JP2005141077A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus of simple configuration capable of achieving space saving of an installation location and capable of performing stable jobs up to a specified number of stocked sheets without troubling a user. <P>SOLUTION: The image forming apparatus comprises an image reading section 10 for reading image information; an image forming section B disposed under the image reading section for forming an image on paper 4; and a paper ejection section 37 disposed in an apparatus case between the image reading section 10 and the image forming section B, and for ejecting the paper 4, wherein the image reading section 10 can be raised such that the space of the paper ejection section 37 is extended upward. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus equipped with a document image reading unit, such as a copying machine or a facsimile machine, and in particular, a paper discharge space is provided in the apparatus casing to save the installation space. The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, there has been known an image forming apparatus that includes an image reading unit that reads an image and an image forming unit that forms an image on a sheet, and has a sheet discharge space in the apparatus housing in order to save the installation space. (For example, refer to Patent Document 1).

  Specifically, an image reading unit that reads an image, an image forming unit that is arranged below the image reading unit and forms an image on a sheet, and an apparatus housing between the image reading unit and the image forming unit, A discharge space portion for discharging the paper, a paper processing means for holding and processing the paper in a substantially vertical state, an in-machine conveyance path for conveying the paper processed by the paper processing means to the discharge space portion, It has composition which has.

  Further, in an image forming apparatus that discharges a sheet to a discharge space between the image reading unit and the image forming unit, the ease of taking out the discharged sheet is improved, and the operability by suppressing the height of the apparatus main body is low. In order to improve and further allow a larger number of trays to be disposed in a limited space, a bin tray provided in the discharge space is configured to be movable up and down (see, for example, Patent Document 2). .)

  FIG. 2 is a basic schematic sectional view of such a conventional image forming apparatus, and shows an example of a digital copying machine. As shown in the figure, a document placing table 3 and a lid 2 for opening and closing the document placing table 3 are provided on the upper part of the main body 1. An image reading unit 10 that reads image information of a document (not shown) placed on the document placement table 3 is disposed below the document placement table 3. The image reading unit 10 includes a light source 11, a movable mirror 12, fixed mirrors 13 and 14, a fixed lens 15, and an image sensor 16 made of, for example, a CCD.

  The light source 11 and the movable mirror 12 are disposed so as to be able to reciprocate below the document placing table 3, and the light source 11 irradiates the document on the document placing table 3. The reflected light reaches the image sensor 16 through an optical system including the movable mirror 12, the fixed mirrors 13 and 14, and the fixed lens 15. As a result, the image data on the document is read by the image reading unit 10. On the other hand, the surface of the photosensitive drum 20 is uniformly charged positively or negatively by the charging device 21. The read image data is written on the surface of the photosensitive drum 20 by a laser scanner (exposure device) 22, and an electrostatic latent image is formed on the surface of the photosensitive drum 20.

  Specifically, in the case of the reverse development method, the charge corresponding to the image is removed, and in the case of the regular development method, the charge corresponding to the background is removed to form an electrostatic latent image. . Next, the electrostatic latent image on the photosensitive drum 20 is visualized with toner by the developing device 23. At this time, the charging polarity of the toner is the same as the charging polarity of the photosensitive drum 20 in the case of the reversal development method, and is opposite to the charging polarity of the photosensitive drum 20 in the case of regular development.

  On the other hand, the paper 4 stored in the paper feed cassette 31 is pulled out by the pickup roller 26, is sandwiched between the paper feed roller 33 and the separating roller 34, and is sent to the conveyance path. Then, the registration roller pair 32 feeds the paper 4 to the transfer unit in time for the toner image on the photosensitive drum 20 to reach the transfer unit. In the transfer portion, the sheet 4 is sandwiched between the photosensitive drum 20 and the transfer roller 24, and a charge having a polarity opposite to the toner charging polarity is applied to the transfer roller 24. Toner image moves onto the paper 4. The toner remaining on the photosensitive drum 20 without moving onto the paper 4 is removed and collected by the cleaning roller 25.

