JPH08227198A - Full-color printing system of single-pass dual drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-path, dual-drum, full-color printing system suitable for a desk top printing system. SOLUTION: This single-path, dual-drum, full-color printing system 200 is generally constituted of a single raster output scanner(ROS) optical system 202, the first four-level zero-graphic station 204 having the first photoreceptor drum 206, and the second three-level zero-graphic station 208 having the second photoreceptor drum 210 in a tandem structure. Each of two photoreceptor drums 206, 210 transfers toner to the same base material sheet 272 such as a paper sheet. The color printing system 200 can generate all picture elements including black, white, and six primary colors.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to single-pass, full-color xerographic printing systems, and more particularly to a raster output scanner (RO).
S) an optical system and a tandem configuration of photoreceptors capable of printing pixels producing black, white and all six primary colors (eg,
Photoreceptor) A color printing system generally comprised of a drum zero graphic station.

[0002]

2. Description of the Prior Art In the practice of conventional two-level xerography, it is a common procedure to first form an electrostatic latent image on a charge holding surface such as a photoconductive member by uniformly charging the charge holding surface. Is. The electrostatic charge is selectively dissipated according to the pattern of excitation radiation that corresponds to the original image. The selective dissipation of the charge leaves a two-level latent charge pattern on the image plane, where the highly charged areas correspond to areas not exposed by radiation. One level of this charge pattern becomes visible when developed with toner. Toners are generally colored powders that adhere to the charge pattern by electrostatic attraction. The developed image is then fixed to the imaging surface or transferred to a receiving substrate such as plain paper and fixed to the substrate by a suitable fusing technique.

In tri-level highlight color image formation, unlike conventional xerography, three charge levels are created on the charge retentive surface during exposure. Highly charged (ie unexposed) areas are developed with toner and more fully discharged areas are also developed, but different color toners are used. Therefore, the charge retentive surface contains three exposure levels, zero exposure, intermediate exposure and full exposure, which correspond to the three charge levels. These three
The two levels are developed so that, for example, black, white and a single color can be printed.

Several scanning techniques are known in the prior art for obtaining three levels of exposure imaging. Conventional flying spot scanners, such as those used on the Canon 9030, use a ROS device,
"Write" the exposed image one pixel at a time on the light-receiving surface. To obtain higher spatial resolution, pulsed imaging scanners can be used. This pulse imaging scanner is based on Richard Johnson et al. (Richard Johnson, whose content is incorporated by reference herein).
et al.) “Scophony Spatial Light Modulator (Scophony Spa
tial Light Modulator) ”(Optical Engineering, Volume 24, No. 1, January 1985, article), also referred to as a scophony scanner. A preferred technique that allows for higher spatial resolution is to use optics similar to flying spot scanners (rotating polygons, laser sources, pre-polygon and post-polygon optics), but many at a given time. With the A / O modulator illuminating the pixels, the scanner will have a coherent imaging response. With this type of scanning system, the exposure level, ie the level at the imaging surface, can be controlled by controlling the drive level of the A / O modulator depending on the video data. In a three level system, two drive levels are used, one for white exposure and a second higher drive level for DAD exposure.

Alternatively, instead of obtaining an intermediate exposure level by controlling the acoustic amplitude, an intermediate exposure can be provided by using pulse width modulation of a pulse imaging system with spatial filtering, the two being combined. You can reduce the level.

In four-level color image formation, four charge levels are created on the charge retentive surface during exposure. Therefore, the charge retentive surface comprises four exposure levels, zero exposure, low intermediate exposure, high intermediate exposure and full exposure, which correspond to the four charge levels. These four levels can be developed and printed, for example black, white and two colors.

The four-level xerographic unit is
Unlike 2-level and 3-level, it does not produce a color image that matches the color of the toner. Two of the toner colors are generated and the third color generated is a combination of one of the first two toner colors and the third color.

Raster output scanner (ROS) optical systems for producing tri-level exposures on recording media generally print black, white and single colors. Raster output scanner optics systems for forming four level exposures on a recording medium typically print black, white and two colors. However, the full color process prints the six primary colors cyan, yellow, magenta, blue, green and red in addition to black and white.

