JPH06324544A - Image forming device - Google Patents

Abstract

PURPOSE:To surely prevent a failure in conveying a transfer material such as transfer paper and image defects, both of which could be caused by the low water content of the transfer material, i.e., drying of the transfer material. CONSTITUTION:Transfer paper sheets 1, taken out of a transfer paper storage tray 13 one by one, have their water contents measured one by one by a transfer-paper water-content measuring device 14. A controller 16 provides no output to a transfer paper humidifying device 15 when the measured water contents are at or greater than a reference value; then the transfer paper humidifying device 15 does not operate and the transfer paper sheets 1 are not humidified at all but simply allowed to pass through the transfer paper humidifying device 15 and conveyed to a transfer drum 2. When the water contents of the transfer paper sheets 1 are smaller than the reference value, the controller 16 operates the transfer paper humidifying device 15; the transfer paper sheets 1 are humidified for a predetermined time by the transfer paper humidifying device 15 and then conveyed to the transfer drum 2. The transfer paper sheets 1 have their water contents held at the reference value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine, an electrostatic recording apparatus provided with a transfer device for forming an image by transferring a toner image formed on an image carrier onto a transfer material.
The present invention relates to an image forming apparatus such as a facsimile, a transmission recording apparatus or a laser printer, and more particularly to an image forming apparatus equipped with a device for preventing conveyance failure and image defect due to drying of a transfer material.

[0002]

2. Description of the Related Art Generally, in a transfer device of an image forming apparatus, a toner image is formed on an image bearing member such as a photosensitive drum,
An image is formed by transferring the toner image on the image carrier to a transfer material such as a transfer drum, a transfer film, or a transfer belt that is adsorbed and supported on the transfer material carrier.

In such an image forming apparatus, it is troublesome to replenish the transfer material each time an image is formed. Therefore, a transfer material storage tray capable of storing a large amount of transfer material is generally provided. There is. Then, the transfer material is taken out of the package and stored in the transfer material storage tray, and the stored transfer material is left in the transfer material storage tray for a long time until it is used. Therefore, depending on the surrounding environment, the transfer material in the transfer material storage tray is sometimes affected by containing water or sometimes drying.

Further, in the case of the transfer paper most frequently used as the transfer material, especially in the case of the bundled transfer paper, the center of the transfer paper is hard to dry due to the moisturizing effect of the transfer paper itself which is in direct contact with air. On the other hand, the edges of the transfer paper easily absorb moisture due to the capillary phenomenon of the transfer paper itself. Due to the moisture absorption of the transfer paper, as shown in FIG. 2, the transfer paper 1 is deformed such that the four corners 1a and the four sides 1b are corrugated and the central portion 1c is flat. Due to such deformation of the transfer paper 1,
The image transferred to the transfer paper 1 is disturbed, and the transfer paper 1 is not properly conveyed.

Generally, in an image forming apparatus for forming an image by electrostatic means, the moisture content (hereinafter also referred to as water content) of the transfer paper is preferably 3 to 8% in order to obtain a high quality image. If the water content of the transfer paper is higher than 8%, the electric charge for transferring the toner to the transfer paper will flow out through the water contained in the transfer paper during the transfer process. There is a problem that you cannot get it.

On the contrary, when the transfer paper has a low water content of less than 3% (drying of the transfer paper), the transfer paper is electrostatically adsorbed to the transfer paper carrier to be electrified to transfer the transfer paper. Since electric discharge occurs between the transfer paper and the transfer paper carrier, the transfer paper is not adsorbed well, and there is a problem in that the transfer paper is hindered.

From the above, in order to deal with the problem due to the high water content of the transfer paper, the transfer paper is dehumidified by dehumidifying the transfer paper accommodating cassette by the dehumidifying means. The device is JP-A-59-48335.
It is proposed in the publication. According to the dehumidifying device of this publication, the problem due to the high water content of the transfer paper can be solved.

