JPH02181573A - Picture forming device - Google Patents

Abstract

PURPOSE:To add a different color even to the background of a character and a picture by forming pictures for the dark part and the light part of an original picture on a picture formed medium according to the picture forming signals of plural colors and the designation of the colors. CONSTITUTION:For example, color replacement data having '1' for the dark part and '0' for the light part are stored in a color replacement data storing part as color replacement data corresponding to yellow out of yellow, magenta, cyan, and black by a main control part 81. Further, while a '1' signal is supplied to a thermal head temperature control part 93 as a color 1 signal corresponding to the dark part when the '1' signal is supplied from a binarization circuit 88 as a binary signal, a '0' signal is supplied to the thermal head temperature control part 93 as a color 2 signal corresponding to the light part when the '0' signal is supplied as the binary signal, respectively. Thus, the dark part such as the line part of the character or the picture and the background part of the character or the picture, namely, the light part, can be printed in designated different colors on the picture formed medium.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus such as a color copying machine that reads an image of a document and forms a full-color image on a sheet of paper in accordance with the read signal.

(Prior Art) In recent years, as a copying machine, a color copying machine that utilizes digital technology and uses a thermal transfer type ink ribbon has been developed and put into practical use.

In such devices, there is a demand for one in which the backgrounds of characters and images can also be colored in different colors.

(Problem to be Solved by the Invention) As mentioned above, there is a demand for something that can be given a different color to the background of text and images. The purpose is to provide an image forming apparatus that can.

[Structure of the Invention] (Means for Solving the Problems) The image forming apparatus of the present invention includes a scanning means for optically scanning a document and reading it as a plurality of types of color signals, and a plurality of color signals obtained by the scanning means. A color conversion means for converting into a color image forming signal, an instruction means for instructing colors to be used when forming images of dark and light parts of a document image, and a plurality of color image forming signals obtained by the color conversion means and the above instructions. By forming an image on an image forming medium using a plurality of color image forming media in accordance with the color instructions provided by the means, images are formed in different colors for the dark and light parts of the original image. It consists of an image forming means.

(Function) The present invention instructs colors for image formation of dark and light parts of a document image, and uses a plurality of color image forming media in accordance with a plurality of color image formation signals and the color instruction. By forming an image on the image forming medium using the image forming apparatus, images are formed on the dark and light parts of the original image in different colors.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows, as an example of the image forming apparatus of the present invention, a thermal transfer type color copying machine that can selectively produce multicolor copies. In other words, 1 is the copying machine main body,
An operation panel 50 is provided at the front of the upper surface of the main body 1 . The upper part of the main body 1 is a document table (transparent glass) 2.
Original scanning unit 3 that scans and reads original 0 set above
, and an image forming section 4 at the bottom. Note that 5 is a document cover provided on the document table 2 so as to be openable and closable.

Further, the document table 2 is fixed to the main body 1.

As shown in FIG. 3, the operation panel 50 includes a copy key 51 for starting a copying operation, a numeric keypad 52 for setting the number of copies, etc., and a copy mode setting key 53a1 for setting a color copy mode, a monochrome copy mode, etc. Setting key 5
A copy mode display 53b that displays the copy mode set in step 3a, . . . a copy density setting key 5 that sets the copy density.
4a, 54b, a copy density display 54 that displays the copy density set by the copy density setting keys 54a, 54b;
c, . . . DOWN key 55a as a copy magnification setting key for setting the copy magnification, 100% key 55b, UP key 55c1, jam display section 56 that displays the jam position, number of copies, copy magnification, and various other keys. A message display section 57 for displaying a message, and a color density setting section 58
, a help key 59 for instructing help for printing an operation manual, etc., and a mode key 60 for coloring.

The DOWN key 55a and the %UP key 55c are respectively used as NO and YES keys when the help key 59 is turned on, and are used to instruct NO and YES corresponding to the message displayed on the message display section 57. ing.

