JP2015001638A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which forms a monochrome image and is capable of utilizing space.SOLUTION: An image forming apparatus 1' includes toner replenishing means 7' which includes: multiple toner bottles 71d all containing toner of a same color; multiple sub hoppers 72d which are respectively provided for the multiple toner bottles 71d, and which temporarily store therein toner discharged from the respective toner bottles 71d; and a long screw which feeds toner stored in the sub hoppers 72 to a replenishing sub hopper 72d. The image forming apparatus 1' further includes: a photosensitive drum 32d; and developing means 34d which develops, with toner replenished from the replenishing sub hopper 72d, an electrostatic latent image formed on the photosensitive drum 32d.

Description

  The present invention relates to an image forming apparatus capable of printing a monochrome image on a sheet.

  First, in this specification, an image forming apparatus capable of printing only a single color image (monochrome image or monocolor image) is referred to as a “monochrome machine”, and an image forming apparatus capable of printing a full color image (including a monochrome image) is referred to as “full color”. Sometimes called “machine”.

  As is well known, an image forming apparatus employing an electrophotographic system develops an electrostatic latent image formed on a photosensitive drum with toner. Next, the image forming apparatus transfers and fixes the toner image formed on the photosensitive drum onto a sheet such as a sheet or an OHP sheet. Thereafter, the image forming apparatus discharges the fixed sheet to the outside of the apparatus (for example, see Patent Document 1).

International Publication No. 2010/032634

  By the way, among recent monochromatic machines, there are those that use most of the full-color machines. Specifically, a full-color machine from which an image forming unit for three colors (yellow, cyan, magenta) other than black, a toner bottle, and a sub hopper are removed is sold as a single-color machine. However, in such a single color machine, the space where the toner bottles and the sub hoppers for the three colors are used is not utilized, and it becomes a dead space.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus dedicated to monochromatic images that can utilize space.

  In order to achieve the above object, one aspect of the present invention is an image forming apparatus, wherein a plurality of toner containers that store toner of the same color are provided separately for each of the plurality of toner containers. A plurality of storage means, a plurality of storage means for temporarily storing the toner discharged from the corresponding toner container, and a toner stored in the plurality of storage means are selected from any of the plurality of storage means. An electrostatic latent image formed on the photosensitive member with toner replenishing means including a replenishing storage means, a photoconductor, and toner replenished from the replenishing storage means. Developing means for developing.

  According to the above aspect, toner can be replenished from a plurality of toner containers to a specific developing unit. Therefore, when the full color machine is diverted to a single color machine, the space occupied by the toner containers of a plurality of colors can be utilized without becoming a dead space.

1 is a diagram illustrating a configuration when an image forming apparatus according to an embodiment of the present invention is used as a full-color machine. It is a perspective view which shows the detailed structure of the sub hopper of FIG. It is a front view which shows the detailed structure of the sub hopper of FIG. FIG. 2 is a control block diagram of toner replenishing means in FIG. 1. It is a figure which shows the structure at the time of diverting the full-color machine of FIG. 1 to a monochromatic machine. It is a perspective view which shows the detailed structure of the sub hopper of FIG. It is a front view which shows the detailed structure of the sub hopper of FIG. 5, and is a figure which shows the detailed structure of a long screw. FIG. 6 is a control block diagram of the toner replenishing means of FIG. 5. FIG. 6 is a flowchart showing a first toner supply processing procedure in the toner supply means of FIG. 5.

<Embodiment>
Hereinafter, an image forming apparatus according to an embodiment will be described in detail with reference to the drawings.

<< Introduction >>
First, the X axis, Y axis, and Z axis in the figure will be described. The X axis, the Y axis, and the Z axis are orthogonal to each other. Further, the X axis, the Y axis, and the Z axis indicate the left-right direction, the front-rear direction, and the up-down direction of the image forming apparatus 1. The direction of the Y axis is the viewing direction when the image forming apparatus 1 is viewed from the front. The reverse direction of the Z-axis is the viewing direction when the image forming apparatus 1 is viewed from above.

  In addition, alphabetic small letters a, b, c, and d described after the reference numerals are subscripts representing yellow (Y), magenta (M), cyan (C), and black (Bk). For example, the photosensitive drum 32a means a yellow photosensitive drum.

