JP3036358B2 - Image forming device - Google Patents

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 for forming an image on a sheet material such as a printer or a facsimile, and more particularly, to a mechanism structure thereof.

[0002]

2. Description of the Related Art A typical example of a conventional image forming apparatus or cartridge is disclosed in JP-B-63-67185 and JP-B-3-10942, or JP-B-6-196.
A structure as disclosed in Japanese Patent Publication No. 01-63185 is generally known. In the main figure of Japanese Patent Publication No. 63-67185, a photosensitive member which is driven to rotate by a main body of the apparatus drives a developing means. The driving force is concentrated on the driving part of the photoconductor, and the driving part of the apparatus main body and the driven part on the cartridge side are
The need for high rigidity makes the device large and expensive, and the developing unit has a toner hopper for storing a desired amount of toner. In some cases, the support state of the developing unit changes in accordance with the change in the value, and the relationship between the photosensitive member and the developing unit may become unstable.

On the other hand, Japanese Patent Publication No. 3-10942 discloses a cartridge having a toner storage unit consumed by a developing unit or a waste toner storage unit removed from a photoreceptor by a cleaning unit. When it arrives, the photoconductor and the toner storage unit or the waste toner storage unit are exchanged integrally, so that the cartridge becomes large and it is difficult to configure a small-sized image forming apparatus. The cartridge is mounted as a cartridge in which a predetermined amount of toner corresponding to the operating life is enclosed in a casing of an integral construction, and the workability of replacement maintenance is enhanced, but it is an expensive image forming apparatus.

Further, in Japanese Patent Publication No. 6-19601, an electric circuit unit in which an operation control circuit of each mechanism and a controller relating to control relating to image formation are mounted and arranged is arranged at the lowermost end of the apparatus. Immediately above the electric circuit unit, a function unit for image formation, a function mechanism for paper conveyance, a transfer device and a fixing device, a drive mechanism for driving each function, and the like are arranged. A power supply circuit section and a high-voltage power supply section are arranged on the left and right of the device.
There is a difficulty in handling the memory expansion circuit including the above and the like, and the interface expansion circuit having a function of connection interface with an external device.

[0005]

As described above, according to the prior art, not only the apparatus is increased in size but also an expensive image forming apparatus.

[0006] By the way, in the environment surrounding computers these days, with the rise of small notebook computers, the downsizing has been increasingly spurred, and the market for personal use has expanded, so that it is possible to place the computers with sufficient room on the desktop. As described above, there has been an increasing demand for downsizing external terminals such as printers and facsimile machines corresponding to the downsizing of computers and the appearance of inexpensive products.

Accordingly, the present invention is to solve the above-mentioned problems, and the object of the present invention is to provide various devices that can be configured in a small size and at a low cost, and to reduce the overall configuration of the image forming apparatus. In addition, a small and inexpensive image forming apparatus has been developed by arranging structural parts in order to reduce the space space inside the apparatus to a limited extent, and particularly to meet the demand in the personal use market.

[0008]

According to the present invention, there is provided a sheet material for transferring and fixing the toner image to a substantially central portion of the entire apparatus which is a lower part of a photosensitive member and a developing means for developing a toner image on the photosensitive member. In an image forming apparatus having a sheet conveying path for feeding and discharging, a drive transmission unit for driving a mechanical unit is disposed on one of both side surfaces orthogonal to a sheet conveying direction deviating from the sheet conveying path area. At the same time, a control circuit board is divided into a first control circuit board on which at least a power supply circuit section and an operation control circuit section of a mechanism section are mounted and arranged, and a second control circuit board on which a controller for controlling image formation is mounted and arranged. The first control circuit board is arranged in a plane just below the sheet material conveyance path, and the second control circuit board is arranged in a sheet material conveyance path deviating from the sheet material conveyance path area. Characterized in that arranged on the other sides perpendicular to the.

Further, the first control circuit board is disposed between a main chassis and a shield plate,
The main chassis has a squeezed portion formed in a height direction of a circuit portion on which the first control circuit board is mounted and arranged.

[0010]

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

1 to 10 show a suitable embodiment of the (cartridge and) image forming apparatus of the present invention, FIGS. 11, 12 and 13 show other embodiments, and FIG. FIG. 2 is a cross-sectional view of a main part on the left side showing the entire configuration of the image forming apparatus;
FIG. 2 is a sectional view of a main part of the front showing a cross section of the front main part.

FIG. 3 is a left side sectional view showing a main part of the cartridge of the present invention. 4 and 5 are cross-sectional views of main parts of the right side of the image forming apparatus of the present invention. FIG. 4 is a cross-sectional view of main parts of a first right side, and FIG. 5 is a cross-sectional view of main parts of a second right side. Are cross-sectional views at different positions.

FIG. 6 is a developed cross-sectional view showing a part of a developed cross-section of the rotation drive transmitting portion of the image forming apparatus of the present invention.

FIG. 7 is a cross-sectional view of a main part of the right side of the cartridge of the image forming apparatus according to the present invention, showing the relation of the cartridge to be rotated.

FIG. 8 is a cross-sectional view of a main part of the upper surface of the cartridge of the image forming apparatus according to the present invention.

FIG. 9 is a cross-sectional view of a main portion of the upper surface of the cartridge showing the rotational driving relationship of the cartridge of the image forming apparatus of the present invention.

FIGS. 10 to 13 are views for explaining the rotational drive relationship of the cartridge of the present invention. FIG. 10 is an explanatory view of a first rotary drive system, FIG. 11 is an explanatory view of a second rotary drive system, and FIG. FIG. 13 is an explanatory diagram of a three-rotation drive system, and FIG. 13 is an explanatory diagram of a fourth rotation drive system.

First, the image forming section of the present embodiment will be described with reference to FIG. 1 and other figures.

The main part of the image forming means of this embodiment is shown in FIG.
The photosensitive drum 1, the charging roller 2, the cleaner unit 90, the developing unit 10,
It is constituted by the toner conveying sections 30 and 30a.

Referring to FIG. 1 and FIG. 3, the image forming process will be described. The charging roller 2 in this embodiment is formed of a semiconductive elastic material such as rubber, for example. DC (-) 2k while following the drum 1
When a bias of about v or less is applied, the photosensitive drum 1 can be charged to a charging potential of (−) 600 V to (−) 700 V.

The charging roller 2 is pressed and supported toward the photosensitive drum 1 by a pressing mechanism constituted by a spring 3 and the like, and is pressed against the photosensitive drum 1 with a total pressure of approximately 1 kg.

Next, the photosensitive drum 1 is image-exposed to form a latent image by a light beam emitted from an exposure unit 40 to be described later and incident from an optical path 49, and the potential of the image exposure unit is set to (-). ) 10 V to (−) 150 V.

