JPH11208896A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device having the small size and the small installation area, and excellent in conveying performance of a sheet material. SOLUTION: A rotary shaft of a motor 4 is approximately horizontally arranged, a light beam emitted upward from a polarizing scanning means 5 is reflected by a reflection mirror 6 and irradiated to a sensitive body 1 so as to draw an incident light locus surface 9 at about 25 deg. in relation to the gravity direction. A paper feeding tray 16 is so locked that a sheet material P may be held on a sheet material placing member 17 of a sheet feeding part at about 25 deg. in relation to the gravity direction, and a paper discharging tray 35 is so constituted that a sheet material P discharged from a discharging roller 32 may be held at about 25 deg. in relation to the gravity direction. The paper sheets P are sequentially discharged into the sheet material placing surface 36 of the paper discharging part in the face down state.

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 using an electrophotographic method such as a printer or a facsimile, and more particularly, to an image forming apparatus having a characteristic in the arrangement of sheet materials.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a paper feed cassette (sheet material storing means), an image forming apparatus main body, and a discharge tray (discharge sheet material storing means) are linearly arranged. And requires a large image forming apparatus main body volume and a large image forming apparatus installation area.

Therefore, in an image forming apparatus typified by a printer or a facsimile, as a measure for solving such a problem, a sheet material storage means and a discharged sheet material as disclosed in JP-A-4-339678 are disclosed. There has been proposed a device in which the accommodation means is arranged vertically to reduce the body volume and the installation area.

[0004]

However, in the above-mentioned prior art, since the installation state of the sheet material in the sheet material storing means and the discharged sheet material storing means is unstable, the sheet material is not used depending on the width of the sheet material used. If the sheet is conveyed greatly skewed, or if a sheet of high humidity is used, the sheet may not be conveyed, causing a feeding failure, the sheet may curl under its own weight, or a paper jam may occur if the sheet is curled. This causes a problem in that the sheet material is not arranged in the order of the ejected pages.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an image forming apparatus capable of stably conveying a sheet material with a simple configuration without increasing the size of the apparatus. Is to provide. Another object of the present invention is to provide an image forming apparatus having a small installation area under conditions that allow stable storage and conveyance of sheet materials.

[0006]

According to the present invention, there is provided an image forming apparatus comprising: a sheet material storing means for placing a sheet material; a feeding means for feeding the sheet material from the sheet material storing means; Transfer means for transferring the transferred toner image to the sheet material, fixing means for fixing the toner image transferred on the sheet material to the sheet material, discharge means for discharging the sheet material having the toner image fixed thereon, discharge The discharged sheet material accommodating means for placing the resulting sheet material so that the surface on which the toner image is fixed faces down, and the light beam emitted from the light emitting element is exposed to the photoconductor via a deflection scanning means. An exposure unit for forming a latent image, wherein the surface of the sheet material storage unit and the sheet material storage unit on which the sheet material is placed is placed on the same side with respect to the direction of gravity by 10 to 40. Incline Characterized in that disposed.

According to the present invention, the surfaces of the sheet material storage means and the discharged sheet material storage means on which the sheet material is placed are inclined at the same side with respect to the direction of gravity at an angle of 10 to 40 degrees, thereby reducing the size. Because the installation area is small, the sheet material slides and locks with each other by its own weight, the edges are aligned, and it is held without curling by its own weight, so the sheet material is fed and held stably, An image forming apparatus having excellent sheet material storability and transportability can be obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a main part showing an embodiment of the image forming apparatus of the present invention.

In the present invention, since the image forming apparatus is formed by using the electrophotographic method, first, the image forming process of the present embodiment will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a drum-shaped photoreceptor. The photoreceptor 1 is an organic photoreceptor having a charge generation layer and a charge transport layer formed in this order on an alumite-treated aluminum drum. After the photosensitive member 1 is charged to a predetermined potential by a charging unit, an electrostatic latent image is formed by an exposing unit, toner is adhered to the electrostatic latent image by a developing unit, and the electrostatic latent image is visualized. The transfer unit transfers the sheet to the sheet material conveyed from the sheet feeding unit, then the fixing unit fixes the toner image to the sheet material, and the sheet unit on which the desired image is formed is discharged by the sheet discharging unit. After the transfer, the photoreceptor 1 has its residual toner removed from the surface by the cleaning means, and then the charging and subsequent processes are repeated again. This process is described in detail below.

In the drawing, reference numeral 2 denotes a charging roller serving as a charging means. The charging roller 2 is formed of a semiconductive elastic material such as rubber, for example, and is driven by the photosensitive member 1 which rotates in the direction of the arrow in the drawing. When a bias of about DC (-) 1.2 kV is applied while applying a bias, the photosensitive member 1 is moved from (-) 600 V to (-).
It is charged to a charging potential of 700 V.

