JPH09244447A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the constitution of a fixing unit. SOLUTION: An upper fixing unit 71 is simply coupled to a lower fixing unit 72 and a front surface part 4b being one part of an upper housing 14 is made to intervene in the middle of the turning allowable range θmax of the unit 71. As the result, when a cover 3 is opened, the Unit 71 is not turned to the miximum within the range θmax but it abuts on the front surface part 4b in the middle. That means, the turning action of the unit 71 is restricted within a prescribed range θTH. Thus, the fixing unit can be simplified in comparison with a case that it is provided with a spring member and the like. Besides, since the turning action of the unit 71 is regulated by the upper housing 4, the fatigue of a supporting point part being the center of the turning action of the unit 71 can be reduced.

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 such as a small printer for personal use. More specifically, the present invention relates to an image forming apparatus to which an openable / closable cover is attached.

[0002]

2. Description of the Related Art With the recent trend of downsizing of computers, individuals are often using personal computers (personal computers) or workstations on their desks. Along with this trend, there is a demand for a small printer that can be placed on a personal desk so that documents and tables created by a personal computer can be easily printed out.

By the way, in order to reduce the size of the printer, it is necessary to make the internal structure as simple as possible. Therefore, it is necessary to simplify the configuration of the fixing unit. On the other hand, the fixing unit also needs to be configured to easily remove jammed paper. As a configuration for facilitating removal of jammed paper, it is known that an upper fixing unit is usually divided into an upper fixing unit and a lower fixing unit, and the upper fixing unit is rotatable (Japanese Patent Laid-Open No. 60-201361). , JP-A-63-192072, JP-A-1-30
See Japanese Patent No. 3472. )

[0004]

However, in the configuration disclosed in each of the above-mentioned publications, the fixing unit is provided with a dedicated spring, a supporting plate, a cam, etc., so that the configuration of the fixing unit becomes complicated. There is a defect. Therefore, an object of the present invention is to provide an image forming apparatus that can solve the above-mentioned technical problems and can simplify the configuration of a fixing unit.

[0005]

According to a first aspect of the present invention for achieving the above object, an image is formed whose appearance is constituted by a main housing and a cover attached to the main housing so as to be openable and closable. A device,
A fixing unit for fixing the image transferred to the paper is provided in the main housing. The fixing unit includes a lower fixing unit including a lower roller fixed to the main housing, and a lower fixing unit. It has an upper fixing unit including an upper roller, which is rotatably connected to each other. When the cover is closed, the cover presses the upper fixing unit so that the upper roller presses against the lower roller, and when the cover is opened, the upper fixing unit is fixed. In the image forming apparatus, the unit is in a rotatable state, and the main housing is provided with a restricting member for restricting a rotating range of the upper fixing unit when the cover is opened. is there.

According to a second aspect of the invention, the main housing includes a lower housing and an upper housing fitted to the lower housing, and the regulating member is provided in the upper housing. The image forming apparatus according to Item 1. According to a third aspect of the present invention, the upper roller is elastically attached to the upper fixing unit in a direction orthogonal to the axial direction of the upper roller, and the upper fixing unit is elastically moved by the elastic force when the cover is opened. The roller rotates in a direction away from the lower roller, and the rotation is stopped at a position where the upper fixing unit abuts against the regulating member. Image forming apparatus.

The fixing unit in the present invention has a structure in which the upper fixing unit is rotatably connected to the lower fixing unit. Therefore, the structure of the fixing unit is simplified. Moreover, since the main housing is provided with the restricting member for restricting the rotation range of the upper fixing unit, the upper fixing unit does not rotate too much when the cover is opened.

[0008]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a simplified external configuration of a printer according to an embodiment of the present invention, and FIGS. 2 and 3 are views showing the printer as viewed from the left side in order to explain the internal configuration of the printer. Is. In FIG. 2 and FIG. 3, in order to emphasize the internal configuration of the printer, the configuration relating to the external appearance is shown by a chain double-dashed line.

First, an outline and an external structure of this printer will be described below. This printer is of a so-called personal use that is used by being placed on the desk of each individual. That is, this printer is connected to a personal computer (personal computer) or the like used by each individual, and is used for the purpose of easily printing out documents, tables and the like created by the individual on the personal computer.