<< Configuration and operation of image forming device (full color machine) >>
In FIG. 1, an image forming apparatus 1 is, for example, a multifunction peripheral (MFP) that employs an electrophotographic system. Further, the image forming apparatus 1 prints a full-color image on a sheet (for example, paper or an OHP film) by, for example, a tandem method. Such an image forming apparatus generally includes a supply device 2, an image forming unit 3, and a fixing unit 4.

  A plurality of sheets S are placed on the supply device 2 as a sheet bundle. The feeding device 2 picks up the sheets S one by one from the sheet bundle, and sends them out to a conveyance path (hereinafter referred to as a conveyance path α) indicated by a one-dot chain line arrow α.

  In the image forming unit 3, the charging units 31a to 31d uniformly charge the peripheral surfaces of the rotating photosensitive drums 32a to 32d. The peripheral surfaces of the charged photosensitive drums 32a to 32d are irradiated with light beams Ba to Bd from the exposure device 33. As a result, Y, M, C, and Bk electrostatic latent images are formed on the photosensitive drums 32a to 32d. 32d. The developing means 34a to 34d supply toner to the photosensitive drums 32a to 32d carrying the corresponding electrostatic latent images, thereby forming Y, M, C, and Bk toner images. The toner images on the photosensitive drums 32a to 32d are sequentially transferred to the same area of the intermediate transfer belt 35 that rotates in a predetermined direction (primary transfer). As a result, a full-color synthetic toner image is formed on the intermediate transfer belt 35. The synthesized toner image is conveyed toward the secondary transfer region 36 while being carried on the intermediate transfer belt 35.

  Further, the sheet S sent out from the supply device 2 is transported on the transport path α and abuts against the timing roller pair 37 that is stopped without rotating. Thereafter, the timing roller pair 37 starts to rotate so as to coincide with the transfer timing in the secondary transfer area 36 and sends the temporarily stopped sheet S to the secondary transfer area 36.

  In the secondary transfer region 36, the composite toner image on the intermediate transfer belt 35 is transferred to the sheet S sent out from the timing roller pair 37 (secondary transfer). The sheet S after the secondary transfer is sent out downstream of the transport path α as an unfixed sheet S.

  The fixing unit 4 is, for example, a heat roller fixing type, and includes two rotating bodies. These rotating bodies come into contact with each other to form a fixing nip. An unfixed sheet S is introduced into the fixing nip. The fixing unit 4 heats the unfixed sheet S passing through the fixing nip with one rotating body and presses it with the other rotating body. As a result, the synthetic toner image on the unfixed sheet S is fixed. The fixed sheet S is sent out from the fixing nip to the downstream side of the conveyance path α and finally discharged to the tray 5.

  The control circuit 6 includes a microcomputer, a main memory, and the like, and controls each component of the image forming apparatus 1.

<Toner supply to developing means>
As can be seen from the above, since toner is consumed by printing, it is necessary to replenish the developing means 34a to 34d as appropriate. For this purpose, the image forming apparatus 1 includes a toner replenishing unit 7 that replenishes toner to each of the developing units 34a to 34d.

  The toner supply means 7 is provided with toner bottles 71a to 71d and sub hoppers 72a to 72d. Since the toner bottles 71a to 71d are not so important in the present embodiment, their illustration is simplified.

  Here, the developing units 34 a to 34 d are linearly arranged in the image forming apparatus 1 along the X axis. In the present embodiment, the developing means 34a is arranged on the leftmost side. Further, the developing units 34b to 34d are arranged on the right side of the developing units 34a to 34c.

  The toner bottles 71a to 71d are linearly arranged above the intermediate transfer belt 35 from left to right along the X axis. In the present embodiment, the toner bottle 71a is disposed on the leftmost side. The toner bottles 71b to 71d are arranged on the right side of the toner bottles 71a to 71c. In addition, the toner bottles 71a to 71d extend in the front-rear direction of the image forming apparatus 1, and store corresponding color toners in advance.

  In addition, spiral protrusions are formed on the inner walls of the toner bottles 71a to 71d. Each of the toner bottles 71a to 71d is rotated under the control of the control circuit 6 (details will be described later). As a result, the toner accommodated in each of the toner bottles 71a to 71d is conveyed in the front end direction, for example. The conveyed toner is discharged from discharge ports provided at the front end portions of the toner bottles 71a to 71d, and is supplied to the sub hoppers 72a to 72d.

