JP3121420B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, the present invention relates to an image forming apparatus having a function of forming an image on both sides of a sheet.

[0002]

2. Description of the Related Art An image forming apparatus includes, for example, a copier or an LB (LB) which forms an image on a plain paper by an electrostatic latent image technique by forming an image on a photoreceptor by enlarging or enlarging or reducing an original by a lens. Laser printers, LED (light emitting diode) printers, optical printers such as LCDA (liquid crystal array) printers, printers such as ink jet printers, digital copiers incorporating these printers to form images, and high-performance facsimile machines. is there.

Some of such image forming apparatuses have a double-sided printing function for forming an image on both sides of a sheet in addition to a single-sided printing function for forming an image on one side of a sheet. It is also widely used because it is effective in solving the increasing number of storage locations of documents together with the purpose of the above.

For example, as shown in Japanese Patent Application Laid-Open No. 61-295942, in the case of single-sided printing, paper fed from a paper feed cassette is mainly used for an image forming engine (hereinafter simply referred to as "engine"). After an image is formed by passing through a set, the sheet is discharged to a sheet discharge tray located downstream thereof. In the case of double-sided printing, a loop section for returning the paper to the paper supply side and a reversing section for reversing the paper transport direction are provided to reverse the paper and re-feed it to the main engine. After the image was formed, the sheet was returned to the paper supply side by the loop portion, the conveyance direction was reversed by the reverse feeding portion, and the sheet was re-fed to the main engine portion.

Generally, the loop portion and the reverse feeding portion are provided in advance in the main body of the image forming apparatus as shown in the above-mentioned publication as a double-sided printing feeding device, or can be combined with the main body of the image forming device as an option. It was something. Therefore, a method has been adopted in which this double-sided printing feeding device is controlled by the engine control unit.

[0006]

However, the loop portion can be accommodated in the length of the paper feeding path of the apparatus main body and the thickness can be made relatively thin, but the reverse feeding portion can feed the maximum length of paper to be used. Since the length of the double-sided printing feeder is large enough to accommodate the print once, the total system has been increased in size and cost.

Further, since the double-sided printing feeder is controlled by the engine controller, an I / O port for connecting signal lines and control lines of sensors, motors, clutches and the like in the double-sided printing feeder to the engine controller. Need to be added, which may exceed the control capability of the engine control unit.
Therefore, compared with the CPU of the engine control unit of the image forming apparatus without the double-sided printing function, the use of the gradated CPU causes an increase in cost.

A CPU independent of the CPU of the engine control unit
To control the duplex printing feeding device,
U also has a low cost, and the cost of the two CPUs is lower than that of a graduated CPU. Instead, complex communications had to be exchanged between the two CPUs in order to work reliably.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide an image forming apparatus having a double-sided printing function in which the apparatus main body is small in size and low in cost, and operates reliably with simple internal communication. I do.

[0010]

According to the present invention, in order to achieve the above object, a paper feed cassette and a duplex apparatus can be selectively mounted on a common paper feed unit of an image forming apparatus main body. An image is formed on one side of the sheet fed from the paper supply cassette when the sheet is loaded, and an image is formed on one side of the sheet fed from the double-sided apparatus when the duplexer is mounted. An image forming apparatus for forming an image on the other surface by re-feeding the sheet after returning to

According to a first aspect of the present invention, an image forming apparatus main body includes an engine control section for controlling an engine, and a duplex control section for communicating with the engine control section to control a duplex apparatus. An identification means for identifying whether or not the paper cassette or the duplex apparatus is mounted and which one is mounted, and when the identification means recognizes that the paper cassette is mounted, the communication with the duplex control unit is stopped; And one-side control means for controlling the formation of an image on one side of the sheet.

The engine control unit communicates with the duplex control unit when the identification unit recognizes that the duplex device is mounted, and controls the formation of images on both sides of the sheet if a response is received from the duplex control unit. and has a two-sided control means for performing.