As shown in FIGS. 1 to 3, this printer has a structure including an apparatus main body 1 and a paper feed tray 2.
The external appearance of the apparatus main body 1 is constituted by an openable / closable cover 3, and an upper housing 4 and a lower housing 5 which are fitted to each other. The paper feed tray 2 is for holding paper to be printed, and is removable from the apparatus body 1.

The cover 3 is, as shown in FIGS. 1 to 3,
It is attached to the apparatus main body 1 so as to cover the upper front part of the printer. The cover 3 can be opened in the direction of arrow A from the front surface of the printer toward the rear surface around the fulcrum portion 6. FIG. 3 shows a state in which the cover 3 is opened.
Note that it is preferable to remove the paper feed tray 2 when the cover 3 is opened.

A tray insertion port 7 is formed on the rear side of the cover 3. The paper feed tray 2 can be attached by inserting it into the tray insertion port 7, and can be removed by pulling it out from the tray insertion port 7.
A connector 8 is attached to the rear surface portion 4a of the upper housing 4. The connector 8 is for connecting this printer to a personal computer or the like. That is, the printer cable 9 having one end connected to the personal computer is connected to the connector 8.

As can be seen from FIGS. 2 and 3, the connector 8 and the printer cable 9 project from the rear surface portion 4a of the upper housing 4. The protrusion length L is
It is determined by the type of connector 8 and the type of printer cable 9 used. As shown in FIGS. 1 and 2, the paper feed tray 2 is shaped so as to extend obliquely upward and rearward from the apparatus main body 1 when inserted into the tray insertion port 7. The paper feed tray 2 has a size such that the upper end 2a thereof protrudes from the rear surface 4a of the upper housing 4 by a predetermined length when attached. Specifically, the projected image 11 of the upper end portion 2a of the paper feed tray 2 on the printer installation surface 10 is substantially the same as the protruding length L of the connector 8 and the printer cable 9 in the rear surface portion 4a of the upper housing 4.
It has a size that protrudes from it.

The protrusion length L differs depending on the type of the connector 8 and the type of the printer cable 9 used as described above. The shape and is designed. As a result, when installing the rear surface of this printer along the wall,
The operator does not collide the connector 8 and the printer cable 9 with the wall by setting the upper end 2a of the paper feed tray 2 as a reference and aligning the upper end 2a with the wall.
Therefore, it is possible to reduce the burden of installation work on the operator and prevent damage to the connector 8.

Moreover, the printer installation surface 10 of the upper end 2a
The length of the projected image 11 with respect to the rear surface portion 4a of the upper housing 4 is determined by the length of the connector 8 and the printer cable 9.
Is almost the same as the protrusion length L of Therefore, it is possible to meet the demand for a smaller installation space. Next, the internal configuration of this printer will be described in detail mainly with reference to FIGS.

As shown in FIGS. 2 and 3, this printer is provided with a paper feeding section 20, a laser beam irradiation unit 30, an imaging unit 40, a developing unit 50, a transfer unit 60 and a fixing unit 70. A discharge port 80 is formed on the front surface of the printer. The discharge port 80 has an upper housing 4 and a lower housing 5.
It is formed near the boundary with.

The paper placed on the paper feed tray 2 is fed by the paper feed unit 20, the imaging unit 40, the transfer unit 60, and the fixing unit 70 along the conveyance path 90 formed by the broken line on the apparatus main body 1. The sheets are sequentially conveyed, and finally discharged from the discharge port 80 to the outside of the apparatus. Transport route 90
2, is formed in a substantially straight line having a downward slope from the paper feed tray 2 toward the discharge port 80. This is because the shape is optimal for downsizing the printer.

The paper feed section 20 is for feeding the paper placed on the paper feed tray 2 to a conveyance path 90 formed in the apparatus main body 1. The paper feeding unit 20 is attached to the cover 3, and is lifted together with the cover 3 when the cover 3 is opened. The sheet feeding unit 20 is provided with a sheet feeding roller 21 (the sheet feeding roller 21 includes a separation roller and a conveyance roller as described later).
The paper feed roller 21 is provided at a position where it abuts the surface of the paper feed tray 2 when the paper feed tray 2 is inserted into the tray insertion port 7.