Next, in the developing unit 10, a supply roller 13 formed of a semiconductive elastic material such as foamed rubber, for example, and rotating in the direction of the arrow in FIG. The surface of the toner is coated with toner in a storage unit 11 that rotates, and rubs against a developing roller 12 that is formed of a semiconductive elastic material such as a rubber material that rotates in the direction of the arrow in the drawing, and rubs the toner. Is frictionally charged to the negative polarity, and the surface of the developing roller 12 is coated with toner.

The toner coated on the surface of the developing roller 12 is formed of an elastic material such as a stainless steel plate, and is in contact with the outer periphery of the developing roller 12 at a total pressure of approximately 1 kg over substantially the entire area in the axial direction. By rubbing the applied toner with a regulating blade 14 for regulating the toner to a coating layer having a predetermined thickness, approximately 10
The toner layer is regulated by a toner layer having a thickness of about μm and is triboelectrically charged to a more uniform (−) polarity.

The DC (-) 200 is applied to the developing roller 12.
A bias of about V to (−) 400 V is applied,
The thinned toner layer is conveyed to the photosensitive drum 1 and reversely developed on a nip portion formed by pressing the developing roller 12 and the photosensitive drum 1 against each other and in the vicinity of the nip portion.

Incidentally, the toner in the storage unit 11 is as shown in FIG.
As shown in detail in FIG.
Cartridge lower case 18, regulating blade 14, pressing member 16 for regulating blade 14, developing roller 12
The space surrounded by the supply roller 13 is stored in a narrow predetermined space formed of, for example, a foamed rubber material and partitioned by an elastic seal 15.

Next, the toner image reversely developed on the image exposure portion of the photosensitive drum 1 is transferred by a transfer portion 80 described in detail later, and the remaining toner is a thin plate material such as a Mylar sheet material. The rake sheet 91 slides through the formed rake sheet 91 and is scraped off by the cleaning blade 92 pressed against the photosensitive drum 1, and is stored in a predetermined space 93 formed by the rake sheet 91 and the cleaning blade 92.

The cleaned photosensitive drum 1 can be transferred to the next image forming process again. If the potential remaining on the photosensitive drum 1 is removed after cleaning by light irradiation or the like, the surface potential of the photosensitive drum 1 can be reduced. Can be brought closer to the initial state.

Here, the handling of the toner will be described. A conventional image forming apparatus is mounted as a cartridge in which a predetermined amount of toner corresponding to the operating life of the main components such as a photoreceptor is enclosed in an integrated casing, which not only increases the size of the entire apparatus but also replaces it. Although the workability of maintenance is enhanced, the image forming apparatus is expensive, but in this embodiment, the configuration is completely different from the conventional concept.

First, the amount of toner in the storage unit 11 is reduced to a minimum necessary amount which does not hinder the above-described image forming process, and the space of the storage unit 11 is reduced. The toner that decreases with the development is dropped and replenished from the toner transport unit 30a that transports the toner, which will be described in detail later, in the space of the storage unit 11.

On the other hand, the toner scraped off by the cleaning blade 92 is stored in a predetermined space 93 formed by the rake sheet 91 and the cleaning blade 92.
Move to zero.

As will be described in detail later, the toner conveying portions 30 and 30a include endless coil springs 31 and 31a (endless coil springs 31 and 31a are separately provided for the sake of convenience in the drawing, but are endless and integrated). A mechanism for transporting the toner by the transporting means is provided, and the toner transporting units 30 and 30a, which are disposed at substantially horizontal left and right positions with the photosensitive drum 1 being substantially at the center in the figure, are formed by a structure described in detail later. The toners of the toner transport unit 30 and the toner transport unit 30a are connected and circulated and transported.

Next, the toner circulation function will be described. With respect to the amount of toner (development toner amount) in the storage unit 11 consumed by the above-described development, the amount of untransferred toner scraped off by the cleaning blade 92 and transferred to the toner conveyance unit 30 (reproduction toner amount) Is 10% to 30% in the present embodiment. Even if the toner is circulated and conveyed, the toner is consumed by the repetition of the development, Will decrease.

Therefore, in this embodiment, in order to compensate for the reduced toner, as will be described in detail later, a toner replenishing means which falls by its own weight is arranged in the conveyance path for circulating the toner. Is supplied and circulated and transported together with the above-mentioned regenerated toner.
1 is configured to be replenished.

Next, a stable structure of the nip portion formed by pressing the developing roller 12 and the photosensitive drum 1 rotatably supported by the cartridge lower case 18 will be described with reference to FIGS. 3, 8 and 9. explain.

The supply roller 13 made of a semiconductive elastic material such as foamed rubber and the developing roller 12 made of a semiconductive elastic material such as rubber are used as metal cores, respectively. The support portions 12a and 13a are provided at both ends of the elastic body, and the support portions 12a and 13a are rotatably supported by the support member 5 as shown in FIG. Have been. 9 shows a state in which the supply roller 13 and the developing roller 12 support the right side, but the opposite side has the same support structure, and is rotatably supported by the support member 5A in FIG.

The supply roller 13 and the developing roller 12
3 is supported at a fixed pitch that is smaller than the pitch at which the outer circumferences of the supply roller 13 and the developing roller 12 are in contact with each other, and the outer circumferences of both rollers are evenly contacted over the entire area in the longitudinal direction. It is configured in the positional relationship shown in detail.

Then, the supply roller 13 and the developing roller 12
Are rotationally driven in the direction of the arrow shown in the drawing to rub. When the distance between the support pitches is extremely narrow, the rotational driving torque increases, and the deterioration of the toner rubbed between the two roller nips is deteriorated. In this embodiment, in consideration of the absorption of the variation of the components related to the support, the support is performed at a fixed pitch 0.25 mm narrower than the pitch at which the outer circumferences of the supply roller 13 and the development roller 12 are in contact with each other.

The supporting member 5 and the supporting member 5A, which rotatably support both ends of the supply roller 13 and the developing roller 12, respectively,
As shown in FIG. 3, the support member 5 is rotated by a support pin 5a inserted through a part of the cartridge lower case 18, and is firmly connected via a connecting member 6 by fixing means such as a screw. 3 shows a state in which only one side is supported, but the other side has the same supporting structure, and the supporting member 5 shown in FIG.
A is inserted through a part of the cartridge lower case 18 and is rotatably supported by a similar support pin 5Aa disposed at the same sectional position as the support pin 5a shown in FIG.

Then, the supply roller 13 and the developing roller 12
Are rotatably supported at both ends by a supporting member 5a and a supporting pin 5Aa together with the regulating blade 14 in a state of being connected by a connecting member 6 so that the above-described image forming process is not hindered. It can rotate integrally with the photosensitive drum 1 in the space of the toner storage unit 11 configured to limit the storage amount.

When the support pin 5a and the support pin 5Aa are arranged at the above positions, the cartridge lower case 18 and the support member 5 and the support member 5A can be easily rotated based on the above-mentioned integrated structure. The relationship is such that a gap is formed so as to be free in the rotation direction, and this gap is shielded by an elastic seal member (not shown) to prevent leakage of toner.

