JPH07244445A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of preventing a deterioration in a photoreceptor due to loading/unloading in/from a device main body by controlling the driving of the photoreceptor so as not to stop its joint in a position corresponding to the open part of a process unit. CONSTITUTION:The position of the joint 41 of the photoreceptor 1 rotated along photoreceptor carrying rollers 3 and 4 is detected by a photoreceptor position detecting sensor 2 and the photoreceptor 1 is stopped in the position where the joint 41 is not in the open part 42 of the process unit 40. Therefore, at the time of taking in/out the process unit 40 from the opening part for loading/unloading of the device main body 43, the joint 41 is never damaged by its contact with the opening part for loading/unloading. Thus, a compact long-life image forming device can be provided.

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 which is small in size and can extend the life of a latent image carrier.

[0002]

2. Description of the Related Art Conventionally, printers of various principles have been proposed as output terminals for personal computers, workstations, etc., but a laser beam printer (hereinafter referred to as LBP) using an electrophotographic process and laser technology has been proposed. It is highly advantageous in terms of recording speed and print quality, and is rapidly becoming popular.

On the other hand, there is an increasing demand for full color LBP in the market, but in the case of full color LBP, it is necessary to stack toners of three primary colors of printing, cyan, magenta, yellow and black, so that a specific latent image carrier is formed. Each color image must be formed on top of it in the correct position. Generally, for this alignment, a method is used in which a reference mark is provided on a latent image carrier on which images are superimposed, and the image forming process for each color is started when the reference mark is detected.

The LBP which forms a color image by applying the electrophotographic process technique selectively irradiates a light beam corresponding to each color on a photosensitive member having a photosensitive layer to form an image, and forms an image among a plurality of predetermined color components. A method of forming a color image on one transfer material by developing a plurality of electrostatic latent images corresponding to the specific components of the above with respective predetermined toners and superposing the toner images of the single color ing.

Next, a conventional image forming apparatus will be described. FIG. 5 is a block diagram of a conventional image forming apparatus. In FIG. 5, reference numeral 1 denotes a photoconductor in which a photosensitive layer such as an organic photoconductor (OPC) is applied in a thin film on the outer peripheral surface of a Ni (nickel) belt substrate, and has a structure having a seam 1. ing. Reference numeral 2 denotes a photoconductor position detection sensor that detects the reference position of the photoconductor 1, and detects the reference position by a photoconductor reference mark such as a slit arranged at one end of the photoconductor 1. Photoconductor 1
Is supported by two photoconductor transport rollers 3 and 4 so that a vertical plane is formed between the photoconductor transport rollers 3 and 4,
A photoconductor transport roller 3, by a drive motor (not shown)
It rotates along arrow 4 in the direction of arrow a.

On the peripheral surface of the belt-shaped photoconductor 1, along the rotation direction thereof, a charger 5, an exposure optical system 6, a black (K),
The developing devices 7K, 7Y, 7M, and 7C for yellow (Y), magenta (M), and cyan (C), the intermediate transfer body unit 8, the photoconductor cleaning device 9, and the neutralizer 10 are provided. 31K, 31Y, 31M and 31C are developing sleeves provided in front of the developing devices 7K, 7Y, 7M and 7C. The charger 5 includes a charging wire 11 made of a tungsten wire or the like, a shield plate 12 made of a metal plate, and a grid plate 13. -4 to charging line 11
By applying a high voltage of about 000 V to -5000 V, the charging line 11 causes corona discharge, and the grid plate 1
The photoconductor 1 is uniformly charged via 3.

