Illuminating device, image reading device, and image forming apparatus

An aspect of the present invention provides an illuminating device including point-light-sources arranged in a line, that emit light; an optical guide member formed by injection molding and one end face of the optical guide member facing the point-light-sources, that guides light emitted from the point-light-sources to a surface to be illuminated such that the light emitted from the point-light-sources is incident on the one end face and the light incident on the one end face exits from the other end face; and first pin marks formed by projection pins used when removing the optical guide member when injection molding, the first pin marks being formed on one of faces of the optical guide member facing in a thickness direction of the optical guide member at the one end face side, and being formed in positions offset from the point-light-sources in a direction along which the point-light-sources are arranged.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2009-166817 filed Jul. 15, 2009.

BACKGROUND

Technical Field

The present invention relates to an illuminating apparatus, an image reading apparatus, and an image forming apparatus.

SUMMARY

A illuminating device of an aspect of the invention includes: point light sources arranged in a line, that emit light; an optical guide member formed by injection molding and one end face of the optical guide member facing the point light sources, that guides light emitted from the point light sources to a surface to be illuminated such that the light emitted from the point light sources is incident on the one end face of the optical guide member and the light incident on the one end face of the optical guide member exits from the other end face of the optical guide member; and first pin marks formed by projection pins used when removing the optical guide member when injection molding the optical guide member, the first pin marks being formed on one of faces of the optical guide member facing in a thickness direction of the optical guide member at a side of the one end face, and being formed in positions offset from the point light sources in a direction along which the point light sources are arranged.

DETAILED DESCRIPTION

An example of an image forming apparatus according to an exemplary embodiment of the invention will be described with reference toFIGS. 1 to 13.

General Configuration

As shown inFIG. 13, at an upper part of an apparatus body10A of an image forming apparatus10according to the exemplary embodiment, an automatic document transport device12that automatically transports plural read documents (documents to be read) G one by one, a first platen glass16on which one read document G is placed, and a document reading device14that reads the read document G transported by the automatic document transport device12or the read document G placed on the first platen glass16, are provided. The arrow “UP” in the diagram indicates upside in the vertical direction.

As shown inFIG. 11, the automatic document transport device12includes a document stand13on which the plural read documents G are placed, a feed roll15for feeding the read documents G one by one from the document stand13, and a first transport roll(s)17for transporting the read document G fed by the feed roll15.

The automatic document transport device12also has a first transport path19in which the read document G fed from the document stand13is transported. The first transport path19is provided with: a second transport roll(s)21for transporting the read document G to the downstream side in the transporting direction of the read document G; a third transport roll(s)23for transporting the read document G to the further downstream side in the transporting direction; a position adjustment roll(s)25for temporarily stopping rotation, restarting the rotation thereafter, and transporting the read document G while performing adjustment of a tip position (registering adjustment) of the read document G with respect to the document reading device14; an assist roll27for assisting the transport of the read document G in a state of being read; and a fourth transport roll(s)29for transporting the read document G which has been read to the further downstream in the transporting direction. Although a guide member for guiding the read document G which is transported is provided to the first transport path19, it is not shown in the drawings.

A second transport path31is provided on the downstream side in the transporting direction of the fourth transport roll29. On the downstream side in the transporting direction of the second transport path31, a discharge roll(s)35for discharging the read document G which has been completed of reading to a discharge part33are provided.

A third transport path37to which the transported read document G is sent by the discharge roll35being reverse-rotated is provided between the discharge roll35and the third transport roll23. By making the read document G transported along the third transport path37, the read document G which is turned upside down is again transported along the first transport path19. The details of the document reading apparatus that reads a surface to be read of the read document G transported along the first transport path19will be described later.

On the other hand, as shown inFIG. 13, in a center part in the vertical direction of the apparatus body10A, plural image forming units30forming toner images of different colors and arranged in the inclined state with respect to the horizontal direction are provided. Further, above the image forming units30, an endless intermediate transfer belt32which is driven in circulation manner in the arrow A direction of the drawing and onto which toner images of the colors formed by the image forming units30are transferred is provided.

