JP2000235297A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a defective white-spotted image caused by discharge during image transfer regardless of the resistance of a recording material to be used. SOLUTION: This device is provided with a function for outputting a diagnosing chart for correcting the output of recording material carrier electrifying means (inner electrifier 5d and outer electrifier 5e) constituted of plural patch images. A user optionally accesses this function by the operation of a display constituted of a touch panel regularly, or at the time when a low density and a defective white-spotted image are caused in an outputted image, and the diagnosing chart is printed. The optimum patch in the diagnosing chart is selected from an image reference sheet, and the output correction value of the recording material carrier electrifying means corresponding to the patch is inputted from the display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus such as a copying machine or a printer, and more particularly to a recording material holding a visible image formed on an image carrier. The present invention relates to an image forming apparatus that transfers an image to a recording material on a body to form an image.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional color image forming apparatus. The color image forming apparatus shown in FIG. 5 has a digital color image reader section at the upper part and a digital color image printer section at the lower part.

In an image reader section, a document 30 is placed on a document table glass 31 and a reflected light image from the document 30 obtained by exposing and scanning with an exposure lamp 32 is
The light is condensed on the full-color sensor 34 by the lens 33 to obtain a color-separated image signal. This color-separated image signal is amplified by an amplifier circuit (not shown), processed by a video processing unit (not shown), and sent to a printer unit.

In a digital color image printer section,
The photosensitive drum 1, which is an image carrier, is a photosensitive member such as an organic photoconductor, and is rotatably supported in a direction indicated by an arrow in the figure. Around the photosensitive drum 1 is a photosensitive drum 1
A pre-exposure lamp 11 for initializing the surface, a corona charger 2 for uniformly charging the surface of the photosensitive drum 1, a photosensitive drum 1
A laser exposure optical system 3 for forming an electrostatic latent image corresponding to image information thereon, a potential sensor 12 for detecting a potential on the surface of the photosensitive drum 1, and developing the electrostatic latent image formed on the photosensitive drum 1 into a visible image For storing developers (toners) of different colors
A fixed arrangement of developing units 4C, 4M, 4Y, and 4K; a light detecting unit 13 for detecting an amount of toner on the photosensitive drum 1; a transfer device 5 including a transfer drum 5a as a recording material carrier; A cleaning unit 6 for removing the developer remaining on the drum 1 is provided.

[0005] In this embodiment, the laser exposure optical system 3
A polygon mirror 3a, a lens 3b, a mirror 3c, and the like. A laser beam E from a laser output unit modulated by a color image signal of each color separated from the reader unit is reflected by the polygon mirror 3a. Then, the image is projected on the surface of the photosensitive drum 1 through the mirror 3c to form an electrostatic latent image corresponding to a color image signal of each color.

At the time of image formation in the printer section, the photosensitive drum 1 is rotated in the direction of the arrow shown
1, the surface of the photosensitive drum 1 is neutralized and initialized, and then the surface of the photosensitive drum 1 is uniformly negatively charged by the charger 2, and a light image corresponding to an image signal of each color separated by the laser exposure optical system 3. E is sequentially irradiated onto the surface of the photosensitive drum 1 to form an electrostatic latent image in a predetermined color order.

Next, a predetermined developing unit is operated in the order of cyan (C), magenta (M), yellow (Y), and black (K), which are in a predetermined order of development, so that the latent image on the photosensitive drum 1 is formed. The toner image is developed and a toner image based on a resin is sequentially formed on the photosensitive drum 1. Here, each developing device 4 of the developing device 4
C, 4M, 4Y, and 4K are eccentric cams 24C, 24M, and 2C.
By the operations of 4Y and 24K, a required developing unit is configured to selectively approach the photosensitive drum 1 to perform a developing operation according to the color of the formed latent image.

On the other hand, the recording material cassette 7a, 7b or 7
From c (may be manual feed), pickup roller,
A recording material such as transfer paper fed by a transport system including a paper feed guide, a paper feed roller, and the like is wound around the transfer device 5 in synchronization with a predetermined timing.

In the present embodiment, the transfer device 5 includes a transfer drum 5a, a transfer charger 5b for transferring the toner image on the photosensitive drum 1 to the recording material P, and an adsorption device for adsorbing the recording material to the transfer drum 5a. It has a charger 5c, a suction roller 5g facing the suction charger 5c, a suction guide 5m for guiding the recording material to the suction position, and an inner corona charger 5d and an outer corona charger 5e.

