image information, and a second memory of the second memory.
converting means for converting value image information into multi-value image information; selection means for selecting two types of resolution according to the binary image information of the second memory; binarizing means for converting the multi-valued image information of or the multi-valued image information converted by the converting means into a binary signal according to the density; The outline thereof is to include an image forming means for forming an image.

Preferably, the first memory stores color-separated color multi-value image information.

[Operation] In the above configuration, the first input means inputs multivalued image information. The second input means inputs second image information to be combined with the multivalued image information.

The image forming means is a means for forming an image from the image information inputted by the first and second input means, and forms an image at a first resolution or a second resolution different from the first resolution. The control means selects and controls the first and second resolutions based on the input from the second input means.

Further, in the above configuration, the first memory stores multi-value image information such as a natural image, and preferably stores color-separated color multi-value image information. Also, the second memory contains characters,
Stores binary image information such as graphics. On the other hand, the conversion means is
At the time of printing, the binary image information in the second memory is converted into multi-value image information. Then, the selection means selects two types of resolution according to the binary image information in the second memory, and
The digitizing means converts the multi-valued image information in the first memory or the multi-valued image information converted by the converting means into a binarized signal according to the density at the resolution selected by the selecting means. Then, the image forming means forms an image according to the binarized signal converted by the binarizing means.

[Description of Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows an example color laser beam printer (C
-LBP) is a sectional view of the printer mechanism. In the printer section 2000, a laser beam emitted from a laser element (not shown) is scanned at high speed in the main (horizontal) scanning direction by a polygon mirror 2289, and further reflected by a mirror 2290.
A photosensitive drum 2900 uniformly charged in advance by a charger 2297
Line dot exposure is performed on the top with a maximum resolution of 16 lines/mm. In this embodiment, one horizontal scanning length of the laser corresponds to one horizontal scanning length of the image information.
Corresponds to horizontal scanning length. On the other hand, the photosensitive drum 2900 rotates at a constant speed in the direction of the arrow, thereby forming a planar image (latent image).

Next, for example, if the exposed image is yellow image data, the latent image is developed by a yellow developing device (Y) 2292, and further transferred onto a sheet of paper on a transfer drum 2296 by a transfer charger 2298.

In this way, the above process is repeated for each image data of magenta (M), cyan (C), and black (BK), and a color image is formed by overlapping images of each color on the same sheet of paper.

FIG. 1 is a block diagram of a C-LBP 80 according to an embodiment. The C-LBP80 of the embodiment has an ink face part 100.
and a printer section 2000.

In the interface unit 100, 2 is an external interface circuit, which connects the host system 3 via cable l.
00 to exchange control information, image data, etc. A control unit 3 interprets and executes control commands sent via the external interface circuit 2, and also controls the image memory described later. In the control section 3,
3-1 is a CPU, which performs main control of the control section 3. 3-
2 is a ROM, for example, the sixth
Contains the control program shown in the figure. Also ROM3-2
also stores a font table for converting character code data into character pattern data. 3-3 is RAM
In addition to temporarily storing character code data etc. sent from the host system 300, the CPU 3-1 also uses it as a work area. A direct memory access controller (DMAC) 3-4 performs DMA transfer of color image data to the image memories 5 to 8 under the control of the CPU 3-1.

Image memories 5 to 8 each store color separated color image data. That is, the R memory 5 is red (R) or cyan (C), and the G memory 6 is green (G) or magenta (
M) and B memories 7 store blue (B) or yellow (Y) image data, respectively. The BK memory 8 also stores black (B.) image data or character pattern data (binary data) developed by the CPU 3-1. Reference numeral 27 denotes an F memory, which stores the combining position in a bitmap format when other images are combined into the image memories 5 to 8. 1o is a synchronization signal processing circuit, which processes the image memory 5 in synchronization with the synchronization signal BD from the printer section 200o.
The image data is read from 8 to 8 and sent to the printer section 2000.