The color density setting section 58 sets the color density of each of yellow Y1 magenta M, cyan C1 black B, and sets the color density of each color by dark < (U
P) Color density UP key 58a1... Color density D to make the color density of each color lighter < (DOWN)
It is composed of an OWN key 58b, . . . , and a color density display 58C1, which indicates the color density of each color.

The coloring mode key 60 is a mode in which the color of dark parts such as characters and lines of images and the color of the background, ie, light parts, can be specified and printed in different colors.

The document scanning section 3 is configured as shown in FIGS. 2, 4, and 5, for example. That is, a first carriage 7 is equipped with an illumination lamp 6 as a light source, a second carriage 8 bends the optical path with a mirror, a zoom lens 9, and guides reflected light from the original O to a photoelectric converter 11, which changes the optical path length when changing magnification. The mirror part 10 performs correction, a photoelectric converter (conversion means) 11 receives reflected light from the original O, and a drive system (not shown) changes the positions of these parts.

The first carriage 7 includes an illumination lamp 6 that irradiates light onto the document O, a glue deflector 12 that serves as a reflector that collects the light from the illumination lamp 6 onto the surface of the document, and a second carriage that directs the reflected light from the document 0. A mirror 13 that guides the camera to the 8 side is mounted.

A mirror 8a s8b is mounted on the second carriage 8 to guide the light guided by the mirror 13 to the zoom lens 16. The first and second carriages 7.8 are
They are connected to each other by a timing belt 18, and the second carriage 8 moves at 1/2 the speed of the first carriage 7 in the same direction. This makes it possible to scan so that the optical path length up to the zoom lens 16 is constant.

The zoom lens 16 has a fixed focal length and is moved in the optical axis direction when changing the magnification.

The mirror part 10 is composed of two mirrors 10a110b, and the positions of the mirrors 10a110b are changed according to changes in the optical path length corresponding to the selected magnification ratio, and the light from the zoom lens 16 is By bending the optical path with the two mirrors 10a and 110b, the light is guided to the photoelectric converter 11.

The photoelectric converter 11 converts the image of the original O into cyan by photoelectrically converting the reflected light from the original O.

Green, yellow (or red, green.

It separates and outputs a color signal of (blue) light, and is mainly composed of, for example, a CCDCD billline image sensor. In this case, one pixel of the original O corresponds to three consecutive elements (C, G, Y) of the CCD sensor. The output of the photoelectric converter 11 is output to an A/D converter 91, which will be described later.

The first and second carriages 7.8, mirrors 10a, 10
The movement of b is performed by a stepping motor 18, respectively.

The first and second carriages 7.8, as shown in FIG. It is designed to be moved according to the movement.

The zoom lens 16 has a spiral shaft (not shown) rotated by a corresponding stepping motor (not shown), and is moved in the optical axis direction by this spiral movement.

The image forming section 4 is configured as shown in FIG. 2, for example. That is, the platen drum 22 is disposed approximately at the center of the image forming section 4 . The platen drum 22 has a periphery made of an elastic material such as rubber, and functions as a platen roller for the thermal head 24. The platen drum 22 rotates clockwise to wrap the paper P around itself, thereby preventing the paper P from shifting during overlapping printing. Pressure rollers 25, . . . are provided around the platen drum 22 at predetermined intervals to prevent the paper P from floating up from the platen drum 22.

The circumference of the platen drum 22 is slightly longer than the length in the longitudinal direction of the maximum paper size.

A thermal head 24 is disposed diagonally below and to the left of the platen drum 22 . The thermal head 24 is attached to a heat radiator integrally formed on the rear end surface of the holder. Then, the platen drum 22 and the thermal head 2
4, there is an ink ribbon 26 as an image forming medium.
There is an intervening state.

The cores 30, 31+ of the ink ribbon 26! , is connected to a drive shaft of a motor (not shown) via a drive force transmission mechanism (not shown), and is driven to rotate as required.

