JP5873787B2 - Image forming apparatus - Google Patents

Description

Embodiments of the present invention relates to an image forming equipment of an electrophotographic system that uses laser scanning unit or the optical scanning device.

  In the image forming apparatus, the conveyance direction of the paper is a direction perpendicular to the longitudinal direction of the paper, and a laser beam from a deflector such as a polygon mirror is scanned in a direction perpendicular to the conveyance direction of the paper with respect to the photosensitive drum. A laser scanning unit may be used.

JP 2011-203524 A

  For example, in an image forming apparatus using a laser scanning unit that scans the long side of A4 size paper, the image can be formed on A3 size paper by making the paper transport direction parallel to the long side of the paper. It is. On the other hand, in the laser scanning unit that scans the long side of A4 size paper, it is a case where only the A4 size paper is incorporated in the image forming apparatus that houses the main body, and the paper transport direction is the short side of the paper. It is known that the size of the laser scanning unit is larger than the size of the space for storing the paper.

An object of the present invention is to provide an image forming equipment which suitably set the scan width of the image light due to the size and optical scanning device space for accommodating the paper to be determined based on the conveying direction of the sheet.

In the embodiment, the image forming apparatus includes an optical scanning device, a photoconductor, a developing device, a transfer device, a sheet holding unit, and a sheet conveyance path. The optical scanning device includes a deflector, a holding structure, and a folding structure. The deflector deflects the image light. The holding structure includes a plane portion extending in parallel with a direction in which the deflector deflects the image light, and a partition wall extending in both directions orthogonal to the plane portion, and a floor surface that holds a part of the deflector. A space is provided on the lower side, and a part of the deflector is exposed in a state of protruding to the space side. The folding structure includes a first mirror and a second mirror, and the image light deflected by the deflector is reversed in a plane parallel to a plane including a direction in which the deflector deflects the image light. Lead. The back surface of the floor surface is exposed to the outside of the optical scanning device. The photoconductor is disposed in the reflection direction of the image light reflected by the second mirror, and holds an electrostatic image corresponding to the image light provided by the deflector and the folding structure. The developing device develops the electrostatic image held by the photoconductor to form a developer image. The transfer device transfers the developer image formed by the developing device to a sheet. The sheet holding unit holds the sheet on which the developer image has been transferred by the transfer unit. The sheet conveying path extends in the vertical direction on the opposite side to the second mirror with respect to the photoconductor, and conveys the sheet to be printed out. The protrusion amount at which a part of the deflector protrudes toward the space is an amount that does not hinder the reflected light of the image light reflected by the second mirror toward the photoconductor.

1 illustrates an example of an image forming apparatus according to an embodiment. 1 illustrates an example of a sheet holding unit included in an image forming apparatus according to an embodiment. 1 illustrates an example of an optical scanning device included in an image forming apparatus according to an embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  An image forming apparatus (MFP, Multi-Functional Peripheral) 1 shown in FIG. 1 includes an image reading unit 10 and an image forming unit 20.

  The image reading unit 10 scans and reads images of a sheet document and a book document. The image reading unit 10 includes an automatic document feeder (ADF, Automatic Document Feeder) 11 and a document table (transparent glass) 12. The image reading unit 10 reads an image of a document transported by the automatic document transport device 11 or a document placed on the document table 12. Note that a document image conveyed by the automatic document feeder 11 is a first sensor (for example, a line CCD) 13, and a document image held by the document table 12 is a second sensor (for example, a CMOS sensor) 14. Read and generate image signal. Image signals from the respective sensors are supplied to the image processing unit of the control block 51 and used for image exposure by the optical scanning device 30 described later.

  The image forming unit 20 includes a paper feed cassette 21, a developing device 22, a photosensitive drum 23, a transfer device 24, a fixing device 25, an optical scanning device 30, a paper discharge tray 26, a reverse conveyance path 27, and a paper feed tray (manual paper feed). Part) 28.