An exposure light beam 14 is emitted from the exposure optical system 6. The exposure light beam 14 is obtained by subjecting an image signal from a gradation conversion device (not shown) to light intensity modulation or pulse width modulation by a laser drive circuit (not shown), and a static image corresponding to a specific color on the photoconductor 1. Form a latent image. Each developing device 7K, 7Y,
7M and 7C store toners corresponding to the respective colors. The development of each color corresponds to each color, and both ends of the separation cams 15K, 15Y, 15M are rotatably supported by the machine body.
15C rotates in response to the color selection signal, and the selected developing device, for example, the developing device 7K is brought into contact with the photoconductor 1 to carry out. At this time, the unselected developing devices 7Y, 7M, and 7C are separated from the photoconductor 1. The intermediate transfer body unit 8 is a seamless loop belt-shaped intermediate transfer body 16 made of a conductive resin or the like.
And two intermediate transfer member conveying rollers 17 and 18 supporting the intermediate transfer member 16 and the intermediate transfer member 16 for transferring the toner image on the photosensitive member 1 to the intermediate transfer member 16 so that the intermediate transfer member 16 is exposed. It has an intermediate transfer roller 19 arranged so as to face the body 1.

Reference numeral 20 denotes an intermediate transfer member cleaning device for scraping off the residual toner on the intermediate transfer member 16, and while the composite image is being formed on the intermediate transfer member 16, the intermediate transfer member 1 is provided.
It is separated from 6, and contacts only when it is used for cleaning. Reference numeral 21 is a recording paper cassette that houses recording paper 22. The recording papers 22 are sent from the recording paper cassette 21 one by one to a paper transport path 24 by a half-moon shaped paper feed roller 23. Reference numeral 25 denotes a registration roller for temporarily stopping and waiting the recording paper 22 in order to match the positions of the recording paper 22 and the composite image on the intermediate transfer body 16, and is in pressure contact with the driven roller 26. Reference numeral 27 denotes a transfer roller for transferring the composite image on the intermediate transfer body 16 to the recording paper 22, which rotates in contact with the intermediate transfer body 16 only during transfer. Reference numeral 28 denotes a fixing device composed of a heat roller 29 having a heat source inside and a pressure roller 30, and the combined image transferred onto the recording paper 22 is subjected to pressure and heat as the heat roller 29 and the pressure roller 30 sandwich and rotate. Then, the image is fixed on the recording paper 22 to form a color image.

The operation of the image forming apparatus configured as described above will be described below. Image development is performed in the order of black (K), cyan (C), magenta (M), and yellow (Y). The photosensitive member 1 and the intermediate transfer member 16 are driven by respective drive sources (not shown), and are controlled so that their peripheral speeds are the same constant speed. In this state, first, a high voltage of about −4000 V to −5000 V is applied to the charging wire 11 in the charger 5 connected to the high voltage power source to cause corona discharge, and the surface of the photoconductor 1 is uniformly set to about −700 V. Charge. Next, the photosensitive member 1 is rotated in the direction of arrow a, and an exposure light beam 14 of a laser beam corresponding to a predetermined black (K) of a plurality of color components is formed on the surface of the uniformly charged photosensitive member 1. Upon irradiation, the electric charge disappears in the irradiated portion on the photoconductor 1 to form an electrostatic latent image. On the other hand, the developing device 7K for black (K) is pressed in the direction of arrow b by the rotation of the separation cam 15K and comes into contact with the photoconductor 1 after the elapse of a predetermined time. On the other hand, immediately before contact, a negative potential of about -300 V is applied to the developing sleeve 31K having toner on its surface. If the toner is given a negative charge in advance, the photoconductor 1
The toner adheres only to the portion (electrostatic latent image portion) where the upper exposure light beam is irradiated and the charge is removed, and development is performed by a so-called negative-positive process.

The developing device 7K, which has completed development, has a separating cam 15
The rotation of K by 180 degrees moves from the contact position with the photoconductor 1 to the separated position. The toner image formed on the photoreceptor 1 by the developing device 7K is transferred to the intermediate transfer body 16 by applying a high voltage of +800 V to the intermediate transfer roller 19 arranged in contact with the photoreceptor 1 for each color. The residual toner that has not been transferred from the photoconductor 1 to the intermediate transfer body 16 is removed by the photoconductor cleaning device 9, and the charge on the photoconductor 1 from which the residual toner has been scraped off is removed by the static eliminator 10.

