Patent Description:
<CIT> discloses a printed-material transport device including: a first transport mechanism that can horizontally transport a printed material at a first speed while supporting the lower surface of the printed material with a revolving belt member; a second transport mechanism that is disposed downstream of the first transport mechanism in a printed-material transport direction such that a predetermined distance of a parallel transport section is formed and that can horizontally transport the printed material at a second speed, which is lower than the first speed, while holding the printed material with a jaw mechanism; and a jaw opening/closing mechanism that closes the jaw mechanism, which is open in the parallel transport section, at a predetermined gripping position and opens the jaw mechanism at a predetermined releasing position in a transport section with the second transport mechanism on the downstream side of the parallel transport section.

<CIT> discloses a fixing device and an image-forming apparatus, provided with a noncontact heating means for heating a recording medium in a noncontact manner. The noncontact heating means has a condition under which a heat quantity given to the recording medium when the recording medium is colored becomes smaller than a heat quantity given to the recording medium when the recording medium is white and is relatively thinner than when being colored.

<CIT> discloses a Fixing device and image forming device provided with a heating unit for heating a sheet member transported on a transporting path.

<CIT> discloses a sheet material post-processor and image forming device.

The present invention is provided by the appended claims. The following disclosure serves a better understanding of the present invention. Accordingly, it is an object of the present disclosure to simplify the adjustment among a forming part, a transport part, and a fixing part at the time of installation of an image forming apparatus, compared with a configuration in which any of the forming part, the transport part, and the fixing part is disposed in a housing other than the housing of the others.

According to a first aspect of the present disclosure, there is provided an image forming apparatus including: a forming part that forms an image on a recording medium; a fixing part that fixes the image formed on the recording medium; a revolving part having a revolving member stretched over multiple rotary members, the revolving member revolving between the forming part and the fixing part to transport the recording medium from the forming part to the fixing part; a feed part that feeds the recording medium to the forming part; a discharge part that discharges the recording medium to which the image has been fixed in the fixing part; a branch part that is provided so as to be split from the discharge part and along which the recording medium, to one side of which the image has been fixed, is transported to the feed part after switching the leading end and the trailing end of the recording medium; a first housing accommodating the forming part, the fixing part, and the revolving part; and a second housing connected to the first housing and accommodating the feed part, the discharge part, and the branch part.

According to a second aspect of the present disclosure, the image forming apparatus may further include: a first transport part that is accommodated in the first housing and transports the recording medium fed from the feed part to the forming part; a second transport part that is accommodated in the first housing and transports the recording medium to which the image has been fixed in the fixing part from the fixing part to the discharge part; and a joint part that joins the first housing and the second housing together, the joint part being disposed at a position closer to a connecting part between the feed part and the first transport part than to a connecting part between the second transport part and the discharge part.

According to a third aspect of the present disclosure, the feed part and the first transport part may be disposed on the lower side of the first housing and the second housing and may transport the recording medium in a direction parallel to the horizontal direction at the connecting part between the feed part and the first transport part, and the joint part may be disposed on the lower side of the first housing and the second housing.

According to a fourth aspect of the present disclosure, the position of the joint part may overlap the connecting part between the feed part and the first transport part in the vertical direction.

According to a fifth aspect of the present disclosure, the first housing and the second housing may be arranged side-by-side in the horizontal direction, the joint part may include a positioning part that positions the first housing and the second housing with respect to each other in an intersecting direction intersecting, in the horizontal direction, the direction in which the first housing and the second housing are arranged side-by-side, and a fixing part that fixes the first housing and the second housing to each other at a position away from the positioning part in the vertical direction, and the connecting part between the feed part and the first transport part may be located between the positioning part and the fixing part in the vertical direction.

According to a sixth aspect of the present disclosure, the first housing and the second housing may be arranged side-by-side in the horizontal direction, and the joint part may be provided on each of side walls in the intersecting direction intersecting, in the horizontal direction, the direction in which the first housing and the second housing are arranged side-by-side.

According to a seventh aspect of the present disclosure, the joint parts may each include the positioning part that positions the first housing and the second housing with respect to each other in the intersecting direction using a projecting portion projecting in the direction in which the first housing and the second housing are arranged side-by-side, and a receiving portion that is open at the top and into which the projecting portion is inserted.

According to an eighth aspect of the present disclosure, the positioning part may be provided only on one of the joint parts.

According to a ninth aspect of the present disclosure, the image forming apparatus may further include a position adjusting part that is accommodated in the first housing and adjusts the position of the recording medium to be transported to the forming part.

According to a tenth aspect of the present disclosure, the image forming apparatus may further include a first transport part that is accommodated in the lower side of the first housing and transports the recording medium fed from the feed part toward the forming part in the horizontal direction. The revolving part may be disposed above the first transport part such that a space is formed between the revolving part and the first transport part in the vertical direction, and the position adjusting part may be disposed in the space.

According to an eleventh aspect of the present disclosure, the branch part may be disposed above the feed part, and the discharge part may be disposed above the branch part.

According to a twelfth aspect of the present disclosure, the image forming apparatus may further include another feed part that is accommodated at a position below the branch part in the second housing, transports a recording medium fed from the outside of the second housing, and joins the feed part.

According to a thirteenth aspect of the present disclosure, the image forming apparatus may further include a measurement part that measures the dimensions of the recording medium transported to the branch part.

According to a fourteenth aspect of the present disclosure, the image forming apparatus may further include another measurement part that is accommodated in the first housing and measures the dimensions of the recording medium transported from the feed part to the forming part.

In the image forming apparatus according to the first aspect, compared with a configuration in which any of the forming part, the revolving part, and the fixing part is accommodated in a housing other than the housing of the others, the adjustment among the forming part, the revolving part, and the fixing part at the time of installation of the image forming apparatus is simple.

In the image forming apparatus according to the second aspect, compared with a configuration in which the joint part is disposed at a position closer to the connecting part between the second transport part and the discharge part than to the connecting part between the first transport part and the feeding unit, a recording-medium transport error occurring between the feeding unit and the first transport part is suppressed.

In the image forming apparatus according to the third aspect, in the configuration in which the feeding unit and the first transport part are disposed at the lower side of the first housing and the second housing, respectively, compared with a configuration in which the joint part is disposed only on the upper side of the first housing and the second housing, a recording-medium transport error occurring between the feeding unit and the first transport part is suppressed.