  On the other hand, the paper 4 on which the toner image is placed is conveyed to the fixing roller pair 35. Here, the toner image is heated and pressurized by the fixing roller pair 35 and fixed on the paper 4. Then, the paper 4 is discharged to the paper discharge unit 37 by the discharge roller pair 36. The paper 4 placed on the manual feed tray 38 is sent to the registration roller pair 32 by the paper feed roller 39, and thereafter passes through the same path as the above-described transport path. As described above, the paper discharge unit 37 for discharging the paper 4 is provided between the image reading unit 10 and the image forming unit including the photosensitive drum 20 and its peripheral portion. The space is saved.

Further, an upper limit detection sensor S is provided at the upper corner of the paper discharge unit 37 near the discharge port a on the downstream side of the discharge roller pair 36. In this case, when the paper 4 discharged to the paper discharge unit 37 is stacked by a predetermined number, for example, about 250, the upper limit detection sensor S is activated to stop the discharge operation.
Japanese Patent Laid-Open No. 2003-156891 JP 2000-355458 A

  However, in the conventional configuration as described above, since the paper discharge unit is provided between the image reading unit and the image forming unit, a large space cannot be taken, and the number of sheets that can be stacked on the paper discharge unit is also naturally. Limits arise. On the other hand, if the height of the image forming apparatus is increased to increase the space for the paper discharge unit, the image reading unit is also positioned higher, making it difficult for the user to set a document.

  Further, when various types of papers on the market or papers left outside the apparatus are used, a phenomenon that the discharged paper curls frequently occurs. At this time, if the space of the paper discharge unit is narrow, when the curled paper (curled paper) is stacked, the paper discharge unit is filled with a small number of sheets. Specifically, if the specification stock number of the paper discharge unit is 250 sheets, the upper limit detection sensor is normally activated when about 250 sheets are stacked, but when the curled sheets are stacked, the apparent thickness increases, For example, there is a problem that the upper limit detection sensor operates even when only about 180 sheets are stacked.

  In this case, if the user is away from the site while the device is in operation, even if the upper limit detection sensor is activated in the middle of the job and the device stops, the user cannot detect it. It will not be. In addition, when the upper limit detection sensor is activated, the apparatus cannot be restarted unless the paper is removed from the paper discharge unit, which is inconvenient because the user has to remove the paper many times at the time of mass copying.

  In view of the above-described problems, the present invention can reduce the installation space with a simple configuration, and can perform a stable job up to the specification stock number without bothering the user. An object of the present invention is to provide an image forming apparatus that can perform the above-described process.

  To achieve the above object, according to the present invention, an image reading unit that reads image information, an image forming unit that is disposed below the image reading unit and forms an image on a sheet, the image reading unit, and the image forming unit An image forming apparatus provided in an apparatus housing between the two sections, and having a sheet discharge section for discharging the paper, wherein the image reading section is lifted so as to widen the space of the sheet discharge section upward It is characterized by being made possible.

  In addition, when the upper limit of the sheet stocked in the paper discharge unit is detected with a smaller number than the predetermined stock number, the image reading unit is raised by a predetermined amount.

  Further, the image reading unit is raised by a predetermined amount according to the stacking height based on the number of sheets stocked in the paper discharge unit and the curl amount of the paper.

  Further, when a number of jobs larger than a predetermined number of sheets of paper stocked in the paper discharge unit is set, the image reading unit is raised by a predetermined amount according to the number of jobs. And

  According to the present invention, an image forming apparatus that can save space at an installation place with a simple configuration and can perform a stable job up to the number of specification stocks without bothering the user. Can be provided.

  Specifically, the image reading unit can be raised so as to widen the space of the paper discharge unit, so that the number of stocks can be increased, paper in the paper discharge unit can be easily taken out, and maintenance can be performed. It becomes easy to do.

  In addition, when the upper limit is detected with a smaller number of sheets than the predetermined number of stocks, the image reading unit is raised by a predetermined amount, so that jobs can be reliably performed up to the specified number of stocks without bothering the user. It can be carried out.

  Further, by raising the image reading unit by a predetermined amount according to the stacking height based on the number of sheets and the curl amount, stable stock is performed even when the curled sheet is discharged, and jamming is performed. Save time and effort.

