Image forming apparatus to print according to a plurality of image forming types

An image forming apparatus having a first image forming unit and a second image forming including a printing medium supplier which supplies a printing medium, a selection guide which selectively guides the printing medium from the printing medium supplier to one of a first supplying path of the first image forming unit and a second supplying path of the second image forming unit, and a first feed roller which is disposed between the selection guide and the printing medium supplier, and transfers the printing medium from the printing medium supplier to the selection guide.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C 119(a) from Korean Patent Application No. 10-2007-0060431, filed on Jun. 20, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present general inventive concept relates to an image forming apparatus, and more particularly, to an image forming apparatus which is capable of printing according to a plurality of image forming types.

2. Description of the Related Art

An image forming apparatus is an electronic device which forms a desired image on a printing medium. The image forming apparatus may be classified according to image forming types including: an inkjet image forming apparatus which discharges an ink droplet to form an image; an electrophotographic image forming apparatus which forms an image using toner through charging, exposing, developing, transferring, and cleaning operations; and a thermoelectronic image forming apparatus which uses an ink ribbon.

Generally, the image forming apparatus forms an image using only one of the foregoing image forming types. If a user desires to print with an inkjet type in one instance and with an electrophotographic type in another instance, the user should have both an inkjet printer and a laser printer to respectively provide the desired image forming types.

To solve the above a problem, image forming apparatuses which employ both an electrophotographic type and an inkjet type as discussed below.

Japanese Patent First Publication No. H09-311513 discloses an image forming apparatus which includes an inkjet image forming unit and an electrophotographic image forming unit on a single printing medium transfer path. However, the above image forming apparatus has a problem such that a printing medium printed by one of the image forming types may be adversely affected by elements of the other image forming type. For example, if the printing medium printed by the inkjet unit passes through the elements of an image receptor and a fusing unit disposed within the electrophotographic unit, the foregoing elements may be contaminated by wet ink on the printing medium. Alternatively, if the printing medium passes through the fusing unit of the electrophotographic unit, thereby causing the printing medium to have a higher temperature, and then passes through a head chip of an inkjet unit, the head chip will be thermally deformed and printing quality may be degraded.

To solve the foregoing problem, Japanese Patent First Publication No. H08-310047 discloses an image forming apparatus which includes an electrophotographic unit and an inkjet unit on different printing medium moving paths. In this case, however, a plurality of rollers are disposed on the printing medium moving paths to move the printing medium, thereby causing a complicated printing medium moving configuration and raising production costs.

SUMMARY OF THE INVENTION

The present general inventive concept provides an image forming apparatus which simplifies a printing medium moving configuration and employs a plurality of image forming types.

The present general inventive concept also provides an image forming apparatus which reduces production costs and employs a plurality of image forming types.

The present general inventive concept also provides an image forming apparatus which improves accuracy in moving a printing medium and employs a plurality of image forming types.

The foregoing and/or other aspects of the present general inventive concept can be achieved by providing an image forming apparatus having a first image forming unit and a second image forming unit including a printing medium supplier which supplies a printing medium, a selection guide which may selectively guide the printing medium from the printing medium supplier to one of a first supplying path of the first image forming unit and a second supplying path of the second image forming unit, and a first feed roller which may be disposed between the selection guide and the printing medium supplier, and may transfer the printing medium from the printing medium supplier to the selection guide.

The first image forming unit and the second image forming unit are different image forming types.

The image forming apparatus may also include a second feed roller which moves the printing medium guided along the first supplying path to the first image forming unit.

A distance from the first feed roller to the second feed roller may be shorter than a length of a predetermined printing medium.

The image forming apparatus may also include a driver which drives the first feed roller and the second feed roller.

The image forming apparatus may also include a controller which controls the driver to drive the first feed roller while the second feed roller is in an idle state, to align the printing medium.

The image forming apparatus may also include a controller which controls the driver to set the first feed roller in an idle state after the second feed roller grips the printing medium.

The first image forming unit may include a printing head which has a nozzle to discharge an ink.

The second image forming unit may include an image receptor which forms a toner image thereon, and a transfer roller which grips the printing medium that is guided along the second supplying path having the image receptor and transfers the toner image to the printing medium.

A distance from the first feed roller to the image receptor or the transfer roller that grips the printing medium is shorter than a length of a predetermined printing medium.