On the other hand, in order to form a stable nip portion by pressing the developing roller 12 and the photosensitive drum 1 in the above state, the developing roller 12 is rotated by using the support pin 5a and the support pin 5Aa as a supporting shaft, and the developing roller 12 is exposed to light. Springs 8 and 8A for urging in the direction of the drum 1 are provided between the lower cartridge case 18, the support member 5, and the support member 5A.

In the meantime, regarding the support member 5 and the support structure of the support member 5A by the support pin 5a and the support pin 5Aa, in this embodiment, as a means for preventing a rotation problem even if a difference occurs between the left and right support positions. In one of the support portions, the insertion portion through which the cartridge lower case 18 and the support pin 5a of the support member 5 are inserted is rotatably formed by supporting the support pin 5a in a desired relationship, and the other support portion is provided with the cartridge lower portion. The insertion part through which the support pin 5Aa of the case 18 and the support member 5A is inserted is not shown in detail, but the support pin 5Aa
Is provided with a desired clearance so as to be able to move toward and away from the photosensitive drum 1 to prevent the occurrence of a rotation problem of the above configuration.

In this embodiment, the desired clearance is provided in the support portion of the support pin 5a. However, the desired clearance may be provided in the support pin 5Aa.
Even if it is provided on both sides of Aa, the occurrence of the rotation failure of the above configuration is prevented.

Here, the toner replenishing means and the toner conveying means for circulating and conveying the toner will be described with reference to FIG. 2, FIG. 7, and FIG.

As shown in FIG. 3, while the endless coil springs 31 and 31a for circulating and transporting the toner are sealed by the cartridge upper case 17 and the cartridge lower case 18, the toner tank 20 can be freely attached and detached (attachment / detachment mechanism). Is filled with a predetermined amount of toner, is mounted in a toner-enclosed state and replenishes toner, and when this toner is consumed, it is replaced with a new toner tank 20. It has a configuration.

The endless coil springs 31 and 31a for circulating and transporting the toner are separated from each other for convenience of explanation in the drawing, but are formed as an endless and integral one.

The main part of the toner tank 20 is composed of a cylindrical tank case 21 having a bottom at the bottom in the figure, a cover 22 fixed above and sealing the toner, and a tank case 21 and a cover 22. Plural blades 23 that stir rotatable toner sealed with toner
b, and an endless coil spring 31 for circulating and transporting the toner.
The attachment / detachment operation is possible (the attachment / detachment mechanism is omitted from the illustration in detail) with respect to the state in which the cartridge 31a is enclosed by the cartridge upper case 17 and the cartridge lower case 18.

On the other hand, in order to drive the endless coil springs 31 and 31a for circulating and transporting the toner in the direction of the arrow in FIG. 8, an endless coil enclosed by a cartridge upper case 17 and a cartridge lower case 18 so as to be able to circulate. The drive means 25 of the coil springs 31 and 31a is arranged in a part of the arrangement path of the springs 31 and 31a.
When the toner tank 20 is mounted at a predetermined position, the wedge-shaped rotatable convex portion 25a and the concave portion 23c formed at one end of one agitator 23 are engaged and driven to rotate. You.

The driving means 25 of the endless coil springs 31 and 31a for circulating and conveying the toner can be driven by a rotating body which can be engaged with the coil springs 31 and 31a. The engagement relationship with the coil springs 31, 31a is stabilized by employing a helical gear having a twist angle approximating the lead angle of the stretched state of the 31, 31a.

The toner agitated by the rotation of the agitator 23 circulates and transports the toner through an opening 21a formed in the bottom of the tank case 21 and an opening 17a of the cartridge upper case 17 provided opposite the opening 21a. Endless coil springs 31, 31a
Is dropped by its own weight into the toner circulation / conveying path in which the toner tank 20 is disposed.
1a and opening 17a are opened and closed. (Not shown) The toner dropped by its own weight in the toner circulating conveyance path in which the coil springs 31 and 31a are disposed is circulated and conveyed in the direction of the arrow in FIG.
When the flow goes to a, the toner drops by its own weight from the upper portion of the supply roller 13 and is stored in the toner storage unit 11 described above with reference to FIG. 3, but as described above, the toner storage unit 11 is configured to be extremely narrow. The toner storage unit 11 may be full due to the relationship between the toner consumption and supply depending on the image form. In this state, the toner is circulated and conveyed by the coil springs 31 and 31a without falling by its own weight. The structure is such that the fall of the toner from the toner tank 20 by its own weight is also interrupted.

The above is the main part of the image forming means of this embodiment. The photosensitive drum 1, the charging roller 2, the cleaner 90, the developing unit 10, and the toner conveying units 30, 30a are arranged in the above-described relationship. A cartridge lower case 18 which mainly serves as a main part and a cartridge upper case 17 which also plays a role of a cover thereof can be detachably attached to the main body as a cartridge having a unit structure. To perform repair or replacement.

The relationship between the cartridge and the main body is determined by positioning means (not shown) and fixed by fixing means (not shown).

Next, the transfer section 80 for transferring the reversely developed toner image to the image exposure section of the photosensitive drum 1 will be described with reference to FIG.

The main part of the transfer unit 80 of this embodiment is pressed by the pressing mechanism 82 toward the photosensitive drum 1 at a total pressure of several hundred g from below, and the latent image of the image exposure unit of the photosensitive drum 1 is reversely developed. DC1K of opposite polarity to the toner image
A means for applying a bias of about V is provided. The rotatable transfer roller 81 is formed of a conductive or semiconductive elastic material such as rubber, for example. The sheet material transport base 71 supports the transfer roller 81 together with the constituent members. The sheet material transport base 71 is engaged with a positioning portion formed on a main chassis 100 serving as a reference of the internal structure of the apparatus. (Not shown), and is fixed to the main chassis 100 by fixing means such as screws.

The toner image conveyed to the nip formed by the pressing action of the photosensitive drum 1 and the transfer roller 81 is separated from the sheet fed from the sheet conveyer 70 described later in detail. It is transferred and merged.

Next, the fixing section 60 for feeding the sheet material on which the toner image on the photosensitive drum 1 is transferred and fixing the sheet material will be described.

The main part of the fixing section 60 of this embodiment is a fixing roller which is disposed on the downstream side in the sheet conveying direction and has a built-in heating element such as a halogen heater as a heat generating means in a hollow part of the aluminum pipe material and is rotatable. 63 and a pressing mechanism such as a spring 66 pressed against the fixing roller 63 with a total pressure of several kg as pressing means for pressing the toner image transferred onto the sheet material. A pressure roller 67 formed at least on the surface of a semiconductive elastic body and rotatable at the same peripheral speed as the fixing roller 63; and a discharge roller pair for discharging the conveyed sheet material to the outside of the apparatus. 61, and a fixing base 64 that supports the fixing members and supports the fixing unit 60 in a unit configuration. The fixing base 64 serves as a reference for the internal configuration of the apparatus. Is fixed to the main chassis 100 by chromatography by engagement of the positioning portion (not shown) for positioning portion formed in the sheet 100 is positioned at a predetermined position, for example, screws or the like fixing means.