Further, in order to deal with the problem due to the low water content of the transfer paper, the humidity detecting means and the temperature detecting means arranged in the transfer paper storing device detect the humidity and temperature in the transfer paper storing device, Japanese Patent Laid-Open No. 58-31416 discloses a transfer paper humidifier that humidifies the inside of the transfer paper storage device only when the humidity inside the transfer paper storage device is determined to be lower than a reference value based on the detected humidity and temperature. Proposed. According to the transfer paper humidifier of this publication, the humidity in the transfer paper storage device is maintained at the reference value.

[0009]

However, in the transfer paper humidifier disclosed in Japanese Patent Laid-Open No. 58-31416, the object for detecting humidity is not the transfer paper itself but the humidity, temperature, etc. in the transfer paper humidifier. Because of the atmosphere, the water content of the transfer paper itself is not kept at the reference value. Therefore, this transfer paper humidifier cannot obtain the effect of keeping the water content of the transfer paper at the reference value. Moreover, since this transfer paper humidifier humidifies the transfer paper in a bundled state, as described above, the moisture content of the outer edge of the transfer paper increases and
Non-uniformity of water content occurs such that the water content inside the transfer paper becomes low, resulting in image quality defects such as image quality unevenness and conveyance failure. As described above, the transfer paper humidifying device of the above publication cannot reliably and sufficiently deal with the problem due to the low water content of the transfer paper.

The present invention has been made in view of the above problems, and an object thereof is a low water content of a transfer material such as a transfer paper, that is, poor transfer material transfer and image defects due to drying of the transfer material. An object of the present invention is to provide an image forming apparatus capable of reliably preventing the above.

[0011]

In order to solve the above-mentioned problems, in the image forming apparatus according to the first aspect of the invention, the image forming apparatus is taken out from the transfer material storing tray in the transfer material conveying path of the transfer material conveying means. A transfer material humidifying device for humidifying the transfer material is provided. This transfer material humidifying device humidifies the transfer materials taken out from the transfer material storage tray one by one.
Therefore, the transfer material is humidified relatively uniformly, and the non-uniformity of the water content of the transfer material that occurs when the transfer material is humidified in a bundled state can be prevented.

In particular, according to the second aspect of the invention, the transfer material moisture content measuring device measures the water content of the transfer material, and the control device controls the transfer material moisture content measuring device based on the measurement result of the transfer material moisture content measuring device. Is used to control the humidification amount of the transfer material. Therefore, the water content of the transfer material can be reliably maintained at the reference value.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing a portion of a photosensitive drum and a transfer drum in a multiple transfer device of an image forming apparatus to which an embodiment of the present invention is applied. It goes without saying that the present invention can be applied to other transfer devices such as a black and white transfer device other than the multiple transfer device.

As shown in FIG. 1, the image forming apparatus according to the present embodiment includes a transfer drum 2 which is a transfer material carrier for adsorbing and supporting a transfer paper 1 which is a transfer material, and a toner in the vicinity of the transfer drum 2. The photosensitive drum 3 is an image bearing member on which an image is formed. The transfer drum 2 is a ring provided on the transfer drum 2 for securing a predetermined gap between the transfer drum 2 and the photoconductor drum 3 (not shown: provided on a conventional general transfer drum). (The same as the above) is selectively set to either the tracking position (the position shown in FIG. 1) where it contacts the photosensitive drum 3 or the non-tracking position (not shown) that is separated from the photosensitive drum 3. ing.

A transfer corotron 4 and a transfer baffle 5 are arranged inside the transfer drum 2 at positions facing the photoconductor drum 3. Furthermore, on the downstream side of the transfer corotron 4 in the direction of rotation of the transfer drum, a peeling corotron 6 for removing the electric charge of the transfer paper 1 and a peeling claw 7 for peeling the transfer paper 1 from the transfer drum 2 are provided outside the transfer drum 2. ing.