A transfer sheet 5f made of a dielectric material, which is a recording material carrier, is integrally stretched in a cylindrical shape in a peripheral opening area of the transfer drum 5a which is rotatably driven. Have been. In this embodiment, a polycarbonate film having a thickness of 150 μm is used as the transfer sheet 5f.

In order to control the image density, a patch image of a fixed density is developed on the photosensitive drum 1 at a position not facing the recording material P on the transfer drum 5a during image formation, and a sensor (FIG. The density of the patch image is read by a CPU (not shown), the density is calculated by a CPU (not shown), toner is supplied to the developing device, and the image density is kept constant.

Prior to image formation, the transfer sheet 5f is uniformly charged by an inner charger 5d and an outer charger 5e, which are charging means for a recording material carrier. In the case of this example, the inner charger 5d and the outer charger 5e are each controlled with a constant current, and the transfer sheet 5f is stably charged by applying biases of opposite polarities.

On the other hand, the recording material is fed from the cassette 7a, 7b or 7c to the transfer device 5. Here, the suction roller 5g is brought into close contact with the transfer sheet 5f by a driving source (not shown), and a suction current (charge) is injected from the suction charger 5c. Since the suction roller 5g is electrically grounded, a current (charge) in the opposite direction (reverse polarity) to the current (charge) injected by the suction charger 5c is induced (induced). As a result, the recording material P Is attracted to the transfer sheet 5f by static electricity.

When the recording material is supplied to the transfer position by the transfer sheet 5f, the transfer charger 5b operates when the recording material passes, and the above-described color-separated toner images are transferred one by one to the recording material in synchronization. .

In the case of this embodiment, the transfer current is controlled by a constant current, and the absolute moisture content of the use environment is calculated from the value read by the environment sensor 36 which detects the temperature and humidity of the use environment. The value of the transfer current is determined by referring to the table.

In this embodiment, the mode can be selected depending on the type of recording material, and the type of recording material (thick paper,
The transfer current is set according to each of the coated papers.

Even when the transfer is performed by low voltage control, the above-described transfer current table based on the environmental control means and paper type is often used.

Since only one color image is formed in one image forming process, the color separation process of the original is performed by the number of toner colors, that is, yellow (Y), magenta (M), and cyan (C). , Black (K) four times to form a full-color image.

In the case of forming a full-color image, when the transfer of the four color toner images is completed in this way, the recording material P is discharged by the separating charger 5h, and then transferred by the action of the separating push-up roller 8b and the separating claw 8a. The toner image on the recording material P is separated from the drum 5 a and guided to the fixing device 9. The toner image on the recording material P is mixed and colored in this fixing process, and is discharged onto the external tray 10, thereby completing one full-color copy.

On the other hand, after the transfer, the photosensitive drum 1 is cleaned with a cleaning device 6 to remove the residual toner on the surface, and then subjected to the image forming process again.

When forming images on both sides of a recording material,
Immediately after the recording material is discharged from the fixing device 10, the conveyance path switching guide 19 is driven to transfer the recording material to the conveyance vertical path 20.
Through the inversion path 21a. Thereafter, the reversing roller 21 b is rotated in the reverse direction, and the recording material is retracted in a direction opposite to the direction in which the recording material was fed into the reversing path 1 a, with the rear end thereof as the head, and temporarily stored in the intermediate tray 22. Thereafter, the recording material is again conveyed from the intermediate tray 22 to the transfer device 5, and an image is formed on the other surface by the above-described image forming process.

Further, in order to remove powder adhering on the transfer sheet 5f of the transfer drum 5a and oil adhering to the recording material, a fur brush 14, a backup brush 15 facing the fur brush 14 via the transfer sheet 5f, an oil The cleaning is performed by the action of the backup brush 17 facing the oil removing roller 16 via the removing roller 16 and the transfer sheet 5f. Such cleaning is performed before or after image formation, and at any time when a jam (paper jam) occurs.

In this embodiment, the gap between the transfer sheet 5f and the photosensitive drum 1 can be arbitrarily set by operating the eccentric cam 25 at a desired timing and operating the cam follower 5i integrated with the transfer drum 5a. It can be set. For example, during standby (standby) or when the power is off, the interval between the transfer drum 5a and the photosensitive drum 1 is increased.