The toner image transferred from the transfer unit 80 to the sheet material and conveyed to the nip formed by the pressing action of the fixing roller 63 and the pressure roller 67 is transferred to the sheet at a predetermined temperature at the nip. Be established.

Next, the paper feeding section 70 for feeding a sheet material such as paper toward the transfer section 80 will be described.

A sheet tray 72 is provided at the lower end of the sheet tray 72 which accommodates a large number of sheets of paper P such as paper. Part 7
A well-known pressing mechanism 74 that selectively presses the paper feed roller 73 that can rotate freely is provided.

The sheet feeding section 70 on the apparatus main body side is arranged to face the sheet feeding roller 73 with the sheet material P interposed therebetween, and only the uppermost sheet material among the many sheet materials P is fed to the sheet feeding roller 73. A sheet material feed control mechanism 75 for separating the sheet material so as to be fed by the rotation of the sheet 73 and for preventing the second and subsequent sheet materials from being fed; A sheet material detecting unit 77 including a photo sensor and the like, which is disposed in a sheet material conveying path for feeding a sheet material such as paper toward 80, and detects the presence or absence of the sheet material; A sheet conveying base 71 for supporting the above-described transfer roller 81 together with a constituent mechanism is provided. Further, although not shown, a mechanism for releasing the pressing of the transfer roller 81 against the photosensitive drum 1 is also provided. Transfer unit 80 The sheet material transport base 71 is supported in a unit configuration. As described above, the sheet material transport base 71 engages with a positioning portion formed on a main chassis 100 serving as a reference of an internal configuration of the apparatus (see FIG. (Omitted), and is fixed to the main chassis 100 by fixing means such as screws.

When the paper feed roller 73 is driven to rotate in the above-described configuration, one sheet material follows the sheet material conveyance path and is fed to the transfer unit 80 described above.

Here, the sheet feeding control will be described. The sheet feeding roller 73 is rotated and driven by a desired command to feed one sheet material into the sheet material conveying path, and in response to a detection signal of the sheet material detecting means 77, the sheet feeding roller 73
The sheet is stopped in a state where the sheet material is sandwiched, and a standby state (standby state) for the above-described transfer is performed.

The stop timing of the paper feed roller 73 may be stopped by a detection signal of the sheet material detection means 77, but is stopped after a predetermined time elapses from the detection signal by a delay means such as a timer. May be.

That is, the toner image reversely developed on the image exposure portion of the photosensitive drum 1 at the nip portion formed by pressing the developing roller 12 and the photosensitive drum 1 under pressure is transferred to the photosensitive drum 1 by the rotation of the photosensitive drum 1. The time required for the roller 81 to reach the transfer section 80 having a nip formed by pressing and contacting;
It is only necessary that the time required for feeding the sheet material from the standby state and for the sheet material to reach the transfer unit 80 be controlled to a desired relationship,
In the present embodiment, the latter is adopted.

In the present embodiment, a sheet material detecting means 77 including a photo sensor for detecting the presence or absence of a sheet material is disposed in the sheet material transporting path of the sheet feeding section 70, Fixing roller 63 and pressure roller 6
7, a second sheet material detecting means 65 similar to the sheet material conveying direction downstream from the nip portion formed by the pressing action of the sheet material 7, and detects the sheet material conveying state. The detection signal from the sheet material detection means 65 is processed in a predetermined relationship to monitor the jam state in the apparatus.

As described above, in the image forming apparatus of this embodiment,
A configuration in which a sheet material conveyance path through which a sheet material P is discharged from a fixing unit 60 including a pair of paper discharge rollers 61 from a paper supply unit 70 via a transfer unit 80 is disposed at a lower center of the cartridge and substantially in the center of the entire apparatus. It is.

Next, the exposure device 40 for exposing the photosensitive drum 1 to a latent image will be described. The main part of the exposure device 40 includes a motor 41 rotating at 10,000 rpm, a control circuit board (not shown) for controlling the rotation of the motor 41, and a motor 41.
A deflection scanning means 43 which is mounted on the output shaft of the scanner and rotates and deflects and scans a light beam emitted from a light emitting element such as a semiconductor laser (not shown), and an optical path 49 for irradiating the light beam toward the photosensitive drum 1. A reflection mirror 44 to be formed,
An exposure unit case 42 is formed by housing the above-mentioned main constituent members to form a unit. The exposure unit case 42 engages a positioning portion with a positioning portion formed on a main chassis 100 which is a reference of an internal configuration of the apparatus. (Not shown), and is fixed to the main chassis 100 by fixing means such as screws.

As for the deflection scanning means 43, Japanese Patent Application No. 5-121995 filed earlier by the present applicant.
As described in detail in Japanese Patent Application Laid-Open No. 6-75162, it is possible to perform small and inexpensive optical scanning. In this embodiment, the optical path length from the deflection scanning means 43 to the photosensitive drum 1 is substantially set. Although set to 160 mm, a short optical path length of about 140 mm can be handled.

Next, the control section 50 for controlling the above-mentioned respective mechanical sections will be described with reference to FIGS. 1, 2 and 8. The main part of the control unit 50 includes a first control circuit board 51 which is arranged at the lowermost end of the device and at least a power supply circuit unit and an operation control circuit unit of each mechanism are arranged. The second control circuit board 52, which is arranged substantially perpendicular to the left end of the device and joined by a joining means such as a connector 53, for example, and connected to a connector means for receiving an external signal, is compactly and centrally arranged. I have.

The second control circuit board is provided with a controller which mainly controls image formation. The memory expansion circuit 54 including, for example, a RAM and the like, and an interface expansion having a connection interface function with an external device are provided. Circuits and the like are configured to be detachable from the left end side of the device.

The first control circuit board 51 is provided between the main chassis 100 made of metal sheet and the lower shield plate 55 made of metal sheet, which is disposed at the lowermost end of the apparatus and increases the rigidity of the apparatus and also has a shielding function. Are located,
Electromagnetic noise intrusion from outside or electromagnetic noise outflow to outside is prevented.

The main chassis 100 has an upwardly squeezed portion 10 corresponding to a component mounted on the first control circuit board 51 and having a large mounting height, such as a power transformer.
0a is formed to improve the planar accuracy and rigidity of the main chassis 100, maintain the fixing unit 60, the sheet feeding unit 70, the transfer unit 80, and the like in a stable relationship, and form the first control circuit board. This effectively produces 51 mounting spaces and contributes to the downsizing of the entire device.

Further, connection from the first control circuit board 51 to each mechanism is required, and the wiring connector 10 provided at the end of the lead wire of the drive motor 103 to simplify this connection.
3b and the like are intensively connected, or the lead terminals 57 having elasticity are brought into pressure contact with each other to conduct electricity, thereby making electrical connection to various points.