Further, on the downstream side of the peeling claw 7 in the direction of rotation of the transfer drum, inside and outside the transfer drum 2, an inner charge-eliminating corotron 8 and an outer charge-eliminating corotron 9 are arranged so as to face each other. Further, an adsorption corotron 10 is provided inside the transfer drum 2 on the downstream side of the inner static elimination corotron 8 and the outer static elimination corotron 9 in the transfer drum rotation direction, and the adsorption corotron 10 is provided outside the transfer drum 2.
Opposing rolls 11 are arranged to face each other.

Further, the transfer paper conveying means 12 is used to transfer the transfer drum 2 between the suction corotron 10 and the opposing roll 11.
Is arranged so as to supply the transfer paper 1 on the surface of the.
The transfer paper transporting means 12 has a transfer paper transporting path 12a, and the transfer paper transporting path 12a is connected to a transfer paper storage tray 13 that stores the transfer papers 1 collectively. The transfer paper storage tray 13 is provided with a dehumidifying means (not shown), and the dehumidifying means dehumidifies the transfer paper 1 stored in the transfer paper storage tray 13 and holds it in a dry state to some extent. I am trying.

In the transfer paper transport path 12a on the transfer paper storage tray 13 side, a transfer paper moisture content measuring device 14 composed of a commercially available water content measuring device or the like and a transfer paper humidifying device 15 consisting of steam or the like are commercially available. Is provided. The transfer paper moisture content measuring device 14 measures the water content of the transfer paper 1, and the transfer paper humidifying device 15 humidifies the transfer paper 1.

The transfer paper moisture content measuring device 14 is connected to the input side of the control device 16, and the output side of the control device 16 is connected to the transfer paper humidifying device 15.
The control device 16 has a predetermined reference value (for example, 3%) for the measured water content of the transfer paper 1 based on the water content measurement signal input from the transfer paper water content measurement device 14.
When it is smaller, an operation signal is output to the transfer paper humidifier 15, and when the measured water content of the transfer paper 1 is greater than or equal to a predetermined reference value, the operation signal is not output to the transfer paper humidifier 15. I have to. In that case, the control device 16
Outputs an operation signal for a time period according to the magnitude of the difference between the reference value and the measured water content.

Further, in the transfer sheet conveying path 12a, a belt conveying means 17 arranged to face the transfer sheet moisture content measuring device 14, an inlet conveying roller 18 arranged at the entrance of the transfer sheet humidifying device 15, and a transfer sheet. An outlet transport roller 19 arranged at the outlet of the humidifying device 15 and intermediate transport rollers 20, 21 are provided. Although not shown, the transfer paper humidifier 1
A predetermined number of transport rollers are also provided in 5. These belt conveying means 17, each roller 18, 19, 20, 21
The transfer roller in the transfer paper humidifying device 15 is the transfer paper 1
When an operation key (not shown) of the image forming apparatus is operated to form an image, the image is rotated.

When an operation signal is output from the control device 16 to the transfer paper humidifying device 15, when the transfer paper 1 is conveyed to a predetermined position in the transfer paper humidifying device 15, the transfer paper humidifying device 15 is operated. The transport rollers are controlled to stop,
The transfer paper 1 is set at a predetermined position in the transfer paper humidifier 15. Needless to say, it may be humidified during transportation without being set at a predetermined position. Further, when the humidification of the transfer paper 1 by the transfer paper humidifier 15 is completed, the transfer roller in the transfer paper humidifier 15 is controlled to rotate again, and the transfer paper 1 is transferred to the transfer paper humidifier 15
The transfer drum 2 is carried out. The rest of the configuration of the image forming apparatus is the same as the configuration of a conventional general image forming apparatus including this type of multiple transfer device, and therefore the description thereof is omitted.

Next, the operation of this embodiment will be described.
Normally, the transfer drum 2 is set at a tracking position close to the photosensitive drum 3. When the operation key of the image forming apparatus is operated to form an image on the transfer sheet 1, the belt conveying means 17, each roller 18, 19, 20, 21 and the conveying roller in the transfer sheet humidifying device 15 are rotated. As a result, the set number of transfer sheets 1 stored in the transfer sheet storage tray 13 are taken out one by one. When the transfer paper 1 taken out passes through the transfer paper water content measuring device 14, the transfer paper water content measuring device 14 measures the water content of the transfer paper 1 one by one.