  In the present embodiment, the toner bottles 71a to 71d themselves are rotated and the toner is conveyed. However, the present invention is not limited to this, and the toner may be transported by a transport screw provided in the toner bottle.

  The sub hoppers 72a to 72d are box-like instruments provided directly below the discharge ports of the toner bottles 71a to 71d. Hereinafter, the detailed configuration of the sub hopper 72d will be described on behalf of the sub hoppers 72a to 72d. Since the other sub hoppers 72a to 72c are the same as the sub hopper 72d, their descriptions are omitted.

  As shown in FIG. 2 or 3, the sub hopper 72d has a substantially semicircular first side plate 721d and a second side plate 722d that face each other in the front-rear direction, and a connection plate 723d that connects the upper arc portions of the side plates 721d and 722d. And.

  Here, the upper end of the sub hopper 72d is a relatively wide opening for receiving the toner discharged from the discharge port of the corresponding toner bottle 71d. The supplied toner is stored in a space surrounded by the side plates 721d and 722d and the connection plate 723d. A discharge port (not shown) having a relatively small diameter is formed in the center of the bottom of the sub hopper 72d in order to supply toner to the corresponding developing means 34d.

  Also, two screw holes are formed in the upper end portions of the side plates 721d and 722d. In the case of a full-color machine, the sub hopper 72d is fixed to a frame (not shown) of the image forming apparatus 1 using these screw holes and screws.

  Further, in the side plates 721d and 722d, through holes having substantially the same diameter are formed in substantially the same position in front view and in the vicinity of the lower end. A screw 724d that rotates in conjunction with the toner bottle 71d is inserted into the through hole under the control of the control circuit 6. The screw 724d is rotatably supported by bearings provided one on each of the front and rear sides.

Incidentally, the toner supply to the developing means 34a to 34d by the toner replenishing means 7 is controlled by the control circuit 6 and is roughly divided into the following two stages.
(1) Toner replenishment from the toner bottle to the corresponding sub hopper (hereinafter referred to as first toner replenishment)
(2) Toner replenishment from the sub hopper to the corresponding developing means (hereinafter referred to as second toner replenishment)

<First toner supply>
Hereinafter, with reference to FIG. 4, first, the first toner replenishment from the toner bottle 71d to the sub hopper 72d will be typically described. Since the first toner replenishment to the other sub hoppers 72a to 72c is the same as the first toner replenishment to the sub hopper 72d, the description thereof is omitted.

  In relation to toner replenishment, a known toner remaining amount sensor 725d is provided at the bottom of the sub hopper 72d. When the toner in the sub hopper 72d becomes near empty, the remaining toner sensor 725d outputs a first detection signal FSd indicating that to the control circuit 6. In the opposite case, a signal FSd indicating that the toner amount is not near empty is output. The control circuit 6 receives the signal FSd periodically (for example, every 200 ms) and checks the remaining amount of toner at the time of reception. As a result of the confirmation, if it is near empty, the control circuit 6 gives a drive signal to a motor (not shown) to rotate the toner bottle 71d. As a result, the toner in the toner bottle 71d is supplied to the sub hopper 72d.

<Second toner supply>
Next, the second toner replenishment from the sub hopper 72d to the developing means 34d will be representatively described. Since the second toner supply to the other developing units 34a to 34c is the same as the second toner supply to the developing unit 34d, the description thereof is omitted.

  In connection with toner replenishment, a known toner concentration sensor 341d is provided inside the developing means 34d. The toner concentration sensor 341d outputs a second detection signal SSd indicating the remaining amount of toner in the developing unit 34d to the control circuit 6. The control circuit 6 determines a toner replenishment amount to the developing unit 34d based on the received signal SSd, and then gives a drive signal to a motor (not shown) to rotate the screw 724d of the sub hopper 72d by an amount corresponding to the determined replenishment amount. Let Thus, the toner in the sub hopper 72d is discharged from the bottom through-hole toward the developing unit 34d and replenished to the developing unit 34d.

