JPH02257149A - Image forming device - Google Patents

Abstract

PURPOSE:To convey a paper to a transfer means with high accuracy and to stabilize transfer efficiency by integrally incorporating a drum-like photosensitive body and a transfer means in a developing unit and providing a paper conveying guide in the transfer means. CONSTITUTION:The drum-like photosensitive body 20 and the transfer means 24 are integrally incorporated in the developing unit 23 and the paper conveying guide 24 is provided in the transfer means 24. The paper conveying guide 24 is formed of a turnable roller and the transfer means 24 is attachably and detachably positioned and mounted in the developing unit 23. Even if the paper is conveyed to the transfer means 24 on the upper side of the drum-like photosensitive body 20, the transfer efficiency is stabilized and the cleaning after transfer is surely executed in the developing unit 23 by thus constituting the device. Thus, the transfer efficiency is stabilized and the cleaning is performed in the developing unit so as not to influence image quality in next printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to an improvement in an image forming apparatus such as a laser printer or an electronic copying machine.

(Prior Art) Conventionally, in this type of image forming apparatus, for example, a laser printer, an image carrier (hereinafter referred to as
This is called a drum-shaped photoreceptor).
By converting the electrophotographic processing device, which serves as an image forming process means with simultaneous development cleaning, transfer, memory removal, fixing, and other functions, into a cartridge, it can be loaded in a replaceable manner as needed, allowing for regular maintenance and inspection work. Some devices have a simple configuration.

With conventional laser printers like this,
The paper fed to the electrophotographic process is conveyed so as to pass under the drum-shaped photoreceptor, and a movable or fixed paper conveyance guide is attached to the main body of the apparatus.

In addition, as a cleaning means for the image bearing member, by cleaning the developer (hereinafter referred to as toner) on the drum-shaped photoreceptor after transfer with a blade, even if the transfer efficiency decreases, the next print can be performed. This ensures that image quality is not affected.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional image forming apparatus, by providing a movable or fixed four paper feed guide on the apparatus main body side, a constant level between the photoreceptor and the transfer means is provided. The current situation is to maintain the transfer efficiency of .

However, in an image forming apparatus configured to transport paper so that it passes above a ram-shaped photoreceptor 1, a paper transport guide is provided on the main body of the apparatus in a movable or fixed manner. , transfer efficiency tends to become unstable,
This makes it very difficult to maintain transfer efficiency.

Further, when the transfer efficiency decreases in this way, it becomes impossible to clean the inside of the developing unit, which causes a problem of affecting the image quality of the next print.

The present invention has been made under the above circumstances, and an object thereof is to provide an image forming apparatus that does not affect the image quality of the next pudding 1.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method for conveying paper to a transfer means constituting an image forming process means by transferring the paper to an image position corresponding to a developing unit. An image forming apparatus in which the image bearing member and the transfer means are integrated into a developing unit, and the transfer means is provided with a paper conveyance guide. Preferably, the guide is formed of a rotatable roller, and the transfer means is removably positioned and mounted on the developing unit 1-.
.

(Function) That is, in the present invention, the image carrier and the transfer means are
Since the transfer means is integrated with the T unit and the transfer means is provided with a paper conveyance guide to the transfer means, the transfer efficiency can be stabilized even if the paper is conveyed to the transfer means above the image carrier. In addition, post-transfer cleaning can be performed reliably within the developing unit.

(Example) Hereinafter, the present invention will be described in detail with reference to an illustrated example.

FIG. 2 shows the external appearance of a laser printer as an electrophotographic image forming apparatus using a semiconductor laser, and FIG. 3 shows its internal configuration.

This laser printer is connected to a host system (not shown), which is an external output device such as a computer or word processor, via a transmission controller such as an interface circuit, and receives a print start signal from the host system. It starts the image recording operation, records on paper as a transfer material, and outputs the image.It has the following configuration.

That is, as shown in FIGS. 2 and 3, reference numeral 1 in the figures is a main body of the apparatus, and a main control board 2 is disposed in the center of the main body 1 of the apparatus. Behind this main control board 2 (third
An electrophotographic process unit 3 for forming an image is arranged on the right side (in the state shown in the figure), and a control board accommodating a plurality of control boards 4 for adding functions is located at the front lower part of the unit 3. The storage section 5 is in a state in which a paper discharge section 6 is formed at the front upper part thereof.

