JPH10171202A - Two-color both-face printing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the melting phenomenon of solid ink at the time of fixing toner in a laser beam printer by fixing only a toner image, without disturbing a solid ink image, in a two-color both-face printing system for attaining printing with the second color by a solid-ink-jet printer, after printing with the laser beam printer. SOLUTION: In the two-color both-face printing system having a printing surface where the toner formed by an electrophotographic process and the solid ink 7 coexist, for fixing the toner image, flash fixing in a state where the density of power supplied to a lamp in light emission at a time is in the range of 1.0J/cm<2> -2.5J/cm<2> is used. Further, a cooling member which is made of a material whose thermal conductivity is >=10W/(m.k) as necessary and further, whose surface is kept <=30 deg.C as necessary is provided on the rear surface of a sheet of paper at a flash fixing position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a laser beam printer and a solid ink jet printer.
The present invention relates to a color duplex printing system.

[0002]

2. Description of the Related Art As a method for realizing a two-color two-sided printing system, a two-color two-sided printing system has been proposed in which printing is performed by a laser beam printer and then a second color is printed by an inexpensive inkjet printer.

In a typical example, a laser beam printer and an ink jet printer are arranged in this order along a paper path, and a paper reversing device is provided for performing double-sided printing. The same paper path as when printing the front side is used. In this method, the same printing system is used for printing the front side and the back side, so that the volume occupied by the apparatus can be reduced as compared with other methods, and the cost can be reduced. However, there was a problem that the fixing method was difficult.

[0004]

That is, the problem with the above-mentioned conventional method is that the solid ink melts when the toner of the laser beam printer is fixed in the following manner.

More specifically, in the case of single-sided printing, it is easy to dispose the ink jet printer after the fixing portion of the laser beam printer so that the solid ink is not affected by the toner fixing. .

However, in double-sided printing, when printing on the back side of a sheet, it is necessary to perform laser beam recording while fixing a solid ink image on the back side of the sheet and perform fixing.

In heat roller fixing, which is a general method of fixing toner, solid ink is melted at the same time as toner is fixed, and in the worst case, solid ink adheres not only to paper but also to the fixing roller and the entire fixing area. There was a problem of contamination.

Therefore, a method of selectively fixing only toner when performing double-sided printing is indispensable for realizing a two-color double-sided printing system.

[0009]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems of the prior art. According to the present invention, toner and solid ink formed by an electrophotographic process are used. In a two-color double-sided printing system having a mixed printing surface, flash fixing that can perform non-contact fixing is used for fixing a toner image. In the flash fixing, the power density applied to the lamp in one light emission is about 1.9 J / cm ² (joule / square centimeter), more preferably 1.0 J / cm ² to 2.
Flash fixing in the range of 5 J / cm ² is used, and if necessary, a material having a thermal conductivity of 10 W / (m · K) or more, and if necessary, a surface temperature of 30 ° C. or less. The cooling member is provided on the back surface of the sheet at the flash fixing position.

According to the above fixing method, only the toner image is fixed for the following reason, and a good fixing effect which does not affect the solid ink image can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a conceptual diagram showing the configuration of a printing system of a two-color duplex printing system.

1 is a photoreceptor, 2 is a charger, and 3 is a developing machine.

Reference numerals 4 (4a to 4e) denote paper paths, and the paths (including 4a and 4b) indicated by solid lines are used when printing the front side of the first paper and printing the back side of the second paper. The path through which the sheet passes, and the dotted lines (including 4c and 4d) are the paths through which the sheet passes for the second time through the sheet reversing device and printing on the back side of the sheet. 4 indicated by a dashed line
e is a paper path at the time of discharging the printing paper.

Reference numeral 5 denotes a transfer unit, 6 denotes a flash lamp fixing unit, and 7 denotes a solid ink head.

Reference numeral 8 denotes a sheet reversing device, which is a sheet path control mechanism for printing on the back side of the sheet.

Reference numeral 9 denotes a cooling belt made of a cooling member provided as needed.

FIG. 2 is a cross-sectional view schematically showing the state of toner and solid ink printed on paper.

10 is paper, 11 is powder toner before fixing,
12 is a toner after fixing, 13 is a solid ink head 7
This is an ink image ejected from the image.

Reference numerals 14 and 15 denote powder toner and ink particles before fixing, which adhere to the back surface of the paper 10, respectively.

Reference numeral 16 denotes a solid ink which has been heated more than necessary and melted to the surroundings after being recorded on the sheet 10.

Reference numeral 17 denotes a partially fixed powder toner image.

Next, an outline of the operation will be described.

The photoreceptor 1 is charged by a charger 2 and is exposed by an optical system (not shown) to form an electronic latent image on the surface, and is converted by a developing device 3 into a powder toner image.

The powder toner image is transferred by the transfer unit 5 onto the sheet 10 sent via the sheet path 4a.

When this process has been completed, 2 in FIG.
A cross section of the sheet as shown in FIG.

