JP2000238926A - Image forming device - Google Patents

Abstract

(57) [Summary] To prevent meandering of a sheet conveying belt of an image forming apparatus at low cost. SOLUTION: A sheet conveying belt meandering restricting member 10d is provided on one end side of the back surface over the entire circumference, and the peripheral length 10a on the side where the sheet conveying belt meandering restricting member 10d is provided is a sheet conveying belt meandering restricting member. An endless belt-shaped paper transport belt 10 provided with a peripheral length difference longer than the peripheral length 10b on the side where 10d is not provided, and a paper transport belt meandering restricting member 10d when the paper transport belt 10 rotates circumferentially. The image forming apparatus is provided with a plurality of paper transport belt support rollers 11 that are provided with a fitting step 11a that fits the paper transport belt 10 in an uneven manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using a belt for conveying a sheet.

[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, an image forming apparatus using a belt for conveying a sheet is very suitable for promoting colorization due to its configuration.

A conventional image forming apparatus using such a paper transport belt will be described below.

FIG. 3 is a perspective view showing an example of a sheet conveying belt in a conventional image forming apparatus, FIG. 4 is a perspective view showing another example of a sheet conveying belt in a conventional image forming apparatus, and FIG. FIG. 6 is an explanatory view showing an example of a sheet conveying belt provided with position regulating means in the image forming apparatus of FIG.
FIG. 7 is an explanatory view showing another example of the sheet transport belt provided with the position regulating unit in the conventional image forming apparatus, and FIG. 7 is still another example of the sheet transport belt provided with the position regulating unit in the conventional image forming apparatus. FIG.

The surface is coated with a layer of an organic photoconductive material, for example, yellow (Y), magenta (M),
Around the four toner image carriers provided for the respective colors of cyan (C) and black (K), there are provided a discharging unit, a cleaning unit, a charging unit, a developing unit, and an exposure unit. Further, a paper transport belt is provided in contact with the toner image carrier. Further, a transfer roller for transferring the toner image on the toner image carrier to the printing paper conveyed on the paper conveying belt is arranged.

In such an image forming apparatus, the surface of the toner image carrier is uniformly charged, and when a laser beam corresponding to an image of each color is irradiated, an electrostatic latent image is formed on each toner image carrier. Is formed. When the toner of each color from the developing means containing the toner transfers to the electrostatic latent image, a visible toner image appears on the toner image carrier. The toner image on the toner image carrier is transferred to a printing sheet conveyed on a sheet conveying belt by a transfer roller.

In the case of four-color development, a series of such operations forms a composite image by superimposing toner images of four colors C, M, Y, and K on printing paper.

However, in the conventional image forming apparatus as described above, when the paper transport belt 10 rotates, one end side peripheral portion generated in a processing step of the welding portion 10c of the paper transport belt 10 shown in FIGS. Due to the difference in circumference between the length 10a and the circumference 10b on the other end side, the phenomenon that the paper transport belt 10 meanders right and left on the paper transport belt support roller 11 occurs, and when the color images are superimposed, a slight displacement occurs. Tends to occur.

Therefore, as shown in FIG. 5 in which the paper transport belt 10 of FIG. 3 is attached to the paper transport belt support roller 11, the paper transport belt support roller 11 meanders so as to abut on both sides of the paper transport belt 10. Regulation step 11a
As shown in FIG. 6 in which the paper transport belt 10 of FIG. 4 is attached to the paper transport belt support roller 11, the convexity of the paper transport belt meandering restricting member 10 d extends over the entire circumference of both sides on the back surface of the paper transport belt 10. Is provided on both sides of the paper transport belt support roller 11 to provide a meandering regulation step 11a to which the roller is continuously fitted to prevent meandering. Alternatively, as shown in FIG. 7, the paper transport belt supporting roller 11 supporting the paper transport belt 10 is tapered (outer diameter difference).
Processing is performed, and the paper transport belt 10 is moved in one direction of the rotation axis of the paper transport belt support roller 11 to fit the meandering regulating member 10d and the meandering regulating step 11a.

[0010]

However, according to the meandering control technique shown in FIG. 5, both sides of the paper transport belt 10 are damaged due to the meandering control step 11a.