On the other hand, the second control circuit board 52 is arranged to face the main chassis 100 made of metal sheet, and
Protected by a shield case surrounding the periphery, intrusion of electromagnetic noise from the outside or outflow of electromagnetic noise to the outside is prevented similarly to the first control circuit board 51.

From now on, the drive transmission relationship of each of the above-described structural parts will be described with reference to FIGS. 2, 4, 5, and 6, 7, 7, 8, 9, 10, 11, and 12. explain.

The main part of the drive transmission unit of the present embodiment is the second control circuit board 5 with the first control circuit board 51 substantially at the center.
2 and are centrally arranged on the right side surface of the main chassis 100. The first wheel train 101 and the second wheel train 1
02 are provided opposite to each other, and a drive motor 103 having a drive gear 103a on an output shaft and several kinds of drive gear trains to be described later are rotatably supported on the two wheel train receivers to form a unit structure. Main chassis 100 as a reference for configuration
The positioning of the portion to be positioned with the positioning portion (not shown) formed in the
4 and the like.

In this embodiment, the first wheel train 101 and the second wheel train 102 are formed in a sheet metal structure, and will be described later in detail. Is the feature.

In this embodiment, the first control circuit board 5
1 is disposed immediately below the above-described sheet material transport path so that its plane area is substantially the same as the sheet material transport path, and the second control circuit board 52 and the main part of the drive transmission unit deviate from this sheet material transport path area. This arrangement is arranged on one side and the other side orthogonal to the sheet material conveyance direction, and contributes to downsizing of the apparatus, particularly downsizing in the height direction, which seeks to reduce the space and space to the limit.

Further, with respect to the arrangement of the toner tank 20 described above, similarly to the second control circuit board 52 and the main part of the drive transmission section, as shown in FIG. In addition to being arranged on one side and protruding from the outer case of the apparatus so that it can be mounted, not only contributes to downsizing of the apparatus in pursuit of reduction of the space and space, but also the outer case when the toner tank 20 is mounted. It is not necessary to release the operation, and the wearability is extremely good.

Referring to FIG. 4 and FIG. 5, the entire driving system of this embodiment will be described. 4 and 5 show a preferred embodiment of a drive system used in the image forming apparatus of the present invention. Each of the drawings is a cross-sectional view at a different position. Both FIGS. 4 and 5 show the rotational center position of each gear. Is marked with + in the figure.
(Similarly in FIG. 7) First, referring to FIG. 5, for the driving system of the present embodiment, individual driving is performed after the common A # gear driven by the driving gear 103a provided on the output shaft of the driving motor 103. A description will be given for each system.

<First Driving System> The first driving system for rotating the photosensitive drum 1 is A # gear → J # gear → K #.
The gears are driven in the order of gear → L # gear, and the L # gear is a gear fixed to one end of the photosensitive drum 1 by a fixing means such as an adhesive, and is formed integrally with the photosensitive drum 1 by the attachment / detachment of the cartridge described above. , Connected to or disconnected from the first drive system.

The mounting and dismounting of the cartridge in this embodiment is performed by moving the cartridge in the vertical direction in the figure.

<Second Drive System> A second drive system for rotating and driving the developing roller 12, which is a main component of the developing unit 10, includes A # gear → B # gear → C # gear → D # gear → E.
The # gear is driven in the order of the # gear, and the E # gear is rotatably supported by the cartridge lower case 18 at substantially the same axial center position as that of the developing roller 12 as described later. The driving force is transmitted to an F # gear fixed to a protruding end of a support portion 12a extending to one end of the developing roller 12 by, for example, fixing means such as press-fitting. 2 Connect or disconnect from the drive system.

<Third Drive System> The third drive system, which rotates the supply roller 13, which is a main component of the developing unit 10, is driven in the order of F # gear → G gear → H # gear. The # gear is a gear fixed to a protruding end of the support portion 13 a extending to one end of the supply roller 13 by a fixing means such as press-fitting.

<Fourth Driving System> Driving means 25 for driving the endless coil springs 31 and 31a for circulating and conveying the toner and the agitator 2 for the toner tank 20
The fourth drive system for rotating the third gear 3 is shown in FIGS. 4 and 7, and is driven in the order of the E # gear → M gear → N # gear.
The N # gear is a helical gear fixed to one end of the driving means 25 by, for example, fixing means such as press fitting.
The M # gear for driving this is a helical gear rotatably supported by the cartridge lower case 18 described above.

<Fifth Driving System> A fifth driving system for rotatingly driving the above-described paper feed roller 73 is shown in FIG.
The gears are driven in the order of B # gear → C # gear → P # gear → Q # gear → R # gear. The R # gear is a gear mounted on a clutch disposed at one end of the above-described paper feed roller 73. It is connected to the fifth drive system.

<Sixth Driving System> The sixth driving system for rotating the fixing roller 63 is A # gear → S # gear → T
The gears are driven in the order of # gear → U # gear, and the U # gear is a gear provided at one end of the fixing roller 63 described above.

<Seventh Drive System> The above-described paper discharge roller pair 61
Is driven in the order of the U # gear → V # gear → W # gear, and the W # gear is a gear provided at one end of the above-described paper discharge roller pair 61.

Next, the essential parts of the drive system will be described in detail.

<First drive system> A # gear → J # gear → K
The first drive system for rotatingly driving the photosensitive drum 1 driven in the order of # gear → L # gear has a structure shown in detail in FIG. 6, and FIG. 6 is an exploded sectional view of this first drive system.

The drive gear 103a provided on the output shaft of the drive motor 103 mounted on the first train wheel receiver 101 faces the first train wheel receiver 101 and the second train wheel receiver 102, and its outer peripheral portion is mirror-finished. A rotatably supported by projection portions 101a and 102a formed in a state.
The gear # is driven, and the L # gear is driven by driving the K # gear via a J # gear rotatably supported by a projection portion 101b formed on the first wheel train 101 with the outer periphery mirror-finished. Leads to.

The J # gear is connected to the projection unit 101.
The detachment from the projection part 101b is prevented by the bush 105 attached to the tip end of the projection b.

For the K # gear support structure, A #
Similarly to the gears, the first wheel train 101 and the second wheel train 10
2 are rotatably supported by projection portions 101c and 102c formed in a mirror-finished outer peripheral portion so as to face each of the two, and have a very simple and inexpensive configuration that does not require a support shaft or a bearing member. .