Further, the engine control unit, one side when none of the paper feed cassettes and the double-sided device recognizes that it is not attached, corresponding respectively to the paper feed cassette or duplex device was last mounted by the identification means the control means or both control means are have a control standby unit to keep it on standby.

According to a second aspect of the present invention, an image forming apparatus main body includes an engine control section for controlling an engine, and a duplex control section for controlling the duplex apparatus by communicating with the engine control section. Identification means for identifying whether or not a paper cassette or a duplex device is mounted and which is mounted,
Means for unilaterally interrupting communication with the engine control unit when the identification means recognizes that the sheet cassette has been mounted, and the engine control unit includes a single-sided sheet of paper when communication with the duplex control unit is not possible. And a one-side control means for controlling the formation of an image.

The above-mentioned double-sided control unit feeds paper by an identification unit.
Check that neither the cassette nor the duplexer is installed.
When the printer recognizes that the paper cassette
Communication with the engine control unit according to the
Communication state holding means for holding the state where communication has been stopped or started
It has.

Further , the both-side control unit uses the identification means to control both sides.
Engine control when it recognizes that the surface device has been mounted
Means for starting communication with the unit, wherein the engine control unit comprises:
When communication is possible with the duplex controller, images are printed on both sides of the paper.
It is preferable to have double-sided control means for performing the control performed .

[0017]

The image forming apparatus according to the first aspect of the present invention includes an engine control unit and a double-sided control unit. Since the engine control unit has an identification unit and a single-sided control unit, the identification unit is provided with a sheet cassette. When recognizing the fact, the engine control unit stops communication with the duplex control unit, and the simplex control unit forms an image on one side of the sheet.

Further, since the engine control unit has a duplex control unit , when the identification unit recognizes that the duplex device is mounted, the engine control unit communicates with the duplex control unit and performs the duplex control unit. control of two-sided control means if there is a response from the
An image is formed on both sides of the sheet by control .

Furthermore, since the engine control unit has a control standby unit, the identification means recognizes that none of the paper feed cassette and double-side unit is not mounted, the control waits means are finally mounted The single-side control unit or the double-side control unit corresponding to the paper feed cassette or the double-sided device, respectively, is kept on standby . Therefore , it does not become unstable.

An image forming apparatus according to a second aspect of the present invention includes an engine control unit and a double-sided control unit. The engine control unit includes a single-sided control unit, and the double-sided control unit includes an identification unit and a unit for temporarily stopping communication. Therefore, when the identification unit recognizes that the sheet cassette has been mounted, the unit for unilaterally suspending the communication unilaterally suspends the communication with the engine control unit. Since communication with the two-sided control unit is disabled, the one-sided control unit forms an image on one side of the sheet.

The double-sided control unit has communication state holding means.
Therefore, if the identification means is either a paper cassette or a duplex
Communication status is maintained when it recognizes that
The means is the last installed paper cassette or double-sided device
In accordance with each, stop communication with the engine control unit or
The starting state is kept as it is. Therefore,
There is no stable state.

Further, a means of two-sided control unit starts communication
If so, the identification means indicates that the duplexer has been mounted.
When recognized, the means for starting communication is
Since communication starts, the engine control unit
Performs communication and performs duplex control if there is a response from the duplex control unit
The means forms images on both sides of the paper.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an LB according to an embodiment of the present invention.
FIG. 2 is a perspective view showing the appearance of a (laser beam) printer;
FIG. 2 is a schematic configuration diagram showing an example of the configuration.

The LB printer 1 as the image forming apparatus shown in FIGS. 1 and 2 has a printer main body 2 and a printer main body 2.
And a double-sided cassette 5 which is a double-sided device provided with a sheet feeding section which can be selectively attached to the sheet feeding port 3 which is a common sheet feeding section.

Inside the printer body 2, a double-sided control board 6, which is a double-sided control unit for controlling the double-sided cassette 5 when the double-sided cassette 5 is mounted in the paper feed port 3, is detachably provided. A controller 7 for controlling communication, image processing, and overall control of the LB printer 1 and an engine control board 8 as an engine control unit for controlling an engine unit are provided fixedly.