In the control board accommodating section 5, up to three control boards 4 for adding functions can be installed depending on the degree of addition of functions, such as adding more types of kanji, etc. Further functions can be added by inserting an IC card 8 for adding functions into the IC card connector 7 on the front edge side of the control board 4 for adding functions located at the bottom. There is. Furthermore, two interfaces (not shown) are provided on the left end surface of the control board 4 for adding functions located at the bottom, and these interfaces are formed on the left side surface of the device main body 1. It is arranged to face the opening 9 .

Further, in the figure, numeral 10 is a cassette accommodating portion that accommodates a paper feed cassette formed in the lower part of the apparatus main body 1.

As shown in FIG. 2, the single-load paper ejection section 6 consists of a recess formed on the front upper surface of the apparatus main body, and a paper ejection tray 2 is located at the front edge of the recess, as shown in solid lines. It is provided to be rotatable for folding and unfolding in the direction of the arrow, and the size of the paper discharge section 6 can be adjusted according to the size of the paper P to be discharged.

Further, on the upper surface of the left frame portion 1a of the apparatus main body 1 located on the left side of the paper ejecting portion 6, a control panel 16 is provided with display LEDs, 3.2-digit status display segments 1 to 14, and a switch 15. On the other hand, a manual feed tray 17 is attached to the rear end surface side of the apparatus main body 1.

Next, the installation of the electrophotographic process unit 3, which performs image forming process means such as charging, exposure, development, transfer, peeling, cleaning, and fixing, will be described in detail with reference to FIG.

In the figure, reference numeral 20 denotes a drum-shaped photoreceptor as an image carrier, which is located approximately in the center of the unit housing section in the main body 1 of the apparatus. Around the photoconductor 20, along the direction of rotation thereof, a charging means 21 made of a scorotron, an exposure section 22a of a laser exposure unit 22 as an electrostatic latent image forming means,
A magnetic brush type developing unit 23 that simultaneously performs a developing process and a cleaning process, a transfer means 24 made of a scorotron, a memory removing means 25 made of a brush member, and a pre-exposure means 26 are arranged in this order.

Reference numeral 29 in the figure denotes a paper conveyance path formed in the apparatus main body 1, in which paper P is fed from the paper feed cassette 11 via the paper feed means 27 and paper manually fed from the manual feed tray 17. P to the upper side of the photoreceptor 20 and the transfer means 24
The sheet is guided to the discharge section 6 via the image transfer section 28 between the sheet conveyance path 29 and the image transfer section 28, and a pair of aligning rollers 31
A pair of transport rollers 32 are arranged, and a fixing unit 40, which will be described later, is arranged downstream thereof.

In the figure, 33 is a cooling fan unit disposed above the pair of transport rollers 32, 34 is an aligning switch provided near the pair of aligning rollers 31, and 35 is a discharger disposed downstream of the fixing unit 40. Paper roller units 1-.

As shown in FIG. 1, each of the developing units 1 to 23 includes a magnet roller 232 and first and second agitating rollers 233 within a casing 231 containing a developer T.
The cartridge body 230 includes a photoreceptor 20 corresponding to the magnet 1-roller 232, and a charging means 21 and a memory removing means located around the photoreceptor 20. 25 are assembled together to form a cartridge as a whole, and a transfer means 24 is removably attached to the upper part of the cartridge body 230 via a support member 235, and a lower part of the transfer means 24 is , a paper conveyance guide extending upstream of the image transfer section 28 is provided.

Furthermore, 100 in the figure is the aforementioned cartridge 1-ridge body 230.
This paper waste removal brush 1 is removably provided at a position corresponding to the aligning roller pair 31 of the paper waste removal brush 1.
00 is the cartridge 1-ridged developing unit 23
When loaded into the apparatus main body 1, paper scraps adhering to the aligning roller pair 31 are scraped off by contacting with the lower roller 31a of the aligning roller pair 31, thereby removing paper scraps that have an adverse effect on image formation. It is designed to prevent paper waste from entering the image transfer section 28.

When a print start signal is received from the host system, the drum-shaped photoreceptor 2o rotates and the photoreceptor 20
is charged by the charging means 21. Next, the laser beam a modulated in response to the dot I-image data from the host system is scanned and exposed onto the photoconductor 2o using the laser exposure units 1 to 22, thereby exposing the photoconductor 20 to light. Forms an electrostatic latent image corresponding to an image signal. This electrostatic latent image on the photoreceptor 20 is developed and visualized by a 1-ner in a developer magnetic brush (not shown) in the developing units 1 to 23.

