Image forming apparatus

Abstract

To prevent short circuit of an electric contact while a transfer roller is separated without using an interlock switch.SOLUTION: An image forming apparatus comprises: an opening and closing unit 21 that is openable and closable; a transfer roller that is provided on the opening and closing unit 21, and brought into contact with an image carrier when the opening and closing unit 21 is closed and is separated from the image carrier when the opening and closing unit 21 is opened; a feeder-side contact 23C that is provided at an end of a feeder 23; and a transfer roller-side contact 21C that is separated from the feeder-side contact 23C when the opening and closing unit 21 is opened. The feeder 23 includes a first contact 231, and a second contact 232 that is allowed to contact and separate from the first contact 231. The opening and closing unit 21 includes a contact part 21T that comes into contact with the second contact 232 to move the second contact 232. The contact part 21T brings the second contact 232 into contact with the first contact 231 when the opening and closing unit 21 is closed, and separates the second contact 232 from the first contact 231 when the opening and closing unit 21 is opened.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Generally, the housing of an image forming apparatus is provided with an openable cover. Opening the cover allows for operations such as replacing units and removing sheets jammed in the conveyance path. Assuming an image forming apparatus having a function of separating a transfer roller from an image carrier when the cover is opened, an electrical circuit supplying power to the transfer roller is provided with electrical contacts, which are configured to be disconnected in conjunction with the separation of the transfer roller. Furthermore, to prevent a short circuit if a user's hand touches the electrical contacts, a high-voltage power supply board is controlled so that high voltage is not applied to the electrical circuit when the transfer roller is separated. Furthermore, in case the high-voltage power supply board becomes uncontrollable, an interlock switch is provided that is linked to the opening and closing of the cover (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-173404 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-26656 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the interlock switch is expensive and becomes an obstacle to reducing the cost of the image forming apparatus.

[0005] SUMMARY OF THE INVENTION In consideration of the above circumstances, an object of the present invention is to prevent short-circuiting of electrical contacts when the transfer roller is separated without using an interlock switch. [Means for solving the problem]

[0006] In order to solve the above problems, an image forming apparatus according to the present invention includes a main housing having an opening, an opening / closing unit that can be opened and closed at the opening, an image carrier that is provided inside the main housing and that carries a toner image, a transfer roller that is provided in the opening / closing unit and that comes into contact with the image carrier when the opening / closing unit is closed and that moves away from the image carrier when the opening / closing unit is opened, a power supply line that supplies power to the transfer roller, a power supply line side contact provided at an end of the power supply line, and a power supply line side contact that is provided on the transfer roller and that moves away from the opening / closing unit. and a transfer roller side contact that contacts the power supply line side contact when the unit is closed and moves away from the power supply line side contact when the opening / closing unit is opened, the power supply line has a first contact and a second contact that can contact and move away from the first contact, the opening / closing unit has a contact portion that contacts the second contact and moves the second contact, the contact portion brings the second contact into contact with the first contact when the opening / closing unit is closed and moves the second contact away from the first contact when the opening / closing unit is opened.

[0007] The second contact may contact the first contact by elastic force when the opening / closing unit is closed, and the contact portion may pull the second contact away from the first contact when the opening / closing unit is opened.

[0008] When the opening / closing unit is closed, the second contact may come into contact with the first contact by an elastic force of the power supply line.

[0009] The opening / closing unit may be swingable around a shaft supported by the main body housing, and the contact portion may be provided on the shaft. [Effects of the Invention]

[0010] According to the present invention, it is possible to prevent short-circuiting of electrical contacts when the transfer roller is separated without using an interlock switch. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing the appearance of an image forming apparatus according to an embodiment of the present invention; [Figure 2] 1 is a side view schematically illustrating an internal configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 3] FIG. 10 is a perspective view showing a state in which the cover according to the embodiment of the present invention is opened. [Figure 4] 1 is a perspective view showing an opening / closing unit according to an embodiment of the present invention in an opened state. [Figure 5] 1 is a perspective view showing an opening / closing unit according to an embodiment of the present invention in an opened state. [Figure 6] FIG. 2 is a perspective view showing the state in which the opening / closing unit according to the embodiment of the present invention is closed. [Figure 7] 1 is a perspective view showing an opening / closing unit according to an embodiment of the present invention in an opened state. DETAILED DESCRIPTION OF THE INVENTION

[0012] An image forming apparatus 1 according to one embodiment of the present invention will be described below with reference to the drawings.

