JPH01267592A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To form a multicolor image which uses character fonts with simple constitution by referring to a font storage part with input image code data and also referring to fonts regarding image information, color by color, in surface order according to input color information. CONSTITUTION:Plural kinds of fonts are stored and characters, etc., are recorded by an electrophotographic method capable of high-density recording according to image data which is generated by using the fonts. When an input image is a color character image, pieces of image information which are decomposed by colors are converted into image data in surface order by referring to font data 1a-1d by color components. Toner images are formed on an image formation body in surface order by the color components according to said image data and put one over another to form a multicolor toner image. Plural kinds of character fonts are used and selected optionally. Consequently, not only black characters, but also chromatic characters of yellow, magenta, cyan, etc., are printed with high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multicolor image forming apparatus using electrophotography, and particularly to a multicolor image forming apparatus using character fonts.

[Background of the Invention] Image forming apparatuses are known in which character information is transferred in the form of code data, which is converted into image data consisting of pixels of one to several bits to produce a visible image.

The data referred to in this conversion is called a font, and a dedicated data conversion means is used to convert this into image data.

[Problems to be Solved by the Invention] Incidentally, the conventional image forming apparatus described above creates image data using a character font, and forms a black and white toner image based on this. , there was nothing that could record color characters.

On the other hand, various types of image forming apparatuses for forming color images are known, but the apparatus described in Japanese Patent Application Laid-Open No. 184381/1983 has a simple structure and is a feature of electrophotography. This is an excellent product that takes advantage of high speed and high image quality. A feature of this device is that toner images of one color are formed one on top of the other on a photoreceptor (image forming body).

It was conventionally thought that when recording color characters, it was sufficient to use a black and white character font.

However, especially when using an electrophotographic recording apparatus as described above as a recording means, the following problems arise.

In other words, such a recording device has a drum-shaped image forming body, and after forming a first color toner image, a second color toner image is formed on top of the first color toner image in the next process. , such an imaging process is performed for all color separation images.

When all image forming processes are completed, fixing and separation processes are performed, and the color original is copied and recorded on regular recording paper.

When using such a recording unit that forms multi-color toner images by superimposing them, the details will be described later, but the amount of adhered toner images of the first color and the second color differs, resulting in poor color reproducibility. will deteriorate.

Furthermore, it would be extremely convenient if the font data could be configured to be selectable according to the user's preference.

The present invention takes these points into consideration and proposes a multicolor image forming apparatus that can perform color recording using fonts and improve color reproducibility.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention, at least the characters, the size of the characters,
an image input means that outputs coordinate information of characters on the screen as image code data; a font storage unit that stores multiple types of font data and outputs font data according to an input address signal; It has a font data conversion section that has a function of converting image code data into image data consisting of pixel information, and an image buffer memory that temporarily stores the image data output from the font data conversion section. Image data is created based on the selected font data, and a toner image is formed on the image forming body one color component at a time based on this image data, thereby forming a multicolor toner image. It is characterized by the following.

[Function] The multicolor image forming device according to the present invention has a built-in font,
Based on image data formed using this, characters and the like are recorded by electrophotography, which allows high-density recording.

When the input image is a color character image, the color-separated image information is converted to image data in a frame-by-frame manner by referring to the photo data for each color component.

Based on the image data obtained in this way, toner images are formed on the image forming body one color component at a time, one by one, and are sequentially superimposed to form a multicolor toner image.

As a result, it is possible to print not only black characters but also chromatic characters such as yellow, magenta, and cyan with high quality.

A plurality of types of character fonts are prepared and can be arbitrarily selected. As shown in FIG. 2, the font may have a shape with different line thicknesses and pixel areas depending on the color to be recorded, or it may have a different font.

If fonts with different line widths are used, even if a multicolor toner image is formed, the amount of toner adhering will be constant, and color reproducibility will be improved.

[Example] Next, an example of the multicolor image forming apparatus according to the present invention will be described in the first example.
This will be explained in detail with reference to the figures below.