The image forming apparatus may also include a driver which drives the image receptor, the transfer roller and the first feed roller; and a controller which controls the driver to set the first feed roller in an idle state if the printing medium is gripped by the image receptor and the transfer roller.

The printing medium supplier may include a plate which stores the printing medium, and a pickup roller which picks up the printing medium and transfers the printing medium to the first feed roller.

The image forming apparatus may also include a driver which drives the first feed roller and the pickup roller.

The image forming apparatus may also include a controller which controls the driver to set the pickup roller in an idle state if the driver drives the first feed roller.

The image forming apparatus may also include a controller which controls the driver to drive the pickup roller while the first feed roller is in an idle state, to align the printing medium.

The image forming apparatus may also include a controller which controls the selection guide to select one of the first and second supplying paths corresponding to a user's selection.

The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing an image forming apparatus having a selection guide to selectively guide a printing medium from a common path to a first supplying path of a first image forming unit and a second supplying path of a second image forming unit, and a first feed roller which may be disposed in the common path to feed the printing medium along the first supplying path for a first period of time and along the second supplying path for a second period of time.

The first supplying path may correspond to a first length and the second supplying path corresponds to a second length and the first length may be longer than the second length.

The first length may be the distance from the first feed roller to a second feed roller which may be disposed along the first supplying path.

The second length may be the distance from the first feed roller to a transfer roller which may be disposed on the second supplying path.

The selection guide unit may be a moveable guide unit having a common branch and a pair of sub-branches and as the guide unit moves in a first direction, the common branch may block the second supplying path to feed the printing medium toward the first supplying path. As the selection guide moves in a second direction, the common branch may block the first supplying path to feed the printing medium toward the second supplying path.

As a leading edge of the printing medium contacts the second feed roller disposed on the first supplying path, the first feed roller does not feed.

The foregoing and/or other utilities of the present general inventive concept may also be achieved by providing an image forming apparatus including a selection guide unit to selectively guide a printing medium in a first direction toward a first image forming apparatus formed on a first supplying path and toward a second image forming apparatus formed on a second supplying path, a first feed roller to feed the printing medium along the first supplying path and the second supplying path.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated inFIG. 1, an image forming apparatus100according to the present general inventive concept includes a printing medium supplier110, a first feed roller120, a first image forming unit130, a second image forming unit140and a selection guide150.

The printing medium supplier110includes a plate113which stores a printing medium P to be supplied to the first and second image forming units130and140, and a pickup roller115which picks up the printing medium P from the plate113.

The printing medium P is picked up by the pickup roller115and transferred to the first feed roller120.

The first feed roller120aligns the picked printing medium P and transfers the aligned printing medium P to the selection guide150by a controller180which will be described in further detail below.

As illustrated inFIGS. 1-2, the selection guide150includes a rotation shaft151, a branch member152which rotates with respect to the rotation shaft151and a branch member driver155to drive the branch member152.

The branch member152rotates to supply the printing medium P that is picked up by the pickup roller115to one of a first supplying path S1of the first image forming unit130or a second supplying path S2of the second image forming unit140. As illustrated inFIG. 1, the branch member152may have a Y-shape, including a common branch153and a pair of sub-branches152aand152b. The common branch153extends in a lower direction and the pair of sub-branches152aand152bextend in opposing directions with respect to each other and in a direction opposite to the common branch153. However, the present general inventive concept is not limited thereto. For instance, the branch member152may vary in shape and size as long as it performs the designated function of the selection guide150.

As illustrated inFIGS. 2-3, the branch member driver155includes an electric motor which rotates the branch member152clockwise and counterclockwise, depending upon the selected image forming apparatus. In particular, as the electric motor rotates the branch member152clockwise, the sub-branch152ais aligned with a portion of guide104and the common branch153moves in an opposite direction to contact the second supplying path S2to connect a common path Sc to the first supplying path S1and block the second supplying path S2from the common path Sc. As a result, the printing medium P is supplied from the common printing path Sc to the first supplying path S1to connect the common path Sc to the second supplying path S2and to block a connection between the common path Sc and to first supplying path S1. Alternatively, when the electric motor rotates the branch member152counter-clockwise, the sub-branch152bis aligned with a potion of guide105and the common branch153moves in an opposite direction to contact the first supplying path S1. As a result, the printing medium P is supplied from the common printing path Sc to the second supplying path S2. A solenoid may be provided when necessary to rotate the branch member152clockwise and counterclockwise. Additionally, the branch member152of the present general inventive concept is not limited thereto and may be driven by any other known methods.