[0013] First, the overall configuration of the image forming apparatus 1 will be described. Fig. 1 is a perspective view showing the exterior of the image forming apparatus 1. Fig. 2 is a side view showing the internal configuration of the image forming apparatus 1. In the following description, the left side of the paper in Fig. 2 is the front side (front side) of the image forming apparatus 1, and the left and right directions will be described based on the direction when the image forming apparatus 1 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr represent top, bottom, left, right, front, and rear, respectively.

[0014] The image forming apparatus 1 includes a rectangular parallelepiped main body housing 3. A paper feed cassette 4 that stores sheets S and a paper feed roller 5 that feeds sheets S from the paper feed cassette 4 are provided at the bottom inside the main body housing 3. An image forming device 6 that forms a toner image by electrophotography is provided above the paper feed cassette 4, and a fixing device 7 that fixes the toner image to the sheet S is provided above the rear of the image forming device 6. A discharge roller 8 that discharges the sheet S with the fixed toner image, and a discharge tray 9 on which the discharged sheet S is stacked are provided above the fixing device 7.

[0015] Inside the main body housing 3, there is provided a conveying path 10 that runs from the paper feed roller 5 through the image forming device 6 and the fixing device 7 to the discharge roller 8. The conveying path 10 is mainly formed of plate-like members that face each other with a gap therebetween to allow the sheet S to pass through, and conveying rollers 17 that sandwich and convey the sheet S are provided at multiple locations in the conveying direction Y. A registration roller 18 is provided upstream of the image forming device 6 in the conveying direction Y. Behind the fixing device 7, there is provided a reversing conveying path 10R that branches off from the conveying path 10 downstream of the fixing device 7 in the conveying direction Y and merges with the conveying path 10 upstream of the registration roller 18 in the conveying direction Y.

[0016] The image forming device 6 includes a photosensitive drum 11 whose potential changes when irradiated with light, a charging device 12 that charges the photosensitive drum 11, an exposure device 13 that emits laser light corresponding to image data, a developing device 14 that supplies toner to the photosensitive drum 11, an intermediate transfer unit 15 that transfers the toner image from the photosensitive drum 11 to a sheet S, and a cleaning device 16 that removes toner remaining on the photosensitive drum 11. The intermediate transfer unit 15 includes an endless intermediate transfer belt 15B wrapped around a drive roller 15D and a driven roller 15N, a primary transfer roller 151 that faces the inner surface of the intermediate transfer belt 15B at a position corresponding to the photosensitive drum 11 and generates a primary transfer bias, and a secondary transfer roller 152 that faces the outer surface of the intermediate transfer belt 15B at a position corresponding to the drive roller 15D and generates a secondary transfer bias. A toner container 20 that supplies toner to the developing device 14 is connected to the developing device 14.

[0017] The control unit 2 includes a calculation unit and a storage unit (not shown). The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit performs various processes by reading and executing control programs stored in the storage unit. Note that the control unit 2 may be realized by an integrated circuit that does not use software.

[0018] An operation panel 19 is provided on the top surface of the main body housing 3. The operation panel 19 includes a display panel, a touch panel provided on top of the display surface of the display panel, and a keypad adjacent to the display panel (not shown). The control unit 2 displays a screen showing the operation menu and status of the image forming apparatus 1 on the display panel, and controls each part of the image forming apparatus 1 in response to operations detected by the touch panel and the keypad.