On the other hand, the first wheel train first receiver 1 provided opposite thereto.
01 and the projection unit 10 of the second train wheel receiver 102
1a and 102a, projection units 101c and 102
c, it is necessary to secure a relative positional relationship between the projection units 101b in order to make each gear stably rotatable. In the present embodiment, in order to achieve the above object, it is necessary to secure a gear train. A plurality of projection portions 101d are provided from one receiver 101, and a plurality of projection portions 102d are provided facing each other from the second train wheel train 102. An engagement recess 101e is formed at a protruding end of the projection portion 101d.
Is provided at the protruding end of the projection portion 102d.
01e to engage with each other to form an engaging projection 102e for positioning.
The unit 1 and the wheel train second receiver 102 are connected to each other by a screw 106 while maintaining a predetermined positional relationship and a relative interval to form a unit.

The engaging concave portion 101e or the engaging convex portion 102e is not shown in the drawing, but the engaging concave portion is in the projection portion 102d, the engaging convex portion is in the projection portion 101d, or The above-mentioned contents may be combined in the plurality of projection units 101d and 102d, and the projection units 101a and 101a of the first train wheel 101 and the second train wheel 102 may be combined.
02a, the projection portions 101c and 102c, and the projection portion 101b can be easily determined to have a predetermined relative positional relationship by pressing the wheel train first receiver 101 and the wheel train second receiver 102 of the sheet metal structure using a progressive die or the like. Configurable.

Although the above-described structure has been described by taking the first drive system as an example, the present embodiment is also applied to the other drive systems described above, although illustration is omitted.

The driving motor 103 of this embodiment is
An inexpensive PM type stepping motor is used, and smooth continuous rotation driving is enabled by controlling input pulses and current.

<Second Driving System> and <Third Driving System> The developing roller 12 which is a main component of the developing unit 10 described above is used.
The main components of the second drive system for rotating the drive roller and the third drive system for rotating the supply roller 13 are structures shown in detail in FIGS. 10, 11, 12 and 13, and FIG. FIG. 11, FIG. 12, and FIG. 13 show another embodiment, and FIGS. 11, 12, and 13 are different from FIG. 10 in cross sections AA and BB in the drawings. This is a part, and the other parts are configured in exactly the same manner.

The D # gear of the second drive system, which is driven in the order of A # gear → B # gear → C # gear → D # gear → E # gear, is each of the D # gears described using the first drive system as an example. Like the gears, the first and second gear trains 101 and 102 are rotatably supported by projection portions 101f and 102f, each of which has an outer peripheral portion formed in a mirror-like state, facing each of the first and second gear trains 101 and 102. The E # gear which is connected to or disconnected from the D # gear by attachment / detachment is firmly connected to the D # gear via the connecting member 6 described above with reference to FIGS.
a and a fixing means such as press-fitting to a protruding end of a support member 5 rotatably supported by a support pin 5Aa and a support portion 12a extending to one end of a developing roller 12 rotatably supported by the support member 5A. F fixed by
Opposite to the # gear, it is rotatably supported by a support shaft 19 provided by a fixing means such as press-fitting in a cartridge lower case 18 substantially at the same axis position as the developing roller 12.

Similarly, an H # gear fixed to a protruding end of a support portion 13a extending to one end of the supply roller 13 rotatably supported by the support member 5 and the support member 5A by, for example, press-fitting. Is configured to transmit drive from the F # gear to the H # gear via a G # gear rotatably supported by a shaft portion 5b protruding from the support member 5,
The developing roller 12 and the supply roller 13 are rotatably supported by the support member 5 and the support member 5A, and are supported by the support pin 5a and the support pin 5Aa together with the regulating blade 14.
As shown in FIGS. 3, 8, and 9, the developing roller 12 is urged toward the photosensitive drum 1 by the springs 8 and 8A. 1, and a stable nip portion is formed. The position of the developing roller 12 is influenced by, for example, variations in the outer diameter of the photosensitive drum 1 and the developing roller 12 and the rotation of the rotating shaft.

Therefore, in the present embodiment, the gears from the E # gear to the F
In order to stably transmit the rotational driving force to the # gear, in the embodiment of FIG. 10, a convex portion E, which is parallel to a line symmetry orthogonal to the rotation axis, is provided on the BB cross section of one E # gear. #A, and a convex portion F # a parallel to the line axis orthogonal to the rotational axis is formed in the AA cross section of the other F # gear, and both convex portions E # a and convex portions F # a are formed. #A orthogonally slidable concave portion 26 that engages with #a
a so-called universal coupling 110 for transmitting a rotational driving force from the E # gear to the F # gear in the direction of the arrow in the figure with the piece member 26 having
In addition to absorbing the difference between the rotational axes of the gear and the F # gear, for example, in the case of meshing drive, a nip portion formed by pressing the developing roller 12 and the photosensitive drum 1 against each other due to the generation of axial force generated by the pressure angle of the gear. It will be unstable,
In this embodiment, the above phenomenon is reduced.

In this embodiment, as a consideration for facilitating the assembly of the universal coupling 110, a contour E # b is formed in the BB cross section of the E # gear, and the concave portion 26a is formed in the convex portion E # a. Is prevented from falling off, thereby facilitating engagement of the F # gear with the convex portion F # a.

The universal coupling 110 constructed as shown in FIG. 10 has the above-mentioned scores, but the drive transmission efficiency and the axial force are reduced by the convex portion E # a of the E # gear and the piece member. 26 recess 26a and piece member 26
This is achieved by the reduction of the sliding friction loss between the concave portion 26b and the convex portion F # a of the F # gear and the effective driving force transmission direction.

Therefore, in another embodiment shown in FIG. 11, a recess having surfaces E # c parallel to each other symmetrically with respect to the axis of rotation is formed in the BB cross section of one E # gear, and the other F # gear is formed. # Surfaces F # parallel to each other symmetrically with respect to the rotation axis center point on the AA cross section of the gear
c, and a piece member 27 having projections 27a and 27b slidable in the orthogonal direction by being engaged with the recess having the surface E # c and the recess having the surface F # c. So-called universal coupling 110 for transmitting rotational driving force from the E # gear to the F # gear in the direction of the arrow in the figure.
And performs the same operation as described above with reference to FIG. 10. In particular, in the structure shown in FIG. 11, the rotation drive transmission from the surface E # c to the convex portion 27a and the rotational drive from the convex portion 27b to the surface F # c
With regard to the transmission of the rotational drive to the motor, the operating direction at the point of application of the rotational drive transmission coincides with the respective rotational directions, so that the transmission efficiency is good.

Further, in the structure shown in FIG.
The #gear is formed of a resin such as polyacetal which is rich in slidability, and the bridge member 27 is formed by die casting of, for example, zinc, aluminum, brass or the like to improve the sliding compatibility with plastic.