A paper feed roller 41 is provided at the lower portion of the main body 1, and is configured to take out sheets P, which serve as image forming media, stored in the paper feed cassette 2o one by one.

The paper P taken out by the paper feed roller 41 is transferred to the transport roller 42
The transport roller 42 is sent to the registration roller 21 disposed diagonally above and to the left of the conveyance roller 42, and its tip is aligned.Then, the registration roller 21 transports it toward the platen drum 22 via a guide 43, and the gripper 23. When pressed, the paper is wound around the platen drum 22 by the rollers 25, . . . , and is thereby accurately fed.

Here, the paper feed cassette 2o is detachable from the side of the main body 1. Note that 46 in FIG. 4 is a manual paper feeding device for manually feeding paper P and the like. The paper P fed from the manual paper feeder 46 is also wound around the platen drum 22 in the same manner as described above.

The paper P whose leading edge is fixed by the gripper 23 is wound around the platen drum 22 by clockwise rotation, and after the leading edge passes through the printing area, the paper P is placed in the thermal head 24.
is pressed against the platen drum 22, and printing is performed.

When printing of the first color is completed, the platen drum 22 has made approximately one rotation. Here, the thermal head 24 is once released, the ink ribbon 26 is wound up, and the next color is located.

Then, the platen drum 22 starts rotating clockwise again, printing is performed by the thermal head 24, and the next color is overprinted (printed).

In this manner, in the case of full-color copying, image formation is performed by four operations of yellow, magenta, cyan, and black, or three operations of yellow, magenta, and cyan. In the case of a single color such as black, it is performed in one operation.

When discharging the paper, the platen drum 22 is rotated clockwise until the trailing edge of the paper P reaches the paper discharging guide 27, and when the rear end of the paper P reaches the paper discharge guide 27, the platen drum 22 is rotated counterclockwise. A separation claw (not shown) separates the rear end of the paper P from the platen drum 22 and guides it to the paper discharge guide 27. Finally, the leading edge of the paper P is released from the gripper 23, and the paper P, which has been copied and transported by the paper discharge guide 27, is discharged onto the paper discharge tray 28.

FIG. 6 schematically shows the overall control system, which includes a main control section 81, a first control section 82, and a second sub-control section 83. The main control section 81 includes an operation panel 50, a correction circuit 84, a luminance/color difference separation circuit 85, an image quality improvement circuit 86, a color signal conversion circuit 87, a binarization circuit 88, a first sub-control section 82,
It is connected to the second sub-control unit 83, the trimming, masking, color replacement circuit 71, and the manual storage unit 72, and controls these.

The first sub-control section 82 is connected to a light source control section 89, a motor drive section 90, the photoelectric converter 11, an A/D converter 91, and a resolution conversion section 92, and controls these. The light source control section 89 is connected to the illumination lamp 6 and controls its lighting and light amount. That is, the illumination lamp 6 is turned on during a normal image reading operation.

The motor drive unit 90 drives the scanning motor 18 . The second sub-control unit 83 includes a thermal head temperature control unit 9
3. It is connected to the thermal head 31, various detection switches 94, and drive section 95, and controls these. The drive unit 95 is connected to a drive system 96 such as a motor and a solenoid, and drives the drive system 96 .

The correction circuit 84 performs shading correction on image data (after resolution conversion) obtained by A/D converting the reflected light from the original O, that is, correction of variations in the photoelectric converter 11.

When the main control unit 81 is supplied with a signal from the help key 59 of the operation panel 50, it determines that it is in the help processing mode,
The message display section 57 is used to ask questions regarding instructions regarding help contents. The content of this question includes whether to instruct the output of various operation manuals or output the settings (image forming conditions) using various setting keys. When outputting this setting content, if the setting content is trimming, masking, etc., a pattern (frame) indicating the actual corresponding area is printed instead of a number as area data, and if it is related to color, the color is printed. The actual color is printed instead of the indicated number.