The charging roller 2 is pressed and supported toward the photoreceptor 1 by a pressing mechanism (not shown).
With the photosensitive member 1 at the total pressure of

Next, an exposing means for exposing the photosensitive member 1 will be described. Here, the potential of the image exposure portion of the photoconductor 1 is (-)
It becomes 50V-(-) 150V.

A laser scanning unit 3 as exposure means
Is for irradiating the photosensitive member 1 with a laser beam.
pm, a control circuit board (not shown) for controlling the rotation of the motor 4, and light emitted from a light-emitting element such as a semiconductor laser or the like, which is mounted on the output shaft of the motor 4 and rotates and is not shown. A polarization scanning unit 5 for polarizing and scanning the beam, a reflection mirror 6 for reflecting the light beam polarized by the polarization scanning unit 5 toward the photoreceptor 1, and an exposing unit configured to house and constitute the above main components. The exposing unit case 7 is fixed to a main chassis 8 serving as a reference for the internal configuration of the apparatus. In particular, in the configuration of FIG. 1, the rotation axis of the motor 4 is arranged to be substantially horizontal, and the light beam is emitted upward from the polarization scanning unit 5,
The light is reflected by the reflection mirror 6 and is approximately 2
The photosensitive member 1 is irradiated as if drawing the incident light trajectory surface 9 at an angle of 5 degrees. Here, the incident light trajectory surface 9 indicates a trajectory drawn when the central axis of the light beam is scanned in the main scanning direction. Since the arrangement cannot be performed, the arrangement of each component of the apparatus main body is greatly affected. Therefore, in reducing the size of the apparatus, the relative arrangement between the incident light trajectory surface 9 and each component constituting the apparatus is important as described later. .

As for the deflection scanning means 5, if a small laser scanning unit as described in detail in Japanese Patent Application No. 5-121995 filed by the present applicant is used, the A4 size (scanning width) is used. When an image is formed on a recording paper of about 210 mm), the photosensitive member 1
The optical path length to 140 to 200 mm can be shortened to approximately half of the scanning optical system using a conventional polygon mirror,
This is advantageous for reducing the size of the image forming apparatus.

Next, a developing means for applying the electrostatic latent image toner on the photosensitive member 1 formed by the charging means and the exposure means will be described.

The developing means develops an electrostatic latent image formed on the photoreceptor 1 with charged toner, and is a conductive and elastic developing roller which transports the toner and rotates in the direction of the arrow in the figure. A roller 10, a storage unit 11 in which toner is stored,
The developing roller 10 is mainly constituted by a regulating blade 12 made of a thin metal plate for thinning the toner on the developing roller 10. The developing roller 10 is urged against the photosensitive member 1 with a total pressure of approximately 1 kg. Due to the leaf spring property, the developing roller 10 is urged and pressed at a total pressure of about 1 kg. The toner that is frictionally charged on the developing roller 10 and charged to the (−) polarity is DC (−) 200 V to (−) 3 applied to the developing roller 10.
With a developing bias voltage of about 00V, the developing roller 10
The nip portion formed by pressing the photoconductor 1 and the photoconductor 1 and the vicinity of the nip portion are subjected to reversal development on the image exposure portion of the photoconductor 1.

Next, the toner image reversely developed on the image exposure portion of the photosensitive member 1 is transferred to a sheet material by a transfer means described later. With a total pressure of g, it is scraped off by the cleaning blade 13 pressing its ridge line and stored in the space formed by the cleaning blade 13 and the like.

The photosensitive member 1 thus cleaned can be transferred to the next image forming process again.
After the cleaning, if the potential remaining on the photoconductor 1 is removed by light irradiation or the like, the surface potential of the photoconductor 1 can be brought closer to the initial state.

In this embodiment, the photosensitive member 1, the charging means, the developing means, and the cleaning means are integrally formed and housed in the cartridge case 14.
Although it is unitized, the amount of toner in the storage unit 11 is reduced to a necessary minimum amount that does not hinder the above-described image forming process, and the space of the storage unit 11 is reduced.

Further, the developing unit and the cleaning unit are endlessly circulated by using the toner circulating / conveying member 15 as described in detail in Japanese Patent Application No. 4-246777 filed by the present applicant. As a configuration for replenishing and recovering the image, the image forming apparatus is further downsized.

Hereinafter, a feeding unit, a transfer unit, a fixing unit, and a discharging unit related to the conveyance of the sheet material will be described.

First, a feeding means for feeding a sheet material such as paper to the transfer means will be described.

In a sheet tray 16 serving as a sheet material storage unit for storing a large number of sheet materials P such as paper, the sheet material P is placed on a sheet material placing member 17 in a sheet feeding section. P is pressed toward the paper feed roller 18. Here, the sheet feeding member 17 is locked so that the sheet P can be held at an angle of about 25 degrees with respect to the direction of gravity. , The sheet material P is held on the sheet feeding tray 16 without curling by its own weight.