In the meandering control technique shown in FIG. 6, it is difficult to maintain the parallelism of the sheet transfer belt meandering control members 10d formed on both sides of the back surface of the sheet transfer belt 10.
Since the elastic member must be used for the sheet conveying belt meandering restricting member 10d, the cost increases.

In the meandering control technology shown in FIG. 7, since the paper transport belt support roller 11 is subjected to a taper (outer diameter difference) process, the transported paper is not only inclined but also hinders the transfer. Since it is difficult to taper the paper transport belt support roller 11, the cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of preventing the paper transport belt from meandering at low cost.

[0014]

In order to solve this problem, an image forming apparatus according to the present invention has a sheet conveying belt meandering restricting member provided on one end side of a back surface over the entire circumference, and a sheet conveying belt meandering restricting member. An endless belt-shaped paper transport belt in which the peripheral length on the side where the member is provided is longer than the peripheral length on the side where the meandering regulation member is not provided, and the paper transport belt. The paper transport belt has a plurality of paper transport belt support rollers provided with a fitting step in which the meandering regulating member is continuously concavely and convexly fitted when the paper transport belt rotates, and has a plurality of paper transport belt support rollers for adjusting the belt of the paper transport belt. Is configured to transfer the toner image formed on the toner image carrier to the printing paper conveyed.

According to this, the movement of the paper transport belt to move to the side where the paper transport belt meandering restricting member is not provided due to the circumferential length difference is caused by the engagement between the paper transport belt meandering restricting member and the fitting step. Since this is prevented, meandering of the endless belt-shaped paper transport belt can be prevented at low cost.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a sheet conveying belt meandering restricting member is provided on one end side of the back surface over the entire circumference, and a sheet conveying belt meandering restricting member is provided. An endless belt-shaped paper transport belt provided with a peripheral length difference longer than the peripheral length of the side on which the paper transport belt meandering regulating member is not provided, and the paper when the paper transport belt is rotated. A printing paper transported on a paper transport belt, having a plurality of paper transport belt support rollers provided with a fitting step at which the transport belt meandering regulating member is continuously fitted in a concave and convex manner, and adjusting the paper transport belt; An image forming apparatus for transferring a toner image formed on a toner image bearing member to a side where a sheet conveying belt meandering regulating member is not provided due to a difference in circumference. Because it is blocked by the engagement between the regulating member and the fitting step has the effect that the meandering of the endless belt-shaped sheet conveying belt it is possible to prevent a low cost.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is a schematic view showing an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a sheet conveying belt and a sheet conveying belt supporting roller in the image forming apparatus of FIG.

In FIG. 1, the surface is coated with a layer of an organic photoconductive material, and four toner images corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K). Carriers 1Y, 1M, 1C, and 1K are provided, respectively. The toner image carriers 1Y, 1
M, 1C and 1K are rotated in the direction of arrow A by a drive motor (not shown).

For the toner image carriers 1Y, 1M, 1C and 1K, respectively, yellow (Y), magenta (M),
Developing means 2Y, 2M, 2C, containing toners 2Yb, 2Mb, 2Cb, and 2Kb of negatively charged polarities of cyan (C) and black (K), and having developing rollers 2Ya, 2Ma, 2Ca, and 2Ka attached thereto. 2K is provided.

The present invention need not be such a four-color development, but may be a two-color or three-color development. In addition, the order of the superposition is not limited to that described later, and can be freely set.

Around the toner image carriers 1Y, 1M, 1C, 1K, there are arranged a charge removing means 3, a cleaning means 4, and a charging means 5, and the toner image carriers 1Y, 1M, 1K are arranged.
Exposure means 6 for irradiating laser light is provided above C and 1K.

The portions of the toner image carriers 1Y, 1Y that have passed through the charging means 5 by corona discharge by the charging means 5
M, 1C and 1K are uniformly charged, and the toner image carriers 1Y and 1K are irradiated with laser light of image data emitted from the exposure unit 6.
The charges of M, 1C, and 1K are partially lost, and electrostatic latent images corresponding to specific components among predetermined color components are formed on the toner image carriers 1Y, 1M, 1C, and 1K, respectively. Then, the developing roller 2 is placed on the portion where the electrostatic latent image is formed.
Ya, 2Ma, 2Ca, 2Ka and toner 2Yb, 2M
b, 2Cb, and 2Kb, the toner image carrier 1
On Y, 1M, 1C and 1K, visible toner images 2Yc, 2Mc, 2Cc and 2Kc appear one after another.