In the image forming apparatus according to the fourth aspect, compared with a configuration in which the position of the joint part in the vertical direction is shifted from the connecting part between the feeding unit and the first transport part, a recording-medium transport error occurring between the feeding unit and the first transport part is suppressed.

In the image forming apparatus according to the fifth aspect, compared with a configuration in which the connecting part between the first transport part and the feeding unit is shifted from the position between the positioning part and the fixing part in the vertical direction, a recording-medium transport error occurring between the feeding unit and the first transport part is suppressed.

In the image forming apparatus according to the sixth aspect, compared with a configuration in which the first housing and the second housing are joined together with a joint part provided only on one side wall in the intersecting direction, a recording-medium transport error occurring between the feeding unit and the first transport part is suppressed.

In the image forming apparatus according to the seventh aspect, compared with a configuration in which the top of the receiving portion is closed, it is easy to visually check, from above, the state of the projecting portion inserted into the receiving portion.

In the image forming apparatus according to the eighth aspect, compared with a configuration in which the positioning part using the projecting portion and the receiving portion is provided on each of the pair of joint parts, it is easy to join together the first housing and the second housing.

In the image forming apparatus according to the ninth aspect, compared with a configuration in which the position adjusting part is accommodated in the second housing, it is possible to suppress transport error of the recording medium to be transported to the forming part.

In the image forming apparatus according to the tenth aspect, compared with a configuration in which the horizontal position of the position adjusting part accommodated in the first housing is closer to the feeding unit than the revolving part is, the horizontal length of the first housing does not increase.

In the image forming apparatus according to the eleventh aspect, an operator can receive, in a standing state, the recording medium discharged from the discharge part.

In the image forming apparatus according to the twelfth aspect, compared with a configuration in which another feeding unit is disposed above the branch part, the vertical length of the second housing does not increase.

In the image forming apparatus according to the thirteenth aspect, compared with a configuration in which only the dimensions of the recording medium transported from the feeding unit to the forming part are measured, it is possible to suppress variation in the dimensional ratio of an image to be formed on the back surface of the recording medium to an image formed on the top surface of the recording medium in duplex printing.

In the image forming apparatus according to the fourteenth aspect, compared with a configuration in which only the dimensions of the recording medium transported to the branch part are measured, the positional accuracy of an image to be formed on the recording medium with respect to the recording medium is high.

Exemplary embodiment of the present disclosure will be described in detail based on the following figures, wherein:.

An image forming apparatus <NUM> according to an exemplary embodiment of the present disclosure will be described below with reference to <FIG>.

In the description below, the vertical direction of the apparatus (height direction), the width direction of the apparatus (horizontal direction), and the depth direction of the apparatus (horizontal direction) when the image forming apparatus <NUM> is viewed from the front, where a user (not shown) stands, will be referred to as the H direction, the W direction, and the D direction, respectively. When one side and the other side of the vertical direction, the width direction, and the depth direction need to be distinguished, the upper side, the lower side, the right side, the left side, the far side, the and near side in front view of the image forming apparatus <NUM> will be referred to as the +H side, the -H side, the +W side, the -W side, the -D side, the and +D side, the respectively.

An image forming apparatus <NUM> according to this exemplary embodiment is an electrophotographic image forming apparatus, in which a toner image is formed on a sheet member P, serving as a recording medium. As shown in <FIG>, the image forming apparatus <NUM> includes storage parts <NUM>, a first feed part <NUM>, a second feed part <NUM>, an image forming unit <NUM>, a discharge part <NUM>, a branch part <NUM>, an output part <NUM>, and a controller <NUM> that controls these components.

The image forming apparatus <NUM> further includes an apparatus body accommodating these components. The apparatus body includes three substantially rectangular-parallelepiped-shaped housings joined to one another in the width direction. The three housings include a housing 10a, a housing 10b, and a housing 10c, in this order from the -W side. The housing 10c accommodates the image forming unit <NUM>. The housing 10b accommodates the first feed part <NUM>, the second feed part <NUM>, the discharge part <NUM>, and the branch part <NUM>. The details of the housings 10a, 10b, and 10c will be described below. As shown in <FIG>, the image forming apparatus <NUM> also includes first joint parts <NUM> for joining the housing 10a and the housing 10b together, and second joint parts <NUM> for joining the housing 10b and the housing 10c together.

The image forming apparatus <NUM> further includes a measurement part <NUM> that measures the dimensions of a sheet member P transported toward a forming part <NUM> (described in detail below) of the image forming unit <NUM>, and a position adjusting part <NUM> that adjusts the position of the sheet member P.

The storage parts <NUM> accommodate sheet members P. The image forming apparatus <NUM> includes four storage parts <NUM>. Sheet members P are selectively fed out from the four storage parts <NUM>.

In this exemplary embodiment, two storage parts <NUM> are disposed in the housing 10a in a vertically stacked manner. The other two storage parts <NUM> are disposed side-by-side in the width direction in the housing 10b.

The first feed part <NUM> transports a sheet member P accommodated in a storage part <NUM> in the housing 10b with multiple transport rollers (not shown) disposed in the housing 10b and feeds the sheet member P to the image forming unit <NUM> in the housing 10c. The first feed part <NUM> is an example of a feed part.

The second feed part <NUM> transports a sheet member P accommodated in a storage part <NUM> in the housing 10a with multiple transport rollers (not shown) disposed in the housing 10a and the housing 10b, joins the first feed part <NUM>, and feeds the sheet member P to the image forming unit <NUM> in the housing 10c. The second feed part <NUM> is an example of another feed part. As shown in <FIG>, the second feed part <NUM> passes between the branch part <NUM> (described below) and the storage parts <NUM> in the vertical direction and joins the first feed part <NUM>. In other words, the second feed part <NUM> is disposed below the branch part <NUM>.

The image forming unit <NUM> is disposed in the housing 10c and electrophotographically forms an image on a sheet member P. The image forming unit <NUM> includes the forming part <NUM> that forms a toner image on a sheet member P, a fixing part <NUM> that fixes the toner image formed on the sheet member P to the sheet member P, and a chain gripper <NUM> that transports the sheet member P from the forming part <NUM> toward the fixing part <NUM>. The image forming unit <NUM> also includes a first transport part 20a that transports the sheet member P supplied from the feed part <NUM> to the housing 10c toward a receiving position D1 (described in detail below), at which the chain gripper <NUM> receives the sheet member P, in a direction parallel to the width direction (horizontal direction). The image forming unit <NUM> also includes a second transport part 20b that transports the sheet member P to which the toner image has been fixed in the fixing part <NUM> toward the discharge part <NUM> in the housing 10b in the direction parallel to the width direction (horizontal direction).

