JP2005089141A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure size of loop reservoir with a predetermined amount, smoothly convey various recording paper to a nip of a conveying belt, and to suppress possibility of jamming. <P>SOLUTION: This image forming device is constituted so that paper separated by a paper feeding roller 9 is fed to a register roller 4 and is further conveyed to the conveying belt 6 by the register roller 4. At this time, an opening and closing guide plate 1 is closed (clearance between it and a fixed guide 8 is narrow) by a solenoid 3. When the tip of paper is meshed into the nip of the conveying belt 6 and the arrival at the nip is detected by a sensor 12, a control circuit makes the opening and closing guide plate 1 open by turning off the solenoid 3 (it is an open state). In this state, the paper feeding amount of the register roller 4 is set larger than the feeding amount of the conveying belt 6, thereby securing the predetermined loop amount. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium such as a copying machine, a printer, and a facsimile machine.

In general, in an image forming apparatus such as an ink jet printer system, if banding (a line-breaking streak, a difference in density in band units, or uneven density in a band) occurs, image quality is greatly damaged.
As a countermeasure against this banding, a paper pool is accumulated between the conveyor belt (sub-scan feed part of the inkjet engine unit) and the registration roller upstream of the conveyor belt using a difference in driving speed between the conveyor belt and the registration roller. There is an image forming apparatus that creates a (loop) to reduce the rotational load of the conveying belt and to reduce variations in the rotational load, thereby improving the image quality.

Further, Patent Document 1 previously filed by the present applicant is a sheet conveying apparatus having two or more parallel sheet conveying paths in which the direction of jam processing is limited to only one direction. The swing guide plate for opening the paper transport path is opened and closed in conjunction with opening and closing of the exterior cover.
JP-A-10-147451

  However, in the above-described conventional image forming apparatus, if a fixed guide formed in a shape for securing a loop pool size of a predetermined amount or more is used, depending on the paper, for example, when the paper is curled, it is smoothly conveyed. There was a problem of not entering the belt nip.

  If the guide plate (guide member) is simply configured to be openable and closable and the guide plate is opened with a paper scraper, depending on the type of paper, for example, when the paper is thick or curled, the guide may be in the middle of paper conveyance. There was a risk that the board would open and cause jamming.

  The above-mentioned Patent Document 1 is a suitable one that facilitates the jam processing, but does not take into account the formation of a loop pool and the smooth entry into the conveyor belt.

  The present invention has been made in view of such a situation, and can ensure a predetermined amount of loop pool size and smoothly convey it to the nip of the conveyor belt even when using various types of recording paper. An object of the present invention is to provide an image forming apparatus capable of reducing the possibility of jamming.

  In order to achieve such an object, an image forming apparatus according to the present invention includes an image forming unit that forms an image on a recording sheet conveyed by a recording sheet conveying unit, a recording sheet storing unit, and an image forming unit that includes a recording sheet storing unit. A sheet feeding / conveying means for conveying the recording paper to the recording paper conveying means, a detecting means for detecting the timing at which the leading edge of the conveyed recording paper reaches the nip portion of the recording paper conveying means, and a recording paper storage Until the detection means detects that the leading edge of the recording paper has reached the nip portion of the recording paper conveyance means after the feeding from the recording section is started, the movable guide member is closed and the detection means And a control means for controlling the movable guide member to be in an open state when detected.

  The control means described above operates in conjunction with a spring member for rotating the movable guide member in a predetermined direction, a base member that rotatably holds the movable guide member, and rotation of the movable guide member. It is preferable to include a lever member and a solenoid member that rotates the movable guide member via the lever member.

  The above-described movable guide member is provided with a manual insertion portion that allows a recording medium to be manually inserted into the above-described recording paper conveyance means, and the above-described movable guide member is formed to prevent the recording medium from being inserted from the manual insertion portion in an open state. It is preferable.

  The paper feeding / conveying means includes a recording paper conveying means proximity fixed guide for guiding the recording paper in the vicinity of the recording paper conveying means, and the movable guide member is in an open state between the recording paper conveying means and the vicinity of the recording paper fixing guide. It is preferable that the recording medium is disposed so as not to be inserted from the manual insertion portion.

  An image reading unit that reads an original image may be further provided, and a function of forming an image read by the image reading unit by the image forming unit may be provided.

The paper feeding / conveying means includes a first roller for conveying recording paper, a second roller, a fixed guide member for guiding the recording paper, and a movable guide member. And the recording paper conveying means are driven by mutually independent driving sources, and the fixed guide member and the open movable type are changed by changing the driving speed difference or feed amount between the second roller and the recording paper conveying means. It is preferable to provide a function of forming a recording paper loop between the guide members.
Further, the recording paper conveying means described above is preferably a conveying belt or a conveying roller.