Next, when the color of cyan (C) is selected, the separation cam 15C is rotated, and this time the developing device 7C is pushed toward the photoconductor 1 and brought into contact with the photoconductor 1 to develop the cyan (C). To start. In the case of a copying machine or printer that uses four colors, the above-described developing operation is sequentially repeated four times, and the intermediate transfer member 16
Four color black (K), cyan (C), magenta (M), and yellow (Y) toner images are superimposed on each other to form a composite image. In the composite image thus formed, the transfer roller 27, which has been separated so far, comes into contact with the intermediate transfer member 16, applies a high voltage of about +1000 V to the transfer roller 27, and conveys the paper from the recording paper cassette 21 by pressure. It is collectively transferred to the recording paper 22 sent along the path 24.

Subsequently, the recording paper 22 on which the toner image is transferred is sent to a fixing device 28, where it is fixed by the heat of the heat roller 29 and the clamping pressure of the pressure roller 30 and is output as a color image. The residual toner on the intermediate transfer body 16 which is not completely transferred onto the recording paper 22 by the transfer roller 27 is removed by the intermediate transfer body cleaning device 20. The intermediate transfer body cleaning device 20 is at a position apart from the intermediate transfer body 16 until a single composite image is obtained. A composite image is obtained, and the composite image is transferred by the transfer roller 27 to the recording paper 22.
After being transferred to, the toner comes into contact and the residual toner is removed. The above operation completes the recording of one image.

[0013]

In the above-mentioned conventional configuration, when the process unit is attached to or detached from the main body of the apparatus at the time of system debugging or service maintenance of the apparatus, the seam of the photosensitive member 1 made of a belt opens the process unit. When the process unit is attached or removed, the seam portion expands outward due to the internal stress of the belt, so that the seam portion comes into contact with the edge of the opening / closing opening opened in the apparatus main body, It has a problem that the joint portion is easily damaged. However, this problem can be solved by enlarging the size of the apparatus main body, but this method is not preferable because the apparatus is required to be downsized.

The present invention solves the above-mentioned conventional problems. When the process unit is attached to or detached from the apparatus body, the seam of the latent image carrier contacts the edge of the opening / closing opening formed in the apparatus body. It is an object of the present invention to provide an image forming apparatus that can realize a long life of the latent image carrier without doing so.

[0015]

In order to achieve this object, the present invention accommodates a latent image carrier having a seam and a conveying roller for rotating the latent image carrier, and the latent image carrier is An image forming apparatus including a process unit having an open opening for exposing and a main body of an apparatus having an opening for taking in / out the process unit, and a sensor for detecting a position of a seam and the sensor. On the basis of the position of the seam detected in step 1, the control means for controlling the rotation of the latent image carrier is provided so that the seam does not stop at the position exposed from the opening.

[0016]

According to the above construction, the joint of the latent image carrier is not exposed from the open portion of the process unit in the state where the rotation of the latent image carrier is stopped. Therefore, the process unit can be attached / detached during system debugging or service maintenance. It is possible to prevent deterioration of the latent image bearing member due to the above.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The configuration of the image forming apparatus according to the embodiment of the present invention is the same as the configuration of the conventional image forming apparatus shown in FIG. In FIG. 5, the photoconductor 1 and the intermediate transfer member 16 are each driven by a drive source (not shown), and are controlled so that their peripheral speeds are the same constant speed. A photoconductor reference mark for determining the photoconductor reference position is provided at one end of the photoconductor 1 so that the photoconductor position detection sensor 2 can detect the photoconductor reference position.