The paper feed section 20 is also provided with a paper detection switch 22. The paper detection switch 22 is for detecting the presence or absence of paper in order to perform paper feed control.
It is provided immediately downstream of the separation roller 21 in the transport path 90. Paper feed control is performed as follows. That is, when the sheet feeding is instructed while the sheet is placed on the sheet feeding tray 2, the sheet feeding roller 21 starts to rotate. As a result, the paper is taken out by the paper feed roller 21 and sent to the conveyance path 90. After the first predetermined time has elapsed from the start of rotation of the paper feed roller 21, the paper is
The paper detection switch 22 is reached. That is, the paper detection switch 22 is turned on.

The rotation of the paper feed roller 21 is stopped after a predetermined second time has elapsed since the paper detection switch 22 was turned on. During the second time, the supplied paper is the fixing unit 7.
It is set long enough to reach zero. The sheet that has reached the fixing unit 70 is conveyed and discharged by the fixing unit 70. When it is necessary to supply the next sheet, the sheet feeding roller 21 is rotated again after a lapse of a predetermined time from the rotation stop.

If the paper detection switch 22 does not turn on even after the first time has elapsed from the start of rotation of the paper feed roller 21, it is recognized that the paper is out. Laser light irradiation unit 3
0 is for outputting a laser beam corresponding to the image signal. The laser light irradiation unit 30 is provided in the lower housing 5 of the apparatus body 1.

The laser light irradiation unit 30 is provided with a laser light source 31 and an optical system 32. The laser light source 31 is composed of a semiconductor laser or the like. Optical system 3
2 is composed of a plurality of reflecting mirrors, lenses, polygon mirrors, and the like. The laser light generated by the laser light source 31 is applied to the imaging unit 40 via the optical system 32.

The laser light irradiation unit 30 has a connector 8
Is electrically connected to Laser light irradiation unit 30
From the personal computer to the printer cable 9 and connector 8
The irradiation light amount of the laser light and the like are determined on the basis of the image data given via the. Then, the laser light is generated from the laser light source 31 based on the determined irradiation amount of the laser light and the like.

The imaging unit 40, the developing unit 50 and the transfer unit 60 are for forming an image on the paper fed from the paper feeding section 20. In the imaging unit 40, the photoconductor 41 that is exposed by the above-mentioned laser light is installed. A charging charger 42 and a paper dust collecting brush 43 are provided along the periphery of the photoconductor 41. As the photoconductor 41, a small one having a diameter of 16 (mm) is used for downsizing of the printer.

The photosensitive member 41 rotates at a constant speed along the arrow B direction during image formation. After the surface of the photoconductor 41 is uniformly charged to a predetermined high potential by the charging charger 42,
It is exposed to laser light from the laser light irradiation unit 30. In the exposed area that receives the light, the electric charge in that area escapes to a low potential. As a result, an electrostatic latent image having a high potential region and a low potential region is formed on the surface of the photoconductor 41.

When the photoreceptor 41 further rotates and the electrostatic latent image reaches the developing unit 50, the electrostatic latent image is developed into a toner image by the developing unit 50. Developing unit 50
Is provided in the upper housing 4 and includes a toner hopper 51,
The configuration includes the sub roller 52 and the developing roller 53. The toner hopper 51 is for filling the toner.

The sub roller 52 and the developing roller 53 are
They are rotated in the same direction as each other. By this rotation, the toner filled in the toner hopper 51 is frictionally charged,
Toner is electrostatically adsorbed on the peripheral surface. Sub roller 52
Are provided to more effectively triboelectrically charge the toner. The sub roller 52 and the developing roller 53 include
A predetermined bias voltage is applied. As a result, the toner attached to the peripheral surface of the developing roller 53 is electrostatically
It is adsorbed only on the exposed region of the surface of the photoconductor 41. So-called reversal development is performed. As a result, a toner image corresponding to the electrostatic latent image is formed on the surface of the photoconductor 41.

When the photoconductor 41 further rotates and the toner image reaches the transfer unit 60, the toner image is transferred onto the sheet conveyed along the conveying path 90. That is, the transfer roller 61 is incorporated in the transfer unit 60. The leading edge of the sheet is supplied between the photoconductor 41 and the transfer roller 61 in accordance with the leading edge of the toner image facing the transfer roller 61. As a result, the toner images formed on the photoconductor 41 are sequentially transferred to the paper.

The transfer unit 60 is attached to the cover 3, and is lifted together with the cover 3 when the cover 3 is opened. On the surface of the photoconductor 41 after transfer,
The toner that was not transferred to the paper remains. Further, when the paper comes into contact with the surface of the photoconductor 41, paper dust and the like generated from the paper also adhere to the surface of the photoconductor 41 together with the residual toner.