The double-sided control board 6 is mounted on the printer body 2 in advance and shipped together with the double-sided cassette 5 to a user who wants a double-sided printing function. The LB printer 1 is shipped cheaper to the user who only needs the single-sided printing function without mounting it. However, if desired, the serviceman only needs to install the double-sided control board 6 and purchase the double-sided cassette 5 later. A double-sided printing function can be easily added.

Paper is supplied to the printer body 2 by installing a paper feed cassette 4 in the paper feed port 3 for single-sided printing and a double-sided cassette 5 for double-sided printing. The cassette mounting section is provided with a cassette sensor 9 as identification means in advance, and the cassette sensor 9 identifies which of the sheet feeding cassette 4 and the double-sided cassette 5 is mounted or none of them.

As the other paper feeding means, a manual tray 11 for feeding paper one by one and a multi-tray 12 for setting a required number of sheets in a desired number at a time in the printer body 2 are provided. Is provided. The sheet fed from any one of the sheet feed cassette 4, the double-sided cassette 5, the manual feed tray 11, and the multi-tray 12 stops once after its leading end contacts the registration roller 13.

Image data input from a host machine (not shown) is converted into bitmap data by image processing of the controller 7 and stored, and then output to the optical writing unit 14 as a video signal. Optical writing unit 14
Deflects laser light modulated according to the video signal,
An electrostatic latent image is formed by forming and scanning a spot on the photoreceptor belt 15 moving clockwise, and the developing unit 16 develops the electrostatic latent image and converts it into a visible toner image.

The toner image is transferred to a sheet conveyed in a timely manner by a registration roller 13, and the transferred sheet is fixed by a fixing unit 17, and then is set in a predetermined one of the discharge trays 18 and 19. Discharged to one of the trays. In the case of double-sided printing in which the double-sided cassette 5 is mounted, if the first side has been printed, the loop unit 2
0, and after the second-side printing, the output trays 18 and 19
Is discharged to any of the The sheet sent to the loop unit 20 is returned to the upper side of the double-sided cassette 5 by the loop unit 20 with the printing surface (first surface) facing down.

As shown in FIG. 1, the double-sided cassette 5 is composed of two upper and lower tiers, and the lower tier contains sheets 22a before printing similarly to the paper feed cassette 4, and the sheets 22a are printed at the time of printing on the first side.
Are fed one by one. The upper section constitutes a reverse feed unit that stores a predetermined number of sheets 22b returned from the loop unit 20 and then re-feeds the sheets 22b one by one to the printer main body 2 at the time of printing on the second side.

Therefore, in the upper stage, when the paper 22b is returned, the paper 22b idles, and when the paper is re-fed, the reverse feed roller 23 reversely feeds the paper 22b, and a motor, a clutch, and a solenoid (not shown) for driving the reverse feed roller 23, respectively. And the like, and the components constituting the reverse feed mechanism are sequence-controlled by the double-sided control board 6, respectively.

Therefore, there is no need to upgrade the engine control board 8 because an excessive load is not applied to the engine control board 8, and an LB printer having only a one-sided printing function can be provided at a low price. In addition, since the sheet sent from the loop unit 20 needs to be stored once, a reverse feeding unit longer than the maximum length of the sheet to be used is provided in the double-sided cassette 5.
The printer body 2 can be reduced in size. Like the paper feed cassette 4, the double-sided cassette 5 originally has a length for accommodating the paper, so that even if the reverse feeding section is provided, the length is not increased.

FIG. 3 is a block diagram showing the configuration of the first embodiment of the printing function control system of the LB printer 1, and FIG. 4 is a flowchart showing an example of the routine. The first embodiment shown in FIG. 3 has a double-sided CPU 30 and a ROM as a storage unit thereof.
A double-sided control board 6A composed of a RAM 31;
The engine CPU 32 includes an engine control board 8A in which the cassette sensor 9 is connected to the engine CPU 32. The two-sided CPU 30 and the engine CPU 32 have serial ports connected to each other to perform communication and control a printing function.