  As described above, according to the present invention, it is possible to secure the size of a predetermined amount of loop (loop pool) of the recording paper, and smoothly enter the nip of the recording paper conveying means even if various recording papers are used. It can be conveyed, and the possibility of causing a jam can be kept low.

Next, an image forming apparatus according to the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, an image forming apparatus according to an embodiment of the present invention includes a scanner unit (image reading unit) A that optically reads a document image and an ink jet engine unit (image forming unit) that forms an image by an ink jet method. ) B and a paper feeding unit C for feeding the paper (recording paper) D from the recording paper storage unit C1 to the inkjet engine unit B.

The inkjet engine unit B includes a conveyance belt (recording paper conveyance unit) 6 that conveys a recording medium, a head 61 that forms an image on the recording medium on the conveyance belt 6 by an inkjet method, and a sub-scanning motor that drives the conveyance belt 6. B1 and an ink tank B2 for storing ink.
As the recording medium, not only the recording paper D but also various media such as thick paper, glossy paper, and OHP sheet can be used by insertion from the manual feed tray 10.

  The paper feeding unit C includes a recording paper storage unit C1 for storing the paper D and a paper feeding motor (HB stepping motor) C2 for driving the registration roller 4, and includes an ink jet engine unit B and a recording paper storage unit C1. In the meantime, a paper feed roller (first roller) 9 that starts transporting the paper D in the recording paper storage unit C1 and a registration roller (second roller) that further transports the paper D conveyed by the paper feed roller 9. Roller) 4 and driven roller 5, a fixed guide (fixed guide member) 8 for guiding the paper D, an open / close guide plate (movable guide member) 1, and an upper guide (fixed guide near the conveyor belt) 7. These function as sheet feeding and conveying means for conveying the sheet D from the recording sheet storage unit C1 to the conveying belt 6 of the inkjet engine unit B.

  The conveying belt 6 described above can be driven and rotated independently of each other by a dedicated DC motor (sub-scanning motor B1), and the registration roller 4 can be driven by a dedicated HB (hybrid) stepping motor C2. This driving rotation is controlled by a control circuit (not shown), and the image forming apparatus according to the present embodiment opens and closes with the fixed guide 8 in the conveyance path of the paper D by the difference in the driving speed between the conveyance belt 6 and the registration roller 4. A function of forming a loop of the paper D between the guide plate 1 and the guide plate 1 is provided.

FIG. 2 is a diagram illustrating a configuration of a portion through which paper is passed from the recording paper storage unit C1 to the conveyance belt in the image forming apparatus as the present embodiment.
The image forming apparatus according to this embodiment includes a spring (spring member) 11 for rotating the opening / closing guide plate 1 in a predetermined direction, a rotating shaft (base member) 13 that rotatably holds the opening / closing guide plate 1, and A lever (lever member) 2 that operates in conjunction with the rotation of the opening / closing guide plate 1 and a solenoid (solenoid member) 3 that rotates the opening / closing guide plate 1 via the lever 2 are provided. The circuit functions as a control unit that switches the open / close state of the opening / closing guide plate 1 described above.

  In addition, an upper guide 7 is provided for guiding the paper D that has passed between the fixed guide 8 and the open / close guide plate 1 to the nip portion (biting start portion) of the transport belt 6, and immediately before (just upstream) the nip portion. A sensor (detecting means) 12 for detecting the timing at which the leading edge of the paper D being conveyed reaches the nip portion of the conveying belt 6 is provided.

Next, the sheet passing operation from the registration roller 4 to the conveyance belt 6 will be described with reference to FIG.
The paper D separated by the paper feed roller 9 is sent to the registration roller 4 and further conveyed to the conveyance belt 6 by the registration roller 4. At this time, the opening / closing guide plate 1 is closed by the solenoid 3 (a state where the gap with the fixed guide 8 is narrow).

When the lever 2 is rotated by the solenoid 3 being attracted, the open / close guide plate 1 is rotated in the direction of the arrow in FIG. In this way, while the paper D is being transported from the paper supply roller 9 to the transport belt 6, the transport path between the fixed guide 8 and the open / close guide plate 1 is narrowed to a predetermined interval (gap 3 mm). Can be transported without difficulty.
Also, with respect to the suction force of the solenoid 3, since the paper D is transported after completion of the suction, it can be sucked without receiving the load (waist) of the paper D, so even a solenoid with a low suction force can be used. Can be possible.

Next, the operation of forming a paper loop will be described with reference to FIG.
When the leading edge of the paper D is caught in the nip of the conveying belt 6 and the sensor 12 detects the arrival at the nip, the control circuit opens the open / close guide plate 1 by turning off the solenoid 3 (set to the open state). . In this state, a predetermined loop amount can be ensured by making the sheet feed amount of the registration roller 4 larger than the feed amount of the conveying belt 6.