The paper dust attached to the photoconductor 41 is attached to the tip of the paper dust collecting brush 43 and collected when passing through the paper dust collecting brush 43 in the imaging unit 40.
Further, the residual toner adhering region of the photoconductor 41 is scattered and scattered by the tip of the paper dust collecting brush 43 when passing through the paper dust collecting brush 43, and the residual toner and the surface of the photoconductor 41 are separated from each other. The electrostatic coupling of is weakened. The residual toner having the weakened electrostatic coupling is collected by the developing roller 53 at the time of the next image formation.

The sheet after transfer is supplied to the fixing unit 70. The fixing unit 70 is for fixing the image transferred onto the sheet, and is provided along the transport path 90 between the upper housing 4 and the lower housing 5. The fixing unit 70 is divided into an upper fixing unit 71 and a lower fixing unit 72. The lower fixing unit 72 is fixed to the lower housing 5. The upper fixing unit 71 is rotatably attached to the lower fixing unit 72 by a fulcrum portion 73 in the arrow C direction.

A part of the conveying path 90 is formed between the upper fixing unit 71 and the lower fixing unit 72, and as described above, it is a straight line having a downward slope from the paper feed tray 2 toward the discharge port 80. Has been formed. Further, both units 71 and 72 are provided with an upper fixing roller 74 and a lower fixing roller 75, respectively. A heater (not shown) is provided inside the lower fixing roller 75 along the axis thereof.

The fixing unit 70 is in the closed state as shown in FIG. 2 when the cover 3 is closed. Specifically, the upper fixing unit 71 is pressed by the pressing portion 3a protruding from the inside of the cover 3. Here, the upper fixing roller 74 is attached to the upper fixing unit 71 so as to be displaceable in a direction orthogonal to the axial direction thereof. Then, it is always elastically urged by a spring or the like in the direction opposite to the arrow C direction. As a result, the upper fixing roller 74 is pressed against the lower fixing roller 75 and brought into pressure contact with a predetermined pressure.

The cover 3 is closed during image formation.
Further, the upper fixing roller 74 is rotated in the arrow D direction, and the lower fixing roller 75 is rotated in the arrow E direction. On the other hand, the sheet after transfer is supplied between the upper fixing roller 74 and the lower fixing roller 75 in this pressure contact state. At this time, the lower fixing roller 75 is heated by the heat of the heater. As a result, the toner image is melted by pressing and heating and is fixed on the paper.

The pressure contact state of the fixing unit 70 is released when the cover 3 is opened, as shown in FIG. That is, when the cover 3 is opened, the pressure contact state of the rollers 74 and 75 is released to facilitate the removal of the jammed paper. At this time, the rotation of the upper fixing unit 71 is restricted by the front surface portion 4b of the upper housing 4. The fixing unit 70 also includes an upper discharge roller 76 and a lower discharge roller 77. More specifically,
The upper discharge roller 76 is attached to the upper fixing unit 71, and is rotated in the arrow F direction (see FIG. 2). The lower discharge roller 77 is attached to the lower fixing unit 72, and is in the direction of arrow G (see FIG. 2).
It is something that can be rotated. Each discharge roller 76, 77
By the rotation of, the sheet after fixing is guided to the discharge port 80 and discharged to the outside of the apparatus.

Next, the structure relating to the fixing unit 70 will be described in detail with reference to FIG. The fixing unit 70 of this embodiment employs a configuration in which the upper fixing unit 71 is simply attached to the lower fixing unit 72 in view of simplification of the internal configuration of the printer. Therefore, originally, the upper fixing unit 71 can be rotated to the maximum within the rotation allowable range θ _max about the fulcrum 73 as shown by the chain double-dashed line in FIG. 4A. Moreover, as in the present embodiment, the rollers 74 and 75 are pressed against each other so that the pressure contact surface is inclined with respect to the horizontal plane, and the fulcrum 73 is moved toward the transport path 9.
When it is provided on the downstream side of 0, the upper fixing unit 71 is vigorously rotated by its own weight.

