JPH0744044A - Image forming device - Google Patents

Abstract

PURPOSE:To automatically perform a nip mark forming operation and to lighten the burden on an operator and to reduce the consumption quantity of toner at the time of the nip mark forming operation by forming a nip mark at a specified part where a toner image is formed on a transfer material. CONSTITUTION:When a nip mark forming mode is selected, an electrostatic charged area is formed at a part from the position of a specified length from the leading edge of the recording paper P of a size selected to the position at an appropriate length for forming a nip mark on the surface of the photoreceptor drum 1 at first, and is developed by a developing device 14 and a toner image is formed. Next, the toner image is transferred on the recording paper P by a transfer part 5 and the recording paper P is separated from the photoreceptor drum 1. Then the recording paper P passes the nip part 83 of a fixing device 80 and is detected by a passing paper detecting sensor 85, and after a fixed time, the rotation of a fixing roller 81 and a pressure roller 82 is stopped, and the toner image part of the recording paper P is stopped at the nip part 83. Also after a specified time, the transportation of the recording paper P is restarted and the recording paper P is ejected to the outside of a copying machine by a paper ejecting roller 88.

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 such as a copying machine, a printer or a facsimile having a heat roller fixing device and a fixing roller nip trace forming mode.

[0002]

2. Description of the Related Art Conventionally, in a heat roller fixing device used in an image forming apparatus such as a copying machine, a printer or a facsimile, a fixing roller is used as a measurement item for controlling the quality of image fixability of a copy. Surface temperature and fixing roller and pressure roller
Since there is a pressure force between the fixing roller and the pressure roller, it is difficult to directly measure this pressure force.Therefore, as an alternative, measure the width of the nip part that is the pressure contact surface between the fixing roller and the pressure roller. I was managing it.

The method for measuring the width of the nip portion is such that a black original or a means for forming a black image is used to form an image, and a transfer paper on which toner is transferred to almost the entire surface is a fixing roller. Stop the power at the nip by turning off the power while passing through the nip.

Then, the transfer paper is taken out and the width of the nip mark formed on the transfer paper is measured. The heat received while the nip portion is stopped increases the gloss of the black image only in that portion, and a nip mark is formed.

The width of this nip trace is measured using a ruler, a caliper, a loupe with a scale, etc., and the pressure between the rollers is adjusted so that the nip width becomes a target control value. I was in control.

[0006]

However, in the above-mentioned method, since the timing of turning off the power depends on the intuition of the operator,
The stop position of the transfer paper is not constant, and therefore the toner image is formed on almost the entire surface of the transfer paper so that the nip mark can be formed at any position.

As a result, in the nip mark forming work,
Since a large amount of toner is consumed and the nip trace forming work is repeated until the nip width reaches the target control value, there is a problem that the consumption amount becomes a considerable amount.

An object of the present invention is to reduce the burden on the operator by automatically performing the nip mark forming work in order to solve the above-mentioned problems, and at the same time, the consumption amount of the toner during the nip mark forming work. It is to provide an image forming apparatus that reduces

[0009]

In order to achieve the above object, the present invention provides a thermal roller fixing device including at least a fixing roller and a pressure roller, and a toner on a transfer material. Toner image forming means for forming an image, conveying means for conveying the transfer material carrying the toner image, detection means for detecting the transfer material passing through the heat roller fixing device, and the fixing In an image forming apparatus having a selecting means for selecting a fixing nip mark forming mode for forming a shape of a pressure contact portion between a roller and a pressure roller as a nip mark remaining on the transfer material, When the fixing nip trace forming mode is selected, a toner image is formed on a predetermined portion of the transfer material, and the transfer material is conveyed to a pressure-bonding portion between a fixing roller and a pressure roller, The predetermined area on the transfer material where the toner image is formed is the fixing roller and the pressure roller. An image forming apparatus, characterized in that it comprises a control means for controlling to convey again the transfer material after a lapse of a predetermined after stopping stops time transport while passing through the contact portion between.

Further, according to one embodiment of the present invention, the size of the toner image formed on a predetermined portion of the transfer material is 10 times or less the width of the nip mark formed on the portion. Have.

According to another embodiment of the present invention, when the scale image forming means and the fixing nip mark forming mode are selected by the selecting means, a toner of a predetermined area is formed on a predetermined portion on the transfer material. -Forming an image and a scale image, conveying the transfer material to a pressure-bonding portion of a fixing roller and a pressure roller, and forming a toner image and a scale image of a certain area on the transfer material. This part is provided with a control means for stopping the conveyance while passing through the pressure contact portion between the fixing roller and the pressure roller, and for controlling the conveyance of the transfer material again after a lapse of a predetermined time after the stop.