<< Configuration and operation of image forming device (single color machine) >>
The image forming apparatus 1 as a full-color machine is changed to a single-color machine. In the following description, such a monochrome machine may be referred to as an image forming apparatus 1 ′.

  As shown in FIG. 5, the image forming apparatus 1 ′ is different from the image forming apparatus 1 in that an image forming unit 3 ′ is provided instead of the image forming unit 3. Here, compared with the image forming unit 3, the image forming unit 3 ′ has image forming units for Y, M, and C colors (for example, charging units 31a to 31c, photosensitive drums 32a to 32c, and developing units 34a to 34a). 34c) is different. The second difference is that a toner replenishing means 7 ′ is provided instead of the toner replenishing means 7. In addition to these, there is no difference between the two image forming apparatuses 1 and 1 ′. Therefore, in FIG. 5, the same reference numerals are given to those corresponding to the configuration of FIG. 1, and description thereof is omitted.

  Next, the operation of the monochromatic machine will be described. In the image forming unit 3 ′, the charging unit 31 d uniformly charges the peripheral surface of the rotating photosensitive drum 32 d. The peripheral surface of the charged photosensitive drum 32d is irradiated with the light beam Bd from the exposure device 33. As a result, a Bk single-color electrostatic latent image is formed on the photosensitive drum 32d. The developing means 34d supplies toner to the photosensitive drum 32d carrying the electrostatic latent image, thereby forming a Bk color toner image. The toner image on the photosensitive drum 32 d is transferred to the intermediate transfer belt 35 and then conveyed toward the secondary transfer region 36 while being carried on the intermediate transfer belt 35.

  In the secondary transfer region 36, the toner image on the intermediate transfer belt 35 is transferred to the sheet S sent out from the timing roller pair 37. After the secondary transfer, the sheet S is introduced into the fixing nip of the fixing unit 4. In the fixing unit 4, the toner image is fixed on the unfixed sheet S. Thereafter, the fixed sheet S is discharged to the tray 5.

<Toner supply to developing means>
The toner replenishing means 7 ′ includes four toner bottles 71d as an example of a plurality of toner containers, and four sub hoppers 72d as an example of a plurality of storage means. The illustration of each toner bottle 71d is simplified from the same viewpoint as described above.

  Here, it is assumed that the position of the developing unit 34d does not change in the case of a full-color machine or a single-color machine. The four toner bottles 71d have the same specifications as the toner bottles 71a to 71d in the full color machine, and are provided at the same positions as the toner bottles 71a to 71d in the full color machine. Each of the toner bottles 71d prestores toner of a common color (in this embodiment, Bk color).

  Each toner bottle 71d is rotated under the control of the control circuit 6 (details will be described later). As a result, the toner accommodated therein is discharged from the discharge port of the toner bottle 71d and supplied to the corresponding sub hopper 72d.

  The four sub hoppers 72d are provided directly below the discharge ports of the corresponding toner bottles 71d. As shown in FIGS. 6 and 7, the leftmost sub hopper 72d is obtained by rotating the sub hopper 72a in a full-color machine, for example, 90 ° clockwise around the Z axis. The sub hopper 72d is fixed to a frame (not shown) of the image forming apparatus 1 using a total of four screw holes formed at the upper end of the connection plate 723d and four screws. The remaining sub hopper 72d is also fixed to the frame of the image forming apparatus 1 in the same manner as the leftmost sub hopper 72.

Here, the four sub hoppers 72d are designed to satisfy the following conditions (1) and (2) at the time of alignment.
(1) The through holes formed in the side plates 721d and 722d of each sub hopper 72d overlap each other in plan view from the X-axis direction. Hereinafter, a plurality of through-holes overlapping when viewed from the X-axis direction are collectively referred to as an insertion hole.
(2) One side plate 721d of the two sub hoppers 72d adjacent in the X-axis direction and the other side plate 722d substantially contact each other. Hereinafter, the two adjacent sub hoppers 72d are referred to as adjacent sub hoppers 72d.

  Here, the adjacent sub hoppers 72d are preferably fixed to each other by screwing using the screw holes of the side plates 721d and 722d adjacent to each other. Thereby, the four sub hoppers 72d are unitized as one large capacity sub hopper.