When the feed roller 18 is driven to rotate, the friction pad 19 urged against the feed roller 18
Due to the frictional resistance between the sheet material P and the sheet material P
, Only the uppermost sheet P is fed, guided by the sheet feed guide 20 and the lower surface of the cartridge case 14, and the sheet P is introduced into the transfer means. In a transfer section located below the photoconductor 1, a bias of about (+) 1 kV DC is applied to a transfer roller 21 which is a transfer unit to transfer the toner image reversely developed on the image exposure section of the photoconductor 1 to
The toner image is transferred onto a sheet material. The transfer roller 21 is formed of, for example, a conductive foam, and is pressed by the transfer roller 21 toward the photoreceptor 1 with a total pressure of several hundred g, and is driven to rotate by the photoreceptor 1 with the sheet material P interposed therebetween. Then, the sheet material P is further conveyed toward the fixing unit.

Next, the sheet material P to which the toner image has been transferred is guided on the back surface by the sheet guide 22 before fixing.
The toner reaches a fixing unit for fixing the toner image.

The fixing means includes a heating roller 24 made of an aluminum pipe in which a heating element 23 such as a halogen lamp is disposed and a fluororesin layer is formed on the surface, and several kg of the heating roller 24 with respect to the heating roller 24. The pressure roller 63 is pressed by the total pressure and has an elastic body such as silicon rubber formed on the surface. Therefore, the heating roller 24 and the pressure roller 25
The toner image on the sheet material P is heated and melted under a pressurized state, and is fixed to the sheet material P in the nip portion formed by (1) and (2). A fixing cover 26 is provided around the heating roller 26 to prevent heat from escaping to the outside, and a peeling claw 27 is in sliding contact with the peripheral surface of the heating roller 26 so that the sheet material P is wrapped around. Preventing.

The sheet material P on which the toner image has been fixed is subsequently transferred to the post-fixing sheet guide 30 and the sheet pressing roller 2.
The sheet is conveyed while being guided by its own weight of 9, and reaches the discharge means while reversing the traveling direction by the sheet reversing lower guide 30 and the sheet reversing upper guide 31.

The discharge means is composed of a discharge roller 32 having an irregular shape formed on its peripheral surface using a cylindrical rubber or the like, and a resin discharge guide roller pressed against the discharge roller 32 with a load of about several tens g. 33, and a sheet holder 34 that can swing about the discharge guide roller 33 as a rotation center.
With such a configuration, the sheet material P is sequentially conveyed to the discharge section sheet material mounting surface 36 of the discharge tray 35 while being guided by the sheet holder 34, and the end portion of the sheet material P is transferred to the discharge roller 32. When the sheet material P comes, the sheet material P is discharged toward the discharge tray 35 by the convex portion of the discharge roller 32. Further, the sheet material P is discharged face down so that the surface on which the toner image is fixed faces down. Here, the discharge unit sheet material mounting surface 36 is configured to be at least partially integrated with the main body case 37 so that the sheet material P can be held at an angle of approximately 25 degrees with respect to the direction of gravity. Due to the frictional resistance between the sheet materials P due to the weight of the sheet material P or between the sheet material P and the sheet discharging section sheet material mounting surface 36, the sheet material P is held by the sheet discharge tray 35 without curling by its own weight. .

It is preferable that the main body case 37 be divided into two parts, upper and lower parts or a plurality of parts. However, in addition to the above-described structure, the paper discharge tray 35 can be expanded or contracted or foldable. In addition, it is possible to increase the storability as a configuration to be attached to. A control unit housing member 38 for housing a circuit board and the like is provided at a lower portion of the main body.

By configuring the image forming apparatus as described above, it is possible to reduce an excess space of the apparatus and to reduce the size of the apparatus. In particular, the sheet material P in the sheet feed tray 16 that stores the sheet material P, which most affects the size of the image forming apparatus,
The surface on which the sheet material P is placed, the surface on which the sheet material P of the sheet discharge tray 35 accommodating the discharged sheet material P is placed, and the surface on which the trajectory of the light beam incident on the photoconductor 1 is formed are parallel to each other. Further, by arranging the image forming apparatus in the upright position as much as possible, it is possible to reduce the size of the image forming apparatus main body and the flat area (foot space) occupied by the image forming apparatus.