The guides104include a pair of first guides which are spaced apart and form and form the first supplying path S1therein. Similarly, the guides105include a pair of second guides which are spaced apart and form the supplying path S2therein.

In particular, first supplying path S1includes the pair of guides104which connect from the branch member152to the first image forming unit130. The second supplying path S2includes the pair of guides105which connect from the branch member152to the second image forming unit140.

The first image forming unit130may be any one of a variety of an inkjet types. For example, the first image forming unit130may be a shuttle type which moves a printing head back and forth, transverse to a supply direction of the printing medium P. The printing head (not illustrated) of the image forming unit includes a plurality of nozzles (not illustrated) to discharge ink droplets and may be disposed in a carrier131which also moves back and forth, transverse to the supply direction of the printing medium P.

The first image forming unit130also includes a second feed roller132which moves the printing medium P toward the carrier131resting on a platen133which is disposed under the carrier131and supports the printing medium P as the printing medium P is printed with the discharged ink droplets. The second feed roller132may includes a pair of rollers that are rotated by a driving force which rotates one of the rollers to activate both rollers. The driving force can be produced by any suitable driving member known in the art.

The first image forming unit130may also include a page-width printing head type having a printing head with a length equivalent to a width of the printing medium P to print a line of image data at one time, in contrast to the shuttle type in which the printing head moves by the carrier131, back and forth across the width of the printing medium P.

As illustrated inFIG. 1, the second image forming unit140may be an electrophotographic type having a developing cartridge141, an exposing unit146, a registration roller R, a transfer roller147, and fusing units148and149.

The developing cartridge141stores a toner member to develop an image that is formed on an image receptor143. The developing cartridge141may accommodate the image receptor143, a charging roller142to charge a surface of the image receptor143with a predetermined electric potential, a developing roller144to develop the image receptor143with the toner, and a supplying roller145to supply the stored toner to the developing roller144.

The registration roller R aligns the printing medium P to be supplied to the image receptor143. If the first feed roller120is driven by a driving force and moves the printing medium P toward the registration roller R, the printing medium P touches the registration roller R in an idle state, and is then aligned.

The image receptor143may be a photosensitive drum. The image receptor functions such that an electrostatic latent image is formed on the surface of the image receptor143by the exposing unit146which exposes a light L according to a transmitted signal that corresponds to the image data to be printed. The exposing unit146exposes the light L when the aligned printing medium P starts moving toward the image receptor143by the registration roller R. Methods of driving the exposing unit146and the registration roller R are well known in the art, and thus the detailed description thereof will be omitted.

The electrostatic latent image is developed, with the toner, by the developing roller144and forms a toner image on the surface of the image receptor143.

The transfer roller147transfers the toner image to the printing medium P when it is disposed between the transfer roller147and the image receptor143. In particular, the transfer roller147is engaged with the image receptor143to form a transfer nip N, and the toner image is transferred from the transfer nip N to the printing medium P.

The toner image that is transferred to the printing medium P is fused to the printing medium P by heat and pressure from the fusing units148and149. The fusing units148and149include a heat roller148to generate heat, and a press roller149to press the printing medium P to the heat roller148.

The printing medium P passing through the fusing units148and149is discharged to the outside of the image forming apparatus by a discharging roller102.

As illustrated inFIG. 2, the image forming apparatus100according to the embodiment of, the present general inventive concept, as illustrated inFIG. 1includes a host interface170which transmits and receives image data from/to a host device (not illustrated), a control panel190, and a driver160.

The host interface170may include a parallel interface, a USB interface, or a network interface such as LAN to connect with the host device.

The control panel190includes an input key (not illustrated) to select either the first image forming unit130or the second image forming unit140, and a display unit (illustrated) to display items selected by the input key. When a user selects either the first or second image forming units130and140, the specific image forming type is automatically determined in the host device by image forming unit drivers installed in the host device. The image forming type is transmitted to the image forming apparatus100through the host interface170without the user having to directly input the image forming type.

The driver160may include a first image forming unit driver161, a second image forming unit driver163, a first feed roller driver165and a pickup roller driver167. The plurality of drivers161,163,165and167may be provided using a known power transmission member such as, a driving motor, one-way gear, swing gear and electronic clutch. The number of driving motors must be greater than 1 may be determined according to need. The driver160may also be one known to those skilled in the art, and thus a detailed description of the driver160will be omitted herein.