As the image forming units30, four image forming units30Y,30M,30C, and30K of yellow (Y), magenta (M), cyan (C), and black (K) are provided in this order. The image forming unit30Y forming a toner image of yellow (Y) to be transferred first to the intermediate transfer belt32is provided in the highest position. The image forming unit30K forming a toner image of black (K) to be transferred at last to the intermediate transfer belt32is provided in the lowest position. The image forming units30Y,30M,30C, and30K are arranged at predetermined intervals therebetween in a state where they are inclined with respect to the horizontal direction.

Basically, the four image forming units30Y,30M,30C, and30K are constructed similarly. In the following, in the case of discriminating colors, the characters (Y, M, C, and K) corresponding to the colors are added to the numerals. In the case where the colors are not discriminated from one another, the characters corresponding to the colors are not added.

As shown inFIG. 12, the image forming unit30of each color is provided with an image carrier34rotated in the arrow D direction by not-shown driving section and, further, a charging member36for uniformly charging the surface of the image carrier34.

On the downstream side in the rotation direction of the image carrier34, of the charging member36, an exposing device40for exposing the surface of the image carrier34uniformly charged by the charging member36with light corresponding to a determined color to form an electrostatic latent image is provided. Further, on the downstream side in the rotation direction of the image carrier34, of the exposing device40, a developing unit42for developing an electrostatic latent image formed on the surface of the image carrier34with a toner of a corresponding color, thereby visualizing it as a toner image is provided.

Above the intermediate transfer belt32, toner cartridges38Y,38M,38C, and38K (refer toFIG. 13) for supplying toners of determined colors to the developing units42of the colors of yellow (Y), magenta (M), cyan (C), and black (K) are provided. Since the use frequency of the toner cartridge38K containing black (K) toner is high, the toner cartridge38K is larger than the toner cartridges of the other colors.

On the other hand, on the side opposite to the image carrier34with the intermediate transfer belt32being sandwiched, first transfer members46for transferring toner images formed on the surface of the image carrier34to the intermediate transfer belt32are provided. Further, a cleaning device44for cleaning residual toner and the like residing on the surface of the image carrier34, which is not transferred from the image carrier34to the intermediate transfer belt32, is provided in contact with the surface of the image carrier34on the downstream side in the rotation direction of the image carrier34, of the first transfer member46.

With the configuration, as shown inFIGS. 12 and 13, image data of the respective colors is sequentially output, from the document reading device14or from the outside in the case of using the apparatus as a printer, to the exposing devices40Y,40M,40C, and40K provided to the image forming units30Y,30M,30C, and30K of the colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Further, with lights emitted in accordance with the image data from the exposing devices40Y,40M,40C, and40K, the surfaces of the image carriers34of the respective colors charged by the charging members36are exposed. Electrostatic latent images are formed on the surfaces of the image carriers34. The electrostatic latent images formed on the surfaces of the image carriers34are developed by the developing units42Y,42M,42C, and42K as toner images of the colors of yellow (Y), magenta (M), cyan (C), and black (K).

Further, toner images of the colors of yellow (Y), magenta (M), cyan (C), and black (K) sequentially formed on the surfaces of the image carriers34are multiply-transferred onto the intermediate transfer belt32disposed inclined above the image forming units30Y,30M,30C, and30K of the respective colors by the first transfer members46.

The intermediate transfer belt32is entrained around (hung on) a drive roll48for applying drive force to the intermediate transfer belt32, a support roll50which is driven and rotated, a tension applying roll54for applying tension to the intermediate transfer belt32, a first idler roll56, and a second idler roll58with predetermined tension.

A cleaning device52that cleans the surface of the intermediate transfer belt32is provided on the side opposite to the drive roll48with the intermediate transfer belt32being sandwiched. The cleaning device52is detachable from the apparatus body10A by opening a front cover (not shown in the drawings) provided on the front side of the apparatus body10A (the front side at which the user stands).

Further, on the side opposite to the support roll50with the intermediate transfer belt32being sandwiched, a second transfer member60for transferring a toner image that is transferred by the first transfer members on the intermediate transfer belt32to a recording sheet P as a recording medium is disposed. That is, a position between the second transfer member60and the support roll50is a second transfer position in which a toner image is transferred to the recording sheet P.