In the printer unit 2000, 2121 is an image processing circuit, which converts input R, G, B data to Y, M if necessary.
,C,B. Convert color to data.

2160 is a gradation control circuit which makes Y, M, C, and Bx data correspond to the color reproduction density of the printer section 2000 and performs PWM conversion according to the density.

2200 is a laser driver, and gradation control circuit 216
The laser element 2223 is driven with a video signal of 0 output.

A control unit 2500 controls the printer unit 2000. Further, the control unit 2500 is connected to the control unit 3 via the line 24.
exchange information with In the control unit 2500,
211o is a CPU, which performs main control of the control unit 2500.

A ROM 2502 stores a control program (for example, a part of FIG. 6) executed by the CPU 2110. 2504 is a RAM, which the CPU 2110 uses as a work area. A potential sensor 2600 detects the amount of charge on the photoreceptor 2900. 2700 is a potential measurement unit (PDU), and a potential sensor 260
The output of 0 is amplified and input to the A/D converter 2503.

2800 is a sensor that detects the position of the leading edge to which an image should be output and outputs an image leading edge signal ITOP. 2298 more
2299 is a humidity sensor, and 2299 is a temperature sensor, which respectively detect humidity and temperature for correcting development characteristics. 2285
is the drive motor of the printer mechanism.

In such a configuration, the host system 300 communicates with the CPU 3-1 via the external ink face circuit 2. For example, the host system 300 specifies the type of image data to be sent, and the designation information is stored in the RAM 3-3.

The following combinations of images can be considered. R, G, B data and character code data (black or color specified), R, G, B data and binary font data (black or R, G, B) Y, M, C, BK data and character code data (black or color specification), Y, M, C, BK data and binary font data (black or R, G, B), etc. Note that instead of binary font data, image data having three or more tones and a relatively small number of tones (for example, color image data created by computer graphics) may be used.

By managing the DMAC 3-4, the CPU 3-1 stores R, G, and B data in the image memories 5 to 7, and stores Y, M, C, and BX data in the image memories 5 to 8.
DMA transfer is performed sequentially.

In addition, in the case of R, G, B data and black character code data, the CPU 3-1 temporarily updates the character code data to RA.
M3-3, converts it into character pattern data in ROM3-2, further controls external ink face circuit 2 to connect signal line 11 and signal line l3, and connects signal line 11 and signal line l3 to address line 14.
is incremented, and the character pattern data is developed in the Bκ memory 8 in a bitmap manner.

In the case of R, G, B data and black font data (B), the font data is temporarily stored in the RAM 3-3, and the address line 14 is incremented in the same manner as described above, and the font data is stored in the B8 memory in a bitmap format. Expand to 8.

In the case of R, G, B data and character code data specifying color (C), store the character code data in RAM 3-3 once, convert it to character pattern data in ROM 3-2, and do the same as above. The address line 14 is incremented and the character pattern data is developed in the F memory 27.

Furthermore, the character pattern data is converted into multi-value R according to the specified color.
, G, and B data, and store them respectively in R, G, and B memory 5.
Synthesize ~7.

Also, R, G, B data and multivalued color fonts, i.e.
In the case of font data having R, G, and B components D)
temporarily stores the font data in RAM3-3,
In the same manner as described above, the address line 14 is incremented and the R, G, B font data is synthesized into the R, G, B memories 5 to 7. Also, during this synthesis, CPU3-
1, any of the R, G, B font data is ゜゛O”
When the data is other than that, a bit of logic "1" is written in the corresponding position of the F memory 27.

Also Y, M, . In the case of C, BK data and black character code data, E), the character code data is temporarily stored in RAM3-3.
This is stored in the ROM 3-2 into character pattern data, and the address line 14 is incremented in the same manner as described above, and the character pattern data is stored in the F memory 27.
Expand to. Also, the corresponding character pattern data 2
The data is converted into various types of multivalued data (for example, OOH or FFH) and synthesized in the B8 memory 8.