[0024]

However, in the conventional image forming apparatus as described above, when the resistance of the recording material to be used is low, a white spot-like image defect or the like due to generation of electric discharge at the time of transfer occurs, resulting in a good image formation. In some cases, a transferred image could not be obtained.

Accordingly, it is an object of the present invention to provide an image forming apparatus capable of preventing a white spot-like image defect due to discharge at the time of transfer regardless of the resistance of a recording material to be used.

[0026]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
An image carrier on which a visible image is formed, a recording material carrier for carrying a recording material onto which the visible image is transferred, and transporting the recording material to the image carrier, and an operation for transferring the visible image onto the recording material An image forming apparatus, comprising: a transfer charging unit for performing charging; a recording material carrier charging unit that operates to charge the recording material carrier before image formation; and an adjusting unit for adjusting output conditions of the recording material carrier charging unit. The image forming apparatus has a function of outputting an image for adjusting output conditions of the recording material carrier charging means.

According to one embodiment of the present invention, the charging bias correction value determined by the adjusting means can be arbitrarily registered in the storage means and arbitrarily called. It is preferable that the transfer charging unit performs constant current control. It is preferable that the recording material carrier charging means is an inner charger and an outer charger.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings. In the following description, the present invention is described as being embodied in the color image forming apparatus shown in FIG. Therefore, description of the overall configuration and functions of the color image forming apparatus will be omitted, and only the features of the present invention will be described.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS. A feature of the present embodiment is that a circuit or a program for outputting a diagnostic chart for correcting the output of the recording material carrier charging means including a plurality of patch images is provided. The recording material carrier charging means in this embodiment is an inner charger 5d and an outer charger 5e.

FIG. 1 shows a diagnostic chart for correcting the output of the recording material carrier charging means composed of a plurality of patch images output from the image forming apparatus of this embodiment.

FIG. 2 shows a state in which the output adjustment screen of the charging means for the recording material carrier is selected on the operation unit (not shown) of the image forming apparatus of this embodiment. The display 40 of the operation unit is a touch panel, and various functions can be selected. One of the functions is an output adjustment function of the recording material carrier charging means.

The user of the image forming apparatus according to the present embodiment can call this function arbitrarily by operating the touch panel 40, for example, when the output image has an image defect such as low density or white spot. Can be.

[0033] On the screen, yellow,
The output adjustment buttons 42, the chart output button 44, and the cancel button 46 for each of the charging means for the recording material carrier for magenta, cyan, and black are displayed.

The procedure for correcting the output of the actual charging means of the recording material carrier using the image forming apparatus of this embodiment and the operation of the image forming apparatus will be described below.

First, the user presses the diagnostic chart output button 44 to correct the output of the recording material carrier charging means composed of a plurality of patch images as shown in FIG. 1, that is, a diagnosis for correcting the charging bias value. The chart 100 is output. In the case of this embodiment, the diagnostic patch 100a has a size of 30 mm × 30 mm and an image density of 30%.
Is a single-color halftone image set to yellow (Y
For each of the colors (ellow), magenta (Magenta), cyan (Cyan), and black (Black), a value of ± 150 μA of the set value is output every 50 μA.

Further, in the vicinity of black, -150 to +1
50 characters (specifically, -150, -100, -50,
0, +50, +100, +150) 100b is printed. In this embodiment, the value (charging current) of the inner charger 5d is displayed. The value of the outer charger 5e is controlled to have the same absolute value at the opposite polarity.

Prior to image formation, an inner charger 5d and an outer charger 5e are arranged along the recording material advancing direction of the transfer sheet 5f.
± 150 μA of the set value (the value of the inner charger 5d)
Is charged stepwise within the range. At this time, in order to ensure the stability of the current, the interval between the patches with respect to the progress of the recording material is preferably separated by 5 mm or more.

As shown in FIG. 1, the patch has a preset value of ± 150 μA (inner charger 5d) along the recording material advancing direction.
Is transferred in order corresponding to the charged position in the range of

Subsequently, the user of the image forming apparatus according to the present embodiment operates the patch 100a of the output diagnostic chart 100.
, The most preferable one for each color is selected. At this time, it is more preferable to select an optimal patch using the image reference sheet 200 as shown in FIG.