  As shown in FIG. 7, a long screw 726 is inserted through the insertion hole of such a large capacity sub hopper. In FIG. 7, the long screw 726 is shown with a broken line because it is seen through. The long screw 726 is configured by connecting the ends of the four screws 724d (that is, the screws 724a to 724d for a full-color machine) with joints after removing the bearings.

  In addition, a bearing 727 is fitted into the two through holes overlapping with each other in the adjacent sub hopper 72d so as to pass through the connecting portion of the long screw 726 as shown in an enlarged view in a circle at the bottom of FIG. Further, a seal member 728 is provided around the bearing 727 so that there is no gap between the outer peripheral portion of the bearing 727 and each through hole.

  Of the four sub hoppers 72d, the sub hopper 72d directly above the developing means 34d is used as the replenishment sub hopper 72d. The through hole formed in the bottom of the replenishment sub hopper 72d is not closed and is used for replenishing toner to the developing means 34d. Further, the through holes at the bottom of the other three sub hoppers 72d are closed.

Incidentally, toner supply to the developing means 34d by the toner replenishing means 7 'is controlled by the control circuit 6 and is roughly divided into the following two stages.
(1) Toner replenishment from the toner bottle to the corresponding sub hopper (hereinafter referred to as first toner replenishment)
(2) Toner replenishment from the sub hopper to the corresponding developing means (hereinafter referred to as second toner replenishment)

<First toner supply>
Hereinafter, with reference to FIGS. 8 and 9, the first toner replenishment from the four toner bottles 71d to the sub hopper 72d will be described representatively. This first toner supply is controlled by the control circuit 6. From this point of view, the control circuit 6 functions as a first toner supply unit.

  As described above, the toner remaining amount sensor 725d is provided at the bottom of the replenishment sub hopper 72d. Based on the received signal FSd from the toner remaining amount sensor 725d, if the replenishment sub hopper 72d is near empty (FIG. 9: S01), the control circuit 6 is the toner bottle 71d that is closest to and directly above the replenishment sub hopper 72d. It is determined whether or not toner remains in the three toner bottles 71d except for the following (sometimes referred to as the proximity toner bottle 71d) (FIG. 9: S02). Hereinafter, the process of S02 will be described in detail.

  First, each toner bottle 71d is also provided with a remaining toner sensor 711d. When the toner bottle 71d becomes near empty, each remaining toner sensor 711d outputs a third detection signal TSd indicating that to the control circuit 6. In the opposite case, the third detection signal TSd indicating that it is not near empty is output.

  In S02, the control circuit 6 acquires the signal TSd from the three toner remaining amount sensors 711d to be a target, and confirms the toner remaining amount at the time of reception. As a result of the confirmation, if all the three toner bottles 71d to be processed are not near empty (that is, if Y in S02), the control circuit 6 gives a drive signal to a motor (not shown), and The individual toner bottles 71d are rotated. Thereby, the toner in the toner bottle 71d is supplied to the sub hopper 72d (S03).

  Conversely, if it is determined as N in S02, the control circuit 6 performs S04. In S04, the control circuit 6 acquires the signal TSd from the toner remaining amount sensor 711d provided in the proximity toner bottle 71d, and confirms the toner remaining amount at the time of reception. As a result of the confirmation, if the proximity toner bottle 71d is not near empty (that is, if Y in S04), the control circuit 6 gives a drive signal to a motor (not shown) to rotate the proximity toner bottle 71d. Thereby, the toner in the proximity toner bottle 71d is supplied to the sub hopper 72d (S05).

  On the other hand, when it is determined as N in S04, since all the toner bottles 71d are near empty, the control circuit 6 displays a message indicating that the toner bottle needs to be replaced, for example, on a display (not shown). It is displayed (S06).

  If the sub-hopper 72d for supply is not near empty in S01, the process in FIG.

<Second toner supply>
Next, the second toner replenishment from the large-capacity sub hopper to the developing unit 34d will be representatively described. This second toner supply is controlled by the control circuit 6. From this viewpoint, the control circuit 6 functions as a second toner replenishing unit. The control circuit 6 determines the toner replenishment amount to the developing means 34d based on the received signal SSd, then gives a drive signal to a motor (not shown), and increases the length of the large-capacity sub hopper by an amount corresponding to the determined replenishment amount. Screw 726 is rotated. As a result, the toner in the large-capacity sub hopper is conveyed toward the replenishment sub hopper 72d, discharged from the bottom through-hole toward the developing means 34d, and replenished to the developing means 34d.