In the case of Y, M, C, BX data and color-designated character code data F), binary character pattern data is first developed in the F memory 27 in the same manner as described above. Furthermore, the character pattern data is multi-valued Y, M, C, BK according to the specified color.
The data is separated into colors and combined into image memories 5-8. Other combinations can be considered in the same manner as above.

Thereafter, the CPU 3-1 sends a data processing completion flag to the host system 300.

The host system 300 learns from this flag transfer that the printer is ready for printing, and sends a print request command. As a result, CPU3-1 is connected to printer section 2000.
Activate.

FIG. 5 is a block diagram of the Bκ memory 8 of the embodiment. In the figure, 802 is a decoder, and the CPU 3-1
The bit brain selection signal from the chip selection signal CSO
Decode to NCS7. 803 is a selector, C
Depending on the selection signal from PU3-1, the chip selection signal CSO-CS7 output from the decoder 802 or the all-chip simultaneous selection signal is output. Thereby, the BK memory 8 can be accessed both as a bit-brain memory and as a normal image data memory.

FIG. 3 is a block diagram of the image processing circuit 2121 of the embodiment. In the figure, 901 is a gamma (γ) RAM, which performs γ conversion on input color image data. γRAM
The contents of 901 can be set by instructions (or γ data) from the host system 300. For example, image memory 5
If YM, C, BK data is stored in ~8, γR
The contents of AM901 may have no conversion (input and output are the same) characteristic.

A selector 905 selects developed color information (Y-
γRAM901 output Y,
Sequentially select M, C, BK data, and then selector 906
Output from. At this time, the binary signal F from the F memory 27 is input to the black processing circuit 903 and is output as is from the line 2116 in accordance with the progress of the output pixels. line 21
The 16-output binary signal F controls the resolution during printing in real time.

In addition, R, G. When B data is stored, the contents of the γRAM 901 have so-called gamma conversion (R, G, BY, M, C) characteristics. Incidentally, the coloring material in the printer section is toner in the case of an electrophotographic method as in this embodiment, ink in the case of an inkjet method, and thermal transfer ink in the case of a thermal transfer method.

Generally, each of these color materials has a different unnecessary absorption portion, so it is not efficient to perform masking calculations for each printer on the host system 300 side. Therefore, a UCR masking circuit 902 is provided in the image processing circuit 2121, which performs masking processing on the Y, M, and C data output from the γRAM 901, removes the undercolor, and also performs inking data B.
K2{= (Y, M, C) ml. } occurs.

Furthermore, the binary data BK has a non-conversion (human output is the same) characteristic, and this output is defined as the binary pattern data Bgl. On the other hand, the black processing circuit 9o3, which will be described later, uses inking data B.
Black data Bx3 is output based on data obtained by multi-value conversion of x2 or the binary pattern data Bwl described above. The selector 904 selects Y, M, C, etc. according to the developed color information of the printer section.
B. One of the data is selected and output. Further, a serial signal of binary pattern data BK1 is outputted to the line 21l6.

FIG. 4 is a block diagram of the black processing circuit 903 of the embodiment. In the figure, binary pattern data BK1 is converted by a multiplexer 907 into a serial binary signal synchronized with pixel output. A buffer 908 converts the serial binary signal output from the multiplexer 907 into multi-value data. For example, when the bit of the binary signal is logic O, it is converted to multi-value data 00H (H is expressed in hex), and when the bit of the binary signal is logic 1, it is converted to multi-value data FFH. 909
is an OR circuit for multi-value data, which takes the logical sum of ink data BK2 and multi-value data (OOH or FFH). As a result, the black data B of the natural image based on the R, G, B data is obtained by combining the logic 1 of the character pattern data.
3 is forcibly set to FFH and images are combined. In addition, in the part where the character pattern data is logical O, the printed output remains as a natural image. 91o is a selector, and CPU2 1
The black data 8.3 selected according to the specification of 10 is output. That is, for example, the combination of image data sent from the host system 300 is the R. In the case of G, B data and black character code data (or black font data), OR circuit 9
Select the output of 09. At that time, serially converted binary pattern data is output from line 2116,
It is used as a resolution selection signal, which will be described later. In addition, in the case of other combinations of image data, the F memory 27
The multiplexer 907 is controlled by the CPU so that the resolution is used, and its output signal F is used as a resolution selection signal.