The engine CPU 32 is connected to the controller 7 (a CPU (not shown)) to perform communication.
PU 30 is a cassette mounted in the paper feed port 3, in this case, a paper sensor 35 for detecting the presence or absence of paper in the double-sided cassette 5.
And, it is connected to the reverse feed mechanism 36 to control the double-sided cassette 5.

When the sheet cassette 4 is mounted instead of the double-sided cassette 5, only the sheet sensor is connected to the double-sided CPU 30. When neither cassette is mounted, the CPU is disconnected from the double-sided CPU 30. However, whether the paper feed cassette 4 or the double-sided cassette 5 is not mounted is identified by the cassette sensor 9, and
The signal is output to engine CPU32.

The printing function control routine according to the first embodiment will be described below with reference to FIG. When the routine starts, the engine CPU 32 determines in step 1 whether or not the sheet cassette 4 is mounted based on a signal from the cassette sensor 9. If the sheet cassette 4 is mounted, the process proceeds to step 4. For example, the process proceeds to step 2 to determine whether or not the double-sided cassette 5 is mounted.
If the is mounted, the process proceeds to step 6, and if not, the process proceeds to step 3.

In step 3, neither the sheet cassette 4 nor the double-sided cassette 5 is mounted, and it is determined whether the last set cassette is the sheet-supply cassette 4 or the double-sided cassette 5. If it is 4, the process proceeds to step 4, and if it is a double-sided cassette 5, the process proceeds to step 6.

In step 4, since the paper feed cassette 4 is mounted or has been mounted, the same as the state where the double-sided control board 6A is not mounted, that is, it is determined that double-sided printing is impossible, The port with the board 6A is closed to stop the serial communication, and in step 5, the engine CPU 32 serving as the one-sided control means stands by for a control routine for one-sided printing (one-sided printing routine) and returns.

In step 6, since the double-sided cassette 5 is mounted or has been mounted, it is determined that the double-sided control board 6A is mounted, that is, double-sided printing is possible, and the port with the double-sided control board 6A is opened. Then, the process proceeds to step 7 to determine whether or not there is a response from the duplex control board 6A. If there is a response, the engine CPU 32 which is also the duplex control means in step 8 executes a control routine for duplex printing (duplex printing). Routine) and returns. If there is no response from the double-sided control board 6A in step 7, the process jumps to step 9 to display the occurrence of a communication error and returns.

The engine CPU 32 detects the type (cassette information) of the mounted cassette and the presence or absence of the mounted cassette by the cassette sensor 9, but the other CPUs also know the cassette information in order to perform smooth and reliable control. There is a need. Therefore, the engine CPU 32 notifies the controller 7 and the host machine (not shown) of the cassette information via the controller 7. The double-sided CPU 30 can know the type of the cassette by detecting the opening and closing of the port of the engine CPU 32 without particularly receiving the cassette information.

Since the engine CPU 32 stores the type of the mounted cassette in the RAM of the ROM / RAM 33, when no cassette is mounted in the flow shown in FIG. Is performed according to the cassette information stored in the. If the stored information does not match the type of the installed cassette, the contents of the RAM are immediately changed.

Therefore, the engine CPU 32, which is also a control standby means, has a ROM
The cassette information stored in the RAM of the RAM 33, that is, the single-sided or double-sided printing routine corresponding to the cassette installed last is kept on standby.

A change in the contents of the RAM occurs when the sheet cassette 4 and the double-sided cassette 5 are exchanged, and there is always a state in which the cassette is not mounted. If the signal of the cassette sensor 9 matches the stored information when the cassette is remounted, this is due to the replenishment of the paper due to the running out of paper or the jam paper removal processing when a paper jam occurs. Since the frequency is more frequent, storing the type of the cassette installed last saves unnecessary processing such as preparation of a routine each time.

Although not appearing in the flow shown in FIG. 4, the engine CPU 32 does not always close the port for the double-sided CPU 30 while the sheet cassette 4 is mounted, and starts, for example, printing one sheet. For example, in the case of inquiring the paper sensor 35 about the presence or absence of a paper before performing the operation, the port is opened and necessary information is received.