When a print command is input, first, the charging wire 11 in the charger 5 connected to the high-voltage power supply is supplied with −4000V to −.
Apply a high voltage of about 5000 V to cause corona discharge,
The surface of the photoconductor 1 is uniformly charged to about -700V.
Next, the photoconductor 1 is rotated in the direction of the arrow a, and an exposure light beam 1 of a laser beam corresponding to a predetermined black (K) of a plurality of color components is formed on the surface of the photoconductor 1 which is uniformly charged.
When 4 is irradiated, the electric charge disappears in the irradiated portion on the photoconductor 1 and an electrostatic latent image is formed. Black (K) developer 7
After a predetermined time has passed, K is pushed in the direction of arrow b by the rotation of the separation cam 15K and comes into contact with the photoconductor 1. On the other hand, immediately before the contact, the developing sleeve 31K having the toner on the surface thereof is -300V.
Apply a negative potential. If a negative charge is given to the toner in advance, the toner adheres only to a portion (electrostatic latent image portion) on the photoconductor 1 where the exposure light beam is irradiated and the charge is removed, and the development is performed by a so-called negative-positive process.

The developing device 7K, which has completed development, has a separating cam 15
The rotation of K by 180 degrees moves from the contact position with the photoconductor 1 to the separated position. The toner image formed on the photoconductor 1 by the developing device 7K is transferred to the intermediate transfer body 16 by applying a high voltage of about +800 V to the intermediate transfer roller 19 arranged in contact with the photoconductor 1 for each color. Residual toner that has not been transferred from the photoconductor 1 to the intermediate transfer body 16 is removed by the photoconductor cleaning device 9, and the static eliminator 10 is further removed.
Thus, the charges on the photoconductor 1 from which the residual toner is scraped off are removed.

Next, when cyan (C) color is selected, the separation cam 15C is rotated, and this time the developing device 7C is pushed toward the photoconductor 1 and brought into contact with the photoconductor 1 to develop cyan (C). To start. In the case of a copying machine or printer that uses four colors, the above-described developing operation is sequentially repeated four times, and the intermediate transfer member 16
Four color black (K), cyan (C), magenta (M), and yellow (Y) toner images are superimposed on each other to form a composite image. Also in the cyan printing process, the reference of the image forming timing is the intermediate transfer member reference position. The composite image formed in this way is transferred to the transfer roller 2 which has been separated until now.
7 comes into contact with the intermediate transfer member 16, and the transfer roller 27 has +10.
A high voltage of about 00 V is applied, and the pressure is applied to the recording paper 22 sent from the recording paper cassette 21 along the paper transport path 24 in a batch.

Subsequently, the recording paper 22 to which the toner image is transferred is sent to a fixing device 28, where it is fixed by the heat of the heat roller 29 and the holding pressure of the pressure roller 30 and is output as a color image. The residual toner on the intermediate transfer body 16 which is not completely transferred onto the recording paper 22 by the transfer roller 27 is removed by the intermediate transfer body cleaning device 20. The intermediate transfer body cleaning device 20 is at a position apart from the intermediate transfer body 16 until a single composite image is obtained. A composite image is obtained, and the composite image is transferred by the transfer roller 27 to the recording paper 22.
After being transferred to, the toner comes into contact and the residual toner is removed. The above operation completes the recording of one image.

Next, a control method for driving the photoconductor 1 will be described with reference to the drawings, in which the drive of the photoconductor 1 is stopped when the seam of the photoconductor 1 is located in a portion where the process unit is not opened. 1 is a block diagram of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart of the operation of the image forming apparatus, FIG. 3 is a configuration diagram of a process unit of the image forming apparatus, and FIG. 4 is the image forming apparatus. It is a figure which shows attachment / detachment of the process unit.

In FIG. 1, A is a central processing unit (CPU) for controlling the photoconductor drive control means B, the photoconductor position detection means G, and the timer value counting means D, and E
Is a ROM in which a program for operating each control means is stored, and F is a RAM which serves as a work area for processing variables and the like required when the program is executed.