Assigned to the same applicant as the applicant of the present application,
US Pat. No. 5,24, incorporated herein by reference
The 3,359 full color printing system provides a common ROS optical system with multiple xerographic stations, one station for each color. Registration criteria are important for the four xerographic stations to print in full color on the same paper. In this system, each of the four ROS beams must be precisely aligned in two axes, and therefore eight very tight alignments during manufacturing, and their useful life. Must be maintained throughout. 4 individual ROs
The cost of S units is a disadvantage, as is the cost associated with the larger physical size of systems with four ROS units.

There is a need for smaller size, lower cost and faster full color printing systems for desktop printers.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a single pass, dual drum, full color printing system suitable for desktop printing systems.

[0012]

SUMMARY OF THE INVENTION In accordance with the present invention, a single pass, dual drum, full color printing system is provided.
Single Raster Output Scanner (ROS) optical system,
First four with first photoreceptor drum in tandem configuration
It generally consists of a second three level xerographic station having a level xerographic station and a second photoreceptor drum. Each of the two photoreceptor drums transfers toner to the same sheet of support material such as paper.

A full-color printing system uses four color toners (black and cyan, magenta and yellow which are the three primary colors of the subtractive method), and black, white and six primary colors (red, green, blue, cyan and magenta). And yellow) generate all pixels. The pixels of the additive primary colors of blue, red, and green are generated by overlapping the toner dots of the combination of the three primary colors of the subtractive method. The printing system can also produce a full color using only the three subtractive primary colors.

A first aspect of the present invention is a single pass, dual drum, full color printing system comprising:
A first raster output scanner optical system for producing a first modulated beam and a second modulated beam, including a sheet of support material, for charging a first photoreceptor drum;
Of xerographic stations, the first photoreceptor drum is then exposed to the first modulated beam, and the first xerographic unit is exposed to a plurality of charge-charge-based charge carriers after exposure of the first modulated beam. Means for adhering the color toners to the first photoreceptor drum, the first photoreceptor drum then transferring the toner to the sheet of support material to charge the second photoreceptor drum. Second
Of xerographic stations, the second photoreceptor drum is then exposed to the second modulated beam, and the second xerographic unit is exposed to a plurality of plurality of charge carriers based on the charge charge after the exposure of the second modulated beam. Means for adhering the color toners to the second photoreceptor drum, the second photoreceptor drum then transferring the toner to the sheet of support material, whereby the color toners are transferred to the support material. To generate pixels of black, white and all six primary colors on the sheet.

According to a second aspect of the present invention, in the first aspect, one of the first and second xerographic stations is a 4-level xerographic station, and the first and second xerographic stations. The other of the xerographic stations is a 3-level xerographic station.

A third aspect of the present invention is a single pass, dual drum, full color printing system comprising:
A first raster output scanner optical system for producing a first modulated beam and a second modulated beam, including a sheet of support material, for charging a first photoreceptor drum;
Of xerographic stations, the first photoreceptor drum is then exposed to the first modulated beam, and the first xerographic unit is exposed to a plurality of charge-charge-based charge carriers after exposure of the first modulated beam. Means for adhering the color toners to the first photoreceptor drum, the first photoreceptor drum then transferring the toner to the sheet of support material to charge the second photoreceptor drum. Second
Of xerographic stations, the second photoreceptor drum is then exposed to the second modulated beam, and the second xerographic unit is exposed to a plurality of plurality of charge carriers based on the charge charge after the exposure of the second modulated beam. Means for adhering the color toners to the second photoreceptor drum, the second photoreceptor drum then transferring the toner to the sheet of support material, which causes the toner to transfer to the support material. Generate black, white and multiple color pixels on the sheet.

[0017]

DETAILED DESCRIPTION OF THE INVENTION A single pass, dual drum, full color printing system 200 is now shown in FIG.
Refer to. The full color printing system 200 includes a single raster output scanner (ROS) optical system 20.
2, a first xerographic station 204 having a first photoreceptor drum 206 and a second photoreceptor drum 2
Second xerographic station 20 having 10
It is generally composed of eight.