[0019] The basic image formation operation of the image forming apparatus 1 is as follows: When a print job for single-sided printing is input to the image forming apparatus 1 from an external computer or the like, the paper feed rollers 5 feed the sheet S from the paper feed cassette 4 to the conveying path 10, the registration rollers 18, whose rotation has stopped, correct any skew in the sheet S, and the registration rollers 18 feed the sheet S to the image creating device 6 at a predetermined timing. In the image creating device 6, the charging device 12 charges the photosensitive drum 11 to a predetermined potential, the exposure device 13 writes a latent image on the photosensitive drum 11, the developing device 14 develops the latent image with toner supplied from the toner container 20 to form a toner image, the primary transfer roller 151 transfers the toner image to the intermediate transfer belt 15B, and the secondary transfer roller 152 transfers the toner image to the sheet S. Next, the fixing device 7 melts the toner image while nipping and conveying the sheet S to fix the toner image to the sheet S, and the discharge rollers 8 discharge the sheet S to the discharge tray 9. The cleaning device 16 removes toner remaining on the photosensitive drum 11. In the case of double-sided printing, the sheet S with a toner image fixed on its first surface is sent into the conveying path 10 via the reverse conveying path 10R, where the toner image is transferred to the second surface.

[0020] Next, the configuration of the image forming apparatus 1 including the opening / closing unit 21 will be described in detail. Fig. 3 is a perspective view showing the state in which the cover 3C is open. Fig. 4 is a perspective view showing the state in which the opening / closing unit 21 is open. Fig. 5 is a perspective view showing the state in which the opening / closing unit 21 is open. Fig. 6 is a perspective view showing the state in which the opening / closing unit 21 is closed. Fig. 7 is a perspective view showing the state in which the opening / closing unit 21 is open.

[0021] [cover] A rectangular opening 3A is provided on the rear surface of the main body housing 3 (see FIGS. 1 and 2). An openable and closable rectangular cover 3C is provided on the opening 3A. The lower end of the cover 3C is connected to the lower end of the opening 3A via a hinge portion 3H. The cover 3C opens and closes in the front-to-rear direction around the hinge portion 3H. Opening the cover 3C makes it possible to remove a sheet S jammed in the conveying path 10 and to perform internal maintenance.

[0022] [Opening and closing unit] An opening / closing unit 21 (see FIGS. 2, 3, and 4) is provided on the front side of the cover 3C. The opening / closing unit 21 includes a housing 21H with a longitudinal direction extending in the left-right direction. The housing 21H is provided with a recessed storage section 21R (see FIGS. 5 and 7) that opens in a direction intersecting the left-right direction. The storage section 21R stores a secondary transfer roller 152 with its axial direction extending in the left-right direction. Arm sections 21A (see FIGS. 5 to 7) that protrude in a direction intersecting the left-right direction are provided on both left and right ends of the housing 21H. Shafts 21S protrude leftward and rightward from the tips of the left and right arm sections 21A, respectively. The left and right shafts 21S are supported by shaft supports 3S provided on the main housing 3. The opening / closing unit 21 can swing around the shafts 21S.

[0023] The main body housing 3 (see FIG. 2) is provided with a plate-like member 10P1 that faces the front surface of the opening / closing unit 21. When the opening / closing unit 21 is closed, the conveying path 10 is formed by the plate-like member 10P1 and the front surface of the opening / closing unit 21. On the inner surface of the cover 3C, a plate-like member 10P2 that faces the rear surface of the opening / closing unit 21 is provided. When the cover 3C is closed, the plate-like member 10P2 and the rear surface of the opening / closing unit 21 form a reverse conveying path 10R.

[0024] When the cover 3C is opened, the opening / closing unit 21 can be opened and closed relative to the opening 3A. Figures 2, 3, and 6 show a state in which the opening / closing unit 21 is closed. In this case, the opening / closing unit 21 is housed inside the main body housing 3. When the opening / closing unit 21 is closed, the secondary transfer roller 152 comes into contact with the intermediate transfer belt 15B (see Figure 2).

[0025] 4, 5, and 7 show a state in which the opening / closing unit 21 is open. In this case, the opening / closing unit 21 is exposed to the outside of the main housing 3 through the opening 3A. When the opening / closing unit 21 is opened, the secondary transfer roller 152 is separated from the intermediate transfer belt 15B (see FIGS. 4 and 5) and is exposed to the outside.