When the main control unit 81 is supplied with a signal from the coloring key 60 of the operation panel 50, it determines that the coloring mode is selected, and uses the message display unit 57 to display guidance for instructing the colors of dark and light parts of the original image. It is something to do.

Further, the color signal conversion circuit 87 will be explained with reference to FIG. Luminance signal (I), color difference signal 1 (C1), color difference signal 2 (C2) sent from the image quality improvement circuit 86
Each signal is sent to a color signal conversion circuit 87, which sends any one of Y, M, C, and H color signals to a binarization circuit 88. ,B
The selection of color signals is performed by the main control section 81. That is, as shown in the table below, the main control unit 81 receives the signal a.

Y is sent to the binarization circuit 88 by the combination of b.

M, C, and B color signals are selected. Note that the above color signals are automatically selected sequentially (for example, Y-M-4C
→B order).

The trimming, masking and color replacement circuit 71 will be explained with reference to FIG. That is, the main control section 8
A replacement color data storage unit 61 stores the replacement color set by 1 and outputs the color 1 signal and color 2 signal as replacement color signals to the data selector 62, image data from the binarization circuit 88, or the replacement color. a data selector 62° that selectively outputs the color 1 signal and color 2 signal supplied from the color data storage unit 61 to the thermal head temperature control unit 93 according to the selection signal supplied from the area memory 63; The region for trimming, masking, and color replacement supplied from the main control section 81 is stored, and when the X coordinate signal and Y coordinate signal supplied from the main control section 81 match the stored region, a selection signal is sent. It is composed of an area memory 63 that outputs to a data selector 62.

The data selector 62 selects between the image data from the binarization circuit 88 and the color 1 signal or color 2 signal supplied from the replacement color data storage section 61 according to a selection signal from the area memory 63. This selects whether to output "1" of the image data from the binarization circuit 88.
Depending on "0", it is selected which of the color 1 signal and color 2 signal supplied from the replacement color data storage section 61 is to be output. In addition, when trimming or masking, trimming or masking can be performed by setting the replacement color data from the replacement color data storage section 61, that is, the color 1 signal or color 2 signal, to the empty state "0". It has become.

The manual storage section 72 stores character patterns of an operation manual as operation guidance corresponding to each function specified by key operations on the operation panel 50, and stores operation guidance from the main control section 81. The character pattern corresponding to the manual to be performed is output to the dot information development section 73. This dot information development section 73 develops the character pattern from the manual storage section 72 into dot information, and the developed dot information is supplied to the thermal head temperature control section 93. Thereby, character information is printed on the paper P as an operation guide corresponding to the function specified by the key operation on the operation panel 50.

Next, the operation in the above configuration will be explained. For example, after the operator has set various copy conditions such as the number of copies, copy magnification, copy density, etc., the copy key 51 is turned on. Thereby, in response to input of the copy key 51, copying is performed according to the various copying conditions set above.

That is, the reflected light of the light irradiated onto the document O from the verification lamp 6 is imaged on the photoelectric converter 11.

The photoelectric converter 11 converts the light into cyan (C) and green (G).
), separated into yellow (Y) analog color signals, and A/
It is sent to the D converter 91. The A/D converter 91 converts each analog color signal into a digital signal, and outputs the digital signal to the resolution converter 92.