Further, in FIG. 3, the process unit 4
On the side surface of 0, an open portion 42 exposing the photoconductor 1 is largely opened. The seam 41 of the photoconductor 1 bulges to the outside of the process unit 40 due to the internal stress of the photoconductor 1. Here, as shown in FIG. 3, when the photoconductor 1 stops rotating with the joint 41 of the photoconductor 1 positioned at the open portion 42 of the process unit 40, as shown in FIGS. When the paper is taken in and out through the opening / closing opening 44 opened in the apparatus main body 43, the joint 41 of the photoconductor 1 comes into contact with the edge of the opening / closing opening 44, and the photoconductor 1 is damaged. To prevent this,
It is necessary to stop the driving of the photoconductor 1 in a state where the joint 41 of the photoconductor 1 is not in the opening / closing opening 44 of the apparatus main body 43. Next, the sequence will be described with reference to FIG.

After the photoconductor drive motor stop request is issued due to the end of printing or the warm-up (step 1), the position of the joint 41 of the photoconductor 1 is detected (step 2). This can be performed by using the photoconductor position detection sensor 2 that serves as a reference for image formation and detecting the photoconductor reference position at one end of the photoconductor 1. The detection is repeated until the photoconductor reference position is detected, and after the photoconductor reference position is detected, the timer is set (step 3). The timer value set by the timer is set in consideration of the distance between the photoconductor reference position and the joint 41 of the photoconductor 1, and the mounting position of the photoconductor position detection sensor 2. That is, the time is set until the photoconductor position detection sensor 2 detects the photoconductor reference position and the joint 41 of the photoconductor 1 reaches the process unit housing portion. After that, the timer value is decremented at regular intervals (step 4), and when the timer value becomes 0 (step 5), the photoconductor 1
Is stopped (step 6). According to the above method, the driving of the photoconductor 1 can be stopped when the joint 41 of the photoconductor 1 is not in the opening / closing opening 44 of the apparatus main body 43.

[0026]

As described above, according to the present invention, the latent image carrier having a joint and the conveying roller for rotating the latent image carrier are housed, and the opening portion for exposing the latent image carrier is opened. In an image forming apparatus including the processed process unit and an apparatus main body having an opening / closing opening for inserting / removing the process unit, a sensor for detecting a position of a seam, and a seam detected by the sensor. Based on the position, the control means for controlling the rotation of the latent image carrier is provided so that the seam does not stop at the position corresponding to the open portion. Therefore, the rotation of the latent image carrier is stopped. Therefore, the seam is not exposed from the open part of the process unit, and therefore the process unit is attached to the device body during system debugging and service maintenance. Sometimes, as the seam does not contact the edge of the loading and unloading opening can be prevented the deterioration of the latent image bearing member, it can be realized an image forming apparatus attained the life of small and consumables.

[Brief description of drawings]

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

FIG. 2 is a flowchart of the operation of the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a configuration diagram of a process unit of an image forming apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing attachment / detachment of a process unit of an image forming apparatus according to an embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional image forming apparatus.

[Explanation of symbols]

 1 Photoconductor 2 Photoconductor Position Detection Sensor 3 Photoconductor Conveying Roller 4 Photoconductor Conveying Roller 40 Process Unit 41 Seam 42 Opening Part 43 Device Main Body 44 Opening / Closing Opening A Central Processing Arithmetic Device B Photoconductor Driving Control Means

Claims (1)

[Claims] 1. A process unit in which a latent image carrier having a seam and a conveying roller for rotating the latent image carrier are housed, and an opening for exposing the latent image carrier is opened, and the process unit. An image forming apparatus having an apparatus main body in which an opening / closing opening for taking in and out is opened, based on a sensor for detecting the position of the joint, and the position of the joint detected by this sensor, An image forming apparatus comprising: a control unit that controls rotation of the latent image carrier so that the joint does not stop at a position exposed from the opening.