Next, the output correction value of the recording material carrier charging means, which is written in the vicinity of the optimal patch of each selected color, is input from the display 40 of the operation unit. This completes the correction of the output of the recording material carrier charging means. The input correction value is written to a storage device (not shown) such as a RAM of the image forming apparatus, and thereafter, the image formation is performed by the above-described correction value until a new adjustment is performed or the data is deleted for some reason. Sometimes, the output of the recording material carrier charging means is corrected.

As described above, according to this embodiment, even when the resistance of the recording material to be used is low, it is possible to prevent the occurrence of a white spot-like image defect due to the occurrence of discharge at the time of transfer, and to obtain good transfer. .

Embodiment 2 Next, a second embodiment of the present embodiment will be described with reference to FIG.
This will be described with reference to (b) and (c).

In this embodiment, in the image forming apparatus shown in FIG. 5, the output correction value of the recording material carrier charging means determined by the output adjustment mode of the recording material carrier charging means is used.
It is arbitrarily registered in a storage device such as a RAM of the image forming apparatus,
The feature is that it can be called arbitrarily.

FIG. 4 shows a display screen of the operation unit in the image forming apparatus of the present embodiment, and the embodiment will be described with reference to FIG.

First, on the display screen 40A as shown in FIG. 4A, the user of the image forming apparatus adjusts the output of the recording material carrier charging means as in the first embodiment. Here, when the memory button 48 is pressed, FIG. 4B appears.

Next, on the display screen 40B of FIG. 4B, the user arbitrarily assigns a file name to the conditions for which the output has been adjusted, and presses the OK button 50 to save the settings.

The saved condition setting can be arbitrarily called up by the user instructing a fill name on the display screen 40C shown in FIG. 4C when forming an image under the same conditions thereafter. . (FIG. 4C) According to the configuration of this embodiment, even when the resistance of the recording material to be used is low, it is possible to prevent a white spot-like image defect due to generation of discharge at the time of transfer, and to obtain good transfer. Further, since the output of the charging means for the recording material carrier can be individually optimized for the recording material frequently used by the user of the image forming apparatus, the recording material carrier independent of the special recording material can be used. Since the output of the charging unit can be set, even when various types of recording materials are used, there is an advantage that it is not necessary to set each time.

[0048]

As is apparent from the above description, according to the present invention, an image bearing member on which a visible image is formed and a recording material on which the visible image formed on the image bearing member is transferred are supported. A recording material carrier to be conveyed to the image carrier, and a transfer charging unit that operates to transfer the visible image onto a recording material,
An image forming apparatus comprising: a recording material carrier charging unit that operates to charge the recording material carrier before image formation; and an adjustment unit that adjusts an output condition of the recording material carrier charging unit. A function of outputting an image for adjusting the output condition of the material carrier charging means is provided, and by adjusting the output of the recording material carrier charging means based on the output adjustment image, the resistance of the recording material used is reduced. Regardless, the occurrence of white spot-like image defects due to discharge at the time of transfer can be prevented, and a high-quality image can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a diagnostic chart of a first embodiment according to the present invention.

FIG. 2 is an explanatory diagram showing a display screen in the first embodiment.

FIG. 3 is an explanatory diagram showing an image reference sheet in the first embodiment.

FIG. 4 is a diagram showing a display screen of a second embodiment according to the present invention, showing output adjustment (a), setting saving (b), and calling a saved condition setting (c). .

FIG. 5 is an overall configuration diagram showing an example of a conventional color image forming apparatus in which the present invention is embodied.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum (image carrier) 5a transfer drum (recording material carrier) 5b transfer charger (transfer charging means) 5d inner charger (recording material carrier charging means) 5e outer charger (recording material carrier charging means) 40 Display screen 100 Diagnostic chart

Claims (4)

[Claims] 1. An image carrier on which a visible image is formed, a recording material carrier for carrying a recording material onto which the visible image is transferred and transporting the recording material to the image carrier, and applying the visible image on a recording material. Transfer charging means operating to transfer the image onto the recording material carrier, charging means operating to charge the recording material carrier prior to image formation, and adjustment for adjusting output conditions of the recording material carrier charging means An image forming apparatus having a function of outputting an image for adjusting an output condition of the recording material carrier charging unit. 2. The image forming apparatus according to claim 1, wherein the charging bias correction value determined by said adjusting unit can be arbitrarily registered in a storage unit and arbitrarily called up. 3. The image forming apparatus according to claim 1, wherein the transfer charging unit performs constant current control. 4. An image forming apparatus according to claim 1, wherein said recording material carrier charging means comprises an inner charger and an outer charger.