The resolution conversion unit 92 performs resolution conversion to match the resolution of the photoelectric converter 11 and the resolution of the thermal head 24, and sends the result to the correction circuit 84. The correction circuit 84 performs correction processing (shading correction) on each of the C, G, and Y color signals sent from the resolution converter 92 in order to correct variations in the photoelectric converter 11, and performs luminance and color difference separation on the results. to circuit 85. The luminance color difference separation circuit 85 is
Various calculation processes are performed on each color signal of C, G, and Y sent from the correction circuit 84, and a luminance signal (1) and a color difference signal 1 are generated.
(C1) and color difference signal 2 (C2), and send them to the image quality improvement circuit 86. The image quality improvement circuit 86 analyzes the luminance signal, color difference signal 1, and color difference signal 2 sent from the luminance color difference separation circuit 85, performs image quality improvement processing such as edge emphasis and character identification, and sends them to the color signal conversion circuit 87. . The color signal conversion circuit 87 performs color conversion based on the luminance signal, color difference signal 1, and color difference signal 2 that have been subjected to image quality improvement processing, and converts the color into yellow (Y
), magenta (M), cyan (C), black (B) [
Any one of the three primary colors (Y, M, C) plus B when printing
The color signals are converted into two color signals (signals corresponding to degrees a) and sent to the binarization circuit 88. The binarization circuit 88 is a color signal conversion circuit 87
Area gradation conversion, that is, binarization, is performed on the color signal (any one of Y, M, C, or B) sent from the computer using the dither method, etc., and the binarized signal is trimmed and masked. , through the color replacement circuit 71 and sent to the thermal head temperature control section 93. The thermal head temperature control unit 93 sends an i11 signal to the thermal head 24 based on the binarized signal supplied from the binarization circuit 88.

Further, in response to the input of the copy key 51, the paper P in the paper feed cassette 20 is taken out by the paper feed roller 41, and the taken out paper P is transported by the transport roller 42 and the registration roller 21.

Then, the paper P conveyed by the registration rollers 21 is guided to the platen drum 22 via a guide 43, and its leading end is fixed by a gripper 23. Thereby, the paper P is wound around the platen drum 22.

Depending on such conditions, the thermal head 24:
Using yellow, magenta, cyan, and black of the ink ribbon 26 sequentially, printing (that is, image formation) is performed on the paper P wound around the platen drum 22 in accordance with the print signal supplied for each color. .

Further, when trimming or masking is specified using a key (not shown) and its coordinates are set using the numeric keypad 52, when the binarized signal from the binarization circuit 88 is supplied to the thermal head temperature control section 93, , only the binary signals within the trimming area or outside the masking area are supplied to the thermal head temperature control section 93.

For example, the main controller 81 may store area data outside the trimming area or within the masking area in the area memory 63.
rOJ is stored as color replacement data in the color replacement data storage section 61, and its output, that is, color 1 signal, color 2 signal,
The signal becomes "0".

As a result, when the binarized data is supplied from the binarization circuit 88, if the selection signal is not supplied, the binarized signal is directly supplied to the thermal head temperature control section 93, and the selection signal is supplied. When it is present, a “0” signal is supplied to the thermal head temperature control section 93.

In addition, the coloring mode is set to the coloring key 60 on the operation panel 50.
If specified by Display. In response to this guidance, the operator enters numerical values corresponding to the colors of the dark and light parts using the numeric keypad 52 and then presses the copy key 51.

By this input, the main control unit 81 stores in the replacement color data storage unit 61 replacement color data each time printing is performed with each color ink corresponding to the selected color.

Therefore, when the binary signal from the binarization circuit 88 is supplied to the thermal head temperature control section 93, if the binary signal from the binarization circuit 88 is "1", the dark part of the document is If it is "0", the color 2 signal corresponding to the light density part is the color 1 signal corresponding to the thermal head temperature control unit 93.
supplied to

For example, the main control unit 81 stores color replacement data corresponding to yellow in the color replacement data storage unit 61 in which a dark part is "1" and a light part is "0", and the output, that is, the color 1 signal is "1". As a result, when a "1" signal is supplied as a binary signal from the binarization circuit 88, the color 2 signal becomes a "1" signal corresponding to a dark part. The “0” signal is supplied to the thermal head temperature control unit 93, and when the “0” signal is supplied, the “0” signal is supplied to the thermal head temperature control unit 93 as a color 2 signal corresponding to the thin portion.