Above the second transfer member60, a fixing device64for fixing the toner image onto the recording sheet P on which the toner image is transferred by the second transfer member60and transported along a transport path62, is provided. The fixing device64is constructed by a heating roll64A that is disposed on the image surface side of the recording sheet P and a pressure roll64B that presses the recording sheet P against the heating roll64A.

Further, on the downstream side in the transporting direction of the recording sheet P (hereinbelow, simply called “downstream side in the transporting direction”) of the fixing device64, a transport roll(s)66for transporting the recording sheet P on which the toner image is fixed are provided. On the downstream side in the transporting direction of the transport roll66, a switching gate68for switching transporting direction of the recording sheet P is provided.

On the downstream side in the transporting direction of the switching gate68, a first discharge roll(s)70for discharging the recording sheet P guided by the switching gate68which is switched in one direction to a first discharge part69is provided.

Further, on the downstream side in the transporting direction of the switching gate68, a second discharge roll(s)74for discharging the recording sheet P guided by the switching gate68which is switched to the other direction and transported by a transport roll(s)73to a second discharge part72, and a third discharge roll(s)78for discharging the recording sheet P guided by the switching gate68which is switched to the other direction and transported by the transport roll73to a third discharge part76are provided.

In a lower part of the apparatus body10A and on the upstream side in the transporting direction of the recording sheet P, of the second transfer member60(hereinbelow, simply called “upstream side in the transporting direction”), paper feed trays80,82,84, and86storing the recording sheets P are provided. In the paper feed trays80,82,84, and86, recording sheets P of different sizes are accommodated.

Further, each of the paper feed trays80,82,84, and86is provided with a paper feed roll88for feeding the stored recording sheet P from each of the paper feed trays80,82,84, and86to the transport path62. On the downstream side in the transporting direction of the paper feed roll88, a transport roll(s)90and a transport roll(s)92for transporting the recording sheets P one by one are provided.

On the downstream side in the transporting direction of the transport rolls92, a positioning roll(s)94for temporarily stopping the recording sheet P and feeding it to a second transfer position at a predetermined timing are provided.

A double-side printing transport unit98that transports the recording sheet P while turning it upside down to form images on both (double) sides of the recording sheet P is provided on a side portion of the second transfer position. The double-side printing transport unit98is provided with an inversion path100to which the recording sheet P transported by making the transport roll73rotate reversely is sent. Further, plural transport rolls102are provided along the inversion path100. The recording sheet P transported by the transport rolls102is transported again to the positioning roll94in a state where the recording sheet P is turned upside down.

A foldable manual paper feed part106is provided adjacent to the double-side printing transport unit98. A paper feed roll108and a transport roll(s)110and a transport roll(s)112for transporting the recording sheet P fed from the opened foldable manual paper feed part106are provided. The recording sheet P transported by the transport rolls110and112is transported to the positioning roll94.

Configuration of Main Part

Next, the document reading device14provided below the automatic document transport device12will be described.

As shown inFIG. 11, on the top face of a casing41of the document reading device14, a first platen glass16on which the read document G is placed in a stationary state and a second platen glass43for reading the read document G transported by the automatic document transporting device12are provided.

The document reading device14includes: a first carriage18including a optical guide member65and light emitting devices61for reading an image of a surface to be read of the read document G, and a second carriage22for guiding light emitted from the light emitting devices61of the first carriage18to an imaging unit20as an example of a reading unit.

The first carriage18emits light L to the surface to be read of the read document G and guides the light L reflected by the surface to be read to the second carriage22while remaining stationary below the second platen glass43as the initial position or while moving along the entire first platen glass16.

The second carriage22includes a second mirror45A reflecting the light L incident from the first carriage18downward, and a third mirror45B reflecting the light L reflected by the second mirror45A and turning to a direction parallel to the first and second platen glasses16and43.

