JPH10142929A - Developing roller and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device by which the color mixing of toner is prevented. SOLUTION: As to this orthogonal transfer system image forming device by which a toner image is transferred to a printing paper in a direction orthogonal to the carrying direction of the printing paper; a step part 26 is provided on a gap 22 for separating the adjacent toner layers 12 of the developing roller 21 of a developing means so that part 26 is thinner than the outside diameter of the part where the toner layer 12 is formed; therefore, the toner mixing from the adjacent toner layers 12 can not cross over the part 26, so that the color mixing of the toner on the roller 21 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roller capable of preventing color mixture of toner and an image forming apparatus of an orthogonal transfer type using the developing roller as a developing means.

[0002]

2. Description of the Related Art In recent years, toner-type image forming apparatuses capable of forming clear images with excellent resolution, such as laser printers, have become widespread. Among such toner-type image forming apparatuses, Japanese Patent Application No. 7-328600.
As described above, the orthogonal transfer type image forming apparatus that moves the toner image carrier in a direction orthogonal to the transport direction of the printing paper and transfers the toner image in small steps at a time is a small-sized product due to its configuration. It is very suitable for promoting the conversion.

[0003] A conventional image forming apparatus which is compatible with color by the orthogonal transfer system will be described below.

FIG. 9 is a schematic structural view of a conventional image forming apparatus, FIG. 10 is a perspective view showing a transfer process of the conventional image forming apparatus, and FIG. 11 is a toner layer of a developing roller of the conventional image forming apparatus. It is a schematic diagram which shows the state of formation.

In FIG. 9 and FIG. 10, a toner image carrier 1 composed of a photoreceptor belt whose surface is coated with a layer of an organic photoconductive material comprises a plurality of support rollers 2, displacement rollers 3, transfer opposing rollers 4, and the like. These rollers are stretched in the direction perpendicular to the direction in which the printing paper 5 is conveyed by the rollers, and rotate in the direction of an arrow during image formation, whereby a toner image is formed on the surface of the toner image carrier 1. Around the toner image carrier 1, charging means 6, developing means 7, cleaning means 8, static elimination means 9 and the like are arranged, and an upper portion of the toner image carrier 1 is exposed to laser light. Means 10 are arranged. As shown by the arrow in FIG.
Rotates in the direction perpendicular to the transport direction of the printing paper 5,
The portion passing through the charging means 6 is uniformly charged to about -600V. Exposure means 10 includes cyan, magenta, yellow,
Based on the image signals of the four primary colors of black, the surface of the toner image carrier 1 is irradiated on one line with laser light corresponding to the four primary colors. The potential of the portion irradiated with the laser beam is -1
By increasing the voltage to about 00 V, electrostatic latent images divided into four for each primary color are simultaneously formed on the surface of the toner image carrier 1. When the four primary colors of toner are pressed against the portion where the electrostatic latent image is formed by the developing roller 11, the toner image carrier 1
The toner images of each of the four primary colors that have become visible images appear one after another.

As shown in FIGS. 9 and 10, the developing means 7 comprises four parts for each primary color.
Is cyan, the developing means 7M is magenta, the developing means 7Y is yellow, and the developing means 7B is black.
Four primary color toner layers of yellow and black are formed on a common developing roller 11 so as to be divided into four for each primary color. FIG.
As shown in FIG. 1, a toner layer 12 of four colors of cyan, magenta, yellow, and black is formed on a developing roller 11 from the left, and each toner layer 12 is separated by a gap 13 or a gap 14 to prevent color mixing. This gap 1
The portions 3 and 14 are sealed by the sealing materials 15 and 16, so that the toner does not normally adhere thereto.

As shown in FIG. 10, the orthogonal transfer type image forming apparatus is characterized in that the rotation of the toner image carrier 1 and the conveyance of the printing paper 5 are temporarily stopped during the transfer, and the printing is stopped. The toner image carrier 1 is transferred onto the sheet 5 by the transfer opposing roller 4.
Is displaced by being rubbed with the movement of the object. At this time, the displacement roller 3 is displaced following the movement of the transfer facing roller 4 in order to eliminate the slack of the toner image carrier 1.