[0026] A transfer roller-side contact 21C (FIGS. 5 to 7) is provided at the right end of the housing 21H. The transfer roller-side contact 21C is an electrical contact connected to the secondary transfer roller 152. A power supply line 23 that applies high voltage to the secondary transfer roller 152 from a high-voltage power supply board (not shown) is provided inside the main housing 3. A power supply line-side contact 23C is provided at the end of the power supply line 23. A coil spring made of metal is used as the power supply line-side contact 23C. The power supply line-side contact 23C is fixed to the lower right of the opening 3A, with its extension direction being the front-to-rear direction. When the opening / closing unit 21 is closed, the transfer roller-side contact 21C is pressed against the power supply line-side contact 23C.

[0027] A first contact 231 and a second contact 232 are provided on the power feeder 23 closer to the high-voltage power supply board than the power feeder-side contact 23C. The first contact 231 is connected to the power feeder-side contact 23C. The first contact 231 is attached to the upper surface of a plate-shaped first contact support portion 231A provided on the main housing 3. The second contact 232 is connected to the high-voltage power supply board. The second contact 232 is attached to a second contact support portion 232A provided on the main housing 3. The second contact support portion 232A is a rod-shaped portion whose longitudinal direction is the front-rear direction. The power feeder 23 is wound around the second contact support portion 232A, and a part of the power feeder 23 functions as a torsion coil spring. The second contact 232 is located above the first contact 231. The second contact 232 is urged toward the first contact 231 by the elastic force of the power feeder 23.

[0028] A contact portion 21T protruding in a direction intersecting the axial direction is provided at the right end of the shaft 21S. The contact portion 21T is integrated with the shaft 21S and swings as the shaft 21S rotates. When the opening / closing unit 21 is opened, the contact portion 21T swings clockwise in FIGS. 6 and 7, and when the opening / closing unit 21 is closed, the contact portion 21T swings counterclockwise.

[0029] When the opening / closing unit 21 is closed (see FIG. 6), the contact portion 21T is located below the second contact 232 and is separated from the second contact 232. In this case, the second contact 232 is pressed against the first contact 231 by the elastic force of the power supply line 23.

[0030] On the other hand, when the opening / closing unit 21 is opened (see FIG. 7 ), the contact portion 21T swings upward as the shaft 21S rotates, and the tip of the contact portion 21T pushes the second contact 232 upward, separating it from the first contact 231. Conventionally, when the opening / closing unit 21 is opened, the power supply line-side contact 23C and the transfer roller-side contact 21C are exposed, which could lead to a short circuit if a user accidentally touches these contacts. Conventionally, therefore, an interlock switch that operates in conjunction with the opening and closing of the opening / closing unit 21 is provided to prevent short circuits. However, because the interlock switch is expensive, it has the drawback of hindering cost reductions for the image forming apparatus 1. In contrast, in this embodiment, the contact portion 21T of the opening / closing unit 21 separates the second contact 232 from the first contact 231, so short circuits of the electrical contacts when the secondary transfer roller 152 is separated can be prevented without using an interlock switch.

[0031] The image forming apparatus 1 according to the present embodiment described above includes a main housing 3 having an opening 3A, an opening / closing unit 21 that can be opened and closed at the opening 3A, an image carrier (intermediate transfer belt 15B) that is provided inside the main housing 3 and that carries a toner image, a transfer roller (secondary transfer roller 152) that is provided in the opening / closing unit 21 and that comes into contact with the image carrier when the opening / closing unit 21 is closed and that moves away from the image carrier when the opening / closing unit 21 is opened, a power supply line 23 that supplies power to the transfer roller, a power supply line side contact 23C provided at an end of the power supply line 23, and a power supply line side contact 23C that is provided on the transfer roller and that connects to the opening / closing unit 21. and a transfer roller-side contact 21C that comes into contact with a power feeder-side contact 23C when the open-close unit 21 is closed and that separates from the power feeder-side contact 23C when the open-close unit 21 is opened, the power feeder 23 has a first contact 231 and a second contact 232 that can come into contact with and separate from the first contact 231, the open-close unit 21 has a contact portion 21T that comes into contact with the second contact 232 and moves the second contact 232, the contact portion 21T bringing the second contact 232 into contact with the first contact 231 when the open-close unit 21 is closed and separating the second contact 232 from the first contact 231 when the open-close unit 21 is opened. This configuration makes it possible to prevent short-circuiting of the electrical contacts when the secondary transfer roller 152 is separated, without using an interlock switch.