Further, a paper feed tray 1 for storing the sheet material P
6, the surface on which the sheet material P is placed, and the discharged sheet material P
The surface of the paper output tray 35 on which the sheet material P is placed has a paper length of about A4 size (approximately 300 mm) with respect to the surface on which the trajectory of the light beam incident on the photoconductor 1 is formed. It is desirable to arrange so that they do not interfere with each other,
In addition, with the above-described device configuration, the distance between the above-described surfaces can be reduced to about 60 to 80 mm.
Considering these facts, the surface on which the sheet material P is placed on the sheet feed tray 16 for storing the sheet material P, that is, the sheet material placing member 17 for the sheet feeding unit, and the sheet discharging device for storing the discharged sheet material P The surface of the tray 35 on which the sheet material P is placed, that is, the sheet discharging portion sheet material placing surface 36, is 15 degrees or less (inclination 80 /
It is desirable to arrange at an inclination angle of 300).

By the way, in consideration of the frictional resistance between the sheet materials P, in order to prevent the stacked sheet materials P from dropping by their own weight, according to the study by the present inventors, it was found that the sheet material It is desirable to arrange the stacked sheet materials P at an angle of 40 degrees or more on coarse paper and 60 degrees or more on smooth paper. However, if this angle is maintained, the sheet materials P must be arranged almost flat. In addition, the foot space of the image forming apparatus cannot be reduced. Therefore, in order to prevent the sheet material P from dropping, the sheet material P
Must be locked to the paper feed roller 18 and to the lower end of the paper discharge tray 35. On the other hand, in the discharge tray 35, the end of the sheet material P is
Since the sheet material P can be easily handled if it is aligned with the lower end of the sheet 5, the sheet material P desirably slides mutually on the sheet material mounting surface 36 of the discharge section. As described above, the angle at which the stacked sheet material P falls under its own weight is 40 degrees or less with respect to the direction of gravity, and therefore, the sheet discharge section sheet material mounting surface 36 of the sheet discharge tray 35 is moved in the direction of gravity. On the other hand, the angle is preferably set to 40 degrees or less. On the other hand, when the lower end of the sheet material P is locked and the sheet material P is further inclined in the direction in which the sheet material P is raised, the sheet material P cannot withstand its own weight at an angle of 10 degrees or less with respect to the direction of gravity. It curls. Therefore, it is preferable that the discharge section sheet material mounting surface 36 of the discharge tray 35 be set to 10 degrees or more with respect to the direction of gravity. For these reasons, the sheet material P is stably conveyed and stably stored by setting the sheet-discharging section sheet material mounting surface 36 of the sheet discharge tray 35 to 10 degrees or more and 40 degrees or less with respect to the direction of gravity. be able to. Moreover,
In such a configuration, since the sheet material P is stored upright, the installation area of the apparatus main body can be reduced as the sheet material P approaches.

Although the embodiment has been described above, the present invention is not limited to the above-described embodiment, and a substantially V-shaped sheet material conveyance path is formed by transferring a toner image to a lower surface of a sheet material at an upper portion of a photosensitive member. It is needless to say that the present invention is also effective when applied to an image forming apparatus having a substantially U-shaped sheet material conveying path inclined by transferring a toner image to a sheet material at a side portion of a photoconductor.

[0036]

As described above, according to the present invention, the surface on which the sheet material is placed of the sheet material storing means and the discharged sheet material storing means is inclined by 10 to 40 degrees to the same side with respect to the direction of gravity. By arranging the sheet material, it is small and the installation area is small, the sheet materials are mutually slid and locked by their own weight, the edges are aligned, and they are held without curling by their own weight,
It is possible to provide an image forming apparatus which stably feeds and holds a sheet material and is excellent in sheet material storability and transportability.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an image forming apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Laser scanning unit 5 Polarization scanning means 6 Reflection mirror 9 Incident light trajectory surface 16 Feed tray 17 Feeder sheet material mounting member 18 Feed roller 19 Friction pad 21 Transfer roller 23 Heating element 24 Heating roller 25 Pressure roller 26 Fixing cover 28 Guide after fixing 29 Sheet press roller 30 Sheet reversing lower guide 31 Sheet reversing upper guide 32 Discharge roller 33 Discharge guide roller 34 Sheet press 35 Discharge tray 36 Discharge section sheet material mounting surface

Claims (1)

[Claims] 1. Sheet material storage means for placing a sheet material,
Feeding means for feeding the sheet material from the sheet material storing means, transfer means for transferring a toner image formed on a photosensitive member to the sheet material, and transferring the toner image transferred on the sheet material to the sheet material. Fixing means for fixing the sheet material on which the toner image is fixed, discharging means for discharging the sheet material on which the toner image is fixed, discharged sheet material containing means for placing the discharged sheet material with the toner image fixed side down, Exposing means for exposing a light beam emitted from a light emitting element to the photoreceptor via a deflection scanning means to form a latent image, wherein the sheet material storing means and the discharged sheet material accommodating means are provided. An image forming apparatus, wherein a surface on which the sheet material is placed is inclined by 10 to 40 degrees on the same side with respect to the direction of gravity.