Further, the main control unit 81 stores color replacement data corresponding to magenta in the color replacement data storage unit 61 in which the dark part is "0" and the light part is "1", and the output, that is, the color 1 signal is "0". The color 2 signal becomes a “1” signal. As a result, when a "1" signal is supplied as a binary signal from the binarization circuit 88, a "0" signal is supplied to the thermal head temperature control unit 9 as a color 1 signal corresponding to a dark area.
3, and when a "1" signal is supplied, a "0" signal is supplied to the thermal head temperature control section 93 as a color 2 signal corresponding to a thin portion.

As a result, dark parts such as lines of characters or images and light parts of the background can be printed in different designated colors.

Next, the help process will be explained with reference to the flowchart shown in FIG. That is, in the standby state or before the copy key 51 is pressed, the help key 59 is pressed by the operator.

Then, the main control section 81 determines the help processing mode, and uses the message display section 57 to provide guidance such as "Please press the operation key for operation guidance." In response to this guidance, the operator inserts a key whose function is unknown. Thereby, the main control section 81 outputs an operation guide instruction for the function corresponding to the input key to the manual storage section 72. Then, the manual storage unit 72 stores the character pattern of the manual corresponding to the function that provides operation guidance into the dot information development unit 7.
Output to 3. This dot information development section 73 develops the character pattern from the manual storage section 72 into dot information, and outputs this developed dot information to the thermal head temperature control section 93. As a result, the operation panel 50
Text information is printed on paper P as operation guidance corresponding to the function specified by the key operation.

Also, by pressing the DOWN key (No key) 55a,
Switch the question displayed by the message display section 57 to "Do you want to print the area that will actually be trimmed?"
By pressing the UP key (YES key) 55c, the guidance (question) is selected. At this time, the coordinates at which the trimming is to be performed are set in advance using the numeric keypad 52 and a trimming mode designation key (not shown). Then, the main control unit 81 stores, in the area memory 63, area data (area of a frame surrounding the trimming area) corresponding to several dots outside the trimming area, based on preset coordinates at which trimming is performed. Further, the main control unit 81 stores data “0”, in which nothing is printed, in the replacement color data storage unit 61 as replacement color data. As a result, "0" is output as the color 1 signal from the replacement color data storage section 61.

The main control unit 81 also controls the image data supplied from the binarization circuit 88 to the data selector 62 to be "1".

Therefore, image data (binarized signal) corresponding to the frame surrounding the trimming range is output to the thermal head temperature control section 93 as image data for one screen. The thermal head temperature control section 93 sends a print signal to the thermal head 24 based on the binary signal supplied from the data selector 62 in the trimming, masking, and color conversion circuit 71.

Further, in response to the input of the UP key 55c, the paper P in the paper feed cassette 20 is taken out by the paper feed roller 41, and the taken out paper P is transported by the transport roller 42 and the registration roller 21.

Then, the paper P conveyed by the registration rollers 21 is guided to the platen drum 22 via a guide 43, and its leading end is fixed by a gripper 23. Thereby, the paper P is wound around the platen drum 22.

Depending on such conditions, the thermal head 24:
Using yellow, magenta, cyan, and black of the ink ribbon 26 sequentially, printing (that is, image formation) is performed on the paper P wound around the platen drum 22 in accordance with the print signal supplied for each color. conduct.

As a result, a frame surrounding the trimming range is printed on the paper P. Thereby, the actual trimming position on the paper P can be confirmed.

Also, regarding masking, a frame surrounding the masking range is printed on the paper P by operating in the same manner as in the case of trimming. Thereby, the actual masking position on the paper P can be confirmed.

Also, by pressing the DOWN key (No key) 55a,
Change the question displayed on the message display section 57 to "Do you want to check the colors that will actually be printed?" and press the UP key (Y).
By pressing 55C (ES key), the guidance (question) is selected. At this time, the color density of each color is set in advance by the color density setting section 58. And the main control section 8
1 is displayed on the message display section 57. ``Please specify the color to print using the numeric keys. 1... Red, 2... Blue, .
"..." is displayed. In response to this guidance, the operator inputs a numerical value corresponding to the color he wishes to confirm using the ten key 52 and then presses the copy key 51.