FIG. 1 shows a block diagram of the basic configuration of the present invention.

The present invention has a font storage section 1 in which fonts such as characters and symbols are stored.

As will be described later, the font storage unit 1 stores a plurality of types of fonts each having different line widths corresponding to each recording color.

The input means 2 for the font data converter 10 is for inputting image information as a code, and this image code data represents at least the type of character, the size of the character, and positional information 1 (coordinate information) of the character. It consists of data.

Of the input image code data, character information is decoded by the font data converting section 10 and sent as an address signal to the font storage section 1 having the font data.

In the font storage section 1, the font data corresponding to address No. 43 that has been completely input is referred to, and this is output to the font data conversion section 10.

In the font data conversion section 10, conversion is performed using information representing the size of characters in the image code data as a parameter to form character image data on a two-dimensional plane.

Next, this character image data is stored in the corresponding area of the image buffer memory 5 according to the position information of the input image data.

When one screen worth of image data regarding certain specific color information is formed, this image data is output in accordance with a request signal from the electrophotographic recording section 6.

In the electrophotographic recording section 6, an electrostatic latent image is formed based on the sent image data, and a toner of a color corresponding to the image is attached and developed.

Each process from image data creation to development is executed for each color in a field-sequential manner, and after a multicolor toner image has been formed, the process moves to fixing processing to record (copy) the desired color document. .

A plurality of types of font data are stored in the font storage section 1 described above, and these are automatically selected according to the recording sequence of the electrophotographic recording section 6.

In this example, the number of fonts corresponding to the recording colors is prepared, and when color recording is performed in four colors of yellow, magenta, cyan, and black as described later, the block 18 for storing font data is prepared. -1d are provided, and address No. 48 is commonly supplied to them, and font selectors 3,
4 is provided.

The font selectors 3 and 4 are both controlled by a sequence signal indicating the order of recording colors in the recording section 6, and font data corresponding to the recording color is selected.

FIG. 2 shows an example of font data. Even if the line width W is the same, fonts with different recording shapes and recording widths are used depending on the color to be recorded.

For example, in the case of yellow Y, the font is configured such that only the edge portions a and b of the line width W are recorded, and in the case of magenta M, the font is configured such that only the center portion C is recorded. It is configured as follows.

For cyan C, the font is configured with a predetermined width e and a predetermined pitch d so as to form horizontal stripes.

On the other hand, black BK is set to a font in which the line width W is recorded as it is.

The reason why the thickness and recording shape are made to vary depending on the color to be recorded even if the line width W is the same is as follows.

When a multicolor toner image is formed by overlapping as described above, when the second color latent image is formed and the photosensitive layer is made conductive by imagewise exposure, 1. The first color toner image absorbs and absorbs the laser light. , 2. The problem is that the charge possessed by the toner cannot be erased by light irradiation.

The factor 1 is the actual amount of exposure that reaches the photosensitive layer,
This means that the charges on the photosensitive layer are not erased sufficiently, and the surface potential of the photosensitive member is not lowered sufficiently.

The second factor is that, unless the toner is a special type of photoconductive material, its charge will not be reduced by exposure to light. Therefore, this also causes the surface potential of the photoreceptor not to decrease.

For these reasons, the difference in surface potential between the exposed area and the unexposed area in the area where the toner image is formed becomes small, making it impossible to develop with a sufficient amount of toner.

In other words, when trying to reproduce colors by layering toner,
The amount of toner adhesion for the second and subsequent colors decreases, and the amount of each toner adhesion becomes unbalanced, resulting in a narrower color reproduction area.

The above two factors depend on the development order of the toner, the spectral characteristics of the image exposure light (laser light), the spectral characteristics of the toner, the amount of charge of the toner, etc., so the color reproducibility changes depending on these values.

Since these tendencies become stronger in the order of yellow, magenta, cyan, and black, it is possible to eliminate the above-mentioned effects by making the thickness of the characters thinner in this order or by making the recording shape different.