On the other hand, the paper is taken out from the paper feed cassette 11 periodically during the forming operations of the 1 to 3 color images, or the paper is removed from the manual feed tray
When the sheet P manually fed from the sheet P is fed through the pair of aligning rollers 31, the toner image previously formed on the photoreceptor 20 is transferred onto the sheet P by the action of the transfer means 24. After this transfer, the paper P passes through the paper conveyance path 29 and is sent to the fixing unit 40.
- After the toner image is fused and fixed on the paper P, it is discharged to the paper discharge section 6 via the paper discharge roller units 1 to 35. In this case, the toner image is transferred onto the paper P. The residual 1-toner remaining on the subsequent photoreceptor 20 is removed by a memory removing means 25 consisting of a conductive brush, thereby removing the memory.

Further, as shown in FIG. 4, each of the fixing units 1 to 40 includes a heat roller 43 having a built-in heater lamp 42 in a casing 41, and a pressure roller 44 which is brought into pressure contact with the upper side of the heat roller 43. By passing the paper P between rollers 43 and 44 serving as fixing rollers, the 1-toner image is melted and fixed onto the paper P. The pressure roller 44 is moved upward by a push-up mechanism (not shown) that is linked to the rotation of a pressure release lever 46 that is pivotally supported on the upper part of the casing 41 via a shaft 45, and the heat roller 43 is moved upwardly. The pressurized state is released with an interval of 1 mm or less between the two. Further, at a position corresponding to the pressure roller 44 of the shaft support end 46a of the pressure release lever 46,
A cleaning member 47 is provided, and this cleaning member 47 has a laminated structure in which a felt member 49 impregnated with silicone oil is integrally attached to an intermediate member 48 made of a cushioning material such as mol-1-prene. has.

That is, when a paper conveyance abnormality such as a jam occurs in the fixing unit 40, the pressure release lever 46 is rotated to release the pressure roller 44 as shown in FIG.
At the same time, the cleaning member 47 is brought into contact with the pressure roller 44 to clean the fixing rollers 43 and 44 by releasing the operation or the pressure, thereby removing the toner from the toner before fixing. This prevents the rollers 43 and 44 from becoming dirty and maintains the image quality of the next print, and also narrows the width of the drive release or pressure release of the fixing unit 40.

Furthermore, 5o in the figure is a top cover that covers the upper surface of the device main body 1, and this top cover 50 rotates by a maximum of 120° around a support shaft 51 provided at the upper rear end side of the device main body 1. When the top cover 50 is opened, most of the paper transport path 29 and equipment facing the paper transport path 29 are exposed, and the paper transport path 29 This makes it easy to remove crystals from the paper P in progress and to easily inspect, maintain, and replace equipment.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[Effects of the Invention] As is clear from the above description, according to the present invention, paper conveyance to the transfer means constituting the image forming process means is
An image forming apparatus in which the image bearing member and the transfer means are integrated into the development unit, and the transfer means is provided with a paper conveyance guide. Therefore, it is possible to achieve miniaturization, and even if the paper is transported to the transfer means above the image carrier, the paper can be transported to the transfer means with high precision.
This makes it possible to stabilize the transfer efficiency.

Further, by stabilizing the transfer efficiency, development can be performed in the same manner as cleaning within the development unit, and the image quality of the next print can be improved, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a schematic enlarged sectional view showing an embodiment of a developing unit of a laser printer as an image forming apparatus according to the present invention, FIG. 2 is an external view showing the overall configuration of the laser printer, and FIG. FIG. 4 is a schematic enlarged cross-sectional view of the fixing unit, and FIG. 5 is a schematic enlarged view showing the pressure release state of the pressure opening of the fixing unit. FIG. 1 . . 3 . . 20 . 23 . 24 . 29 . 31 . 32 . T . , ...Cartridge body, ...Supporting member, ...Transfer means, ...Paper transport guide, ...Paper transport path, ...Aligning roller pair, ...Transport roller pair, -Laser beam, -Developing agent (toner), P...paper.

Claims (1)

[Claims] In an image forming apparatus in which paper is conveyed to a transfer means constituting an image forming process means by passing over an image bearing member located corresponding to a developing unit, the image bearing member and the transfer means are integrated into the developing unit. 1. An image forming apparatus, characterized in that the image forming apparatus is incorporated in the image forming apparatus, and the transfer means is provided with a paper conveyance guide.