FIG. 6 is a flowchart of the control procedure of the control section 3 of the embodiment. In step s1, the host system 300 waits for a control command to be sent.

When the control command is sent, the process proceeds to step s2, where, for example, initial settings and settings are made for the ink face section 100. At this time, the γ data of the image processing circuit 2121 is set, the UCR coefficient is set, and whether the image data is R, G, or B. Specify Y, M, C, BK, etc.

Further, the CPU 3 - 1 provides information regarding the printer section 2000 . For example, the paper size, whether or not the printer is waiting, etc. In step S3, it is determined whether there is command data (such as character code data), and if it is not command data, it is determined in step S11 whether or not it is image data.

If it is image data, the image data is DM in step S112.
All image data (R, G,
B or C, M, Y, BK) is completed. If it is not finished, the process returns to step S12.

If the process is finished, the process advances to step S13.

Further, if the command data is determined in step S3, the process proceeds to step S4, and the character code data is temporarily stored in the RAM 3-3. In step S5, it is determined whether there is BK data,
If BK data is present, data expansion to the BK memory 8 is prohibited in step S15. If there is no Bx data, the process advances to step S6, and character pattern data corresponding to the character code data is developed in the BK memory 8. At this time, character pattern data can be developed into the Bx memory 8 for up to eight sides. In step S7, it is determined whether or not the expansion has ended, and if the expansion has not ended, the process returns to step S6. Further, if the expansion is completed, the process advances to step S8, and the presence or absence of a print output command is detected. If it is not a print output command, the process returns to step Sll. If it is a print output command, the process advances to step S9, where the printer section is activated via the control line 24, and the synchronization signal processing circuit 10 is also driven at the same time. On the other hand, the CPU of the printer section 2000
2110 is the selector 904 or 905 of the image processing circuit 9
, and 906 to selectively output color image information corresponding to the developed color. In step SIO, it is determined whether printing has ended or not, and if so, the host system 3
00 and returns to step S1. If the process does not end for a predetermined period of time or longer, the process proceeds to step S14, and the host system 300 is notified of the error.

This error state can be recovered by pressing a reset button (not shown) of the printer.

FIG. 7 is a circuit diagram of the gradation control circuit 2160 of the embodiment. The main functions of the gradation control circuit 2160 are to synchronize the image clock signal (RCLK) of the ink face section 100 and the image clock signal (VCLK) of the printer section 2000 regarding reading and writing of image data, and to synchronize the image clock signal (VCLK) of the printer section 2000, gradation conversion of input video data according to
Furthermore, the gradation-converted video data is converted into a binary signal number according to its density by PWM modulation.

In the figure, the 8-bit image data output from the image processing circuit 2121 is a horizontal synchronization signal (RHSYNC) from the ink face unit 100 and a video clock signal (RCLK).
It is written to the buffer memory (FIFO) 2105 in synchronization with . Furthermore, this image data is transmitted to the synchronous control circuit 211
It is read out in synchronization with the horizontal synchronization signal (HSYNC) and video clock signal (VCLK) from No. 3. Thereby, speed matching between the ink face section 100 and the printer section 2000 is achieved.

The image data read from the buffer memory 2105 is used as a lookup table {LUT
(2)} Enter in 2 1 06.