The imaging unit20includes an imaging lens24for imaging the light L reflected and turned by the third mirror45B, and an opto-electric conversion element26for opto-electric converting an optical image imaged by the imaging lens24. The electric signal (image signal) converted by the opto-electric conversion element26is sent to an image processing device28electrically connected to the opto-electric conversion element26. The image processing device28image-processes the sent electric signal and transmits it to a control unit71. The control unit71transmits the received signal as image data to the exposing device40(refer toFIG. 13).

Specifically, as shown inFIG. 10, the first carriage18includes: two side plates55A and55B disposed so as to face each other with an interval in a fast scan direction (the arrow Y direction); and a first holder51and a second holder53each formed by a plate, which are disposed with an interval in a slow scan direction (the arrow X direction), whose longitudinal direction is set as the fast scan direction and whose both ends are fixed to the side plates55A and55B.

A third holder47and a fourth holder49are attached to the outside of the side plates55A and55B, respectively.

The top face of the first holder51and that of the second holder53serve as the top face of the first carriage18and are disposed so as to face the surface to be read of the read document G. Further, the interval in the fast scan direction between the side plates55A and55B is wider than the image formation region in the fast scan direction of the read document G (refer toFIG. 13).

A cross-section in the slow scan direction of the first holder51has an L shape. The first holder51includes an upper wall51A serving as the top face of the first carriage18and a side wall51B extending in the direction crossing the upper wall51A.

As shown inFIGS. 3 and 8, on the inside of the first holder51, a bracket57as an example of a support member is formed by a plate member and extends in the fast scan direction. On the side wall51B side of the first holder51in the bracket57, two side walls57A are formed so as to overlap the side wall51B. The bracket57has a shape opening at a lower side thereof.

A detents57C which is cut and extends upright is provided for the side wall57A of the bracket57. By sandwiching the side wall51B of the first holder51between the detent57C and the side wall57A, a position in the slow scan direction (arrow X direction) of the bracket57with respect to the first holder51is determined.

Further, in the side wall57A of the bracket57, a screw hole112in which screw thread is cut and a projection114projecting toward the side wall51B side of the first holder51are formed.

As shown inFIGS. 4,5,9, and10, by inserting the projection114in a notch116formed in the side wall51B and, further, screwing a bolt77into the screw hole112via a through hole122formed in the side wall51B, the bracket57is fixed to the first holder51.

As shown inFIGS. 3 and 8, on the side opposite to the side wall57A in the bracket57, a plane57B inclined with respect to the slow scan direction is provided. On the plane57B, a circuit board59as an example of a substrate whose longitudinal direction is set as the fast scan direction is supported. On the circuit board59, the light emitting devices61as an example of point light sources arranged in a line along the fast scan direction are attached.

Specifically, as shown inFIGS. 3 and 7, the light emitting devices61are attached to one face59A of the circuit board59, and the other face59B of the circuit board59is supported by the plane57B. In the circuit board59, four through holes96are provided at predetermined intervals in the longitudinal direction. Screw holes118in which screw threads are cut are formed in the plane57B corresponding to the through holes96. By screwing four bolts120into the screw holes118via the through holes96, the circuit board59to which the light emitting devices61are attached is supported by the bracket57.

As shown inFIGS. 3 and 6, the shape of the plane57B is determined so that the plane57B of the bracket57supports a projection part86in which the light emitting device61is projected to the other face59B (a back face) of the circuit board59in a state in which the circuit board59is supported by the bracket57.

Further, power is supplied to the circuit board59from the control unit71(refer toFIG. 13) via a flexible board63(refer toFIG. 10) connected to the end of the circuit board59.

Although LED (Light Emitting Diode) elements are used as the light emitting devices61in the exemplary embodiment, the invention is not limited to the LEDs but any light emitting devices which emit in point manner may be used. Other light emitting devices such as an organic EL (Electro Luminescence) element or an inorganic EL element may be used.

The control unit71(refer toFIG. 13) of the image forming apparatus10includes therein a light source drive circuit (not shown in the drawings) that drives the light emitting devices61via the circuit board59. The light source drive circuit includes, for each of the light emitting devices61, a switch for switching on/off state of light emission of the light emitting device61, and a variable resistor for adjusting the amount of light emitted to the surface to be read of the read document G from each of the light emitting devices61. The light source drive circuit makes to emit (drives) the light emitting devices61on the basis of a light drive signal for controlling the on/off state of light emission of the light emitting devices61and an adjustment signal for adjusting the amount of light.