The first transport part 20a and the second transport part 20b each include multiple transport rollers (not shown). The first transport part 20a is connected to the first feed part <NUM>. The second transport part 20b is connected to the discharge part <NUM>. The connecting part between the first transport part 20a and the first feed part <NUM> is a connecting part <NUM>, and the connecting part between the second transport part 20b and the discharge part <NUM> is a connecting part <NUM>.

The first transport part 20a is disposed at the lower side of the housing 10c. More specifically, the first transport part 20a is disposed to the -H side of the center line between the upper surface and the lower surface of the housing 10c. More specifically, the first transport part 20a is disposed at a position within one third of the distance between the upper surface and the lower surface of the housing 10c, to the +H side of the lower surface of the housing 10c.

The second transport part 20b is disposed at the upper side of the housing 10c. More specifically, the second transport part 20b is disposed to the +H side of the center line between the upper surface and the lower surface of the housing 10c. More specifically, the first transport part 20a is disposed at a position within one third of the distance between the upper surface and the lower surface of the housing 10c, to the -H side of the upper surface of the housing 10c.

The forming part <NUM> includes photoconductor units <NUM> that form toner images, and a transfer device <NUM> that transfers the toner images formed in the photoconductor units <NUM> to a sheet member P.

There are multiple photoconductor units <NUM> so as to form toner images of different colors. In this exemplary embodiment, a total of four photoconductor units <NUM>, which correspond to yellow (Y), magenta (M), cyan (C), and black (K), are provided. The letters Y, M, C, and K shown in <FIG> and <FIG> are suffixed to the components corresponding to these colors. When there is no need to distinguish between the colors Y, M, C, and K, these letters are omitted.

The photoconductor units 23Y, <NUM>, 23C, and <NUM> have basically the same configuration except for the toners used.

As shown in <FIG>, the photoconductor units 23Y, <NUM>, 23C, and <NUM> are arranged in a line along an inclined portion of the transfer belt <NUM> (described in detail below) of the transfer device <NUM>.

As shown in <FIG>, each photoconductor unit <NUM> includes a photoconductor drum <NUM> that rotates in the direction of arrow A02, and a charger <NUM> that charges the photoconductor drum <NUM>. The photoconductor unit <NUM> further includes an exposure device <NUM> that exposes the photoconductor drum <NUM> charged by the charger <NUM> to form an electrostatic latent image, and a developing device <NUM> that develops the electrostatic latent image with toner to form a toner image.

The transfer device <NUM> first-transfers, in a superposed manner, the toner images formed on the photoconductor drums <NUM> corresponding to the respective colors to the intermediate transfer body and then second-transfers the superposed toner images to a sheet member P. More specifically, as shown in <FIG>, the transfer device <NUM> includes: the transfer belt <NUM>, serving as an intermediate transfer body; multiple rollers <NUM>; first transfer rollers <NUM>; a second transfer roller <NUM>; and a transfer body <NUM>.

The transfer belt <NUM> is an endless belt stretched over the multiple rollers <NUM> in a substantially inverted triangular orientation. Among the multiple rollers <NUM> holding the transfer belt <NUM> in a substantially inverted triangular orientation, the roller <NUM> on the -W side and the roller <NUM> on the -H side are a roller 32a and a roller 32b, respectively. The transfer belt <NUM> revolves in the direction of arrow X when at least one of the multiple rollers <NUM> is rotationally driven.

The first transfer rollers <NUM> are opposed to the photoconductor drums <NUM> corresponding to the respective colors with the transfer belt <NUM> therebetween. The first transfer rollers <NUM> transfer the toner images formed on the photoconductor drums <NUM> to the transfer belt <NUM> at first transfer positions T between the photoconductor drums <NUM> and the first transfer rollers <NUM>.

The second transfer roller <NUM> is disposed on the inner side of the transfer belt <NUM> so as to be in contact with the transfer belt <NUM> at a position between the roller 32a and the roller 32b among the rollers <NUM> over which the transfer belt <NUM> is stretched in a substantially inverted triangular shape. The transfer body <NUM> extends in the depth direction and is opposed to the second transfer roller <NUM> with the transfer belt <NUM> therebetween. The second transfer roller <NUM> and the transfer body <NUM> transfer the toner image transferred to the transfer belt <NUM> to the sheet member P at a second transfer position NT between the transfer belt <NUM> and the transfer body <NUM>.

The chain gripper <NUM> includes a pair of chains <NUM>, leading-end holding parts <NUM> that hold the leading ends of sheet members P, and pairs of sprockets <NUM>, <NUM>, and <NUM>. The chains <NUM> are an example of a revolving member. The sprockets <NUM>, <NUM>, and <NUM> are an example of rotary members. The chain gripper <NUM> is an example of a revolving part.

As shown in <FIG>, the chains <NUM> are endless chains disposed at a distance from each other in the depth direction. As shown in <FIG>, the chains <NUM> are stretched over the pair of sprockets <NUM> disposed at the ends of the transfer body <NUM> in the longitudinal direction (axial direction). The axial direction of the sprockets <NUM> is parallel to the longitudinal direction. The chains <NUM> are also stretched over the pair of sprockets <NUM> (see <FIG>) disposed at the ends of a pressure roller <NUM> (described below) in the longitudinal direction (axial direction). The axial direction of the sprockets <NUM> is parallel to the longitudinal direction. As shown in <FIG>, the chains <NUM> are also stretched over the pair of sprockets <NUM> disposed at a distance from each other in the depth direction.

The sprockets <NUM> disposed at the ends of the pressure roller <NUM> in the longitudinal direction are disposed to the -W side and to the +H side of the sprockets <NUM> disposed at the ends of the transfer body <NUM> in the longitudinal direction.

As viewed in the depth direction, the pair of sprockets <NUM> are disposed below the sprockets <NUM> and <NUM>, to the -W side of the sprockets <NUM> and to the +W side of the sprockets <NUM>. A transport roller (not shown) is disposed between the pair of sprockets <NUM> so as to be coaxial with the sprockets <NUM>.