FIG. 5 is a block diagram showing the configuration of a second embodiment of the printing function control system of the LB printer 1, and FIG. 6 is a flowchart showing an example of the routine. The second embodiment shown in FIG. 5 also has a double-sided control board 6B and an engine control board 8
B is different from the first embodiment shown in FIG.
Instead, it is connected to the double-sided CPU 30, and the other parts do not change.

The double-sided CPU 30 of the double-sided control board 6B
When the type (cassette information) of the mounted cassette and the presence or absence of the mounted cassette are detected by the cassette sensor 9, the cassette not mounted or the cassette information is already stored in the RAM of the ROM / RAM 31.
If the information matches the information stored in the RAM, the content of the RAM is changed if it is different.

When the double-sided cassette 5 is mounted, the double-sided CPU 30, which is means for starting communication, opens a port connected to the engine CPU 32 to perform communication. When there is, the double-sided CPU 30, which is also a means for unilaterally stopping the communication, closes the port and unilaterally stops the communication with the engine CPU 32.

Further, a double-sided C which is also a communication state holding means
If the cassette is not mounted, the PU 30 holds the cassette information stored in the RAM, that is, the state in which the communication is stopped or started in accordance with the last mounted cassette.

The engine CPU 32 knows the type of the installed cassette by opening and closing the port of the double-sided CPU 30, that is, whether or not there is a response, and notifies the controller 7 and a host machine (not shown) of the cassette information. Double-sided CPU
Reference numeral 30 indicates that the port is not always closed while the paper feed cassette 4 is mounted, and the port
For example, when the printer 5 detects out of paper, it opens a port, interrupts the engine CPU 32, and sends out paper.

A routine for controlling the printing function according to the second embodiment will be described with reference to FIG. When the routine starts, the engine CPU 32 determines in step 11 that the double-sided CPU 3
The request signal is transmitted to 0, and the presence or absence of the response is determined in step 12. If there is a response from the double-sided CPU 30,
If the double-sided control board 6B is mounted and the double-sided cassette 5 is mounted or has been mounted, that is, it is determined that the double-sided printing has been performed. I do.

If there is no response from the double-sided CPU 30, it is determined whether the double-sided control board 6B is not mounted, or it is in the mounted state, but the paper feed cassette 4 is mounted or mounted, that is, it is determined that the single-sided printing is performed. , Step 14
The engine CPU 32, which is also a one-sided control means, stands by for a one-sided printing routine and returns.

In the first and second embodiments described above, the engine CPU 32 communicates with the double-sided CPU 30 to put a double-sided or single-sided printing routine on standby depending on whether or not there is a response.
This is because both are detachable. By doing so, it is possible to provide the LB printer 1 without the duplex control board 6 at a lower cost to a user who does not need the duplex printing function.

For a user who needs a double-sided printing function, the LB printer 1 having the double-sided control board 6 mounted from the beginning.
, And for a user who wants a double-sided printing function later, a simple service of simply adding a double-sided control board is sufficient. In either case, the engine CPU 3
There is no need to change the second program.

In the image forming apparatus according to the present invention, since the double-sided cassette 5 is provided with the reverse feeding portion which needs to have a length sufficient to store the paper after the first-side printing, the size of the apparatus main body can be reduced. I can do it. The double-sided cassette 5 originally has a length for storing the sheet similarly to the sheet feeding cassette, and therefore does not become long due to the provision of the reverse feeding portion.

Therefore, by preparing a double-sided cassette for large-size paper, for example, B4 size or larger, and a medium-size, double-sided cassette for A4 size or smaller, the entire system can be downsized in the case of medium-size paper. Therefore, it can be installed in a place where there is no space, and in the case of large format paper, it is sufficient if there is a margin by the difference between cassettes.

[0057]

As described above, according to the present invention, it is possible to provide an image forming apparatus having a double-sided printing function, which is small in size and low in cost, and which operates reliably with simple internal communication.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of an LB printer according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an example of a configuration of the LB printer illustrated in FIG.