LUT. (2) is image data that has been corrected in advance so that the input image data matches the output characteristics of the printer (e.g. beam spot diameter, toner particle diameter, etc.) (the gradation of the output density increases and becomes linear). It is for creating. The image data of LUT (2) output is D
/A converter 2107, where it is converted into a step-by-step analog video signal and sent to a converter 211.
7 and 2118, respectively. The other terminals of the comparators 2117 and 2118 each have analog video signals that are binarized (PWM modulation) according to their density.
Pattern signals (1) and (2) for this purpose are input. The pattern signal (1) is for reproducing, for example, character images, line images, etc. In this case, the resolution is an issue, so the pattern signal (1) is, for example, the same frequency as the video signal (for example, 4
00 line) pattern signal. That is, one pattern signal is generated per pixel. The pattern signal (2) is, for example, for reproducing a halftone image, and in this case, it is necessary to increase the gradation, so the pattern signal (2) is, for example, 1/2 the frequency of the line drawing pattern signal (for example, 200 lines). The pattern signal is such that That is, one pattern signal is generated for every two pixels.

To explain according to the circuit, the crystal oscillator (XTAL) 21
Reference numeral 12 generates a clock signal having a frequency four times higher than that of the image clock signal. The synchronization control circuit 2113
Main scanning synchronization signal (HSYNC) in synchronization with the TOP signal
and form the basic clock signal (SCLK). A frequency dividing circuit 2114 divides the frequency of the SCLK signal to generate pattern generation clock signals (TVCLK and PVCLK).

This TVCLK signal has, for example, twice the frequency of the video data signal and is a clock signal with a duty ratio of 50%. The pattern generation circuit 2115
An analog pattern signal (1) is generated according to the signal.

In this embodiment, a triangular wave signal is used, for example. Converter 2117 is analog video signal and pattern signal (1)
A PWM signal (1) in which the video density is pulse width modulated (PWM modulated) is output.

Further, the PVCLK signal has a frequency 1/2 times that of the video data signal, and is a clock signal with a duty ratio of 50%.

Pattern generation circuit 2116 generates an analog pattern signal (2) according to this PVCLK signal. - In this embodiment, for example, this is also a triangular wave signal. Comparator 2118 is analog video signal and pattern signal (2)
PWM pulse width modulation of the video density by comparing
Outputs signal (2). Selector 2103 is CPU2
According to the control signal 2123 of 1 1 0, the serial binary image signal 2116 or the selection signal from the CPU 2 110 is selected. When the control signal 2123 selects the serial binary image signal 2116, the selector 2119 selects the PWM signal (1) according to the logic 1 or 0 of the binary image signal 2116.
Or select PWM signal (2). As a result, the character pattern portion is output at high resolution (400 lines), and the other natural image portions are output at low resolution (200 lines). That is, among the above-mentioned modes, C), D), F
In the mode shown in ), 1 is set in the F memory in the character code or font part, so if the input of input terminal 9 is selected in the multiplexer 907, the character or font part will be set to high resolution by the signal on line 2116. settings, allowing high-quality image playback. Furthermore, when the control signal 2123 selects the selection signal from the CPU,
The resolution can be set under the control of the CPU 2110. In this way, the selected PWM signal (1) or (2) is further matched with the movement of the transferred material by the gate circuit 2120, and then manually inputted to the laser driver 2200, and the PWM signal (1) or (2) is
The semiconductor laser 2223 is activated for a time corresponding to the pulse width of the signal.
is driven with a constant current to form an electrostatic latent image on the surface of the photoreceptor drum 2900.

FIG. 8 is a timing chart of main signals in the printer section. The figure shows examples of horizontal synchronization signal BD, planking signal, reference clock signal SCLK, pattern generation clock signals TVCLK, PVCLK, video clock signal VCLK, etc. Although not shown, the blanking signal is formed by a counter that measures a time shorter than the BD signal period and is reset at the falling edge of the BD signal.

FIG. 9 is a block diagram of an image processing circuit according to another embodiment;
FIG. 10 is a block diagram of a black processing circuit according to another embodiment. The UCR masking circuit 902 performs matrix calculations on input image data using predetermined parameters, and performs UCR masking.
The calculation is being performed, but the CPU 2 is used for this part. 10 buses are connected so that parameters can be set from the CPU 2110. Also, in the UCR calculation part, min(Y, M
, C) can be set.