The exposure means 6 includes an LED or LC.
D or the like can also be used.

Each toner image carrier 1Y, 1M, 1
The paper transport belt 10 is installed so as to abut against C and 1K. The paper transport belt 10 is tuned and supported by two paper transport belt support rollers 11.
In order to charge the paper transport belt 10 to a predetermined potential, the paper transport belt charging means 12
It is provided in contact with. Also, the paper transport belt 10
Is provided with a paper ground 13.

The toner image carrier 1 is placed on the paper transport belt 10.
Toner images 2Yc, 2Mc, 2 on Y, 1M, 1C, 1K
In order to transfer Cc and 2Kc, the transfer roller 15 moves the toner image carriers 1Y, 1M, 1
C and 1K are arranged respectively.

A paper cassette 16 for storing the printing paper 9 is provided directly below the paper transport belt 10. Then, the printing paper 9 is transferred from the paper cassette 16 to the paper feeding roller 14.
The sheet is fed toward the sheet transport belt 10 one by one.

In order to fix the composite image transferred to the printing paper 9, a fixing means 7 including a heat roller having a heat source therein and a pressure roller is disposed. Then, the composite image transferred by the pressure and heat is fixed on the printing paper 9 by the pinching rotation of the heat roller and the pressure roller when passing through the fixing unit 7, and a color image is formed.

Here, as shown in FIG. 2, at one end of the back surface of the paper transport belt 10, a convex paper transport belt meandering regulating member 10d is provided over the entire circumference. The paper transport belt support roller 11 on which the paper transport belt 10 is supported has a concave fitting step 11a into which the paper transport belt meandering restricting member 10d continuously fits when the paper transport belt 10 rotates circumferentially. Is provided. Further, in the paper transport belt 10, the circumference 10a on the side where the paper transport belt meandering regulating member 10d is provided is longer than the peripheral length 10b on the side where the paper transport belt meandering regulating member 10d is not provided. The welding process is performed with a difference in circumference.

In the present embodiment, the sheet conveying belt meandering restricting member 10d is formed in a convex shape and the fitting step 11a is formed in a concave shape.
0d may be formed in a concave shape, and the fitting step 11a may be formed in a convex shape. In other words, it is only necessary that the sheet conveying belt meandering restricting member 10d and the fitting step 11a be fitted in a concave and convex manner continuously.

The operation of the image forming apparatus configured as described above will be described below.

In FIG. 1, first, the toner image carrier 1 is subjected to corona discharge by charging means 5 connected to a high voltage power supply.
The surfaces of Y, 1M, 1C, and 1K are uniformly charged.

Next, the toner image carriers 1Y, 1M, 1C,
1K is rotated in the direction of arrow A by a driving device (not shown), and the uniformly charged toner image carriers 1Y, 1M, 1
When the laser light corresponding to the image of each color component is irradiated onto the surfaces of C and 1K, the toner image carriers 1Y, 1M, 1C and 1K
The upper irradiated portion loses the charge and is exposed in a pattern corresponding to the image signal to form an electrostatic latent image.

On the other hand, toners 2Yb and 2M contributing to development
b, 2Cb, and 2Kb are stored in the developing means 2Y, 2M, 2C, and 2K.
2Ca and 2Ka are toner image carriers 1Y, 1M, 1C,
It is in contact with 1K.

Developing rollers 2Ya, 2Ma, 2Ca, 2K
a, a bias voltage is applied to the developing roller 2Y
a, 2Ma, 2Ca, 2Ka Surface and Toner Image Carrier 1
The toners 2Yb, 2Mb, 2Cb, and 2Kb are transferred only to the portions of the toner image carriers 1Y, 1M, 1C, and 1K irradiated with the laser light by the electric field acting between the toner images Y, 1M, 1C, and 1K, and the toner image carrier is carried. Toner images 2Yc, 2Mc, 2Cc, 2Kc that have become visible images on bodies 1Y, 1M, 1C, 1K
Respectively appear.

On the other hand, the printing paper 9 is fed out of the paper cassette 16 toward the paper transport belt 10 by the paper feed roller 14. Then, the sheet is attracted to the sheet conveyance belt 10 by the sheet ground 13 and is conveyed on the sheet conveyance belt 10.