  The image forming unit 20 includes an optical scanning device based on an image signal corresponding to image data corresponding to an image read by the image reading unit 10 from a document, or image data transmitted to the image forming apparatus 1 from an external device. 30 is used to form a latent image (electrostatic latent image) on the photosensitive drum 23. The latent image formed on the photosensitive drum 23 is developed by the developer image supplied by the developing device 22 and moved (transferred) to the sheet P by the transfer device 24. The developer image held by the sheet P is fixed (fixed) to the sheet P by the fixing device 25. The sheet P on which the developer image is fixed is output as a printout (output image) to the paper discharge tray 26. When the developer images are formed on both sides of the sheet P, the sheet P having the developer image fixed on one side by the fixing unit 25 is reversed on the front and back through the reverse conveyance path 27 and is again transferred by the transfer unit 24 ( The developer image (on the photosensitive drum 23) is transferred and fed to the fixing device 25, and the developer image is fixed to the back surface of the surface on which the developer image has already been fixed.

  The paper feed cassette 21 is also a sheet holding member. The sheets P held by the paper feed cassette 21 are fed one by one from the paper feed cassette 21 by the paper feed roller 21a. The sheet P has a predetermined timing whose timing is controlled by the timing roller 21b so that the leading edge of the sheet P and the developer image held by the photosensitive drum 23 coincide with each other at the transfer position where the transfer unit 24 and the photosensitive drum 23 are in contact with each other. To move to the transfer position. The paper feed tray 28 is a second sheet holding unit. The sheets P prepared in the paper feed tray 28 are also fed one by one by the paper feed roller 28a and moved to the transfer position at a predetermined timing whose timing is controlled by the timing roller 21b.

  2A and 2B show a plan view of the image forming apparatus shown in FIG. 1 and a state in which the sheet feeding tray 28 is set so that the sheet P can be fed (sideward).

  As shown in FIG. 2B, the paper feed tray 28 is, for example, twice as long as the length [X] in the direction parallel to the conveyance direction of the sheet P that can be accommodated in the paper cassette 21. A sheet P having a length of [Y = 2X] can be fed. Of course, the paper feed tray 28 can be transported (paper fed) even when the length is shorter than [X]. The size of the sheet P accommodated in the paper cassette 21 is, for example, as shown in FIG. 2A, the length in the direction parallel to the transport direction is [X], and the direction perpendicular to the transport direction. The length is [Z].

  In the sheet P that can be transported by the paper feed tray 28, the width [Z] defined by the pair of sheet guides 28b shown in FIG. 2A is the maximum transportable sheet size, and the length direction [Y] The (sheet) size input by the operation unit 41 shown in 2 (a) is allowed. For example, regarding the length [Y] of the sheet P, it is assumed that, for example, the above-mentioned [Y = 2X] sheet can be conveyed according to the control in the control block 51 according to the input from the operation unit 41.

  That is, for the sheet P fed through the sheet feed tray 28, in the length direction indicated by [Y], for example, a sheet jam is at least twice (2X) as long as the sheet P held by the sheet cassette 21. Control is performed so as not to detect (abnormal conveyance).

  This is true even when the size of the sheet P accommodated in the paper cassette 21 (length in the [X] direction) is set to a width in the short side direction of A4 size, for example, in order to reduce the size of the image forming apparatus 1. Through the paper tray 28, for example, an A3 size sheet P can be transported (paper fed) so that the longitudinal direction thereof is the transport direction. In other words, the size of the sheet P that can be fed through the paper feed tray 28 is not limited by the width of the paper cassette 21 held by the image forming apparatus 1, and has a width equivalent to the longitudinal direction of the A4 size sheet, for example. There is no restriction in the conveyance direction of the sheet, and an image can be formed on an A3 size sheet having a length twice as long as the A4 size short side direction. This is because, as shown in FIG. 2A, the width of the main body of the image forming apparatus 1 in the state where the paper feed tray 28 shown in FIG. 1 is closed (the size in the direction parallel to the [X] direction). This means that an image can be formed even on a sheet P that is substantially the same or longer.

  3A and 3B show the characteristics of the structure of the optical scanning device, FIG. 3A is a plan view, and FIG. 3B includes the rotation center axis of the optical deflector 31 in the transport direction. It is sectional drawing cut | disconnected in the position parallel to.