As shown in <FIG>, each leading-end holding part <NUM> includes an attachment member <NUM> extending in the depth direction, and grippers <NUM> attached to the attachment member <NUM>. The ends of the leading-end holding part <NUM> in the depth direction are attached to the chains <NUM>.

The leading-end holding parts <NUM> are disposed at predetermined intervals in the circumferential direction (revolving direction) of the chains <NUM>.

The grippers <NUM> are attached to the attachment member <NUM> at predetermined intervals in the depth direction. The grippers <NUM> hold the leading end of a sheet member P. More specifically, the grippers <NUM> have jaws 57a. The attachment member <NUM> has a contact part 56a with which the jaws 57a come into contact.

The grippers <NUM> hold a sheet member P by pinching the leading end of the sheet member P between the jaws 57a and the contact part 56a. In the grippers <NUM>, for example, the jaws 57a are pressed against the contact part 56a by springs or the like, and the jaws 57a are brought toward and away from the contact part 56a by the effect of the cams or the like.

In this configuration, when a rotational force is transmitted to any one of the multiple sprockets <NUM>, <NUM>, and <NUM> shown in <FIG>, the pair of chains <NUM> revolve in the direction of arrow C in <FIG> so as to move from the sprockets <NUM> side toward the sprockets <NUM> side.

Furthermore, when a leading-end holding part <NUM> attached to the chains <NUM> reaches the receiving position D1 at the bottom of the sprockets <NUM>, the grippers <NUM> of the leading-end holding part <NUM> pinch the leading end of a sheet member P transported along the first feed part <NUM> and the first transport part 20a, thus holding and receiving the sheet member P. The chains <NUM> revolving in the direction of arrow C transport the sheet member P held by the leading-end holding part <NUM> to the second transfer position NT, where a toner image is transferred to the sheet member P. Furthermore, the revolving chains <NUM> transport the sheet member P from the second transfer position NT to the fixing part <NUM>, where the toner image is fixed to the sheet member P. At a feed-out position D2 located downstream of the fixing part <NUM> in the sheet transport direction, the leading-end holding part <NUM> releases the leading end of the sheet member P after passing through the fixing part <NUM>, and the chain gripper <NUM> feeds the sheet member P to the second transport part 20b and the discharge part <NUM>.

A portion of the path of the revolving chain gripper <NUM> between the point after the fixing part <NUM> (feed-out position D2) and the point after the meeting point with the first transport part 20a (receiving position D1) is inclined downward. This downwardly inclined path extending from the feed-out position D2 to the receiving position D1 is an inclined portion DT. With this configuration, a space S is formed between the inclined portion DT and the first transport part 20a. In this exemplary embodiment, the height of the space S in the vertical direction decreases from the feed-out position D2 side toward the receiving position D1 side in the horizontal direction. In other words, in this exemplary embodiment, the height of the space S in the vertical direction decreases from the fixing part <NUM> side toward the second transfer position NT side in the horizontal direction.

As shown in <FIG>, the fixing part <NUM> is disposed downstream of the transfer body <NUM> in the sheet transport direction.

As shown in <FIG>, the fixing part <NUM> includes a heating roller <NUM> that comes into contact with and heats a sheet member P that is being transported, a pressure roller <NUM> that presses the sheet member P against the heating roller <NUM>, and a driven roller <NUM> that is rotated by the heating roller <NUM>.

The heating roller <NUM> comes into contact with the upper side of the sheet member P that is being transported. The heating roller <NUM> extends in the depth direction such that the axial direction thereof is parallel to the depth direction. The heating roller <NUM> has, at the ends thereof in the depth direction, shafts 44a extending in the depth direction and support members 44b for supporting the shafts 44a.

The driven roller <NUM> is disposed on the opposite side of the heating roller <NUM> from the sheet member P that is being transported, and extends in the depth direction such that the axial direction thereof is parallel to the depth direction. The driven roller <NUM> has a heater (not shown). In this configuration, the driven roller <NUM> is rotated by the heating roller <NUM>. The driven roller <NUM> heats the heating roller <NUM>.

The pressure roller <NUM> is opposed to the heating roller <NUM> with the sheet member P that is being transported therebetween. The pressure roller <NUM> comes into contact with the lower side of the sheet member P that is being transported, and extends in the depth direction such that the axial direction thereof is parallel to the depth direction. The pressure roller <NUM> has, at the ends thereof in the depth direction, shafts 42a extending in the axial direction.

The fixing part <NUM> also includes support members <NUM> that support the shafts 42a of the pressure roller <NUM>, and urging members <NUM> that urge the pressure roller <NUM> toward the heating roller <NUM> with the support members <NUM> therebetween. The support members <NUM> are disposed so as to support the shafts 42a of the pressure roller <NUM> from below in a manner allowing rotation thereof.

In this configuration, the urging members <NUM> urge the pressure roller <NUM> toward the heating roller <NUM>, and the pressure roller <NUM> presses the sheet member P against the heating roller <NUM>. Furthermore, the pressure roller <NUM> receives a rotational force transmitted from a driving member (not shown) and rotates. The rotating pressure roller <NUM> rotates the heating roller <NUM>, and the rotating heating roller <NUM> rotates the driven roller <NUM>. Furthermore, as a result of the heating roller <NUM> and the pressure roller <NUM> nipping and transporting a sheet member P to which a toner image has been transferred, the toner image is heated and fixed to the sheet member P.

The discharge part <NUM> is provided in the housing 10b and discharges, from the discharge port provided in the side surface of the housing 10b on the housing 10a side, a sheet member P transported from the second transport part 20b toward the housing 10b after a toner image has been fixed thereto in the fixing part <NUM> in the housing 10c.

In this exemplary embodiment, the sheet member P discharged from the discharge port in the housing 10b is passed to an extension discharge part 16a provided in the housing 10a and is discharged on the output part <NUM> provided outside the housing 10a.

The branch part <NUM> is provided so as to be split from the discharge part <NUM> in the housing 10b and feeds the sheet member P transported to the branch part <NUM> to the first feed part <NUM> after switching the leading end and the trailing end of the sheet member P. More specifically, the branch part <NUM> changes the transport direction of the sheet member P transported from the discharge part <NUM> to the branch part <NUM> to the direction opposite to the transport direction in the discharge part <NUM> on the downstream side of the fixing part <NUM>.

The branch part <NUM> is disposed above the storage parts <NUM> and below the discharge part <NUM> in the housing 10b.