Next, the operation when the paper D is set from the manual feed tray (manual insertion portion) 10 to form an image will be described with reference to FIG.
When the user uses the manual feed tray 10, the manual feed tray use mode is selected by the operation unit (operating port), whereby the solenoid 3 is turned on and the open / close guide plate 1 is closed. Therefore, the user can set the paper D up to the nip portion of the transport belt 6 so that an image can be formed on the paper D.

Here, if the user erroneously inserts the paper D from the manual feed tray 10 while being fed from the recording paper storage unit C1 in the main body by the paper feed roller 9 and the registration roller 4 as described above, there is a risk of causing a jam. There is.
With respect to this problem, in the image forming apparatus according to the present embodiment, as shown in FIG. 5, the opening / closing guide plate 1 is opened as described above when the leading edge of the paper D is caught in the nip portion of the transport belt 6. Thus, the upper guide 7 and the open / close guide plate 1 are crossed, and the sheet D cannot be inserted up to the transport belt 6 due to the overlap.
This eliminates the risk that the user will accidentally insert the paper D from the manual feed tray 10 and cause a jam.

  To prevent this jamming, the sheet D can be set from the manual feed tray 10 because the solenoid 3 is ON and the open / close guide plate 1 is also closed while the leading end of the sheet is conveyed from the registration roller 4 to the conveying belt 6. Although it is possible, since the time for which the open / close guide plate 1 is closed is as short as about 0.5 seconds, it is considered that the user hardly sets the paper D in the short time. For this reason, it is judged that there is substantially no problem.

  As described above, according to the image forming apparatus of the present embodiment, one of the guide plates for guiding the paper D can be opened and closed, and the guide plate prevents erroneous paper setting from the manual feed tray 10. Therefore, it is possible to improve the transportability of the paper D and prevent the erroneous setting of the paper D with a simple configuration.

  That is, in the present embodiment, one of the guide plates is movable, and the leading edge of the paper D has reached the nip portion of the conveying belt by the sensor 12 after the feeding from the recording paper storage unit C1 is started. Until the paper D is detected, the paper D is conveyed while holding the open / close guide plate 1 so as to narrow the conveyance path of the paper D (in a closed state), and when the leading edge of the paper bites into the conveyance belt, the guide plate Is rotated to be in an open state so that a paper pool can be formed, thereby improving paper transportability and providing a paper pool to prevent banding in ink jet image formation.

This configuration can also be applied to other recording devices (electrophotography, heat sensitive, etc.) other than an inkjet system.
In addition, the image forming apparatus of the present invention is provided with a one-sheet manual feed mechanism that conveys special sheets such as thick sheets, glossy sheets, and OHP sheets. There is a danger that the user mistakenly inserts a sheet from the manual sheet feeding portion (manual feed tray 10) while the paper is being conveyed and causes a jam.
On the other hand, in the present embodiment, a shutter function for stopping the sheet is provided downstream of the manual sheet feeding portion, and the shutter function is configured to be shared by the above-described opening / closing guide plate 1, so that the configuration is simple. Jam can be effectively suppressed while saving space.

As described above, in this embodiment, in order to prevent a decrease in the conveyance performance of the paper D due to the creation of the loop as the banding elimination means, the image having the image recording unit and the paper feeding unit that separates and conveys the paper D to the recording unit. In the image forming apparatus, the guide plate that guides the paper D between the recording unit and the paper feeding unit is rotatable or movable. In the image forming apparatus, the guide plate is a guide plate (fixed guide plate). The gap is fixed at a predetermined interval (gap 3 mm).
By opening and closing the guide plate, a loop can be formed between the recording unit and the sheet feeding unit, and image quality (anti-banding) can be improved. In addition, by fixing the gap between the guide plates at 3 mm, it is possible to prevent the risk of jam even when the paper D such as curled paper is conveyed.

  Here, when the curled paper D is conveyed, the force with which the front edge of the paper presses the guide plate is about 300 gf, and it is necessary to hold the guide plate with a force of about 500 gf in consideration of safety. On the contrary, it is difficult to push open the guide plate with the loop (belly) of the paper D. Therefore, in practice, many restrictions (thickness, paper state, use environment, etc.) may be imposed on the paper, and the above holding force may be reduced to cope with it.

In this embodiment, in order to simplify the mechanism for opening and closing the guide plate, a movable guide member for guiding the paper D, a spring member for rotating the guide member in a predetermined direction, and the guide member are provided. A base member (rotating shaft 13) that is rotatably held, a lever member that rotates the guide member, and a solenoid member that rotates the lever member are provided.
As a result, the above-described effects of the present invention can be realized with a simple configuration.