The first image forming unit driver161drives the first image forming unit130to form an image according to a specified inkjet type, as discussed above. The first image forming unit driver161also drives the carrier131and the second feed roller132of the first image forming unit130.

The second image forming unit driver163drives the second image forming unit140to form an image according to the specifications of the electrophotograhic type. The second image forming unit driver163also drives various rotation bodies142,143,144,145,147,148,149and R of the second image forming unit140.

The first feed roller driver165and the pickup roller driver167drive the first feed roller120and the pickup roller115, respectively.

The operation of the image forming apparatus100including the foregoing elements will now be described with reference toFIGS. 3 and 4below.

The controller180determines whether the host interface170has supplied image data that corresponds to a printing request. Also, the controller180determines which one of the first and second image forming units130and140is selected to print the supplied image data and accordingly determines the image forming type. In particular, the image forming type may be determined by analyzing either the supplied image data or the result input through the control panel190.

If it is determined that the first image forming unit130(i.e., the inkjet type) is selected to print the image data, the printing operation is performed by following printing processes associated with the selected inkjet type.

As illustrated inFIG. 3, after the first image forming unit130is selected, the controller180controls the selection guide150to guide the printing medium P in the printing medium supplier110toward the first supplying path S1. That is, the controller180controls the branch member driver155to rotate the branch member150clockwise (A), and opens the first supplying path S1but closes the second supplying path S2.

The controller180controls the driver160to pick up the printing medium P from the plate113by the pickup roller115and move it toward the first feed roller120. Then, the first feed roller120moves the picked printing medium P toward the selection guide150. When the printing medium reaches the first feed roller120and the first feed roller120is driven, the printing medium P is transferred solely by the first feed roller120by setting the pickup roller115in idle state. Such an operation moves the printing medium P precisely towards the desired supplying path.

The controller180controls the selection guide150so that the branch member152closes the second supplying path S2and opens the first supplying path S1. Thus, the printing medium P is supplied to the first image forming unit130along the first supplying path S1.

A grip distance C, which extends from the first feed roller120to the second feed roller132on the first supplying path S1, is shorter than a length of a predetermined printing medium P so that as a front end of the printing medium P transfers along the first supplying path S1it is almost instantly gripped by the second feed roller132.

Here, the predetermined printing medium P refers to the smallest standard printing medium which may be used in the image forming apparatus100. For example, if A4and B5are the standard sizes of the printing media that can be used in the image forming apparatus100, the smaller B5size (182 mm×257 mm) is the predetermined printing medium P. Assuming that the printing medium P is always supplied in a portrait direction, the first and second feed rollers120and132are disposed accordingly to set the grip distance C to be shorter than 257 mm (i.e., the length of the B5printing medium). Thus, an additional roller is not required between the first feed roller120and the second feed roller132to move the printing medium P.

The controller180controls the driver160to set the second feed roller132in an idle state for a predetermined time so that the printing medium P transferred by the first feed roller120is aligned. Then, the front end of the printing medium P that transfers along the first supplying path S1is aligned when the front end of the printing medium P touches the second feed roller132in the idle state.

After the printing medium P is aligned, the second feed roller132is driven to move the printing medium P to the carrier131. The controller180controls the driver160to set the first feed roller120in the idle state while the second feed roller132grips and moves the printing medium P. If both ends of the printing medium P are gripped by the first and second feed rollers120and132, the printing medium P may not be transferred along the supplying path S1precisely due to minute speed differences between the rollers120and132.

The carrier131moves transverse to the supplying direction (i.e., the vertical direction) of the printing medium and forms an ink image on the printing medium P that is transferred by the second feed roller132. Thus, the image is formed on the printing medium P by the designated inkjet type.

Meanwhile, if a user requests a printing operation by the second image forming unit140, i.e., by the electrophotographic type, the printing operation is performed by following printing processes according to the second image forming unit or electrophotographic type.

As illustrated inFIG. 4, the controller180controls the selection guide150to supply the printing medium P to the second image forming unit140according to a user's selection. That is, the controller180controls the branch member driver155to rotate the branch member152counterclockwise (B) and close the first supplying path S1but open the second supplying path S2.

A grip distance D, which extends from the first feed roller120to the image receptor143and transfer roller147on the second supplying path S2is shorter than a length of the predetermined printing medium P so that as a front end of the printing medium P transfers along the first supplying path S2it is almost instantly gripped by the image receptor143and transfer roller147.