Whenever the transfer for one process is completed, the transfer opposing roller 4 passes over the printing paper 5 and moves out of the area of the printing paper 5, so that the toner image carrier 1 is separated from the printing paper 5. . Then, the conveyance of the printing paper 5 is started, but the conveyance distance of the printing paper 5 is only the width of the toner layer 12 of each color shown in FIG. The printing paper 5 is the toner layer 1
The printing paper 5 on which the image has been transferred is intermittently sent to the fixing unit 17 by two widths.
And a heating roller 19 having a heat source therein to melt the toner particles and fix the toner particles on the printing paper 5.

[0009]

However, in the conventional image forming apparatus as described above, as shown in FIG.
The outer diameter of the developing roller 11 is the same over the entire length. For this reason, even if the gap 13 is formed by sealing the gap between the adjacent toner layers 12 of the developing roller 11 with the sealant 15, the sealing is not performed over the entire circumference of the developing roller 11. Gap 1
3 has been moved to reach the adjacent toner layer 12, and there has been a problem that color mixing of toner occurs.

An object of the present invention is to solve the above problems and to provide a developing roller in which color mixing of toner is prevented and an image forming apparatus in which color mixing of toner is prevented.

[0011]

SUMMARY OF THE INVENTION In order to solve this problem, a developing roller of the present invention is a developing roller for holding toner layers of a plurality of colors at different positions in an axial direction, and between adjacent toner layers. A step portion smaller than the outer diameter of the portion where the toner layer is held is provided so that the toner escaping from the adjacent toner layer does not cross the step portion.

According to the present invention, it is possible to provide a developing roller in which color mixture of toner is prevented.

Further, the image forming apparatus of the present invention transports a toner image carried on a toner image carrier stretched in a direction orthogonal to the transport direction of the printing paper by a plurality of rollers, and transports the printing paper by a transfer opposing roller. An image forming apparatus of an orthogonal transfer system for transferring a toner image transferred to a printing paper in a direction perpendicular to the direction and fixing the toner image transferred to the printing paper, wherein the developing roller of the present invention is used as a developing unit for developing a toner image carrier. This is the configuration used.

According to the present invention, it is possible to provide an image forming apparatus in which color mixture of toner is prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a developing roller for holding a plurality of color toner layers at different positions in the axial direction, wherein the toner layers are held between adjacent toner layers. The stepped portion is formed to have a step smaller than the outer diameter of the portion to be formed, and the toner mixed in from the adjacent toner layer cannot cross the step, so that the toner can be prevented from being mixed at the stage of the developing roller. .

According to a second aspect of the present invention, there is provided an image forming apparatus, wherein a toner image carried on a toner image carrier stretched by a plurality of rollers in a direction perpendicular to a conveying direction of the printing paper is transferred by a transfer opposing roller to the printing paper. 2. An image forming apparatus of an orthogonal transfer system for transferring a toner image transferred to a printing paper in a direction orthogonal to a conveying direction of the toner and fixing the toner image transferred to the printing paper, wherein a developing unit for developing the toner image carrier is provided. The developing roller described above is used, and the toner escaping from the adjacent toner layer cannot cross the step, so that it is possible to prevent color mixing of the toner at the stage of the developing roller and to develop the toner on the toner image carrier. In the stage, in the non-development area of the toner image carrier, the toner image carrier and the developing roller hardly come into contact with each other due to the presence of the stepped portion of the developing roller. It has the effect of being able to stop.

According to a third aspect of the present invention, in the second aspect of the present invention, the toner image carrier is a photoconductor, and an exposure means for exposing the toner image carrier based on an image signal is provided. In this configuration, the toner that has entered from the adjacent toner layer cannot cross the step, so that it is possible to prevent the toner from mixing at the stage of the developing roller, and at the stage of developing the toner image on the toner image carrier. In the non-developing area, the toner image carrier and the developing roller hardly come into contact with each other due to the presence of the stepped portion of the developing roller.

(Embodiment 1) An outline of one embodiment of the present invention is that, in a developing roller in which a plurality of color toner layers are formed on the same roller, the toner is formed in a gap portion for separating adjacent toner layers. If a step portion is provided so as to be thinner than the outer diameter of the portion where the layer is formed, and if the toner escaping from the adjacent toner layer is prevented from crossing the step portion, color mixing of the toner can be prevented. An orthogonal transfer type image forming apparatus using a simple developing roller can prevent color mixing of toner. Hereinafter, an embodiment of the present invention, which is a color-compatible image forming apparatus, will be described in detail with reference to FIG. 1 to FIG.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a transfer process of the image forming apparatus according to an embodiment of the present invention.
FIG. 3 is a schematic diagram illustrating a state of forming a toner layer of a developing roller of the image forming apparatus according to the embodiment of the present invention. 4 to 7 are schematic views showing a state of transfer of the image forming apparatus according to one embodiment of the present invention, and FIG. 8 is a schematic view of a fixing unit of the image forming apparatus according to one embodiment of the present invention. is there.