The transfer paper water content measuring device 14 sends the measured water content to the control device 16, and the control device 16 judges whether or not the input water content is smaller than a reference value. Control device 1
No. 6 does not output the operation signal to the transfer paper humidifier 15 when it judges that the water content is equal to or higher than the reference value,
The transfer paper humidifier 15 does not operate for humidification. Therefore, the transfer paper 1 conveyed from the belt conveying means 17 is
After being carried into the transfer paper humidifying device 15 by the entrance carrying roller 18, and further moved in the transfer paper humidifying device 15 by the carrying roller in the transfer paper humidifying device 15, the exit carrying roller 1
9 is carried out of the transfer paper humidifier 15. The transfer sheet 1 carried out from the transfer sheet humidifying device 15 is further conveyed toward the transfer drum 2 by the intermediate conveying rollers 20 and 21. As described above, the transfer paper 1 whose water content is equal to or higher than the reference value, that is, the transfer paper 1 which has not been dried is not passed through the transfer paper humidifier 15 and is simply passed through the transfer paper humidifier 15 to the transfer drum 2. It will be transported.

On the other hand, when the controller 16 determines that the water content of the transfer sheet 1 is smaller than the reference value, it outputs an operation signal to the transfer sheet humidifier 15, so that the transfer sheet humidifier 15 operates for humidification. . Further, the rotation of the conveying roller in the transfer paper humidifying device 15 is stopped by the operation signal from the control device 16. Therefore, the transfer paper 1 carried into the transfer paper humidifying device 15 by the entrance carrying roller 18 is at a predetermined position in the transfer paper humidifying device 15 since the rotation of the carrying roller in the transfer paper humidifying device 15 is stopped. Stop. In this way, the transfer paper 1 is set at a predetermined position in the transfer paper humidifier 15, and the transfer paper 1 is uniformly humidified by the transfer paper humidifier 15 at this position.

The control device 16 operates the transfer paper humidifying device 15 for a predetermined time according to the difference between the reference value and the water content of the transfer paper 1 to humidify the transfer paper 1. Transfer paper humidifier 1 for a predetermined time
When the humidification of the transfer paper 1 by 5 is completed, the control device 16 stops the operation of the transfer paper humidifier 15 and rotationally drives the transport roller of the transfer paper humidifier 15. As a result, the humidified transfer paper 1 is sent to the exit conveyance roller 19, and the transfer paper humidifier 1 is moved by the exit conveyance roller 19.
5 is carried out. After that, the transfer paper 1 is processed in the same manner as described above.
Are conveyed toward the transfer drum 2. As described above, the transfer paper 1 whose water content is smaller than the reference value, that is, which is dry
After being humidified by the transfer paper humidifier 15 for a predetermined time, the sheet is conveyed to the transfer drum 2. In that case,
Since the transfer paper 1 is humidified for a predetermined time according to the magnitude of the difference between the reference value and the water content, the transfer paper is a transfer paper in which the water content is maintained at the most preferable value of 3 to 8% or more.

When the transfer paper 1 is supplied onto the transfer drum 2 from the transfer paper conveying means 12, the transfer paper 1 is adsorbed onto the transfer drum 2 by the adsorbing corotron 10 and on the transfer drum 2 by the opposing roller 11. Is pressed by.
As a result, the transfer paper 1 is adsorbed and supported on the transfer drum 2.

Transfer paper 1 adsorbed and supported on transfer drum 2.
Are transported toward the photoconductor drum 3 by the rotation of the transfer drum 2. When the transfer paper 1 is conveyed to the position of the photoconductor drum 3, the toner image formed on the photoconductor drum 3 is transferred onto the transfer paper 1 by the transfer electric field of the transfer corotron 4. In that case, this transfer is performed for each color of toner,
That is, for example, yellow, magenta, cyan, and black are sequentially overlapped and sequentially performed.