  Further, when a number of jobs larger than a predetermined number of stocks is set, the image reading unit is raised by a predetermined amount according to the number of jobs, so that operability when a user sets a document is improved. The number of specification stocks can be increased without deteriorating

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present invention, an upper limit detection sensor is disposed in the vicinity of the paper discharge port in the paper discharge unit, and the image reading unit is raised and a drive mechanism is provided so as to widen the space of the paper discharge unit. At this time, the paper discharge portion also rises at the same time. In addition, with respect to the paper conveyance path, the post-fixing paper guide on the image forming unit side and the paper discharge guide on the paper discharge side overlap each other before the image reading unit ascends. Also, the sheet conveyance path is configured to communicate smoothly.

  In such a configuration, during image formation such as copying or printing, the control unit (CPU) counts the number of sheets on which images are formed (the number of jobs), and the upper limit is detected when the number is significantly smaller than the specified stock number. When the sensor is activated, the image reading unit is raised by a predetermined amount. Thus, the job can be surely performed up to the specification stock number, and can be automatically ended.

  Further, for example, a paper curl amount detection unit is disposed in the paper discharge unit, and during image formation such as copying or printing, an image reading unit is obtained based on the curl amount data in the curl amount detection unit and the job number information in the control unit. It is good also as a structure which calculates the raise amount of and raises only the amount. In addition, when the user sets a job number larger than the normal specification stock number, the image reading unit can be raised by an amount corresponding to the job number to increase the stock number.

  FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention, showing an example of a digital copying machine. In addition, the same code | symbol is attached | subjected to the part which is common in the said prior art example, and detailed description is abbreviate | omitted suitably. In the present embodiment, in addition to the configuration shown in FIG. 2, the image reading unit 10 is lifted so as to widen the space of the paper discharge unit 37 upward. At this time, the sheet discharge portion A including the discharge roller pair 36, the upper limit detection sensor S, the discharge port a, and the sheet conveyance path is also raised at the same time.

  Further, with respect to the paper conveyance path, the post-fixing paper guide 40 extending upward from the fixing roller pair 35 on the side of the image forming unit B including the photosensitive drum 20 and its peripheral part is in a state before the image reading unit 10 is raised. On the other hand, the sheet discharge guide 41 on the sheet discharge portion A side that guides the sheet in a curved shape to the discharge roller pair 36 overlaps by the amount of the increase, and the sheet conveyance path communicates smoothly after the increase. Is configured to do. In the figure, a state where the image reading unit 10 is raised to some extent is depicted.

  Further, at least two ball screws 42 extending in a substantially vertical direction are provided near the left and right ends of the main body 1 between the image reading unit 10 side and the image forming unit B side. A motor M is disposed in the vicinity of the lower end of the ball screw 42 on the paper discharge portion A side. As the motor M rotates, the ball screw 42 rotates. In conjunction with this, the other ball screw 42 also rotates, so that the entire image reading unit 10 moves up and down. Note that illustration of guide rails when the image reading unit 10 is raised and lowered is omitted. Reference numeral 43 denotes a partition plate provided between the image reading unit 10 side and the image forming unit B side, and partitions the paper discharge unit 37 side and the paper discharge part A side or the main body 1 from the outside. It expands and contracts as the elevator moves up and down.

  In the configuration as described above, during image formation such as copying or printing, the number of sheets on which images are formed (number of jobs) is counted by a control unit (CPU) (not shown) and stocked in the paper discharge unit 37. When the upper limit detection sensor S is actuated on a sheet 4 that is significantly smaller than the specified stock number, the ball screw 42 is rotated by the rotation of the motor M, and the image reading unit 10 is raised by a predetermined amount. Thus, the job can be surely performed up to the specification stock number, and can be automatically ended.

  Further, since the image reading unit 10 is lowered to the lowest position at the start of the job, the user can set the original without difficulty as usual. Whether the image reading unit 10 is raised while forming an image when the upper limit detection sensor S is activated, or the image forming operation is temporarily stopped and the image reading unit 10 is raised and then automatically restarted. Can be set by the control unit.