1 and 2, a toner image carrier 1 composed of a photoreceptor belt whose surface is coated with a layer of an organic photoconductive material comprises a plurality of support rollers 2, displacement rollers 3, transfer opposing rollers 4, and the like. These rollers are stretched in the direction perpendicular to the transport direction of the printing paper 5 by the rollers, and rotate in the direction of the arrow at the time of image formation to form toner images of four primary colors on the surface of the toner image carrier 1. Around the toner image carrier 1, charging means 6, developing means 20, cleaning means 8, static elimination means 9 and the like are arranged.
Exposure means 10 for irradiating a laser beam is arranged on the upper part of. As shown by an arrow in FIG. 1, when the toner image carrier 1 rotates in a direction perpendicular to the conveying direction of the printing paper 5, the portion passing through the charging means 6 is uniformly charged to about -600V. Exposure means 10 irradiates the surface of toner image carrier 1 with laser light corresponding to the four primary colors on the surface of toner image carrier 1 based on the image signals of the four primary colors of cyan, magenta, yellow, and black. When the potential of the portion irradiated with the laser beam rises to about -100 V, an electrostatic latent image divided into four for each primary color is simultaneously formed on the surface of the toner image carrier 10. When four primary color toners are pressed against the portion where the electrostatic latent image is formed by the developing roller 21, visible toner images of the four primary colors appear one after another on the toner image carrier 1.

When expanded, as shown in FIG.
The development of the four primary colors is performed simultaneously by the four primary color toner layers 12 formed on the common developing roller 21 so as to be divided into four for each primary color. At the time of development, the developing means 20 causes the developing roller 21 to which the negatively charged toners of the four primary colors adhere to the toner image carrier 1 in order to make the respective electrostatic latent images corresponding to the four primary colors visible. To transfer the toners of the four primary colors to the portions of the electrostatic latent image divided into the four primary colors on the surface of the toner image carrier 1 so that the toner images of the four primary colors of cyan, magenta, yellow, and black are It is formed in a state divided into.

As shown in FIGS. 1 and 2, the developing means 20 is composed of four parts for each primary color.
C is cyan, developing means 20M is magenta, developing means 20
Y is yellow and the developing means 20B is black.
Magenta, yellow and black toner layers
The four primary colors are formed on a common developing roller 21 in a divided manner.

As shown in FIG. 3, toner layers 12 of four colors, cyan, magenta, yellow, and black, are formed on the developing roller 21 from the left. Although the gap 22 or the gap 23 is provided, the gap is sealed by the seal materials 24 and 25 so that the toner does not normally adhere thereto. However, even if the gap 22 is formed by sealing the gap between the adjacent toner layers 12 of the developing roller 21 with the sealant 24, the sealing is not performed over the entire circumference of the developing roller 21. It is possible that the toner that has entered reaches the gap 22.

Even in such a case, the developing roller 21 used in the embodiment of the present invention has the surrounding toner layer 1
The gap 22 is made smaller than the outer diameter of the portion where
Is provided with the stepped portion 26, the toner which has entered from the adjacent toner layer 12 does not cross the stepped portion 26, and no color mixing of the toner occurs.

At the stage of development, the gaps 22 and 23 provided on the developing roller 21 cause non-developing areas where toner does not adhere on the toner image carrier 1 to form streaks corresponding to the gaps 22 and 23. Become. In the non-development area corresponding to the gap 22, the gap 22
, The toner image carrier 1 and the developing roller 21 hardly contact each other. For this reason, the image forming apparatus according to the embodiment of the present invention can prevent color mixing of toner at the stage of the developing roller 21 unlike the conventional example, and at the stage of development, unnecessary toner to the toner image carrier 1. Adhesion and fogging can be prevented.

The relationship between the width of the gap 22 of the developing roller 21 and the width of the step 26 may be such that the width of the step 26 can be increased to the entire width of the gap 22.
Developing roller 2 in the non-developing area corresponding to
Since the toner image carrier 1 does not come into contact with the toner image carrier 1 at all, unnecessary adhesion of toner and fogging can be more completely prevented.