Furthermore, in this embodiment, LUT 9 1 1 to 9 for color correction
13 and T-UT 9 and 14 for black correction are added,
An arbitrary curve (conversion characteristic) can be set for each from the CPU 2 1 1 0. As a result, it becomes possible to set parameters that match the performance of the printer's color material and fixing roller. For example, if you add correction to inking data BK2, Y, M,
The overlapping portion of the three colors of C data can be replaced with inking data BK2. This makes it possible to avoid build-up caused by the three-color toner, thereby extending the life of the fixing roller.

Furthermore, since the three-layer toner of Y, M, and C tends to scatter, scattering can be prevented by using a single-layer BK toner.

Note that although the printer unit in the above embodiment has been described using four colors, Y, M, C, and BK, the present invention is not limited to this. Change the developer material in the printer section to Y.
, M, and C may be used.

Further, the density binarization means is not limited to PWM modulation. A dither method etc. may also be used.

Furthermore, in the above-described embodiment, the case where two systems of image data are combined and output is described, but the present invention is not limited to this.

For example, one multi-value image data and the other binary image data may be used only for switching the resolution. That is, for example, in FIG. 4, if the signal on line 2116 is used as a resolution selection signal, but the multi-value data output from encoder 908 is controlled to always be "0",
Substantially no synthesis of binary image data is performed. Therefore, multivalued image data and corresponding binary image data (resolution selection signal) can be prepared on the host system side, thereby allowing fine resolution control with a large degree of freedom.

[Effects of the Invention] As described above, according to the present invention, a high-quality image can be easily formed from a multivalued image and a binary image of characters, figures, etc.
Moreover, the burden on the host system is also significantly reduced.

[Brief explanation of the drawing]

Figure 1 shows an example color laser beam printer (C
-LBP) 80 block diagram, FIG. 2 is an example C
- A sectional view of the printer mechanism of the LBP 80; FIG. 3 is a block diagram of the image processing circuit 2121 of the embodiment; FIG. 4 is a block diagram of the black processing circuit 903 of the embodiment; A block diagram of the memory 8, FIG. 6 is a flowchart of the control procedure of the control section 3 of the embodiment, FIG. 7 is a circuit diagram of the gradation control circuit 2160 of the embodiment, and FIG. 8 is the timing of main signals in the printer section. 9 is a block diagram of the image processing circuit of another embodiment, and FIG. 10 is a block diagram of the black processing circuit of another embodiment. In the figure, 80...Color laser beam printer (C
-LBP), 300-... host system, 1oO-
...Interface section, 2000...Printer section, 2
289...Polygon mirror 2290...Mirror 2
297... Charger, 2900... Photosensitive drum, 22
92...Yellow developer, 2293...Magenta developer, 2294...Cyan developer, 2295...Black developer, 2298...Transfer charger. CPU Figure 5

Claims (1)

[Scope of Claims] (1) A first input means for inputting multi-value image information; a second input means for inputting second image information to be combined with the multi-value image information; and the first input means for inputting second image information to be combined with the multi-value image information. , an image forming means for forming an image from image information inputted by a second input means, the image forming means forming an image at a first resolution or a second resolution different from the first resolution; an image forming apparatus comprising: a control means for selecting and controlling the first and second resolutions based on an input from an input means; (2) A first memory that stores multivalued image information and a second memory that stores binary image information.
a converting means for converting the binary image information in the second memory into multi-value image information; and a selecting means for selecting two types of resolution according to the binary image information in the second memory; Binarization means for converting the multi-value image information in the first memory or the multi-value image information converted by the conversion means into a binary signal according to the density at the resolution selected by the selection means; An image forming apparatus comprising an image forming means for forming an image according to a binary signal converted by the value converting means. (3) The image forming apparatus according to claim 2, wherein the first memory stores color-separated color multi-value image information, respectively.