On the other hand, in the present embodiment, the front surface portion 4b which is a part of the upper housing 4 is interposed in the middle of the rotation allowable range θ _max of the upper fixing unit 71. Therefore,
The cover 3 is opened from the state shown in FIG.
When the pressure contact state of the fixing unit 70 is released, as shown in FIG. 5, the upper fixing unit 71 does not rotate to the maximum within the rotation allowable range θ _max , but in the middle thereof, the front surface portion of the upper housing 4 is Contact 4b. That is, the rotation allowable range θ _max of the upper fixing unit 71 is restricted to the predetermined range θ _TH .

As described above, according to this embodiment, since the upper fixing unit 71 is simply rotatably attached to the lower fixing unit 72, as compared with the prior art including the spring member, the support plate, the cam, and the like. The configuration of the fixing unit 70 can be greatly simplified. Further, the rotation of the upper fixing unit 71 is restricted by the front surface portion 4b which is a part of the upper housing 4. That is, the upper housing 4 constituting the external appearance of the apparatus main body 1 is used to regulate the rotation of the upper fixing unit 71. Therefore, the rotation regulation can be realized without complicating the internal configuration of the apparatus body 1.

In the present embodiment, the case where the apparatus main body 1 is composed of the cover 3, the upper housing 4, and the lower housing 5 is described as an example. However, the apparatus main body 1 may be configured by one housing and the cover 3 that covers the upper front surface of the housing. In this case, it is necessary to interpose the front side of the housing in the middle of the rotation allowable range θ _max of the upper fixing unit 71.

Further, in this embodiment, the housing constituting the external appearance of the apparatus main body 1 is used for restricting the rotation of the upper fixing unit 71. However, it goes without saying that only a portion of the housing that actually regulates the rotation of the upper fixing unit 71 (for example, the front surface portion 4b of the upper housing 4) may be a separate member and the member may be attached later.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and within the scope of technical matters described in other claims. It is possible to make various design changes.

[0042]

As described above, according to the present invention, the fixing unit has a structure in which the upper fixing unit is rotatably connected to the lower fixing unit. Therefore, the structure of the fixing unit can be greatly simplified. Moreover, since the upper fixing unit is restricted by the restriction member provided in the housing, the rotation of the upper fixing unit can be restricted with a simple configuration. As a result, fatigue of the fulcrum member, which is the center of rotation, can be reduced, and the life of the fixing unit can be extended.

In particular, according to the second aspect of the invention, the housing is divided into the upper housing and the lower housing, so that the assembly process can be simplified.

[Brief description of drawings]

FIG. 1 is a perspective view showing a simplified external configuration of a printer according to an embodiment of the present invention.

FIG. 2 is a diagram of the printer as viewed from the left side for explaining the internal configuration of the printer when the cover is closed.

FIG. 3 is a diagram of the printer viewed from the left side for explaining the internal configuration of the printer when the cover is opened.

FIG. 4 is a diagram for explaining a configuration relating to rotation of a fixing unit.

[Explanation of symbols]

1 Device Main Body 3 Cover 4 Upper Housing 5 Lower Housing 70 Fixing Unit 71 Upper Fixing Unit 72 Lower Fixing Unit 74 Upper Fixing Roller 75 Lower Fixing Roller θ _max Allowable Rotation Range θ _TH Predetermined Range

Claims (3)

[Claims] 1. An image forming apparatus comprising a main housing and a cover attached to the main housing so that the cover can be opened and closed. The image forming apparatus fixes an image transferred onto a sheet in the main housing. And a lower fixing unit including a lower roller fixed to the main housing, and an upper unit including an upper roller rotatably connected to the lower fixing unit. It has a fixing unit, and when the cover is closed, the cover presses the upper fixing unit so that the upper roller comes into pressure contact with the lower roller, and when the cover is opened, the upper fixing unit is rotatable. The housing is provided with a regulating member for regulating the rotation range of the upper fixing unit when the cover is opened. An image forming apparatus comprising. 2. The image according to claim 1, wherein the main housing includes a lower housing and an upper housing fitted to the lower housing, and the regulating member is provided in the upper housing. Forming equipment. 3. The upper roller is provided with respect to the upper fixing unit.
The upper fixing unit is elastically attached in a direction orthogonal to the axial direction of the upper roller, and the upper fixing unit rotates in a direction in which the upper roller separates from the lower roller due to the elastic force when the cover is opened. The image forming apparatus according to claim 1 or 2, wherein the unit is configured to stop at a position where it abuts against the regulation member.