FIG. 3 is a block diagram illustrating a configuration of a first embodiment of a print function control system of the LB printer.

FIG. 4 is a flowchart showing an example of a routine of the first embodiment shown in FIG. 3;

FIG. 5 is a block diagram illustrating a configuration of a second embodiment of a print function control system of the LB printer.

FIG. 6 is a flowchart showing an example of a routine of the second embodiment shown in FIG. 5;

[Explanation of symbols]

Reference Signs List 1 LB printer (laser beam printer: image forming apparatus) 2 Printer body 3 Paper feed port (common paper feed unit) 4 Paper feed cassette 5 Double-sided cassette (double-sided device) 6, 6A, 6B Double-sided control board (double-sided control unit) 8, 8A, 8B Engine control board (engine control unit) 9 Cassette sensor (identification means) 22a, 22b
Paper 23 reverse feed roller 30 double-sided CPU (means for unilaterally stopping communication, means for starting communication, communication state holding means) 32 engine CPU (one-sided control means, two-sided control means,
Control standby means)

Claims (3)

(57) [Claims] 1. A sheet feeding cassette and a double-sided device can be selectively mounted on a common sheet feeding section of an image forming apparatus main body, and sheets fed from the sheet feeding cassette when the sheet feeding cassette is mounted. An image is formed on one side of the sheet, and when the double-sided apparatus is mounted, an image is formed on one side of the sheet fed from the double-sided apparatus, and after returning to the double-sided apparatus, the sheet is fed again. An image forming apparatus for forming an image on the other surface, wherein an engine control unit for controlling an image forming engine is provided in the image forming apparatus main body, and the double-sided device is controlled by communicating with the engine control unit. The engine control unit includes an identification unit that identifies whether or not the sheet cassette or the duplex device is attached and which one is attached, and the sheet cassette is attached by the identification unit. Recognize that The stops communication with the two-sided control section, a single-sided control means for performing control to form an image on one side of the paper, the two-sided apparatus of attachment by said identifying means when the
Communication with the duplex control unit when the
If there is a response from the duplex control unit, images are printed on both sides of the paper.
Double-sided control means for controlling the formation of an image;
Depending on the stage, both the paper cassette and the duplexer
When it recognizes that it is not
According to the paper cassette or duplexer
The single-sided control means or the double-sided control means
An image forming apparatus , comprising: a control standby unit for causing the control unit to wait . 2. A paper feed cassette and a duplex apparatus can be selectively mounted on a common paper feed section of an image forming apparatus main body. When the paper feed cassette is mounted, paper fed from the paper feed cassette is provided. An image is formed on one side of the sheet, and when the double-sided apparatus is mounted, an image is formed on one side of the sheet fed from the double-sided apparatus, and after returning to the double-sided apparatus, the sheet is re-fed. An image forming apparatus for forming an image on the other side, wherein an engine control unit for controlling an image forming engine is provided in the image forming apparatus main body, and the double-sided apparatus is controlled by communicating with the engine control unit. A double-sided control unit, wherein the double-sided control unit is provided with an identification unit for identifying whether or not the paper feed cassette or the double-sided device is mounted and which one is mounted, and the paper feed cassette is mounted by the identification unit. Realizing that Sometimes means for unilaterally abort the communication with the engine control unit, the sheet feeding by said identification means
Check that neither the cassette nor the duplexer is installed.
When the printer recognizes that
Engine control according to the set or double-sided device respectively
Communication status that maintains the status where communication with the unit was stopped or started
An image forming apparatus comprising: a holding unit; and the engine control unit includes a one-side control unit that controls to form an image on one side of a sheet when communication with the two-side control unit is not possible. 3. The image forming apparatus according to claim 2 , wherein the double-sided control unit has a unit that starts communication with the engine control unit when the identification unit recognizes that the double-sided device is mounted. The image forming apparatus further includes a double-side control unit that performs control to form an image on both sides of a sheet when the engine control unit can communicate with the double-side control unit.