On the other hand, as shown inFIG. 3, in the first carriage18, the optical guide member65facing the light emission face of the light emitting devices61is provided such that the fast scan direction is as the longitudinal direction. The optical guide member65is a plate-shaped (rectangular parallelopiped shaped) member formed (molded) by injection molding using a transparent resin (for example, acrylic resin) as the material. The optical guide member65is provided with a light incidence face65A as an example of one end face on which light emitted from the light emitting devices61is incident, and a light emission face65B as an example of the other end face from which the light incident from the light incidence face65A goes out. The both ends in the fast scan direction of the optical guide member65are supported by the side plates55A and55B (refer toFIG. 10).

As shown inFIGS. 1 and 14, after formation (molding) of the optical guide member65by the injection molding, at the time of taking out the product (optical guide member65) from a die (a metal mold)200by pushing it by a projection pin(s)210, plural marks by the projection pin210are formed in a line manner on the light incidence face65A side and on the light emission face65B side at a plate face65C as one of faces in the thickness direction of the optical guide member65.

In the exemplary embodiment, one end face side pin marks130as the pin marks on the light incidence face65A side of the plate face65C are formed in positions different (offset) from the light emitting devices61disposed to face the light incidence face65A. Specifically, each of the one end face side pin marks130is formed in the space between neighboring light emitting devices61in the fast scan direction.

In the exemplary embodiment, as shown inFIG. 1, the one end face side pin mark130is formed on the plate face65C at a position at the light incidence face65A side and also in the vicinity of the light incidence face65A in a direction orthogonal to the fast scan direction, further, the one end face side pin mark130is formed on the plate face65C in substantially center position between the neighboring light emitting devices61in the fast scan direction, however, it is not limited to the invention.

On the other hand, the other end face side pin marks132as pin marks by the pushing pins210on the light emission face65B side of the plate face65C are deviated (offset) from the positions of the one end face side pin marks130in the fast scan direction (the arrangement direction of the light emitting devices61). That is, the one end face side pin marks130are formed in positions different from the other end face side pin marks132in the fast scan direction.

In the exemplary embodiment, as shown inFIG. 1, the other end face side pin mark132is formed on the plate face65C at position in the vicinity of the light emission face65B in the direction orthogonal to the fast scan direction, however, it is not limited to the invention.

With the configuration, as shown inFIGS. 2A and 2B, light emitted from the light emitting devices61and incident on the optical guide member65is total-reflected by the plate face65C without incident on the one end face side pin marks130. However, if the one end face side pin marks130are formed in the same positions as the light emitting devices61disposed facing the light incidence face65A, as shown inFIG. 2C, light incident on the optical guide member65is irregularly reflected by hitting the one end face side pin mark130, and a part of the light leaks to the outside from the plate face65C. An illuminating device128is constructed by the optical guide member65, the light emitting devices61, and the circuit board59.

The light of the light emitting devices61incident from the light incidence face65A is scattered inside, and the light emission face65B of the optical guide member65performs plane emission, so that unevenness in the light amount distribution at the light emission face65B are suppressed. Since the optical guide member65guides the light of the light emitting devices61incident from the light incidence face65A close to the surface to be read, preferably, the optical guide member65is made of a material which does not reduce (attenuate) the light amount at least more than air.

As shown inFIG. 3, a diffuser plate67having transparency is joined, such that the fast scan direction is as the longitudinal direction, to the light emission face65B of the optical guide member65. In the surface of the diffuser plate67, concavoconvexs diffusing light emitted from the light emission face65B of the optical guide member65are formed along the fast scan direction.

In a position apart from the diffuser plate67only by predetermined distance in the slow scan direction, a reflector79reflecting a part of the light emitted from the diffuser plate67to the surface to be read of the read document G (refer toFIG. 13) is disposed. The reflector79is a mirror surface member such that the fast scan direction is the longitudinal direction thereof. A face of the reflector79opposite to the reflection face reflecting light is fixed to the second holder53.