  Here, according to the first toner replenishment and the second toner replenishment as described above, the first toner replenishment is rarely performed many times continuously, and in most cases, the first toner replenishment is performed. Immediately after that, the second toner is replenished. In the first toner replenishment, if toner is replenished from the three toner bottles 71d located away from the replenishment sub hopper 72d, the toner is stored at a position away from the replenishment sub hopper 72d. . Therefore, in this case, it is preferable that the long screw 726 is rotated at a relatively high speed to quickly convey the toner to the replenishment sub hopper 72d.

  Contrary to the above, if the toner is replenished from the proximity toner bottle 71d in the first toner replenishment, the toner is stored in the replenishment sub hopper 72d. In this case, even if the long screw 726 is rotated at a relatively low speed, the toner can be quickly supplied to the developing unit 34d.

  As described above, the control circuit 6 preferably controls the rotational speed of the long screw 726 in accordance with the toner storage position in the plurality of sub hoppers 72d.

《Action ・ Effect》
As described above, according to the present embodiment, when a full-color machine is diverted to a single-color machine, the Y, M, C color toner bottle installation space originally provided in the full-color machine is diverted to Bk color. Is possible. Furthermore, a large-capacity sub-hopper for Bk single color can be realized by using the sub-hoppers 72a to 72d for Y, M, C, and Bk colors. As can be seen from the above, according to the present embodiment, it is possible to provide the image forming apparatus 1 ′ in which the installation space for the toner bottles 71 a to 71 c and the sub hoppers 72 a to 72 c can be utilized without becoming a dead space in the monochromatic machine. Is possible.

  In addition to the above, when using as a monochromatic machine, since four toner bottles 71d can be used, the frequency of toner bottle replacement is reduced.

  Moreover, in the said embodiment, the long screw 726 which can be used with a monochromatic machine is formed by connecting the screws 724a to 724d used in the full color machine with a joint. Thereby, diversion of a member is attained between a full color machine and a monochromatic machine. Similarly, the sub hoppers 72a to 72d can be diverted to a monochromatic machine by being rotated 90 degrees and integrated.

《Appendix》
In the above embodiment, the image forming apparatus 1 ′ is described as forming a monochrome image. However, the concept of the above embodiment can be similarly applied to an image forming apparatus that forms a monocolor image.

  The image forming apparatus according to the present invention can utilize space, and is suitable for a copying machine, a printer, a facsimile, and a multifunction machine having these functions as a monochrome printing machine.

DESCRIPTION OF SYMBOLS 1,1 'Image forming apparatus 3, 3' Image forming part 31a-31d Charging means 32a-32d Photosensitive drum 33 Exposure apparatus 34a-34d Developing means 4 Fixing means 6 Control circuit 7, 7 'Toner replenishing means 71a-71d Toner Bottle 72a-72d Sub hopper

Claims (5)

A plurality of toner containers containing toner of the same color;
A plurality of storage means individually provided for the plurality of toner containers, the plurality of storage means for temporarily storing the toner discharged from the corresponding toner container; and the plurality of storage means A toner replenishing unit including a conveying unit that conveys the stored toner to a replenishment storing unit that is one of the plurality of storing units;
A photoreceptor,
An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed on the photoconductor with the toner replenished from the replenishing storage unit.   The image forming apparatus according to claim 1, wherein the transport unit is a long screw formed by connecting a plurality of screws respectively provided in the plurality of storage units by joints. The plurality of storage means are integrated to form a large capacity storage means,
The image forming apparatus according to claim 2, wherein the long screw passes through the large-capacity storage unit.   The toner replenishing means, when replenishing toner from the plurality of toner containers to the plurality of storage means, finally performs toner replenishment from a neighboring toner container which is a toner container closest to the replenishment storage means. The image forming apparatus according to claim 1, wherein toner supply from a toner container other than the proximity toner container is performed among the plurality of toner containers.   The toner replenishing means controls the rotational speed of the long screw in accordance with toner storage positions in the plurality of storage means when toner is replenished from the replenishing storage means to the developing means. The image forming apparatus according to any one of the above.

Images