This is because when characters are constructed using font data that serves as a record as shown in Figure 2, areas where the toner overlaps and areas where the toner does not overlap always appear at a specific ratio, and the toner changes depending on the color. This is because the change in the amount of adhesion can be minimized.

By using such font data, deterioration in color reproducibility can be avoided.

For this reason, the line width and recording shape shown in FIG. 2 are only examples, and the content of the font does not matter as long as it can improve color reproducibility.

FIG. 3 shows an example of the configuration of the font data converter 10 described above.

The character information constituting the image code data is decoded by the decoder 11, and an address signal to the font storage section 1 is created.

Based on the created address signal, the character font corresponding to the character is referred to, and this is the image data forming unit 12.
will be sent to. At this time, in order to select specific font data, the copy sequence signal of the recording section 6 is referred to as shown in FIG.

The image data forming section 12 forms character image data corresponding to the size of the input character from the sent font data and information on the size of the input character, and sends this to the line buffer 13.

Image code data indicating the size of the characters is also roughly supplied to the address signal forming section 14. Address signal forming section 1
4 is supplied with image code data roughly representing character position information, and an address signal indicating the recording position (coordinates) is formed by these data.

This address signal and the image data in the line buffer 13 are output in correspondence, and the image data is stored in the area specified by the address signal.

FIG. 4 shows an example of the electrophotographic recording section 6.

As the electrophotographic recording section 6, a color copying machine using a drum-shaped image forming body can be used.

In FIG. 4, reference numeral 20 denotes an image forming body, which has a photoconductive photoreceptor surface layer made of OPC, Se, etc. on its surface. This is rotated in the direction of the arrow.

A charger 21 uniformly charges the surface of the image forming body 200. In the image forming body 20, a writing unit D performs image exposure of a color image for each color.

Developing units 22 to 25 use toners of different colors such as yellow, magenta, cyan, and black as developers. 26 and 27 are used to easily transfer a color image formed by superimposing a plurality of color toner images onto the recording paper (transfer material) P on the image forming body 20 (or to make it easier for the recording paper P to separate). A pre-transfer charger and a pre-transfer exposure lamp are respectively provided as necessary.

28 is a transfer device for transferring a color image, 29 is a recording paper P
30.31 a fixing device that fixes the toner image transferred to the
are a static elimination lamp and a static elimination corona discharger, respectively.
Use either one or a combination of both.

32 is a separation electrode, and 33 is a cleaning device that comes into contact with the surface of the image forming body 20 after the color image has been transferred to remove residual toner on the surface, which is the surface (site) where the first development was performed. By the time the cleaning blade 34 and the fur brush 3 have separated from the surface of the image forming body 20,
5.

Here, as the charger 21, a scorotron as shown can be used, which can give a stable charge with little influence of the previous charge, since it charges the surface of the image forming body 20 which is already charged. Preferably, a corona discharger is used.

Next, an example of the process of forming a multicolor image using this electrophotographic recording section 6 will be explained based on FIG. 5.

Here, since the image forming body 20 has a photoconductive layer on a conductive substrate, the latent image forming means includes a charger 21 that uniformly charges the surface of the image forming body 20, and a charger 21 that uniformly charges the surface of the image forming body 20, and a light beam such as a laser that charges the image forming body 20.
It is configured in combination with an image exposure device that performs image exposure by irradiating a surface of 0.

FIG. 5 shows the change in the surface potential of the image forming member 20, and TI is the first developed toner image (I!
T2 indicates a toner image developed for the second time. Note that for convenience of explanation, the polarity of the latent image is assumed to be positive.

1. The image forming body 20 is uniformly charged by the charger 21 and has a surface potential of E.

2. The image exposure device performs image exposure for the first color, and the potential of the exposed portion decreases in accordance with the amount of light that has been completely irradiated.

In this way, an electrostatic latent image is formed.

3. The electrostatic latent image is developed by one of the developing units 22 to 25 to which a positive bias approximately equal to the surface potential E of the unexposed area is applied.