In the embodiment shown in FIG. 11, as in the embodiment shown in FIG. 10, as a consideration for facilitating the assembly of the universal coupling 110, a contour portion E # b is provided on the BB cross section of the E # gear. The projection 27a is formed in the recess having the surface E # c.
Is prevented from falling off, and the concave portion having the surface F # c of the F # gear facilitates engagement with the convex portion 27b of the piece member 27. (In this engagement, the piece 2
The protrusion 27b of the No. 7 can enter and be fixed at a predetermined position while rotating the E # gear from one outside of the continuous recess having the surface F # c. Next, another improved embodiment will be described with reference to FIG. In another embodiment shown in FIG. 12, a plane E # d parallel to each other symmetrically with respect to the rotation axis center point is provided on the BB cross section of one E # gear.
A concave portion having surfaces F # d parallel to each other symmetrically with respect to the rotation axis center point at the AA cross section of the other F # gear, and a concave portion having both surfaces E # d. Surface F # d
A rotational driving force is transmitted from the E # gear to the F # gear in the direction indicated by the arrow in the figure by interposing a piece member 28 slidable in the orthogonal direction by being engaged via a roller 29 rotatably supported in a concave portion having a groove. A so-called universal coupling 110 is constructed to perform the same operation as described above with reference to FIG. 10, and in particular, in the structure shown in FIG.
9 and the rotation drive transmission from the roller 29 to the surface F # d, the action directions at the action points of the rotation drive transmission coincide with the respective rotation directions, so that the transmission efficiency is good. The sliding friction loss caused when the member 28 moves is configured to be extremely small due to the rolling friction.

In the structure shown in FIG. 12, the roller 29 is formed of a resin such as polyacetal which is highly slidable.
Numeral 7 is formed by die-casting of zinc, aluminum, brass or the like to improve sliding compatibility with plastic.

In the embodiment shown in FIG. 12, as in the embodiment shown in FIG. 10, as a consideration for facilitating the assembly of the universal coupling 110, a surface E # d formed on the BB cross section of the E # gear is provided. The concave portion having a discontinuity is prevented from falling out of the piece member 28 engaged via the roller 29 by making the F #
The concave portion having the gear surface F # d facilitates engagement with the roller 29 rotatably supported by the piece member 28. (The piece member 2 which rotatably supports the roller 29 in this engagement.
8 can be set in place by rotating the E # gear from one outside of the continuous concave portion having the surface F # d and fixed at a predetermined position.) Next, another further improved embodiment will be described. 13 will be described. Another embodiment shown in FIG. 13 is a further improved structure of the universal coupling 110 having the structure shown in FIG.
Only the portion will be described.

In another improved embodiment shown in FIG. 13, a concave portion having surfaces E # d parallel to each other symmetrically with respect to the center point of the rotation axis is formed in a cross-section of BB of one E # gear. F
A concave portion having surfaces F # d parallel to each other symmetrically with respect to the axis of rotation is formed in an AA cross section of the # gear, and an AA cross section of the F # gear is provided between the E # gear and the F # gear. A concave portion similar to the plane F # d parallel to the rotational axis center point symmetrically formed in the portion and a plane E # d parallel to the rotational axis center point in the BB cross section of the E # gear. Floating member 1 with similar recess
20 and the concave portion having the surface E # d of the E # gear and the concave portion similar to the surface F # d of the floating member 120, and the concave portion similar to the surface Ed of the floating member 120 and the surface F # of the F # gear In the concave portion having a d, two piece members slidably engaged with each other via a roller 29 rotatably supported and interposed in the orthogonal direction are interposed, and the gear member is rotated from the E # gear to the F # gear in the arrow direction in the figure. The so-called universal coupling 110 that transmits the driving force is configured to perform the same operation as described above with reference to FIG.
In the structure shown in FIG. 13, regarding the rotation drive transmission from the surface E # d to the roller 29 and the rotation drive transmission from the roller 29 to the surface F # d, the operation direction at the point of application of the rotation drive transmission is the respective rotation direction. And the transmission efficiency is good, and the sliding friction loss caused when the piece member 28 moves is configured to be extremely small due to the rolling friction, and the rotational axes of the E # gear and the F # gear are greatly different. However, the structure is such that the floating member 120 floats and rotates flexibly without being restrained by anything, and the nip portion formed by pressing the developing roller 12 and the photosensitive drum 1 is further stabilized.

The structure of the universal coupling 110 having the floating member 120 can be applied not only to the improvement of the structure shown in FIG. 12, but also to the improvement of the structure shown in FIGS. 10 and 11. .

On the other hand, in the present embodiment, as described in the above <First drive system> and <Second drive system>, the drive operation of the photosensitive drum 1 and the developing unit 10 is dispersed with respect to the drive of the cartridge. The driven section or the drive section on the main body side has a structure that does not need to be configured with high rigidity, and there is no load state concentrated on the driven section on the cartridge side or the drive section on the main body side. In this configuration, vibration and chatter are suppressed, and driving with less rotation jitter is possible.

Regarding the image forming apparatus or the cartridge of the present embodiment described above, the points to be noted here are summarized as follows.

<About the Size of the Apparatus> The present embodiment is based on the concept of a new product concept, which is a conversion of the conventional product concept, and aims at the emergence of a small and inexpensive image forming apparatus. Therefore, the extreme miniaturization of the device is being pursued.

The structure of the present embodiment is described in JP-B-63-6-6.
Unlike the cartridge of the related art described in Japanese Patent Application Publication No. 7185 and Japanese Patent Publication No. 3-10942, which has a storage unit for the toner consumed by the developing unit and a waste toner accommodating unit removed from the photoreceptor by the cleaning unit, the above-described toner The toner in the storage unit 11 is kept to a minimum necessary amount that does not hinder the image forming process, and the space space of the storage unit 11 is reduced, and the toner that decreases with development is separately detachable. The toner is circulated and supplied from the replaceable toner tank 20 provided in the printer, so that the cartridge, which is the heart of the apparatus, can be reduced in size. As described above, it is arranged on one side perpendicular to the sheet material conveyance direction deviating from the sheet material conveyance path area, and can be mounted by protruding from the outer case of the device. Is configured to not only contributes to downsizing of the apparatus which investigated the reduction of space space, good very wearability need not be performed to release the outer case or the like during mounting of the toner tank 20.

On the other hand, in the apparatus main body, as described above with reference to FIGS. 1 and 2, the sheet material P which is discharged from the fixing unit 60 including the paper discharge roller pair 61 from the paper supply unit 70 via the transfer unit 80 is conveyed. A first control circuit board 51 in which a path is disposed substantially at the center of the entire apparatus below the cartridge and at least a power supply circuit section and an operation control circuit section of each mechanism section are disposed immediately below the sheet material conveyance path. And a second control circuit board 52 on which a controller relationship mainly for controlling image formation is mounted and disposed with respect to the first control circuit board 51. A sheet material that is disposed substantially vertically and is disposed on one side orthogonal to the sheet material conveyance direction deviating from the sheet material conveyance path area, and a main part of a drive transmission unit that drives each mechanism is deviated from the sheet material conveyance path area. Carrying Arranged on the other side perpendicular to the direction,
The fixing unit 60, the first control circuit board 51, and the second control unit 51 are not only configured so as to contribute to downsizing of the apparatus which pursues the reduction of the space to the local limit, particularly to the reduction in the height direction. Although the control circuit board 52 and the main part of the drive transmission unit generate heat correspondingly, when the above arrangement is adopted, the heat generation units are arranged at symmetrical positions and the temperature inside the device becomes substantially uniform. Stable image formation is possible, and the weight balance of the whole device is almost even, and the height direction is reduced, so that the mounting stability and the handling during transportation are excellent. With the rise of computers, the downsizing has been spurred, and in the environment surrounding computers, where the market for personal use has expanded, it has become possible to place them more easily on personal desktops.