When the transfer of the toner images of all colors is completed, the transfer paper 1 is stripped from the transfer drum 2 by the stripping claw 7 after the charges are removed by the stripping corotron 6. The peeled transfer paper 1 is sent to a fixing device (not shown).

According to the image forming apparatus of this embodiment, the transfer paper 1 stored in the transfer paper storage tray 13 is
Has a low water content, that is, when it is dry, the transfer paper humidifier 15 keeps the water content of the transfer paper 1 at a preferable level of 3 to 8%. No discharge occurs between the two. Therefore, the transfer paper 1 is favorably sucked and supported by the transfer drum 2, and the transfer paper 1 is reliably conveyed by the rotation of the transfer drum 2.

Further, according to the present embodiment, the transfer paper humidifier 15 keeps the water content of the transfer paper 1 itself at the reference value one by one, so that the water content becomes uneven. Will be prevented. As a result, the transfer sheet 1 is prevented from being deformed, image quality defects such as image quality unevenness are prevented, and defective transport is more reliably prevented.

In the above-mentioned embodiment, the case where the present invention is applied to the multiple transfer device having the transfer drum is explained. However, the present invention is applicable to other transfer material carrying members such as a transfer film and a transfer belt. The present invention can also be applied to a multi-transfer device having the same. Further, the present invention can be applied to other transfer devices such as a black and white transfer device other than the multiple transfer device. Further, the present invention can be applied to an image forming apparatus in which the transfer paper storage tray 13 is not provided with a dehumidifying means.

[0033]

As is apparent from the above description, according to the image forming apparatus of the present invention, when the transfer material has a low water content, that is, when the transfer material is dry, the transfer material humidifier is used to remove the transfer material. Since the water content is maintained at the reference value, no discharge occurs between the transfer material and the transfer material carrier. Therefore, the transfer material can be favorably adsorbed and supported on the transfer material carrier, and the transfer material can be reliably conveyed.

Further, according to the present invention, since the water content of the transfer material itself is maintained at the reference value one by one by the transfer material humidifying device, it is possible to prevent the water content from becoming nonuniform. As a result, since the transfer material is prevented from being deformed, it is possible to prevent image quality defects such as image quality unevenness, and it is possible to more reliably prevent conveyance defects.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a portion of a photosensitive drum and a transfer drum in a multiple transfer device of an image forming apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing one transfer sheet which is deformed by humidifying the bundled transfer sheets.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transfer paper (transfer material), 2 ... Transfer drum (transfer material carrier), 3 ... Photosensitive drum (image carrier), 4 ... Transfer corotron, 5 ... Transfer baffle, 6 ... Separation corotron, 7 ... Separation claw , 8 ... Inner static eliminating corotron, 9 ... Outside static eliminating corotron, 10 ... Adsorption corotron, 11 ... Opposing roll, 12 ...
Transfer paper conveying means, 13 ... Transfer paper storage tray, 14 ... Transfer paper (transfer material) moisture content measuring device, 15 ... Transfer paper (transfer material)
Humidification device, 16 ... Control device, 17 ... Belt conveying means, 1
8 ... Inlet transport roller, 19 ... Outlet transport roller, 20, 2
1 ... Intermediate transport roller

Claims (2)

[Claims] 1. A transfer material contained in a transfer material storage tray is conveyed and supplied to a transfer material carrier by a transfer material conveying means, and the transfer material is carried on the transfer material carrier, and the transfer material carrier. In an image forming apparatus for transferring a toner image formed on an image carrier to an upper transfer material, a transfer material transportation path of the transfer material transportation means humidifies the transfer material taken out from the transfer material storage tray. An image forming apparatus, comprising: a transfer material humidifying device. 2. A transfer material water content measuring device for measuring the water content of the transfer material is further provided, and the transfer material humidifying device measures the transfer material moisture content based on the measurement result of the transfer material water content measuring device. The image forming apparatus according to claim 1, further comprising a control device that controls a humidification amount.