Below the optical guide member65and the diffuser plate67, a first mirror75that guides the light reflected by the surface to be read of the read document G to the second mirror45A of the second carriage22(refer toFIG. 11) is provided. The both ends of the first mirror75are inserted in and held at holes formed in the side plates55A and55B (refer toFIG. 10).

Operation

With the configuration, as shown inFIGS. 3 and 11, the light L emitted from the light emitting devices61travels inside the optical guide member65while being total-reflected and is diffused by the diffuser plate67. A part of the light L diffused by the diffuser plate67passes through the second platen glass43or the first platen glass16and is emitted to the surface to be read of the read document G. The rest of the light L is reflected by the reflector79, thereafter passes through the second platen glass43or the first platen glass16, and is emitted to the surface to be read of the read document G.

In such a manner, the light emitting devices61of the first carriage18emit the light L to the surface to be read of the read document G from the front side and the rear side in the slow scan direction. The light L emitted to the surface to be read of the read document G is reflected by the surface to be read, then reflected by the first mirror75, and travels from the second carriage22, and is imaged, via the imaging lens24, by the photoelectric conversion element26.

In the case of reading the surface to be read of the read document G placed on the first platen glass16, the first and second carriages18and22move in the movement direction (the arrow E direction shown inFIG. 11) at the ratio of movement distance 2:1. The light L is emitted from the first carriage18to the surface to be read of the read document G, the light L reflected by the surface to be read is guided to the second carriage22, sequentially reflected by the second and third mirrors45A and45B, and guided to the imaging lens24. The light L guided to the imaging lens24is imaged on a light receiving surface of the opto-electric conversion element26. Since the movement distance of the second carriage22is the half of the movement distance of the first carriage18, the optical path length of the light L from the surface to be read of the read document G to the opto-electric conversion element26does not change.

In the case of reading the surface to be read of the read document G transported by the automatic document transport device12, the first and second carriages18and22are stopped at the read position indicated by the solid lines at one end (the left end inFIG. 11) of the document reading device14. In the read position, the light L from the first carriage18passes through the second platen glass43and is emitted to the surface to be read of the read document G transported by the automatic document transport device12. The light L reflected by the surface to be read is guided to the second carriage22.

Specifically, the light L reflected by the first line in the surface to be read of the read document G transported passes through the second carriage22, and is imaged by the imaging lens24. The image is read by the opto-electric conversion element26. That is, one line in the fast scan direction is simultaneously processed by the opto-electric conversion element26as a one-dimensional sensor and, after that, next one line in the fast scan direction of the document G to be read which is transported is read. After the rear end of the read document G passes the read position in the second platen glass43, reading of one page of the surface to be read of the read document G in the slow scan direction is completed.

As shown inFIG. 1, the one end face side pint marks130formed in the optical guide member65guiding light emitted from the light emitting devices61to the surface to be read of the read document G are formed in positions different from the light emitting devices61disposed facing the light incidence face65A in the fast scanning direction.

As shown inFIGS. 2A and 2B, the light emitted from the light emitting devices61and incident on the optical guide member65is total-reflected by the plate face65C without hitting the one end face side pin marks130. That is, it is suppressed that the light incident on the optical guide member65is irregularly reflected by hitting the one end face side pin marks130so a part of the light is leaked to the outside from the plate face65C such as shown inFIG. 2C.

That is, it is suppressed that the reflection property of the optical guide member65is deteriorated due to the one end face side pin marks130of the projection pins added to the optical guide member65at the time of injection molding so the amount of light emitted to the surface to be read becomes non-uniform.

The other end face side pin marks132are deviated (offset) with respect to the one end face side pin marks130in the fast scan direction (the arrangement direction of the light emitting devices61). Consequently, as compared with the case where the other end face side pin marks132are in the same positions as the one end face side pin marks130in the fast scan direction, it is further suppressed that amount of light emitted to the surface to be read becomes non-uniform.

Since the surface to be read of the read document G is illuminated with light whose amount is uniformed, the intended latent image is formed on the surface of the image carrier34.