  As shown in FIG. 3B, the optical deflector 31 is located at a predetermined position of the deflector holding structure 32 extending in parallel with the output direction of the deflected light 35. The deflector holding structure 32 does not have to be exactly parallel to the output direction of the deflected light 35, has a slight angle, and the case where it is substantially parallel is defined as parallel in this embodiment. The deflector holding structure 32 includes a plane portion 32a that supports the optical deflector 31, first and second orthogonal structure portions 32b that extend in a direction orthogonal to the plane portion 32a and a direction orthogonal to the output direction of the deflected light 35, 32c is integrally formed. The plane portion 32 a and the first and second orthogonal structure portions 32 b and 32 c are covered with a cover (lower) 33 and a cover (upper) 34. However, the cover (lower) 33 is blocked at the position of the dust-proof glass 36 and provides a space 37 at a position corresponding to the position immediately below the optical deflector 31. In other words, a hole 32a1 is provided in the flat portion 32a, and a part of the optical deflector 31 is exposed to the space 37 side through the hole 32a1. Moreover, the hole 32a1 may be a bag hole. In this case, the deflector 31 is not exposed to the space 37 side. That is, the back surface of the floor surface 32a that holds a part of the optical deflector 31 is exposed to the outside. However, the dustproof glass 36 may not be provided.

  Further, in the optical scanning device 30 described above, the image exposure light deflected by the optical deflector 31 is folded back by the first mirror 38 and the second mirror 39 so that the plane defined by the direction of reflection by the optical deflector 31 is reversed. Thus, the light is guided to the photosensitive drum 23 as the deflected light 35.

  That is, the folding structure constituted by the first mirror 38 and the second mirror 39 has a direction opposite to the plane including the direction in which the deflector deflects the image light. Lead to. In the present embodiment, it is defined as the reverse direction if it is not exactly 180 degrees in the reverse direction but is generally in the reverse direction.

  For example, in an image forming apparatus capable of outputting an A3 size, when the developer image on the photosensitive drum 23 is transferred onto the sheet P by the transfer device 24, the optical deflector 31 is used as the optical scanning device 30. 1 is often positioned at a position virtually shown in FIG. 1 in order to output the image exposure light from the image to the photosensitive drum 23 horizontally. This is the case where the paper cassette 21 is configured to convey the A4 size sheet P in the direction parallel to the short side direction as described with reference to FIGS. 1, 2A, and 2B. Is a factor that increases the width of the image forming apparatus 1 (the length in the [X] direction in FIGS. 2A and 2B).

  The width of the image forming apparatus 1 is set so that the short side direction of A4 size is parallel to the transport direction in order to reduce the size, so that the optical scanning apparatus 30 also has the [X] direction of the image forming apparatus 1. It is desirable that the length is shorter than the length.

  From such a background, as shown in FIGS. 3A and 3B, the light (image exposure light) deflected by the optical deflector 31 in the optical scanning device 30 is converted into the first mirror 38 and the second mirror 38. By folding back approximately 180 degrees with the mirror 39 to form a two-layer structure, the size occupied by the paper cassette 21 (in the image forming apparatus 1) configured so that the A4 short side direction is parallel to the transport direction can be effectively used. The image forming apparatus 1 can be obtained in which the size of the image forming apparatus 1, that is, the width in the [X direction] is reduced.

  In the optical scanning device 30, the optical deflector 31 (which can be a noise generation source) is located near the center of the image forming apparatus 1, and thus the level of noise detected outside the image forming apparatus 1 can be reduced. .

  Also, the deflector holding structure 32 that holds the optical deflector 31 is provided with a partition wall (in the “H” shape) in the output direction of the deflected light 35, that is, both in the direction orthogonal to the plane portion 32 a and the plane portion 32 a. By including the first and second orthogonal structure portions 32b and 32c, the second moment of the cross section can be increased as compared with the optical scanning device accommodated in a normal box-shaped housing. An optical scanning device that is not easily affected by the vibration of the deflector 31 is provided.

  Further, by blocking the cover (lower) 33 at the position of the dust-proof glass 36, a space 37 can be provided at a position corresponding to the position immediately below the optical deflector 31, and the cooling efficiency of the motor unit of the optical deflector 31 can be improved. Is possible. Needless to say, the light deflection apparatus 30 may be configured such that, for example, the cover (lower) 33 and the cover (upper) 34 in FIG.

  By adopting such a configuration, for example, in an optical scanning device capable of image exposure in the short side direction (short direction) of an A3 size sheet, that is, the long side direction (longitudinal direction) of an A4 size sheet, the A4 size Held by a paper cassette using an image forming apparatus with a reduced size in a direction parallel to the sheet conveyance direction that accommodates only a sheet feeding cassette that conveys the sheet in a direction parallel to the short side direction (of the sheet) Image formation on a larger sheet (with the same image exposure width and longer length) becomes possible.