A memory expansion circuit 54 including, for example, a RAM, and an interface expansion circuit having an interface function for connection to external equipment can be detachably attached to the second control circuit board from the left side of the apparatus. And its handleability is extremely good.

The arrangement of the cartridge and the toner tank 20 and the arrangement of the first control circuit board 51, the second control circuit board 52, and the main part of the drive transmission unit may be independent from each other. When configured in combination, the above effects are further improved.

Further, in this embodiment, the main parts of the image forming means of the photosensitive drum 1, the charging roller 2, the cleaner unit 90, the developing unit 10, and the toner conveying units 30, 30a are replaced by the cartridge lower case 18 and the cartridge upper case 17. The cartridge is configured to be detachable from the main body as a cartridge that is housed in a unit. However, toner that decreases with development is circulated and supplied from an exchangeable toner tank 20 that is detachably provided. In the present embodiment having such a configuration, there is no problem even if the configuration is not the cartridge configuration detachable to the main body as described above, but is a configuration integrated with the main body.

[0121]

As described above, according to the present invention, there is provided an image forming apparatus in which a cartridge having a photosensitive member and a developing means for developing a toner image on the photosensitive member can be mounted, and the toner image is transferred and fixed. A sheet material transport path for feeding and discharging the sheet material, a first control circuit board on which at least a power supply circuit unit and an operation control circuit unit of a mechanical unit are mounted and arranged, and a controller for controlling image forming are mounted and arranged. A second control circuit board, and a drive transmission unit for driving the mechanism unit. The sheet material transport path is disposed substantially at the center of the entire apparatus below the cartridge, and the sheet material transport path is located immediately below the sheet material transport path. 1) A control circuit board is disposed substantially horizontally, and a second control circuit board is disposed on one side substantially perpendicular to the first control circuit board and perpendicular to a sheet material conveyance direction deviating from the sheet material conveyance path area. Switch the transmission The paper is arranged on the other side perpendicular to the sheet material conveyance direction outside the material conveyance path area, so that the structure of the entire image forming apparatus can be arranged to reduce the space space inside the apparatus to the limit. In addition to the above, not only the apparatus can be reduced in size by reducing the height direction, but also the first control circuit board, the second control circuit board, and the drive transmission unit generate respective heat. In this configuration, the heat generating portions are arranged at symmetrical positions, the temperature inside the apparatus is substantially uniform, stable image formation is possible, and the weight balance of the entire apparatus is substantially uniform, and The size of the personal use market has been reduced and the mounting stability and ease of handling during transportation have been improved. To are those made possible the emergence of low-cost printers and facsimile machines in the compact can be also arranged with a margin in a suitable individual desktop, also,
The second control circuit board is configured such that an extension circuit section for performing function extension can be mounted thereon, and the extension circuit section is configured to be mountable from a lateral direction of the apparatus, so that the handleability is extremely good. Has a very large practical effect.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main part of a left-side surface showing an embodiment of the cartridge of the present invention.

FIG. 4 shows a first embodiment of the image forming apparatus according to the present invention.
FIG.

FIG. 5 shows a second embodiment of the image forming apparatus according to the present invention.
FIG.

FIG. 6 is a developed sectional view showing an embodiment of the image forming apparatus of the present invention.

FIG. 7 is a cross-sectional view of a main part on the right side showing an embodiment of the cartridge of the image forming apparatus of the present invention.

FIG. 8 is a cross-sectional view of a main part of the upper part showing one embodiment of the cartridge and the image forming apparatus of the image forming apparatus of the present invention.

FIG. 9 is a sectional view of a main part of the upper surface of the cartridge showing an embodiment of the cartridge of the image forming apparatus of the present invention.

FIG. 10 is an explanatory diagram of a first rotation drive system showing an embodiment of the cartridge of the present invention.

FIG. 11 is an explanatory view of a second rotation drive system showing another embodiment of the cartridge of the present invention.

FIG. 12 is an explanatory view of a third rotation drive system showing another embodiment of the cartridge of the present invention.

FIG. 13 is an explanatory view of a fourth rotation drive system showing another embodiment of the cartridge of the present invention.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 charging roller 5, 5A support member 5a, 5Aa support pin 8, 8A spring 10 developing unit 12 developing roller 13 supply roller 17 upper cartridge case 18 lower cartridge case 20 toner tank 30, 30a toner transport unit 31, 31a coil Spring 40 Exposure unit 50 Control unit 51 First control circuit board 52 Second control circuit board 60 Fixing unit 64 Fixing base 70 Feeding unit 71 Sheet material transport base 72 Feeding tray 73 Feeding roller 80 Transfer unit 81 Transfer roller 90 Cleaner Part 92 Cleaning blade 100 Main chassis 101 Wheel train first receiver 102 Wheel train second receiver 103 Drive motor 110 Universal coupling

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-242268 (JP, A) JP-A-1-100566 (JP, A) JP-A-4-212877 (JP, A) JP-A-2- 82474 (JP, A) JP-A 1-108544 (JP, U) JP-A 3-114847 (JP, U) JP-A 63-41566 (JP, U) (58) Fields surveyed (Int. ^7, DB name) G03G 15/00 550 G03G 21/16 - 21/18 B41J 29/377 B41J 29/13

Claims (3)

(57) [Claims] 1. A sheet conveying device for feeding and discharging a sheet material for transferring and fixing the toner image to a substantially central portion of an entire apparatus which is a lower part of a photoconductor and a developing unit for developing a toner image on the photoconductor. In the image forming apparatus in which the paths are arranged, a drive transmission unit that drives a mechanism unit is disposed on one of both side surfaces orthogonal to the sheet material conveyance direction deviating from the sheet material conveyance path area, and at least a control circuit board is provided. A first control circuit board on which a power supply circuit section and an operation control circuit section of a mechanism section are mounted and arranged; and a second control circuit board on which a controller for controlling image-related control is mounted and arranged. The circuit board is disposed in a plane just below the sheet material conveyance path, and the second control circuit board is provided on both sides orthogonal to the sheet material conveyance direction deviating from the sheet material conveyance path area. An image forming apparatus characterized in that arranged. 2. The image forming apparatus according to claim 1, wherein the first control circuit board is disposed between a main chassis and a shield plate. 3. The image forming apparatus according to claim 2, wherein the main chassis forms a squeezing portion in a height direction of a circuit portion on which the first control circuit board is mounted and arranged.