[0012]

By using the image forming apparatus of the present invention,
When the fixing nip mark forming mode is selected by the control means, a toner image is formed on a predetermined portion of the transfer material,
Since the control is performed so that a nip mark is formed at a predetermined portion where the toner image is formed on the transfer material, it is possible to automatically perform the nip mark forming operation and necessary for forming the nip mark on the transfer material. Since it is possible to form a toner image only in a certain area and form a nip mark at a predetermined portion where the toner image is formed, the toner amount consumed by the nip mark formation is reduced and the scale image Since the forming means is provided and the scale image is formed on the nip mark forming portion, it is possible to easily measure the nip mark.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic block diagram of an electrophotographic copying machine which is an image forming apparatus to which the present invention is applied. In the figure, the optical system comprises a document glass 50 on which a document D is placed, a moving first mirror table 51 and a second mirror table 54, a lens 57, and a fixed fourth mirror table 58.

The first mirror table 51 is provided with a first mirror 52 and an illumination lamp 53, and moves along the original table glass 40.

A second mirror 55 and a third mirror 56 are arranged on the second mirror base 54. The second mirror table 54 moves in the same direction as the first mirror table 51 at half speed.

The document D placed on the document table glass 50 is illuminated by an illumination lamp 53, and the reflected light of the document image is reflected by the lens 57 and the lens 57 while moving the first mirror table 51 and the second mirror table 54. An image is formed on the exposure unit 2 on the photosensitive drum 1 via the fourth mirror 58.

Around the photosensitive drum 1, a charging device 11, an exposing section 2, a blank exposing device 13, a developing device 14, a transfer charging device 15, a separation charging device 16, a cleaner 17, and a pre-electrification exposing device 1
8 and the like image forming means are arranged, and the image forming processes such as charging, exposure, blank exposure, development, transfer, separation, cleaning, and pre-electrification exposure are carried out on the rotating photosensitive drum 1 and then on the photosensitive drum 1. Form a toner image.

On the other hand, the recording paper P is fed from the cassette 70, temporarily stands by at the registration roller unit 72, and is conveyed to the transfer unit 5 in synchronization with the image forming operation on the photosensitive drum 1.
The toner image on the photosensitive drum 1 is transferred onto the recording paper P, and then the recording paper P is separated from the photosensitive drum 1 and then conveyed to the fixing device 80 by the conveying portion 75. The fixing roller 81 of the fixing device 80
The recording paper P is passed through a nip portion 83 between the pressure roller 82 and the pressure roller 82 to be heated and pressed to fix the toner image on the recording paper P, and the paper is ejected to the outside by the paper ejection roller 88. This paper output roller 8
In the vicinity of 8, a paper passing detection sensor 85 for detecting that the recording paper P is passing through the fixing device 80 is provided.

The control section is driven and controlled by an electric signal sent and received between the main control circuit section 90 for controlling the entire copying machine, the operation section control circuit of an operation section unit (not shown), and the main control circuit section 90. It is composed of electric parts and electronic parts, or detection sensors.

In the ordinary copy mode, the above-described series of copy processes are performed. When the nip trace forming mode is selected by operating an operation unit (not shown), the following nip trace forming mode is executed according to the nip trace forming program stored in the main control circuit unit 90. Control.

A cassette 70 containing a recording paper P of a size suitable for forming a nip trace is selected and the paper feeding operation is started.

At the same time, the photosensitive drum 1 is rotated to control the charging device 11, the blank exposing device 13, etc.
On the surface of the recording paper P of a selected size from a position of a predetermined length to a position of a length suitable for forming a nip mark,
Further, a charged area is formed in a portion having substantially the same width corresponding to the width of the recording paper P, and this is developed by the developing device 14 to form a toner image.

Further, the recording paper P once made to stand by by the registration roller 72 is motivated and conveyed as a toner image on the photosensitive drum 1, and the toner image is transferred onto the recording paper P at the transfer section 5, After the recording paper P is separated from the photosensitive drum 1, the conveying unit 75 conveys the recording paper P to the fixing device 80.

When the recording paper P is passed through the nip portion 83 of the fixing device 80 and the recording paper detection sensor 85 detects the recording paper P, the fixing roller 81 and the pressure roller 82 rotate after a predetermined time. Stop the toner image portion of the recording paper P, and the nip portion 83
Shall be stopped. Further, after a certain period of time, the conveyance of the recording paper P is restarted, and the recording paper P is ejected outside the machine by the paper ejection roller 88.

By executing the nip mark forming mode as described above, a copy image as shown in FIG. 2 can be obtained. Part A is the toner image, and part B is the nip mark. In the figure
The lengths of b1, b2, b3 are measured, and the pressure is adjusted by a pressing force adjusting means (not shown) so as to be within the control value.

The size of the portion A necessary for forming the nip mark is 10 times or less, that is, about several times as large as the control value of the width of the nip mark formed there. Compared with the case of forming
Toner consumption can be reduced to a degree.

FIG. 3 is a schematic block diagram of a laser beam printer which is an image forming apparatus to which the present invention is applied. In the figure, the optical system comprises a laser beam exposure device 60 which is a laser beam printer using a laser beam, and controls the laser beam by a signal from a main control circuit section 90. The exposed portion 2 of the charged photosensitive drum 1 is irradiated to form an image.

Since the configuration other than this optical system is the same as that of the electrophotographic copying machine of FIG. 1, its explanation is omitted.