In a single raster output scanner 202, the light source 212 has two coherent laser beams 2
Emitting 14 and 216, these laser beams are collimated and conditioned by collimating optics 218. Two collimated beams 220 and 222
Are individually modulated by the dual channel modulator 224. The two modulated beams 226 and 228 are again collimated by the optical element 230, further adjusted, and focused on the facets 232 of the rotating multi-faceted polygon mirror 234. Reflected modulated beam 2
Reference numerals 36 and 238 denote f- [theta] imaging and distortion correction optical element 2.
Focused by 40. First beam 242
And the second beam 244 is coupled to the beam splitter 246.
Separated by. The beam splitter 246 can be separated by wavelength or polarization, the beams can be separate parallel paths, or a combination thereof. The first imaging beam 242 is then reflected by the folding mirror 248 onto the first photoreceptor drum 206 of the first xerographic station 204. The second imaging beam 244 is then reflected by the folding mirror 250 to the first photoreceptor drum 210 of the second xerographic station 208.

The first beam 242 is directed to the charging station 252 of the first four-level xerographic station 204 and the first, second and third developer stations 25.
First photoreceptor drum 20 between 4, 256 and 258
Focus is on 6. The second beam 244 is focused on the second photoreceptor drum 210 between the charging station 260 of the second three-level xerographic station 208 and the first and second developer stations 262,264.

The first photoreceptor drum 206 moves in the direction of arrow 266 to continue advancing successive portions of the drum through various processing stations located around the path of the photoreceptor drum. The drum is driven by rollers, a motor, and a belt driving device (not shown) to move forward.

First, the continuous portion of the photoreceptor drum 206 passes through the cleaning station 268. The cleaning station removes any residual toner particles and any residual charge from the photoreceptor drum.

The drum 206 advances and then the charging station 2 of the 4-level xerographic station 204.
Pass 52. The charging station selectively charges the drum to a high, uniform potential V ₀ .

The charged drum is then exposed to a first modulated light beam 242 from a raster output station (ROS) optical scanner 202, which discharges the charged surface of the drum according to the modulated output of beam 242. As mentioned earlier in this application, this results in four separate and different discharge and exposure levels.

The photoreceptor drum 206 then receives the first, second and third developer stations 254, 256 and 258 of the first four level xerographic station 204.
Pass through. The first developer housing 254 deposits the first toner on the portion of the photoreceptor drum 206 having the smallest exposure amount. The second developer housing 256 is
The second toner is attached to the portion of the photoreceptor drum 206 having the largest exposure amount. Third developer housing 258
Attaches the third toner to the portion of the photoreceptor drum 206 having the highest exposure amount and the portion of the photoreceptor drum 206 having the lowest intermediate exposure amount. As described above, the toner is not attached to the photoreceptor drum 206 having a high intermediate exposure amount. Therefore, the four-level xerographic station 204 has the first toner on the photoreceptor drum 206
The third toner, the combination of the second and third toners and the tonerless color image result.

Next, the first photoreceptor drum 206 advances to pass the transfer station 270. A sheet 272 of support material, such as paper, moves and contacts the toner on the first photoreceptor drum 206 at the first transfer station 270 and transfers the toner to the sheet 272.

After transfer, the sheet 272 moves in the direction of the arrow 274 and moves to the second xerographic station 20.
The sheet is advanced towards the second photoreceptor drum 210 of No. 8.

After the toner has been released from the first photoreceptor drum 206, the drum 206 then passes through the cleaning station 268, completing the print cycle of the first xerographic station 204. The cleaning station removes any residual toner particles and any residual charge from the photoreceptor belt.

After the toner has been transferred from the first xerographic station 204 to the sheet 272, but before the sheet advances to the second xerographic station, the sheet advances to pass through the erase section 278, Any residual charge on the top is removed. The erase section does not remove toner on the sheet and does not affect the toner.

After the transfer from the first photoreceptor drum 206,
The seat 272 continues to move in the direction of arrow 274 and the seat is advanced to the intermediate fusing station 280.
As mentioned above, the fusing station 280 is the first
Of the transferred toner image from the photoreceptor drum 206 of
Attached to sheet 272 either temporarily or permanently.

The second beam 244 is directed to the charging station 260 of the second three-level xerographic station 208 and the first and second developer stations 262,2.
The second photoreceptor drum 210 between 64 is focused.

The second photoreceptor drum 210 moves in the direction of arrow 276 to continue advancing successive portions of the drum through various processing stations located about the path of the photoreceptor drum. The drum is driven by rollers, a motor, and a belt driving device (not shown) to move forward.