Here, in accordance with the timing of such sheet conveyance, each color toner image 2Yc, 2Mc, 2Cc, 2 formed on each toner image carrier 1Y, 1M, 1C, 1K.
Kc is sequentially transferred onto the printing paper 9 by the transfer means 15. Thereby, the four colors K, C, M, and Y are printed on the printing paper 9.
The toner images 2Yc, 2Mc, 2Cc and 2Kc are superimposed to form a composite image.

The printing paper 9 on which the composite image is formed in this way is sent to the fixing means 7. Then, the image is fixed by the heat and the clamping force between the heat roller and the pressure roller, and a color image is formed. Finally, the printing paper 9 that has passed through the fixing means 7
Is discharged to a paper discharge tray.

Here, as described above, the paper transport belt 1
At the one end of the back surface at 0, a convex paper transport belt meandering restricting member 10d is provided, and the paper transport belt support roller 11 is provided with a fitting step 11a. Further, in the paper transport belt 10, the peripheral length 10a on the side where the paper transport belt meandering restricting member 10d is provided is longer than the peripheral length 10b on the side where the paper transport belt meandering restricting member 10d is not provided. Perimeter differences are given.

When the paper transport belt 10 rotates around, the paper transport belt 10 tries to move to the side where the paper transport belt meandering restricting member 10d is not provided due to the aforementioned difference in the circumferential length. Belt meandering control member 1
Such movement is prevented by the fitting of Od with the fitting step 11a.

Thus, the paper transport belt meandering restricting member 10d, which increases the cost, is provided only on one side of the back surface of the paper transport belt 10, and the cost-effective taper processing is not performed on the paper transport belt support roller 11. Meandering of the paper transport belt 10 is prevented at low cost.

In the above description, the tandem type color image forming apparatus has been described.
The present invention can be applied to various image forming apparatuses in which the sheet conveyance belt 10 is used for sheet conveyance.

[0043]

As described above, according to the present invention, the movement of the paper transport belt to the side where the paper transport belt meandering restricting member is not provided due to the difference in circumferential length is caused by the step difference between the paper transport belt meandering restricting member and the paper transport belt meandering member. The paper feed belt meandering restricting member, which increases the cost, is provided only on one side of the back surface of the paper feed belt, and the costly taper processing is not performed on the paper feed belt support roller. In addition, it is possible to prevent the meandering of the endless belt-shaped sheet conveyance belt from being reduced in cost.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an image forming apparatus according to an embodiment of the present invention;

FIG. 2 is an explanatory diagram showing a sheet conveying belt and a sheet conveying belt supporting roller in the image forming apparatus of FIG. 1;

FIG. 3 is a perspective view showing an example of a sheet conveying belt in a conventional image forming apparatus.

FIG. 4 is a perspective view showing another example of a sheet conveying belt in a conventional image forming apparatus.

FIG. 5 is an explanatory diagram illustrating an example of a sheet transport belt provided with a position regulating unit in a conventional image forming apparatus.

FIG. 6 is an explanatory view showing another example of a sheet conveying belt provided with a position regulating unit in a conventional image forming apparatus.

FIG. 7 is an explanatory view showing still another example of a sheet conveying belt provided with a position regulating unit in a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Paper conveyance belt 10a Circumference 10b Circumference 10d Paper conveyance belt meandering restricting member 11 Paper conveyance belt support roller 11a Fitting step

Continued on the front page (72) Inventor Eiji Kiba 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 3F049 BA03 BB11 LA04 LB03

Claims (1)

[Claims] A sheet conveying belt meandering regulating member is provided on one end side of the back surface over the entire circumference, and the peripheral length of the side on which the sheet conveying belt meandering regulating member is provided is the paper conveying belt meandering regulating member. An endless belt-shaped paper transport belt provided with a peripheral length difference longer than the peripheral length of the side on which the paper transport belt is not provided, and the paper transport belt meandering regulating member is continuously uneven when the paper transport belt rotates circumferentially. A plurality of paper transport belt support rollers for adjusting the width of the paper transport belt, and a plurality of paper transport belt support rollers, which are formed on a toner image carrier on printing paper transported on the paper transport belt; An image forming apparatus for transferring a toner image.