  In addition, the optical deflector that can be a source of noise can be positioned closer to the center of the image forming apparatus, and noise detected outside the apparatus can be reduced.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] A deflector for deflecting image light, a flat portion extending in a direction parallel to a direction in which the deflector deflects the image light, and a partition wall extending in a direction orthogonal to the flat portion, the deflector An optical scanning device comprising: a holding structure in which a back surface of a floor surface that holds a part of the floor surface is exposed to the outside.
[2] The light according to [1], further including a folding structure that guides the image light deflected by the deflector in a reverse direction in a plane parallel to a plane including a direction in which the deflector deflects the image light. Scanning device.
[3] A photosensitive member holding an electrostatic image corresponding to the image light provided by the deflector and the folding structure, and developing the electrostatic image held by the photosensitive member to form a developer image A developing unit, a transfer unit that transfers the developer image formed by the developing unit to a sheet, and a sheet holding unit that holds the sheet on which the developer has been transferred by the transfer unit, The sheet holding portion is compared with an exposure length defined by the image light from the deflector when a short direction of the sheet is defined in parallel with a sheet conveyance direction and the optical scanning device does not have the folding structure. An image forming apparatus including the optical scanning device [1] or [2] having a short length in the sheet conveyance direction.
[4] The apparatus further includes a second sheet holding unit capable of conveying a sheet having a longer length in a direction parallel to the conveyance direction than the sheet held by the sheet holding unit, and the second sheet holding unit The image forming apparatus according to [3], which is capable of outputting an image to a supplied sheet.
[5] The apparatus further includes a control unit that does not detect a conveyance abnormality up to at least twice the length of the sheet held by the sheet holding unit, so that the second sheet holding unit can output an image on the sheet to be supplied and printed. ] Or the image forming apparatus of [4].

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 21 ... Paper cassette (sheet holding part), 23 ... Photosensitive drum, 24 ... Transfer device, 25 ... Fixing device, 28 ... Paper feed tray (2nd sheet holding part), 30 ... Optical scanning Device 31... Optical deflector 32. Deflector holding structure 51. Control block (control unit).

Claims (5)

A deflector for deflecting image light;
The deflector has a flat portion extending in a direction parallel to the direction in which the image light is deflected, and a partition wall extending in a direction orthogonal to the flat portion, and below the floor surface holding a part of the deflector. A holding structure that has a space and is exposed in a state in which a part of the deflector protrudes toward the space;
A folding structure configured by a first mirror and a second mirror, for guiding the image light deflected by the deflector in a direction opposite to a plane parallel to a plane including a direction in which the deflector deflects the image light; ,
And the back surface of the floor surface is exposed to the outside of the optical scanning device,
A photoconductor disposed in a reflection direction of the image light reflected by the second mirror and holding an electrostatic image corresponding to the image light provided by the deflector and the folding structure;
A developing device for developing the electrostatic image held by the photoconductor to form a developer image;
A transfer unit for transferring the developer image formed by the developing unit to a sheet;
A sheet holding unit for holding the sheet on which the developer image is transferred by the transfer unit;
A sheet conveyance path that extends in the vertical direction on the opposite side of the second mirror with respect to the photoconductor and conveys the sheet to be printed out;
The amount of protrusion by which a part of the deflector protrudes toward the space is an amount that does not inhibit the reflected light of the image light reflected by the second mirror from traveling toward the photoconductor. The holding structure includes a partition wall extending in the direction of the flat surface portion and two orthogonal structure portions extending in a direction orthogonal to the flat surface portion, and increases the second moment of the cross section of the optical scanning device. The image forming apparatus according to claim 1, wherein the image forming apparatus is less affected by the vibration of the image . Before SL sheet holding unit, the short-side direction of the sheet is defined parallel to the sheet conveyance direction, the exposure length the image light is defined from the deflector when no said folded structure of the optical scanning device in comparison, the sheet length in the conveying direction is shorter claim 1 or 2 images forming apparatus. The sheet holding unit and the second sheet holding portion conveyor which is capable of the sheet by remote conveying direction is long in the direction parallel to the sheet further comprising holding said second sheet holding portion is supplied The image forming apparatus according to claim 3, wherein an image can be output to the sheet. The images can be output in respect to the second of said sheet sheet holding portion you supply, claims wherein the sheet holding portion is maintained until at least twice the length of the sheet, further comprising a control unit does not detect the abnormal transport 3 or 4 image forming apparatus.

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