When the nip mark forming mode is selected by operating an operation unit (not shown) or the like, the same nip mark forming mode as in FIG. 1 is controlled. In this embodiment,
After charging the photosensitive drum 1 with the charger 11, the laser beam
And a latent image for forming a nip trace is formed.

The shape of the image formed at this time is controlled so as to be a combination of a rectangular shape divided into three pieces as shown in FIG. 4 and a plurality of parallel short lines close to these. Since the short line is used as a scale for measuring the width of the nip mark, the interval between the short lines should be an interval suitable for measurement, for example, 1
The spacing may be about mm.

As shown in FIG. 5, the short line is developed by the developing device 14 to form a toner image, which is transferred onto the recording paper P, and the fixing device 80 forms a nip mark to obtain a copy image. To be

The control of the nip width is performed by measuring the widths at three locations near both ends and the central portion as shown in FIG. Therefore, it is possible to form the toner image only in the vicinity of the measuring portion and omit the toner image other than that portion.

By forming such a toner image, it is possible to reduce the amount of toner consumed during the work of forming the nip mark. In addition, the width of the nip trace can be measured without measuring a special length measuring device by the scales of a plurality of parallel short lines that are close to the rectangular portion.

The present invention is not limited to the above embodiments, but can be implemented in other modes by making appropriate design changes.

[0036]

As is apparent from the above description, in the image forming apparatus of the present invention, when the fixing nip mark forming mode is selected by the control means, the toner is transferred to a predetermined portion on the transfer material. -Forming an image and controlling so as to form a nip mark on a predetermined portion where the toner image is formed on the transfer material, the problems of the prior art are effectively solved, and the nip mark forming work is automatically performed. The toner image can be formed on the transfer material only in the area necessary for forming the nip trace, and the nip trace can be formed at a predetermined portion where the toner image is formed. Since the amount of toner consumed by the nip mark formation is reduced and the scale image forming means is provided to form the scale image on the nip mark formation portion, it is possible to easily measure the nip mark.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic copying machine that is an image forming apparatus to which the present invention is applied.

FIG. 2 is a plan view of a copy image on which a nip mark of FIG. 1 is formed.

FIG. 3 is a schematic configuration diagram of a laser beam printer which is an image forming apparatus to which the present invention is applied.

FIG. 4 is a diagram showing an image shape for forming a nip trace in FIG.

FIG. 5 is a plan view of a copy image on which a nip mark is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Exposure part 5 Transfer part 11 Charging device 13 Plank exposure device 14 Developing device 60 Laser beam exposure device 75 Conveying part 80 Fixing device 81 Fixing roller 83 Nip part 85 Paper passing detection sensor 90 Main control circuit Part A Toner image B Nip trace P Recording paper

Claims (3)

[Claims] 1. A toner image forming means for forming a toner image on a transfer material, and a toner image forming means for forming a toner image on a transfer material, the thermal roller fixing device including at least a fixing roller and a pressure roller. Conveying means for conveying the carried transfer material, detecting means for detecting the transfer material passing through the heat roller fixing device, and a shape of a pressure contact portion between the fixing roller and the pressure roller are formed. An image forming apparatus having a selecting means for selecting a fixing nip mark forming mode formed after the nip remaining on the transfer material, wherein the transfer material is selected when the fixing nip mark forming mode is selected by the selecting means. A toner image is formed on a predetermined portion on the transfer material, and the transfer material is conveyed to a pressure contact portion between a fixing roller and a pressure roller, and the predetermined portion on the transfer material where the toner image is formed is fixed on the fixing material. -While passing through the pressure contact part between the roller and the pressure roller, stop the conveyance and wait for a predetermined time after stopping. An image forming apparatus comprising: a control unit that controls the transfer material to be conveyed again after an excess. 2. The toner image according to claim 1, wherein the size of the toner image formed on a predetermined portion of the transfer material is 10 times or less the width of the nip mark formed on the portion. An image forming apparatus characterized by. 3. A toner image forming means for forming a toner image on a transfer material, and a toner image forming means for forming a toner image on a transfer material, the thermal roller fixing device including at least a fixing roller and a pressure roller. Conveying means for conveying the carried transfer material, detecting means for detecting the transfer material passing through the heat roller fixing device, and a shape of a pressure contact portion between the fixing roller and the pressure roller are formed. In an image forming apparatus having a selecting means for selecting a fixing nip mark forming mode to be formed after the nip remaining on the transfer material, a scale image forming means and the fixing nip mark forming mode are selected by the selecting means. At this time, a toner image and a scale image of a certain area are formed on a predetermined portion of the transfer material, and the transfer material is conveyed to a pressure-bonding portion of a fixing roller and a pressure roller and is transferred onto the transfer material. The fixed part where the toner image and the scale image of a certain area are formed is fixed. An image forming apparatus comprising: a control unit that stops the conveyance while passing the pressure contact portion between the roller and the pressure roller, and controls the conveyance of the transfer material again after a predetermined time has elapsed after the stop. .