The branch part <NUM> includes a measurement part 17a that measures the dimensions of the sheet member P transported to the branch part <NUM>. As shown in <FIG>, the measurement part 17a includes multiple measurement sensors 17b. The measurement part 17a measures the dimensions of the sheet member P to which a toner image has been fixed in the fixing part <NUM> and which has been transported to the branch part <NUM> and the dimensions of the image fixed to the sheet member P, and then transmits the measurement results to the controller <NUM>.

The sheet member P transported to the branch part <NUM> and then fed to the first feed part <NUM> is transported to the second transfer position NT in a reversed state as compared with the state thereof before being transported to the branch part <NUM>, because the leading end and the trailing end thereof have been switched. More specifically, a sheet member P that is transported to the branch part <NUM>, fed to the first feed part <NUM>, and transported the second transfer position NT receives a toner image on the other side (back surface) of the side (top surface) on which a toner image has been formed before the sheet member P is transported to the branch part <NUM>. At this time, on the basis of the measurement results obtained by the measurement part 17a of the branch part <NUM>, the controller <NUM> corrects the size of the toner image to be formed on the back of the sheet member P, in accordance with the measured dimensions of the sheet member P and dimensions of the toner image formed on the top surface.

As shown in <FIG>, the position adjusting part <NUM> is accommodated in the housing 10c such that an upper portion thereof is located in the space S, and adjusts the position of the sheet member P to be transported to the receiving position D1. As shown in <FIG>, the position adjusting part <NUM> includes multiple rollers <NUM>, multiple sensors <NUM>, and a stopper <NUM>.

The multiple rollers <NUM> are disposed above and below the first transport part 20a so as to form pairs along the first transport part 20a. More specifically, the position adjusting part <NUM> includes, along the first transport part 20a, roller pairs 91a, 91b, and 91c in this order from the - W side.

The stopper <NUM> is a substantially N-shaped member, as viewed from the +D side, provided on the roller pair 91b. The downstream end of the stopper <NUM> in the sheet transport direction is a gate portion 93a standing upright so as to intersect the first transport part 20a. As a result of the leading end of a sheet member P fed to the position adjusting part <NUM> being butted against the gate portion 93a, the sheet transport timing, misregistration in the sheet width direction, inclination of the sheet member P, and the like are adjusted. In other words, the position adjusting part <NUM> adjusts the position of the sheet member P to be transported to the receiving position D1 with the gate portion 93a provided on the roller pair 91b.

A lifting member (not shown) including a gear and a motor is provided upstream of the stopper <NUM> in the sheet transport direction. The stopper <NUM> moves the gate portion 93a of the stopper <NUM> up and down with the lifting member.

When the gate portion 93a is moved upward, the gate portion 93a is located at a position where it blocks the first transport part 20a. In this case, a sheet member P transported along the first transport part 20a is stopped at the position of the gate portion 93a. When the gate portion 93a is moved downward, the gate portion 93a is located at a position where it does not block the first transport part 20a. In this case, a sheet member P transported along the first transport part 20a is transported without being interfered by the gate portion 93a.

The multiple sensors <NUM> detect whether a sheet member P that is being transported along the first transport part 20a has passed or not. Upon receipt of signals from the sensors <NUM>, the controller <NUM> appropriately controls the operation of the rollers <NUM> in the position adjusting part <NUM>.

The measurement part <NUM> is disposed along the first transport part 20a, on the upstream side of the position adjusting part <NUM> in the transport direction and includes multiple sensors (not shown). The measurement part <NUM> measures the dimensions of a sheet member P transported along the first transport part 20a and transmits the measurement results to the controller <NUM>. On the basis of the measurement results obtained by the measurement part <NUM>, the controller <NUM> corrects the position of the toner image to be formed on the sheet member P relative to the sheet member P according to the measured dimensions of the sheet member P. The measurement part <NUM> is an example of another measurement part.

The housings 10a, 10b, and 10c each have a rectangular-parallelepiped-shaped frame and walls on the sides of the frame. Of the walls constituting the housings 10a, 10b, and 10c, the walls located on the -W side, +W side, -D side, and +D side are called side walls, and the walls located on the -H side are called bottom walls.

In the housing 10c, the side wall located on the -W side has openings through which the first transport part 20a and the second transport part 20b are connected to the first feed part <NUM> and the discharge part <NUM> in the housing 10b at the connecting part <NUM> and the connecting part <NUM>, respectively.

In the housing 10b, the side wall located on the +W side has openings through which the first feed part <NUM> and the discharge part <NUM> are connected to the first transport part 20a and the second transport part 20b in the housing 10c at the connecting part <NUM> and the connecting part <NUM>, respectively. In the housing 10b, the side wall located on the -W side has openings through which the discharge part <NUM> and the second feed part <NUM> are connected to the extension discharge part 16a and the second feed part <NUM> in the housing 10a, respectively. The housing 10b is an example of a second housing.

In the housing 10a, the side wall located on the +W side has openings through which the extension discharge part 16a and the second feed part <NUM> are connected to the discharge part <NUM> and the second feed part <NUM> in the housing 10b, respectively.

The housings 10a, 10b, and 10c each have, on the bottom-side frame thereof, multiple extendable legs (not shown), so that the height thereof in the vertical direction can be changed. The positions of the housings 10a, 10b, and 10c in the vertical direction can be changed by extending or contracting the legs in the vertical direction.

The first joint parts <NUM> and the second joint parts <NUM> have basically the same structure, except for the objects they join. Hence, the structure of the second joint parts <NUM> will be described as an example.

As shown in <FIG>, the second joint parts <NUM> are provided on both side walls in the depth direction, at the boundary between the housing 10b and the housing 10c, to join the housing 10b and the housing 10c together. As shown in <FIG>, the second joint parts <NUM> are disposed to the -H side of the center line of the housing 10b and the housing 10c in the vertical direction. More specifically, the second joint parts <NUM> are disposed at the lower side of the housing 10b and the housing 10c. In other words, the second joint parts <NUM> are disposed at a position closer to the connecting part <NUM> between the feed part <NUM> and the first transport part 20a than to the connecting part <NUM> between the second transport part 20b and the discharge part <NUM>.

As shown in <FIG>, the second joint parts <NUM> include a block part <NUM> provided on the +D-side side walls of the housing 10b and the housing 10c and a block part <NUM> provided on the -D-side side walls of the housing 10b and the housing 10c. More specifically, the block part <NUM> and the block part <NUM> form a pair. The block part <NUM> and the block part <NUM> are an example of a joint part.