The ratio of the width of the toner layer 12 for one color to the width of the gap 22 in the developing roller 21 is {1: 1}, {2:
1}, {3: 1}, etc. are conceivable, but it is ideal for the sake of simplicity of explanation, but it is assumed that the toner layers of the four primary colors are formed without gaps. Let's talk about. When the printing paper 5 is transported, the transport distance requires the width of the toner layer 12 for one color.

At the time of transfer to the printing paper 5, as shown in FIG.
7 (see FIG. 1), the printing paper 5 is stopped, and the rotation of the toner image carrier 1 is also stopped. Then, the portion of the toner image carrier 1 where the four primary color toner images are formed is rubbed against the printing paper 5 by rolling the transfer opposing roller 4 from the back side to transfer the four primary color toner images. Is displaced in the opposite direction from the left end or the right end by one step.
At this time, the transfer end surface Z of the toner image carrier 1 on which the transfer of the toner images of the four primary colors has been completed is sequentially separated from the printing paper 5 as the transfer opposing roller 4 passes. During the transfer step, a positive voltage is applied to the transfer plate 27 on which the printing paper 5 is placed, and the negatively charged four primary color toner images are attracted from the surface of the toner image carrier 1 to be separated and transferred to the printing paper 5. . In addition,
The transfer by the toner image carrier 1 can be performed not only on the outward path but also on the return path as described above. At this time, when the moving direction of the toner image carrier 1 is viewed from the printing paper 5 side, the toner image carrier 1 is displaced on the printing paper 5 in a direction orthogonal to the transport direction of the printing paper 5.

Whenever the transfer for one process is completed, the transfer opposing roller 4 moves over the printing paper 5 and moves out of the area of the printing paper 5, so that the toner image carrier 1 is separated from the printing paper 5. . Then, the conveyance of the printing paper 5 is started, but the conveyance distance of the printing paper 5 is only the width of the toner layer 12 for one color as described above.

The method of forming a color toner image starts from the state shown in FIG. 4, but only transfers a {black} toner image in one step. Next, as shown in FIG. 5, the {Black, Yellow} toner image is transferred in one step, and the {Black, Yellow} toner image is superimposed on the first column.
Similarly, as shown in FIG. 6, the toner image of {black, yellow, magenta} is transferred in one step, and the toner image of {black, yellow, magenta} is in the first column, and {black, yellow} is in the second column. The toner image of｝ is superimposed. Thereafter, as shown in FIG. 7, black, yellow,
The magenta and cyan toner images are transferred, and the first column forms a color toner image by the black, yellow, magenta and cyan toner images, and the second column forms the black and yellow toner images.
The yellow and magenta toner images are superimposed, and the {black and yellow} toner images are superimposed on the third row. At the end of the transfer, the toner image of {Black, Yellow, Magenta, Cyan} was transferred in one process, but the black was lost {Yellow, Magenta, Cyan}.
, And furthermore, yellow is also missing, resulting in {magenta, cyan}, and finally, only {cyan}.

As shown in FIG. 1, the cleaning means 5
Removes the residual toner on the surface of the toner image carrier 1 with a cleaning blade or a cleaning brush, collects the waste toner, and physically cleans the surface of the toner image carrier 1. Then, the charge removing unit 9 neutralizes the negative charge remaining on the surface of the toner image carrier 1 after removing the residual toner, and electrically cleans the surface of the toner image carrier 1. Note that the installation of the charge removing means 9 is not an essential requirement.

After repeating the above steps, the printing paper 5 is gradually fed to the fixing means 17 as shown in FIG.
The fixing means 17 sandwiches the printing paper 5 on which the image has been transferred between the pressing roller 18 and the heating roller 19 having a heat source therein, melts the toner particles, and fixes the toner particles on the printing paper 5. After all the images have been transferred to the printing paper 5,
Since the printing paper 5 is carried out without stopping, the heat source of the heating roller 19 may be kept on. However, printing paper 5
When the image is being transferred to the printing paper 5, the printing paper 5 is in a stopped state, so it is necessary to temporarily turn off the heat source of the heating roller 19 or to move the heating roller 19 away from the printing paper 5. As shown in FIG. 8, a fixing unit 28 composed of a heat source 29 and a reflecting plate 30 is employed, and a reflecting plate 31 is provided below the fixing unit 28 to improve thermal efficiency. There is also a method of fixing without contacting the toner. Thus, a series of image forming steps is completed.