Further, in the present embodiment, as a countermeasure against the possibility of jamming by manual sheet feeding (insertion of a recording medium from the manual feed tray 10), when the internal paper feeding unit is operating (from the recording paper storage unit C1) While the leading edge of the paper D is transported to the transport belt 6, it is configured such that the paper cannot be transported from the single manual feed member (manual feed tray 10).
As a result, it is possible to prevent the danger that the user mistakenly inserts the sheet D from the single manual feed member while the sheet D is being conveyed from the main body sheet feeding unit, and causes a jam.

In the present embodiment, as a simplified configuration, the movable guide member described above is disposed at a position where the sheet D cannot be set / conveyed to a single manual feed member.
As a result, it is possible to prevent the danger that the user erroneously inserts the paper D from one manual feed member and causes a jam while the paper D is being conveyed from the main body feed with a simple configuration.

  In this embodiment, an image reading and recording apparatus to which the present invention is applied is provided by including a scanner unit and forming an image read by the scanner unit with an image forming unit (inkjet engine unit). be able to.

In the above-described embodiment, the recording paper conveyance unit that conveys the recording medium to the head 61 is described as the conveyance belt 6. However, the present invention is not limited to this, and may be a conveyance roller, for example. .
Further, although it has been described that the paper pool is formed by using the difference in driving speed between the conveyance belt 6 and the registration roller 4, the method of forming the paper pool is not limited to this method as long as the feed amount can be changed. Other methods may be used.

1 is a diagram illustrating an outline of a configuration of an image forming apparatus as an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a portion through which a sheet is passed from a recording paper storage unit C1 to a conveyance belt in the image forming apparatus (the open / close guide plate 1 is in a closed state). FIG. 3 is a diagram showing a state when the loop is formed in the image forming apparatus (the open / close guide plate 1 is in an open state). FIG. 4 is a diagram illustrating a state in which paper D is set from a manual feed tray in the image forming apparatus. FIG. 5 is a diagram illustrating a state in which the opening / closing guide plate 1 is in an open state and the paper D cannot be inserted from the manual feed tray.

Explanation of symbols

1 Open / close guide plate (movable guide member)
2 Lever (Lever member)
3 Solenoid (solenoid member)
4 Registration roller (second roller)
5 driven roller 6 transport belt (recording paper transport means)
61 Head 7 Upper guide (Conveyor belt vicinity fixed guide)
8 Fixed guide (fixed guide member)
9 Feed roller (first roller)
10 Bypass tray (manual insertion slot)
11 Spring (spring member)
12 Sensor (detection means)
13 Rotating shaft (base member)
A Scanner unit (image reading means)
B Inkjet engine part (image forming part)
B1 Sub-scanning motor B2 Ink tank C Paper feed unit C1 Recording paper storage unit C2 Paper feed motor C3 Loop sensor D Paper (recording paper; recording medium)

Claims (7)

Image forming means for forming an image on recording paper conveyed by the recording paper conveying means, a recording paper storage section, and paper feeding for conveying the recording paper from the recording paper storage section to the recording paper conveyance means of the image forming means Transportation means,
Detecting means for detecting the timing at which the leading edge of the recording paper being conveyed reaches the nip portion of the recording paper conveying means;
The movable guide member is closed after the feeding from the recording paper storage unit is started until the detection unit detects that the leading edge of the recording paper has reached the nip portion of the recording paper transport unit. An image forming apparatus comprising: a control unit configured to control the movable guide member to be opened when the detection unit detects the detection unit.   The control means includes a spring member for rotating the movable guide member in a predetermined direction, a base member for rotatably holding the movable guide member, and interlocking with the rotation of the movable guide member. The image forming apparatus according to claim 1, further comprising: an operating lever member; and a solenoid member that rotates the movable guide member via the lever member. A manual insertion portion that allows a recording medium to be manually inserted into the recording paper conveying means;
The image forming apparatus according to claim 1, wherein the movable guide member is formed so as to prevent the recording medium from being inserted from the manual insertion portion in an open state. The paper feeding / conveying means comprises a recording paper conveying means vicinity fixing guide for guiding recording paper in the vicinity of the recording paper conveying means,
4. The movable guide member is arranged so that a recording medium cannot be inserted from the manual insertion portion in an open state between the movable guide member and a fixed guide in the vicinity of the recording paper conveying means. Image forming apparatus. An image reading means for reading a document image;
The image forming apparatus according to claim 1, wherein the image read by the image reading unit is formed by the image forming unit. The paper feeding and conveying means includes a first roller for conveying recording paper, a second roller, a fixed guide member for guiding the recording paper, and a movable guide member,
The second roller and the recording paper conveying means are driven by mutually independent driving sources, and the fixed guide is changed by changing a driving speed difference or a feed amount between the second roller and the recording paper conveying means. The image forming apparatus according to claim 1, further comprising a function of forming a recording paper loop between the member and the movable guide member in an open state. The image forming apparatus according to claim 1, wherein the recording paper transport unit is a transport belt or a transport roller.

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