As shown in <FIG>, the block part <NUM> includes a block <NUM> provided on the housing 10b, a block <NUM> provided on the housing 10c, and a bolt <NUM> that fastens the block <NUM> and the block <NUM> together.

As shown in <FIG>, the block <NUM> includes a rectangular-parallelepiped-shaped body 83a and a substantially cylindrical positioning pin 83b projecting to the -W side from the upper side of the -W-side end face of the body 83a. The positioning pin 83b is an example of a projecting portion. The block <NUM> also has a screw hole 83c penetrating through the body 83a in the width direction, at a position to the -H side of the positioning pin 83b, for receiving the bolt <NUM>. The body 83a is disposed so as to cover the first feed part <NUM> in the housing 10b in the vertical direction. In other words, the position of the body 83a overlaps the first feed part <NUM> in the vertical direction. As shown in <FIG>, the positioning pin 83b is formed to the +H side of the first transport part 20a in the housing 10c. The screw hole 83c is formed to the -H side of the first transport part 20a in the housing 10c.

The positioning pin 83b has a tapered face formed by chamfering the edge of the distal end thereof.

As shown in <FIG>, the block <NUM> has a rectangular-parallelepiped-shaped body 82a. The body 82a has a recess 82b provided in an upper portion of the +W-side end face of the body 82a, and a through-hole 82c penetrating through the body 82a in the width direction, at a position corresponding to the screw hole 83c in the block <NUM>, for receiving the bolt <NUM>. The body 82a is disposed so as to cover the first transport part 20a in the housing 10c in the vertical direction. In other words, the position of the body 82a overlaps the first transport part 20a in the vertical direction. The recess 82b is sized such that it can receive the positioning pin 83b of the block <NUM>. The recess 82b is an example of a receiving portion. The dimension of the recess 82b in the depth direction is larger than the dimension of the positioning pin 83b of the block <NUM> in the depth direction, such that the positioning pin 83b is loosely fitted to the recess 82b. The recess 82b has an open-top groove shape extending from the +H-side end face of the block <NUM> toward the -H side. The recess 82b is formed to the +H side of the first feed part <NUM> in the housing 10b. The through-hole 82c is formed to the -H side of the first feed part <NUM> in the housing 10b.

The recess 82b has a tapered face formed by chamfering the +W-side edge thereof. The tapered face of the recess 82b guides the positioning pin 83b on the housing 10c, which is to be inserted into the recess 82b, into the recess 82b.

The block part <NUM> is symmetrical to the block part <NUM> in the depth direction, except that the block part <NUM> does not have the positioning pin 83b and the recess 82b provided in the block part <NUM>. In other words, in the second joint part <NUM>, the positioning pin 83b and the recess 82b are provided only on the block part <NUM>, which is located on the +D side.

More specifically, as shown in <FIG>, the block part <NUM> includes a block <NUM>, a block <NUM>, and a bolt <NUM>, instead of the block <NUM>, the block <NUM>, and the bolt <NUM> in the block part <NUM>. The position of the block part <NUM> in the vertical direction is the same as that of the block part <NUM>. Specifically, the position of the block part <NUM> overlaps the first transport part 20a (connecting part <NUM>) in the vertical direction.

As shown in <FIG>, the block <NUM> has a screw hole 88c, instead of the screw hole 83c in the block <NUM>. The -W-side end face of the block <NUM> is flat, except for the screw hole 88c.

As shown in <FIG>, the block <NUM> has a through-hole 87c, instead of the through-hole 82c in the block <NUM>. The +W-side end face of the block <NUM> is flat, except for the through-hole 87c.

When the surface of the block <NUM> and the surface of the block <NUM> facing each other and the surface of the block <NUM> and the surface of the block <NUM> facing each other are brought into contact with each other in the width direction, the +W-side side wall of the housing 10b and the -W-side side wall of the housing 10c face each other at a predetermined distance from each other. More specifically, when the surface of the block <NUM> and the surface of the block <NUM> facing each other and the surface of the block <NUM> and the surface of the block <NUM> facing each other are brought into contact with each other in the width direction, the housing 10b and the housing 10c are positioned with respect to each other in the width direction. In other words, when the surface of the block <NUM> and the surface of the block <NUM> facing each other and the surface of the block <NUM> and the surface of the block <NUM> facing each other are brought into contact with each other in the width direction, the first feed part <NUM> and the first transport part 20a are positioned with respect to each other in the width direction.

Furthermore, when the +H-side end faces of the block <NUM> and the block <NUM> and the +H-side end faces of the block <NUM> and the block <NUM> are in flush with each other, the positions of the first feed part <NUM> and the first transport part 20a in the vertical direction are aligned. More specifically, when the +H-side end faces of the block <NUM> and the block <NUM> and the +H-side end faces of the block <NUM> and the block <NUM> are in flush with each other, the first feed part <NUM> and the first transport part 20a are positioned with respect to each other in the vertical direction. Note that "in flush with each other" means that two surfaces are located within an area of -<NUM> to +<NUM> in the vertical direction from a predetermined height position in the vertical direction.

Furthermore, when the entirety of the positioning pin 83b of the block <NUM> is inserted into the recess 82b in the block <NUM>, the positions of the first feed part <NUM> and the first transport part 20a in the depth direction are aligned. Specifically, when the entirety of the positioning pin 83b of the block <NUM> is inserted into the recess 82b in the block <NUM>, the first feed part <NUM> and the first transport part 20a are positioned with respect to each other in the depth direction. The combination of the positioning pin 83b and the recess 82b is an example of a positioning part.

As a result of the first feed part <NUM> and the first transport part 20a being positioned with respect to each other by the blocks <NUM> and <NUM> this way, the first feed part <NUM> and the first transport part 20a are connected to each other. Furthermore, the housing 10b and the housing 10c are positioned with respect to each other by the blocks <NUM> and <NUM>. After the first feed part <NUM> and the first transport part 20a are positioned with respect to each other, the bolt <NUM> is screwed into the through-hole 82c and the screw hole 83c, and the bolt <NUM> is screwed into the through-hole 87c and the screw hole 88c to fix the housing 10b and the housing 10c to each other. The combinations of the bolts <NUM> and <NUM>, the through-holes 82c and 87c, and the screw holes 83c and 88c are an example of a fixing part.