First, the continuous portion of the photoreceptor drum 210 passes through the cleaning station 282. The cleaning station removes any residual toner particles and any residual charge from the photoreceptor drum.

The drum 210 is then charged to the charging station 2 of the second three-level xerographic station 210.
Pass 60. The charging station selectively charges the drum to a high, uniform potential V ₀ .

The charged drum is then exposed to a second modulated light beam 244 from a raster output station (ROS) optical scanner 202, which discharges the charged surface of the drum according to the modulated output of beam 244. As mentioned earlier in this application, this results in three separate and different discharge and exposure levels (zero exposure, intermediate exposure and full exposure).

The photoconductor drum 210 is then connected to the first and second of the second three-level xerographic station 208.
Of developer stations 262 and 264. As described above, the first developer housing 262 deposits the fourth toner on the portion of the photoreceptor drum 210 having zero exposure, and the second developer housing 264 is the photoreceptor drum 2.
A fifth toner is applied to the portion having a full exposure of 06. As previously mentioned, no toner is deposited on the photoreceptor belt with intermediate exposure.

Next, the second photoreceptor drum 210 advances to pass the second transfer station 284. The sheet 272 of support material, such as paper, moves and approaches the toner on the second photoreceptor drum 210 at the transfer station 284 and transfers the toner to the sheet 272.

Second xerographic station 20
The toner from the eight developer housing can be deposited on the toner on the sheet 272 from the first xerographic station 204 developer housing. The toner transferred to the sheet includes toner from both xerographic stations 204 and 208.

After the transfer from the second photoreceptor drum 210,
The seat 272 continues to move in the direction of arrow 274 and is advanced to the fusing station 286. As described above, fusing station 286 permanently attaches the transferred toner image to sheet 272.

The sheet 272 moves linearly along the direction 274. Avoid sharp folds in the paper.

After the toner has been released from the second photoreceptor drum 210, the drum 210 then passes through a cleaning station 282, completing the print cycle of the second xerographic station 208. The cleaning station removes any residual toner particles and any residual charge from the photoreceptor belt.

In a single-pass, dual-drum, full-color printing system 200, toner from the second xerographic station 208 can be deposited on top of previously deposited toner at the first xerographic station 204. And the toner dot pixels on the toner dots occur on the sheet of support material. However, two or three types of toner from the same xerographic station cannot deposit toner dots on the toner dots to produce pixels on the photoreceptor drum.

Second xerographic station 20
The toner from the two developer housings of No. 8 has the same spot (sheet 27 as the toner deposited on the three developer housings of the first xerographic station 204).
2)) can be attached. These combinations allow one color toner to be deposited on top of another color toner to form different color pixels on the sheet.

Both beams 242 and 244 originate from similar sources or a single monolithic multi-beam source,
Alignment is simplified because it reflects from the facets of the same polygon and passes through a common optical element. After static alignment of the beam, the beam tracks with high accuracy. What leaves the degree of freedom that requires alignment is alignment along the paper path. This alignment is accomplished by means commonly used in printers with four drums and four exposure stations. Generally, the drum drive motors can be phased and alignment marks are used on the photoreceptor drum. Prior art printer systems require eight critical alignments (4 beams x 2 axes), unlike the 1 critical alignment for the present invention.

A full-process full-color printing system uses four color toners (black and the three subtractive primary colors cyan, magenta and yellow) to produce black, white and six primary colors (red, green, blue, All pixels (cyan, magenta and yellow) can be generated. Additive primary colors (blue, red and green)
Pixel is generated by superimposing toner dots on toner dots of a combination of three primary color toners of the subtractive color method. Using the three primary colors of the subtractive method and black toner dots without combination with other toner dots, a full color palette can be formed by adjoining eight resulting pixels.

The use of black toner in one of the xerographic station developer stations presents a special situation that differs from the use of any primary color toner. Black attached and combined with any other color produces only black. Thus, any color toner subsequently deposited on black will still produce black, and black toner deposited on any color will also produce black. If one of the mixed colors contains black, then there are no possible color combinations.

One embodiment of the color printing system of the present invention relates to the use of black toner and tricolor toner in five developer stations of two xerographic stations.

The toner color must be a combination of black and the subtractive primary colors (cyan, yellow and magenta).