As a result, the positively charged toner (T1) adheres to the relatively low potential area (exposed area), and the first color toner image T1
is formed.

4. The image forming body 20 is charged by the charger 21 with the toner image attached thereto.
The surface potential of the image forming member 200 becomes E regardless of the presence or absence of toner.

5. The image exposure device performs image exposure for the second color, and the exposed area P
The potential of H decreases depending on the amount of irradiated light. In this way, an electrostatic latent image is formed.

When the area to which the toner has adhered during the first color development is exposed again, the potential becomes approximately equal to the potential after development.

Develop with toner of a different color from the first color toner in the same manner as in 6.3. As a result, two color toner iT1. T2 is obtained on the imaging member 20.

Thereafter, the same process is repeated a necessary number of times to obtain a multicolor toner image on the image forming body 20. Thereafter, a fixing and separating process is performed, and the color original is recorded on the recording paper P.

In addition, when using the recording unit (multicolor printer) 6 explained in FIGS. 4 and 5, it is possible to take advantage of the advantages of electrophotography, that is, high speed and high resolution, and also to have a simple configuration and small size. It has the advantage of being easy to convert.

FIG. 6 shows another example of the invention.

In this example, the configuration is such that the user can select any type of font.

Arbitrary fonts refer to fonts such as Gothic and Mincho fonts.

Therefore, for example, four types of font data having different fonts are stored in corresponding blocks 1a to 1d.

On the other hand, the image buffer memory 5 contains blocks 1a to 1d.
and image forming colors of the electrophotographic recording section 6 (yellow, magenta,
Storage areas 5a to 5d corresponding to cyan and black are provided, and an input selector 9a is provided at the input stage thereof, and an output selector 9b is provided at the output stage.

The input selector 9a and the font selectors 3 and 4 are both selected by a font selection signal from the control section 7. This allows the user to select a font of their choice.

The output selector 9b is selected by a copy sequence signal from the recording section 6.

[Effects of the Invention] As explained above, according to the configuration of the present invention, a font storage section is provided, and the font storage section is configured to be referenced by input image code data, and the font storage section is configured to be referenced by input image code data, and the font storage section is configured to refer to the font storage section using input image code data. This is configured to refer to fonts related to image information for each color.

According to this, it is possible to form a multicolor image using character fonts with an extremely simple configuration.

Roughly speaking, a plurality of types of font data are prepared and configured so that they can be selected according to the recording sequence. This greatly improves color reproducibility.

Furthermore, since the font data can be configured to be selectable according to the user's preference, there is also the practical benefit of being able to select any font.

Therefore, the multicolor image forming apparatus according to the present invention is extremely suitable for application to electrophotographic color copying machines and the like.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a multicolor image forming apparatus according to the present invention, FIG. 2 is a diagram showing an example of an image recorded using different font data, and FIG. 3 is a diagram showing a specific example of a font data converter. FIG. 4 is a configuration diagram showing an example of an electrophotographic recording section, FIG. 5 is an explanatory diagram of the image forming process,
FIG. 6 is a system diagram similar to FIG. 1 showing another example of the present invention. 1... Font storage units 1a to 1d... Font data block 2... Input means 5... Image buffer memory 6... Electrophotographic recording unit 7... Control unit 10... Font data Conversion section Fig. 1 Y M CBK Fig. 2 Fig. 5

Claims (1)

[Claims] (1) Image input means that outputs at least characters, character sizes, and on-screen coordinate information of characters as image code data based on input image information, and address signals that store multiple types of font data and are input. a font storage unit that outputs font data according to the font data; a font data conversion unit that has a function of converting the image code data into image data consisting of pixel information based on the font data; and output from the font data conversion unit. Image data is created based on the font data selected from among the font data, and image data is created based on the image data, one color component at a time, plane sequentially. 1. A multicolor image forming apparatus, wherein a toner image is formed on an image forming member, thereby forming a multicolor toner image.