When the housing 10b and the housing 10c are positioned with respect to each other and fixed to each other, the positions of the block parts <NUM> and <NUM> overlap the connecting part <NUM> between the first feed part <NUM> and the first transport part 20a in the vertical direction. Furthermore, when the housing 10b and the housing 10c are positioned with respect to each other and fixed to each other, the connecting part <NUM> between the first feed part <NUM> and the first transport part 20a is located between the recess 82b and the bolt <NUM> in the vertical direction.

The first joint parts <NUM> have the same configuration as the second joint parts <NUM>, except that, as shown in <FIG> and <FIG>, the first joint parts <NUM> are provided on both side walls in the depth direction, at the boundary between the housing 10a and the housing 10b, to join the housing 10a and the housing 10b together. Furthermore, the first joint parts <NUM> are disposed to the -H side of the center line of the housing 10a and the housing 10b in the vertical direction. In other words, the first joint parts <NUM> are disposed on the lower side of the housing 10a and the housing 10b.

When positioning the housings 10a, 10b, and 10c with respect to one another in the vertical direction, the vertical positions thereof are adjusted by extending or contracting the multiple legs (not shown) to make the +H-side end faces of the block <NUM> and the block <NUM> flush with each other. The +H-side end faces of the block <NUM> and the block <NUM> and the +H-side end faces of the opposed blocks in the first joint parts <NUM> are also made flush with each other in this way.

Next, effects and advantages of the exemplary embodiment will be described. When a comparative example to the exemplary embodiment will be described below, the same reference signs and names will be used for the same components as those of the image forming apparatus <NUM> according to the exemplary embodiment.

In the image forming apparatus <NUM> according to the exemplary embodiment, the image forming unit <NUM> is disposed in the housing 10c. Specifically, in the image forming apparatus <NUM> according to the exemplary embodiment, the housing 10c accommodates the forming part <NUM>, the fixing part <NUM>, and the chain gripper <NUM>.

In the image forming apparatus <NUM>, when a toner image is to be formed on a sheet member P, first, a sheet member P stored in a storage part <NUM> is transported to the receiving position D1, where the chain gripper <NUM> receives the sheet member P, with the first feed part <NUM> and the first transport part 20a. Next, the sheet member P transported to the receiving position D1 is held by the chain gripper <NUM> and is transported to the second transfer position NT, where a toner image formed in the forming part <NUM> is transferred (formed). The sheet member P to which the toner image has been transferred at the second transfer position NT is then transported to the fixing part <NUM> while still being held by the chain gripper <NUM>, and the toner image is fixed to the sheet member P. The sheet member P to which the toner image has been fixed in the fixing part <NUM> is then transported to the second transport part 20b and the discharge part <NUM>. In simplex printing, the sheet member P transported along the second transport part 20b and the discharge part <NUM> is further transported along the extension discharge part 16a and is discharged onto the output part <NUM>. In duplex printing, the sheet member P transported along the second transport part 20b and the discharge part <NUM> is transported to the branch part <NUM>, where the leading end and the trailing end of the sheet member P are switched, and is then fed to the first feed part <NUM> so as to be transported again to the receiving position D1 and the second transfer position NT.

As described, when a toner image is to be formed on a sheet member P with the image forming apparatus <NUM>, the sheet member P is transported to the respective parts of the image forming apparatus <NUM>. Hence, the sheet transport accuracy needs to be adjusted at the time of installing the image forming apparatus <NUM>. In particular, the sheet transport accuracy among the chain gripper <NUM>, the forming part <NUM>, and the fixing part <NUM> needs to be adjusted so that the toner image formed on the sheet member P does not deviate from the position set by a user. Furthermore, because the image forming apparatus <NUM> includes multiple housings, the sheet transport accuracy needs to be adjusted across the different housings at the time of installing the image forming apparatus <NUM>.

In the image forming apparatus <NUM> according to the exemplary embodiment, the forming part <NUM>, the fixing part <NUM>, and the chain gripper <NUM> are accommodated in a single housing, 10c. Hence, in the image forming apparatus <NUM>, the sheet transport accuracy among the forming part <NUM>, the fixing part <NUM>, and the chain gripper <NUM> does not need to be adjusted across the different housings at the time of installing the image forming apparatus <NUM>. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which any of the forming part <NUM>, the chain gripper <NUM>, and the fixing part <NUM> is accommodated in a housing other than the housing of the others, the adjustment among the forming part <NUM>, the chain gripper <NUM>, and the fixing part <NUM> is simple. Specifically, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with the above-described configuration, the adjustment among the forming part <NUM>, the chain gripper <NUM>, and the fixing part <NUM> at the time of installing the image forming apparatus <NUM> is simple.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the second joint parts <NUM> are disposed at positions closer to the connecting part <NUM> between the first feed part <NUM> and the first transport part 20a than to the connecting part <NUM> between the second transport part 20b and the discharge part <NUM>. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the second joint parts <NUM> are disposed at positions closer to the connecting part <NUM> than to the connecting part <NUM>, it is possible to suppress sheet transport error between the first feed part <NUM> and the first transport part 20a.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the second joint parts <NUM> are disposed at the lower side of the housing 10b and the housing 10c. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the second joint parts <NUM> are disposed only at the upper side of the housing 10b and the housing 10c, it is possible to suppress sheet transport error between the first feed part <NUM> and the first transport part 20a.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the position of the second joint parts <NUM> in the vertical direction overlaps the connecting part <NUM> between the first feed part <NUM> and the first transport part 20a. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the position of the second joint parts <NUM> in the vertical direction is shifted from the connecting part <NUM> between the first feed part <NUM> and the first transport part 20a, it is possible to suppress sheet transport error between the first feed part <NUM> and the first transport part 20a.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the connecting part <NUM> between the first feed part <NUM> and the first transport part 20a is located between the recess 82b and the bolt <NUM> in the vertical direction. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the connecting part <NUM> is shifted from the position between the recess 82b and the bolt <NUM> in the vertical direction, it is possible to suppress sheet transport error between the first feed part <NUM> and the first transport part 20a.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the block part <NUM> and the block part <NUM> are provided on both side walls of the housing 10b and the housing 10c in the depth direction. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the housing 10b and the housing 10c are joined together with a joint part provided only on one side wall in the depth direction, it is possible to suppress sheet transport error between the first feed part <NUM> and the first transport part 20a. Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the housing 10b and the housing 10c are joined together with a joint part provided only on one side wall in the depth direction, it is possible to suppress sheet transport error between the second transport part 20b and the discharge part <NUM>.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the top of the recess 82b in the block <NUM> is open. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the top of the recess 82b is closed, it is easy to visually check, from above, the state of the positioning pin 83b inserted into the recess 82b.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, in the second joint parts <NUM>, only the block part <NUM> has the recess 82b and the positioning pin 83b. The image forming apparatus <NUM> according to the exemplary embodiment and an image forming apparatus <NUM> according to a comparative example will be compared below.