[0032] Furthermore, according to the image forming apparatus 1 of this embodiment, when the opening / closing unit 21 is closed, the second contact 232 comes into contact with the first contact 231 by elastic force, and when the opening / closing unit 21 is opened, the contact portion 21T separates the second contact 232 from the first contact 231. According to this configuration, when the opening / closing unit 21 is closed, the second contact 232 can be reliably brought into contact with the first contact 231.

[0033] Furthermore, according to the image forming apparatus 1 of this embodiment, when the opening / closing unit 21 is closed, the second contact 232 comes into contact with the first contact 231 due to the elastic force of the power supply line 23. With this configuration, there is no need to provide a member that biases the second contact 232, which reduces the number of parts.

[0034] Furthermore, in the image forming apparatus 1 according to this embodiment, the opening / closing unit 21 is swingable around the shaft 21S supported by the main body housing 3, and the contact portion 21T is provided on the shaft 21S. This configuration allows the second contact 232 to be separated from the first contact 231 with a simple configuration.

[0035] The above embodiment may be modified as follows.

[0036] In the above embodiment, an example in which the present invention is applied to a color printer is shown, but the present invention may also be applied to a monochrome printer. In this case, the image carrier is the photosensitive drum 11.

[0037] In the above embodiment, an example is shown in which the contact portion 21T is provided on the shaft 21S, but the contact portion 21T may also be configured to oscillate via a link mechanism that operates in conjunction with the rotation of the shaft 21S.

[0038] In the above embodiment, an example is shown in which the second contact 232 is brought into contact with the first contact 231 by the elastic force of the power supply line 23, but the second contact 232 may also be brought into contact with the first contact 231 using a biasing member such as a spring.

[0039] In the above embodiment, an example is shown in which the second contact 232 comes into contact with the first contact 231 by elastic force when the opening / closing unit 21 is closed, and the contact portion 21T pulls the second contact 232 away from the first contact 231 when the opening / closing unit 21 is opened, but the second contact 232 may also be configured to move away from the first contact 231 by elastic force when the opening / closing unit 21 is opened, and the contact portion 21T may be configured to press the second contact 232 against the first contact 231 when the opening / closing unit 21 is closed.

[0040] In the above embodiment, an example has been shown in which the opening / closing unit 21 swings around the shaft 21S, but the opening / closing unit 21 may be configured to slide in the front-rear direction. [Explanation of symbols]

[0041] 3 Main body housing 3A opening 15B Intermediate transfer belt (image carrier) 21 Opening and closing unit 21C Transfer roller side contact 21S axis 21T contact part 23 Power line 23C Feed line side contact 152 Secondary transfer roller (transfer roller) 231 First Contact 232 Second Contact

Claims

1. a main body housing having an opening; an opening / closing unit that can be opened and closed at the opening; an image carrier provided inside the main body housing and configured to carry a toner image; a transfer roller provided in the opening / closing unit, the transfer roller coming into contact with the image carrier when the opening / closing unit is closed and moving away from the image carrier when the opening / closing unit is opened; a power supply line that supplies power to the transfer roller; a power supply line side contact provided at an end of the power supply line; a transfer roller-side contact that is provided on the transfer roller and that comes into contact with the power supply line-side contact when the opening / closing unit is closed and that moves away from the power supply line-side contact when the opening / closing unit is opened, The power supply line is A first contact point; a second contact that can come into contact with and be separated from the first contact, The opening and closing unit includes: a contact portion that comes into contact with the second contact and moves the second contact, The contact portion brings the second contact into contact with the first contact when the opening / closing unit is closed, and separates the second contact from the first contact when the opening / closing unit is opened.

2. the second contact comes into contact with the first contact by an elastic force when the opening / closing unit is closed; 2. The image forming apparatus according to claim 1, wherein the contact portion separates the second contact from the first contact when the opening / closing unit is opened.

3. 3. The image forming apparatus according to claim 2, wherein the second contact comes into contact with the first contact due to an elastic force of the power supply line when the opening / closing unit is closed.

4. the opening / closing unit is swingable around an axis supported by the main body housing, 4. The image forming apparatus according to claim 1, wherein the contact portion is provided on the shaft.

Images