Finally, to briefly describe what is related to the second aspect of the present invention, the toner image carrier does not always need to use a photosensitive member, and sometimes does not require an exposure unit. That is, a toner image can be formed by forming an electrostatic latent image with a heat source and developing it.
This is because the toner image carrier, which has been solid-coated with the toner, can be blown off with an air jet to form a toner image as if engraving a print.

[0034]

As described above, the developing roller of the present invention is a developing roller for holding the toner layers of a plurality of colors at different positions in the axial direction, and the portion where the toner layer is held between adjacent toner layers. Is formed so as to prevent the toner escaping from the adjacent toner layer from crossing the step.

As a result, it is possible to prevent color mixing of toner at the stage of the developing roller, so that a clear image can be formed.

In the image forming apparatus of the present invention, the toner image carried on the toner image carrier stretched in a direction perpendicular to the transport direction of the printing paper by a plurality of rollers is transported by the transfer opposing roller to transport the printing paper. An image forming apparatus of an orthogonal transfer system for transferring a toner image transferred to a printing paper in a direction perpendicular to the direction and fixing the toner image transferred to the printing paper, wherein the developing roller of the present invention is used as a developing unit for developing a toner image carrier. This is the configuration used.

As a result, toner mixed in from the adjacent toner layer cannot cross the step, so that it is possible to prevent color mixing of the toner at the stage of the developing roller, and at the stage of development on the toner image carrier, In the non-developing region, the toner image carrier and the developing roller hardly contact each other due to the presence of the stepped portion of the developing roller, so that unnecessary toner adhesion and fogging can be prevented. An image forming apparatus to be formed can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a transfer process of the image forming apparatus according to the embodiment of the present invention;

FIG. 3 is a schematic diagram showing a state of forming a toner layer of a developing roller of the image forming apparatus according to the embodiment of the present invention;

FIG. 4 is a schematic diagram showing a transfer state of the image forming apparatus according to the embodiment of the present invention;

FIG. 5 is a schematic diagram showing a transfer state of the image forming apparatus according to the embodiment of the present invention;

FIG. 6 is a schematic diagram showing a transfer state of the image forming apparatus according to the embodiment of the present invention;

FIG. 7 is a schematic diagram showing a transfer state of the image forming apparatus according to the embodiment of the present invention;

FIG. 8 is a schematic diagram of a fixing unit of the image forming apparatus according to the embodiment of the present invention;

FIG. 9 is a schematic configuration diagram of a conventional image forming apparatus.

FIG. 10 is a perspective view showing a transfer process of a conventional image forming apparatus.

FIG. 11 is a schematic view showing a state of forming a toner layer of a developing roller of a conventional image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 toner image carrier 2 support roller 3 displacement roller 4 transfer opposing roller 5 printing paper 6 charging means 7 developing means 7C developing means 7M developing means 7Y developing means 7B developing means 8 cleaning means 9 discharging means 10 exposure means 11 developing roller 12 toner Layer 13 Gap 14 Gap 15 Seal material 16 Seal material 17 Fixing means 18 Pressure roller 19 Heating roller 20 Developing means 20C Developing means 20M Developing means 20Y Developing means 20B Developing means 21 Developing roller 22 Gap 23 Gap 24 Sealing material 25 Sealing material 26 Step 27 Transfer plate 28 Fixing means 29 Heat source 30 Reflector 31 Reflector

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shinichi Kizu 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Takashi Migita 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazuo Hakugawa 1006 Odaka Kazuma Kadoma City, Osaka Pref. 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A developing roller for holding toner layers of a plurality of colors at different positions in an axial direction, wherein a step portion smaller than the outer diameter of a portion where the toner layer is held is provided between adjacent toner layers. A developing roller. 2. A method according to claim 1, wherein the toner image carried on the toner image carrier stretched by a plurality of rollers in a direction perpendicular to the transport direction of the printing paper is transferred by a transfer opposing roller in a direction perpendicular to the transport direction of the printing paper. And an image forming apparatus of an orthogonal transfer type for fixing the toner image transferred to the print paper, wherein the developing roller according to claim 1 is used as a developing unit for developing the toner image carrier. Image forming apparatus. 3. The image forming apparatus according to claim 2, wherein the toner image carrier is a photoconductor, and an exposing unit that exposes the toner image carrier based on an image signal is provided.