With this input, the main control unit 81 stores area data corresponding to the area to be printed in the area memory 63. Further, the main control unit 81 stores data “0”, in which nothing is printed, in the replacement color data storage unit 61 as replacement color data. As a result, the color 1 signal and color 2 signal from the replacement color data storage section 61 are
"0" is output as a signal. In addition, the main control unit 81
In this case, the color signal outputted from the color signal conversion circuit 87 to the binarization circuit 88 is set to a signal corresponding to the selected color. This binarization circuit 88 receives a color signal (any one of Y, M, C, and B) sent from the color signal conversion circuit 87.
2), area gradation conversion is performed using the dither method etc.
Value conversion is performed, and the resulting binary signal is sent to the data selector 62 in the trimming, masking, and color replacement circuit 71. This data selector 62 sends only the binarized signal within the area specified by the area memory 63 to the thermal head temperature control section 93 . The thermal head temperature control section 93 sends a print signal to the thermal head 24 based on the binarized signal supplied from the binarization circuit 88 .

Further, in response to the input of the copy key 51, the paper P in the paper feed cassette 20 is taken out by the paper feed roller 41, and the taken out paper P is transported by the transport roller 42 and the registration roller 21.

Then, the paper P conveyed by the registration rollers 21 is guided to the platen drum 22 via a guide 43, and its leading end is fixed by a gripper 23. Thereby, the paper P is wound around the platen drum 22.

Depending on such conditions, the thermal head 24:
Using yellow, magenta, cyan, and black of the ink ribbon 26, the paper P is wound around the platen drum 22 in accordance with the print signal supplied for each color.
Printing (that is, image formation) is performed on the image.

Therefore, the specified color is printed on the paper P, and the operator can confirm the color actually printed on the paper P.

As described above, different colors can be applied to dark parts such as characters and lines of an image of a document and light parts such as the background.

In addition, in the above embodiment, the color specified in the faded color mode is explained by inputting the numerical value for each color displayed on the message display section, but the present invention is not limited to this. You can also do it manually.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an image forming apparatus that can add different colors to the backgrounds of characters and images.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention, and FIG. 1 is a simplified block diagram explaining the trimming, masking, and color replacement circuits in detail, and FIG. 2 is a schematic diagram of the overall configuration. 3 is a plan view showing the structure of the operation panel, FIG. 4 is a diagram for explaining the main part of FIG. 2, FIG. 5 is a schematic perspective view showing a part of the structure, and FIG. FIG. 6 is a block diagram schematically showing the overall control system, FIG. 7 is a block diagram for explaining the color signal conversion circuit in detail, and FIG. 8 is a flow chart for explaining the main parts of the operation. . 0... Original, P... Paper (image forming medium) 3...
- Original scanning unit, 4... Image forming unit, 11... Photoelectric converter, 22... Platen drum, 24... Thermal head, 26... Ink ribbon (image forming medium) 50
...Operation panel, 51...Copy key 52...Numeric keypad 55 a-D OW N key (No key), 5
5c...UP key (YES key), 57...Message display section, 59...Help key 60...Coloring km 1...Replacement color data storage section, 62...Data selector, 63. ...Area memory, 71...Trimming, masking, color replacement circuit, 72...Manual storage section, 73...Dot information storage section, 81...Main control section, 87...Color signal conversion circuit , 88...binarization circuit,
97...Counter. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A scanning means for optically scanning a document and reading it as a plurality of types of color signals; a color conversion means for converting each color signal obtained by the scanning means into a plurality of color image forming signals; an instruction means for instructing colors to be used when forming images of dark and light portions of the image, and forming images of a plurality of colors according to a plurality of color image formation signals obtained by the color conversion means and a color instruction by the instruction means; An image forming means for forming an image on a medium on which an image is formed using a medium, thereby forming an image in a dark part and a light part of a document image in different colors, respectively. Forming device.