In the image forming apparatus <NUM>, the recess 82b and the positioning pin 83b are provided both in the block part <NUM> and the block part <NUM>. Except for this point, the image forming apparatus <NUM> according to the comparative example has the same configuration as the image forming apparatus <NUM> according to the exemplary embodiment.

In the image forming apparatus <NUM> according to the comparative example, when the housing 10b and the housing 10c are positioned with respect to each other and joined together, both of the positioning pin 83b of the block part <NUM> and the positioning pin 83b of the block part <NUM> need to be inserted into the recesses 82b.

In contrast, in the image forming apparatus <NUM> according to the exemplary embodiment, only the block part <NUM> of the second joint parts <NUM> has the recess 82b and the positioning pin 83b. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, when the housing 10b and the housing 10c are positioned with respect to each other and joined together, only the positioning pin 83b on the block part <NUM>, among the block part <NUM> and the block part <NUM>, needs to be inserted into the recess 82b. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, the housing 10b and the housing 10c are easily joined together, compared with a configuration in which both of the block part <NUM> and the block part <NUM> have the recess 82b and the positioning pin 83b.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the position adjusting part <NUM> is accommodated in the housing 10c. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, the distance between the position adjusting part <NUM> and the receiving position D1, where the chain gripper <NUM> receives the sheet member P, is short, compared with a configuration in which the position adjusting part <NUM> is accommodated in the housing 10b. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, it is possible to suppress transport error of sheet members P to be transported forming part <NUM>, compared with a configuration in which the position adjusting part <NUM> is accommodated in the housing 10b.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, unlike a configuration in which the position adjusting part <NUM> is accommodated in the housing 10b, the sheet transport accuracy between the position adjusting part <NUM> and the chain gripper <NUM> does not need to be adjusted across the different housings. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the position adjusting part <NUM> is accommodated in the housing 10b, the adjustment of the position of the sheet member P to be transported to the receiving position D1, performed by the position adjusting part <NUM>, is easy.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the position adjusting part <NUM> is disposed in the space S. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the horizontal position of the position adjusting part <NUM> accommodated in the housing 10c is closer to the first feed part <NUM> than the chain gripper <NUM> is, it is possible to reduce the length of the housing 10c in the horizontal direction.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the branch part <NUM> is disposed above the storage parts <NUM> and below the discharge part <NUM> in the housing 10b. Specifically, in the image forming apparatus <NUM> according to the exemplary embodiment, the discharge part <NUM> is disposed above the branch part <NUM>. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, an operator can pick up, in a standing state, a sheet member P discharged from the discharge part <NUM>.

Furthermore, in the image forming apparatus <NUM> according to the exemplary embodiment, the second feed part <NUM> is disposed below the branch part <NUM>. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the second feed part <NUM> is disposed above the branch part <NUM>, it is possible to reduce the length of the housing 10b in the vertical direction.

Furthermore, the image forming apparatus <NUM> according to the exemplary embodiment includes the measurement part 17a of the branch part <NUM>. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the dimensions of a sheet member P are measured only with the measurement part <NUM>, it is possible to suppress variation in the dimensional ratio of an image to be formed on the back surface of the sheet member P to the image formed on the top surface of the sheet member P in duplex printing.

Furthermore, the image forming apparatus <NUM> according to the exemplary embodiment includes the measurement part <NUM>. Hence, in the image forming apparatus <NUM> according to the exemplary embodiment, compared with a configuration in which the dimensions of a sheet member P are measured only with the measurement part 17a of the branch part <NUM>, the positional accuracy of an image to be formed on a sheet member P with respect to the sheet member P is high.

Although specific exemplary embodiment of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described exemplary embodiment, and various modifications, changes, improvements are possible within the scope of the technical idea of the present disclosure.

For example, the image forming apparatus <NUM> includes the chain gripper <NUM> as the revolving part. However, the image forming apparatus according to the present disclosure may include, instead of the chain gripper <NUM>, a transport belt that transports a sheet member P with a revolving belt body stretched over multiple rollers. The rollers of the transport belt are an example of rotary members. The belt body of the transport belt is an example of a revolving member. The transport belt is an example of a revolving part.

Furthermore, the image forming apparatus <NUM> includes the fixing part <NUM> including the heating roller <NUM> and the pressure roller <NUM>. However, the fixing part according to the present disclosure may include a non-contact heating member, such as an infrared heating member.

Furthermore, the image forming apparatus <NUM> is an electrophotographic image forming apparatus. However, the image forming apparatus <NUM> according to the present disclosure may be, for example, an ink jet image forming apparatus or an offset image forming apparatus.

Claim 1:
An image forming apparatus (<NUM>) comprising:
a forming part (<NUM>) that forms an image on a recording medium (P);
a fixing part (<NUM>) that fixes the image formed on the recording medium (P);
a revolving part (<NUM>) having a revolving member (<NUM>) stretched over multiple rotary members (<NUM>, <NUM>, <NUM>), the revolving member (<NUM>) revolving between the forming part (<NUM>) and the fixing part (<NUM>) to transport the recording medium (P) from the forming part (<NUM>) to the fixing part (<NUM>);
a feed part (<NUM>) that feeds the recording medium (P) to the forming part (<NUM>);
a discharge part (<NUM>) that discharges the recording medium (P) to which the image has been fixed in the fixing part (<NUM>);
a branch part (<NUM>) that is provided so as to be split from the discharge part (<NUM>) and along which the recording medium (P), to one side of which the image has been fixed, is transported to the feed part (<NUM>) after switching the leading end and the trailing end of the recording medium (P);
a first housing (10c) accommodating the forming part (<NUM>), the fixing part (<NUM>), and the revolving part (<NUM>); and
a second housing (10b) connected to the first housing (10c) and accommodating the feed part (<NUM>) and the branch part (<NUM>),
the image forming apparatus (<NUM>) being characterized in that:
the discharge part (<NUM>) is accommodated in the second housing (10b).