The paper 10 having the powder toner image 11 is fixed by the flash lamp fixing device 6, and the powder toner image 11 is melted and fixed on the paper 10 to obtain a fixed toner image 12 (2b). .

The paper 10 passes through the solid ink head 7 via the paper path 4b, where printing is performed with the solid ink image 13 of the second color (2c).

The sheet 10 is conveyed by the sheet reversing device 8 so that the sheet is conveyed in the direction of the sheet path 4c, moves in the direction of the sheet path 4d, and again moves in the direction of the sheet path 4a. At this time, it is necessary to note that the front and back sides of the sheet 10 are reversed when the sheet 10 passes the first time. Thereafter, the toner image 14 and the ink image 15 are formed on the back surface of the sheet 10 as in the first process (2e).

Here, when the intensity of the flash lamp fixing device 6 is appropriate, a complete fixed image as shown at 2f can be obtained. That is, the ink image formed on the back surface of the paper 10 is not affected at all.

If the intensity of the flash lamp fixing device 6 is too high, the heat reaches the back surface of the paper 10 and also melts the solid ink image (2 g). Reference numeral 16 denotes a fused ink image. In this case, not only is the image formed by the solid ink disturbed, but also the fused ink adheres to the parts at the fixing portion, the paper transport roller, and the like.
Thereafter, inconveniences such as contamination of the paper passing therethrough and adversely affecting the paper transport system occur.

On the other hand, if the intensity of the flash lamp fixing device 6 is too low, the toner image cannot be sufficiently fixed (2h). Reference numeral 17 denotes a powder toner image partially fixed, but a part of the toner image remains powdered and adheres to the paper, so that the toner image is scattered in the printer or the toner image is disturbed when touched by hand. This causes inconvenience of soiling the hands and surroundings.

As a result of the experiment, the intensity of the flash lamp which can be fixed in an appropriate state as described above is when the power density applied to the lamp in one light emission is about 1.9 J / cm ² (joule / square centimeter). Was appropriate.

If the thickness of the paper is different, the heat conduction changes, so that the conditions suitable for fixing differ. In particular, the ink image on the back side of the fused toner image is easily affected because the toner has good thermal conductivity and is easily heated. As a result of the experiment, 4
In the sheet thickness in the range from 0 kg / m ² of 150 kg / m ^2, it was found to be in the range of 1.0 J / cm ² of 2.5 J / cm ^2.

It has been found that the cooling belt 9 shown in FIG. 1 is effective for ensuring the fixing function. Cooling belt material has thermal conductivity of 10W
It has been found that a cooling member such as a metal of not less than / (m · K) is preferable, and the surface of the cooling belt is preferably maintained at 30 ° C. or lower.

[0036]

As described above, the present invention uses a flash lamp for fixing and limits the input power of the flash lamp for fixing, so that two colors which do not affect the solid ink image even at the time of fixing the toner. A duplex printing system can be provided.

Further, by providing a cooling belt on the opposite side of the fixing portion, it is possible to perform reliable fixing without affecting the solid ink image, and at the same time, it is possible to fix both colors of printing paper of a wide thickness. A printing system can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a two-color duplex printing system.

FIG. 2 is a cross-sectional view schematically illustrating a state of toner and solid ink printed on a sheet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoreceptor, 2 ... Charger, 3 ... Developing machine, 4 (4a-4)
e) paper path, 5 transfer device, 6 flash lamp fixing device, 7 solid ink head, 8 paper reversing device,
9: cooling belt, 10: paper, 11: powder toner image before fixing, 12: toner image after fixing, 13: ink image ejected from solid ink head 7, 14: before fixing attached to the back surface of paper 10 15: Ink particles before fixation adhered to the back surface of the paper 10, 16: Solid ink which was recorded on the paper 10 and then heated more than necessary and melted to the surroundings, 17 ... Powder toner image partially fixed.

Claims (5)

[Claims] 1. A two-color two-sided printing system using a laser beam printer and a solid ink-jet printer, wherein a toner image and an ink image are formed on a first surface of a printing paper, and a flash for fixing the toner image is provided. A fixing step, a sheet reversing step of controlling a path of the printing sheet to form the toner image and the ink image on the second side of the printing sheet, and the toner image and the ink on the second side of the printing sheet. A two-color double-sided printing system, comprising a step of forming an image. 2. The method according to claim 1, wherein the light emission amount of the flash fixing means is 1.0 or less.
Two-color duplex printing system of claim 1, wherein the from J / cm ² in the range of input power density to 2.5 J / cm ² of the flash lamp. 3. The two-color double-sided printing system according to claim 1, wherein a cooling member is provided on a side opposite to the printing paper of the flash fixing unit. 4. The two-color duplex printing system according to claim 3, wherein the cooling member is made of a material having a thermal conductivity of 10 W / (m · K) or more. 5. The two-color duplex printing system according to claim 3, wherein the surface temperature of the cooling member is maintained at 30 ° C. or lower.