The general rule of toner selection for five developer stations in two xerographic stations is that a three-level xerographic station contains black and one of the three subtractive primary colors. Is. A 4-level xerographic station should have two remaining toners of the subtractive primaries and the third toner color is also one of the remaining two subtractive primary colors, which is Combine with the other of the two remaining modal primaries to form the additive primaries.

In a tandem configuration with a 3-level xerographic station, it is also not important that the 4-level xerographic station is the first. The color printing system of the present invention produces the same full color printing system, even though the three level xerographic station is the first in a tandem configuration with the four level xerographic station.

The hue of a color is a primary color. The color saturation ranges from the grayest to the brightest. The color intensity ranges from black to white through a series of lighter grays.

In either embodiment, the individual color spots produced by color printing system 200 are invisible to the human eye. A group of color pixels appear collectively and blurred to the human eye and identify the hue, saturation, and lightness that are identified as a color. In general, depending on the size of the individual spots, these pixels can be clustered into a matrix of 2x4 or 3x3 individual pixels.

The individual pixels in the matrix can be the same color or different colors. If the individual spots have the same color, the pixel has the strongest saturation in that color and the brightest lightness in that color. By providing different colors for the pixels of the matrix, the saturation and hue of the pixels change.

By placing pixels of two adjacent colors of the spectrum exclusively in the matrix, the resulting pixel matrix colors are the most saturated along the hue boundary between the two colors. By providing exclusively two non-adjacent spectrally colored pixels in the matrix, the resulting image matrix colors are of different hue and saturation. By providing a pixel of a matrix of three or more colors, the hue and saturation of the pixel matrix changes.

The brightness of the colors produced by the color printing system 200 is obtained by adding white or black pixels to the matrix. For example, pink or light red is printed by having a pixel matrix of 50% red and 50% white.

Another embodiment of the color printing system of the present invention relates to the use of no black toner on any of the five developer stations of the two xerographic units.

The toner color must be a combination of the subtractive primary colors (cyan, yellow and magenta).

A general rule of toner selection for five developer stations in two xerographic stations is that a three-level xerographic station contains toner of one of the three primary colors of the subtractive method. A 4-level xerographic station should have two remaining color toners of the subtractive primary color,
The toner color is also one of the remaining two subtractive primary colors
Which is combined with another of the remaining two subtractive primary colors to form an additive primary color. The additive primaries formed at the 4-level xerographic station form black when combined with the complementary subtractive primaries from the 3-level xerographic station. The modification of the color order of the particular toner in the developer housing of the two xerographic stations of this embodiment is the same as in the first embodiment.

A first two-level zero with a first photoreceptor drum is used because the fifth toner from the second developer housing of the three-level zero graphics station is not required for a non-black toner full color printing system. A graphics station, a second four level zero graphics station having a second photoreceptor drum in tandem therewith and a raster output scanner (ROS)
The optical system forms a single pass, dual drum, non-black toner, full color printing system. The various cleaning, charging, erasing, transfer and fusing stations of the non-black toner full color system are the same as the single pass full color printing system 200 of FIG. The first two-level xerographic station has a single developer housing to deposit monochrome toner onto a first photoreceptor drum, which transfers the toner to a sheet of support material such as paper. A second four-level xerographic station has three developer housings to deposit three different color toners onto a second photoreceptor drum, which transfers the toner to a sheet of support material.

The non-black toner full color printing system has the same toner color pattern as the non-black toner full color printing system using the 4-level xerographic station and the 3-level xerographic station. A single developer housing of a 2-level xerographic station can have yellow toner, and three developer housings of a 4-level xerographic station can have cyan, cyan and magenta toners, respectively.

4 of 2 xerographic stations
The general rule in selecting toner for one developer station is that a two-level xerographic station contains toner for one of the three subtractive primary colors. A 4-level xerographic station should have two remaining toners of the subtractive primaries and the third toner color is also one of the remaining two subtractive primary colors, which is Another of the remaining two primary colors of the law
In combination with one another to form the additive primary colors.

The additive primaries formed at the 4-level xerographic station form black when combined with the subtractive primaries from the 3-level xerographic station.

It is also not important that the 2-level xerographic station is first in tandem with the 4-level xerographic station. The color printing system of the present invention produces the same full color printing system, even though the four level xerographic station is the first in tandem with the two level xerographic station.