The printing medium P is picked up by the pickup roller115and then transferred toward the selection guide150by the first feed roller120. The printing medium P is guided to the second supplying path S2by the selection guide150.

The printing medium P that is transferred along the second supplying path S2is aligned by the registration roller R which is in an idle state. After the printing medium P is aligned, the controller180drives the exposing unit146to expose a light L to the image receptor143, and simultaneously drives the registration roller R to transfer the printing medium P between the image receptor143and the transfer roller147.

The distance from the first feed roller120to the location where the image receptor143and the transfer roller147engaged with each other (i.e., to the transfer nip N), is shorter than the length of the predetermined printing medium P. The predetermined printing medium P is described above, and thus the description will not be repeated herein.

If the printing medium P is gripped between the image receptor143and the transfer roller147, the controller180controls the driver160to set the first feed roller120and the registration roller R in the idle state. The printing medium P is then transferred by the image receptor143and the transfer roller147since it is gripped by both the image receptor143and the transfer roller147. In this case, the minute vibrations applied to the printing medium P from the differences in rotation speed of the transfer roller147and image receptor143are minimal and will not negatively affect the precision by which the printing medium P is transferred along the supplying path S2. Thus the number of the rotation bodies which grip and drive the printing medium P is reduced, thereby moving the printing medium P more precisely and improving printing quality.

As the printing medium P passes between the image receptor143and the transfer roller147, the toner image formed on the image receptor143is transferred to the printing medium P. The transferred toner image is fused to the printing medium P by the fusing units148and149, thereby completing the printing operation according to the electrophotographic type. The printed printing medium P is then discharged to the outside by the discharging roller102.

As described above, the first image forming unit130and the second image forming unit140form an image according to the inkjet type and the electrophotographic type, respectively, and vice versa. The first and second image forming units130and140may alternatively form an image according to other known image forming types such as a thermoelectronic type.

According to another embodiment of the present general inventive concept, the first feed roller120may align a printing medium P instead of a registration roller R and a second feed roller132. In this case, the registration roller R may be removed.

More specifically, when a pickup roller115is driven to pick up the printing medium P stored in the plate113, the driver160is controlled to set the first feed roller120in an idle state. As a front end of the printing medium P touches the first feed roller120it is then aligned. The aligned printing medium P is transferred along the first supplying path S1or the second supplying path S2depending upon the rotation of the selection guide150with respect to the rotation of the first feed roller120. The first feed roller120aligns the printing medium P to be supplied to both the first image forming unit130and the second image forming unit140, thereby reducing the number of components.

The timing of transferring the printing medium P along the second supplying path S2by the first feed roller120to the second image forming unit140may be set taking into account the amount of time it takes to develop the image on the image receptor143of the second image forming unit140. Alternatively, if the image is printed by the first image forming unit130, the timing of transferring the printing medium P along the first supplying path S1may be also set taking into account the amount of time it takes to form the inkjet type image on the printing medium P.

Thus, an image forming apparatus according to the present general inventive concept has many benefits, among them including:

First, the image forming apparatus employs a common feed roller (i.e., the first feed roller) in front of a selection guide to transfer a printing medium to respective image forming units, thereby simplifying a printing medium moving configuration. Also, the number of components and production costs are reduced.

The controller180controls the feed roller120disposed in the common path Sc to feed the printing medium along the first path S1for a first period of time and along the second path S2for a second period of time. The first path S1extends along the grip distance C and thus the first period of time corresponds to the length of time that the printing medium P travels along the first path S1and grip distance C. Alternatively, the second path S2extends along the grip distance D and thus the second period of time corresponds to the length of time that the printing medium P travels along the second path S2and grip distance D. Thus, the first period of time is longer than the second period of time and the length C is longer than a length D.

When a leading edge of the printing medium P is fed by either the second feed roller132or the transfer roller147, the first feed roller120does not receive a rotating power from a motor but idles or stops feeding.

Second, a distance from a first feed roller to a second feed roller is shorter than a length of a printing medium, thereby eliminating a need for an additional roller to transfer the printing medium. Thus, a printing medium transferring configuration is simplified and the number of components is reduced.

Third, a first feed roller is set into an idle state since a printing medium is gripped by a second feed roller or a transfer nip, thereby transferring the printing medium more precisely. Also, the quality of an image formed on a printing medium is improved.