  Further, for example, a paper curl amount detection unit is disposed in the paper discharge unit, and during image formation such as copying or printing, an image reading unit is obtained based on the curl amount data in the curl amount detection unit and the job number information in the control unit. It is good also as a structure which calculates the raise amount of and raises only the amount. Specifically, as shown in the figure, for example, on the bottom surface of the paper discharge unit 37, as the paper curl amount detecting means, the paper 4 stocked at the center of the paper discharge direction and the positions of the front and rear ends are used. A height sensor 44 that optically measures the height from the bottom surface of the paper discharge unit 37, for example, by a reflection type or the like is disposed.

  Then, during image formation such as copying or printing, the amount of paper 4 is finally determined from the curl amount data based on the difference in height information from each height sensor 44 and the number of jobs information in a control unit (not shown). Predicting whether the image is stacked up to the height, the amount of increase of the image reading unit 10 corresponding to the load height is calculated, and the amount is increased in advance by that amount.

  Note that only one of the height sensors 44 at the front end and the rear end may be arranged. Although not shown, the curl amount detection means is disposed in the vicinity of the paper discharge portion A instead of being disposed in the paper discharge unit 37, and the curl amount data is obtained by sampling several sheets of paper 4 passing therethrough. Also good. With the configuration as described above, stable stock is performed even when the curled paper is discharged, and the time for jam processing can be saved.

  In addition, when the user sets a job number larger than the normal specification stock number, the image reading unit can be raised by an amount corresponding to the job number to increase the stock number. Specifically, when the normal specification stock number is 250, for example, when the user sets the number of jobs to 500, for example, the image reading unit 10 is raised by an amount corresponding to the difference of 250 sheets. At this time, there is no relation to upper limit detection or curl amount detection.

  The image reading unit 10 may be set to be raised or lowered regardless of the number of jobs. As described above, by allowing the image reading unit 10 to arbitrarily move up and down, it is possible to increase the number of stocks, and it is easy to take out paper from the paper discharge unit and to perform maintenance.

  Although the present invention has been described with reference to a copying machine as an embodiment, the present invention is not limited to this, and may be any document that includes a document image reading unit such as a facsimile and a paper discharge space in the apparatus housing. It is applicable to any device.

1 is a schematic cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 6 is a basic schematic cross-sectional view of a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Cover 3 Original mounting table 4 Paper 10 Image reading part 11 Light source 12 Movable mirrors 13 and 14 Fixed mirror 15 Fixed lens 16 Image sensor 20 Photosensitive drum 21 Charging device 22 Laser scanner 23 Developing device 24 Transfer roller 25 Cleaning roller 26 Pickup roller 31 Paper feed cassette 32 Registration roller pair 33 Paper feed roller 34 Rolling roller 35 Fixing roller pair 36 Paper discharge roller pair 37 Paper discharge unit 38 Manual feed tray 39 Paper feed roller 40 Paper guide after fixing 41 Paper discharge guide 42 Ball screw 43 Partition plate A Paper discharge part B Image forming part M Motor S Upper limit detection sensor

Claims (4)

An image reading unit for reading image information;
An image forming unit disposed below the image reading unit and forming an image on a sheet;
A paper discharge unit provided in an apparatus housing between the image reading unit and the image forming unit, for discharging the paper;
In an image forming apparatus comprising:
An image forming apparatus, wherein the image reading unit can be lifted to widen the space of the paper discharge unit.   The image reading unit is raised by a predetermined amount when an upper limit is detected when the number of sheets stored in the paper discharge unit is smaller than a predetermined number of sheets. Image forming apparatus.   2. The image reading unit according to claim 1, wherein the image reading unit is raised by a predetermined amount in accordance with a stacking height based on a number of sheets stocked in the sheet discharge unit and a curl amount of the sheet. Item 3. The image forming apparatus according to Item 2.   When a number of jobs larger than a predetermined number of sheets of paper stocked in the paper discharge unit is set, the image reading unit is raised by a predetermined amount according to the number of jobs. The image forming apparatus according to claim 1.

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