The single pass color printing system also
Generally from a Raster Output Scanner (ROS) optical system, a first four level xerographic station having a first photoreceptor drum and a second four level xerographic station having a second photoreceptor drum tandem therewith. Composed.

In general, for all embodiments of color printing systems, white toner may be used in the developer housing of the xerographic unit if the sheet of support material is not white.

If the first and second modulated beams have the same wavelength, the color printing system has simpler modulators and optics that do not need to be calibrated for the two wavelengths and the optical paths of the two beams. Have easier calculations. It is not impossible to have different lengths in the same optical path, but the optical paths of the two beams should be of the same length. The dual channel converter can compensate for any optical path length difference.

The use of a dual beam source with two emitted beams sharing the same optics in a raster output station optical system improves the accuracy of pixel placement on the photoreceptor belt because common polygon facets are used. . The use of 4-level and 3-level xerographic stations also facilitates the accuracy of pixel placement on the photoreceptor drum. Sharing optics also reduces the physical size, number of optics, and cost of a single pass full color printing system.

However, the sharing of optical elements by dual beams is merely an example of a color printing system. Two separate light sources can each emit a beam. Each beam may have a separate ROS optics system, or may only share some ROS optics, such as the facets of a rotating polygon mirror.

In other embodiments, the photoreceptor drum of the present invention can be a belt photoreceptor or other equivalent. In another embodiment, the rotating polygon raster output scanner (ROS) optical system 202 is an LED.
It can be an imaging bar or other equivalent.

The light source 212, collimating optics 218 and dual channel converter 224 can be replaced by electronically modulated diode lasers.

Toners need not be color in the visible spectrum. Ultraviolet toner, infrared toner or magnetic ink toner can be used in the color printing system of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a full-color printing system using a single Raster Output Scanner (ROS) optical system and a two-tandem photoreceptor drum xerographic station formed in accordance with the present invention.

[Explanation of symbols]

200 Single Pass, Dual Drum Full Color Printing System 202 Raster Output Scanner (ROS) Optical System 204 First Xerographic Station 206 First Photoreceptor Drum 208 Second Xerographic Station 210 Second Photoreceptor Drum 226, 228 Modulated Beam 272 Support Material Sheet

Claims (3)

[Claims] 1. A single pass, dual drum, full color printing system comprising a single raster output scanner optics system for producing a first modulated beam and a second modulated beam, comprising a sheet of support material. , A first xerographic station for charging a first photoreceptor drum, said first photoreceptor drum being then exposed to said first modulated beam, said first modulated beam being exposed after said first modulated beam. One xerographic unit has means for adhering a plurality of color toners to said first photoreceptor drum on the basis of electrostatic charge, said first photoreceptor drum then depositing said toner onto said sheet of support material. A second xerographic station for transferring and charging a second photoreceptor drum, said second photoreceptor drum then producing said second modulated beam. The second xerographic unit is provided with means for adhering a plurality of color toners to the second photoconductor drum on the basis of charging charges after the exposure of the second modulated beam. A body drum then transfers the toner to the sheet of support material,
A single pass, dual drum, full color printing system whereby the color toners produce black, white and all six primary color pixels on the sheet of support material. 2. One of the first and second xerographic stations is a 4-level xerographic station and the other of the first and second xerographic stations is a three-level xerographic station. A single-pass, dual-drum, full-color printing system according to claim 1. 3. A single pass, dual drum, full color printing system including a single raster output scanner optics system for producing a first modulated beam and a second modulated beam, including a sheet of support material. , A first xerographic station for charging a first photoreceptor drum, said first photoreceptor drum being then exposed to said first modulated beam, said first modulated beam being exposed after said first modulated beam. One xerographic unit has means for adhering a plurality of color toners to said first photoreceptor drum on the basis of electrostatic charge, said first photoreceptor drum then depositing said toner onto said sheet of support material. A second xerographic station for transferring and charging a second photoreceptor drum, said second photoreceptor drum then producing said second modulated beam. The second xerographic unit is provided with means for adhering a plurality of color toners to the second photoconductor drum on the basis of charging charges after the exposure of the second modulated beam. A body drum then transfers the toner to the sheet of support material,
This causes the toner to be black on the sheet of support material,
Single-pass, dual-drum, full-color printing system that produces white and multiple color pixels.