JP2000172032A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a printer of a transportation system by a transporting belt for improving overlap printing accuracy. SOLUTION: The transporting belt 5 for transporting a printing medium 8 in a prescribed transporting direction is provided with a magnetic section along the transporting direction. A recording head 16 magnetically record the prescribed information to the magnetic section in a first printing section 100a which first executes printing to the printing medium 8. A read head 27 reads the information magnetically recorded in the magnetic section and a control section 20 controls an exposure section 22 and a transfer roller 23 based on this information, by which the printing timing at the time of printing to the printing medium 8 is regulated. The printing in a second printing section 100b may, therefore, be executed under the same condition as for the condition of the printing in the first printing section 100a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem-type printing apparatus in which a plurality of printing units are connected in series.

[0002]

2. Description of the Related Art Generally, in an electrophotographic color printing apparatus, a printing unit is provided for each of a plurality of color components, and a printing medium such as a printing paper is sequentially conveyed to the plurality of printing units to perform each printing. This is realized in such a manner that the toner of a predetermined color component is transferred to the print medium by the unit. A printing apparatus in which a plurality of printing units of the same type are connected and arranged in series as described above is generally called a tandem-type printing apparatus.

Since the printing scale of an electrophotographic color printing apparatus is relatively small, a high-precision printing apparatus, such as an offset printing method, which is realized by employing a plurality of metal drums and rollers, is used. There is a situation in which a suitable printing medium transport method cannot be adopted due to the size of the apparatus and cost.

For this reason, a conventional electrophotographic color printing apparatus generally employs a transport system using a transport belt which can be constructed relatively inexpensively and relatively inexpensively. That is, a transport belt is installed between a plurality of printing units connected and arranged, and by driving the transport belt in a state where the print medium is set on the transport belt, the print medium is sequentially transported to each printing unit. Was realized.

[0005]

However, while the transport system using the transport belt has been adopted as a result of sacrificing the transport accuracy from the viewpoint of the apparatus size and cost, the transport accuracy may pose a problem. Many. That is,
Since the transport belt does not have the rigidity of a metal drum, misregistration occurs at the print execution position of each printing unit, resulting in misalignment when performing toner transfer for each color component. There was a problem that the printing accuracy deteriorated.

For this reason, when a transport system using a transport belt is employed in an electrophotographic color printing apparatus, a register mark is printed at a predetermined position on a print medium when printing the first color (toner transfer). When printing the second and subsequent colors, attempts have been made to eliminate the positional deviation by optically reading the register mark and moving the position of the register mark to a predetermined position.

However, even in this case, since the register mark is optically read, the detection accuracy is reduced when the register mark is blurred or the like, so that it is difficult to completely eliminate the positional deviation. Met.
Further, since the reading of the register mark needs to be performed on the upstream side of the print execution position in each printing unit, it occurs between the time when the print medium is conveyed to the print execution position after the position of the register mark is read. There was also a problem that the positional deviation could not be eliminated.

Furthermore, conventionally, it has not been possible to correct the positional deviation occurring in the width direction of the conveyor belt.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a printing apparatus of a transport system using a transport belt which has a simple structure and which accurately improves overprinting accuracy. .

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a print medium is transported in a predetermined transport direction by a transport belt, and the printing medium is printed in a plurality of printing units. A printing device that sequentially performs printing on a medium, comprising: a magnetic unit provided on the transport belt along the transport direction; and a head that first prints on the print medium among the plurality of print units. A printing unit for magnetically recording predetermined information on the magnetic unit; and a subsequent printing unit for performing printing on the print medium after the second of the plurality of printing units. Reading means for reading the read information, and control means for controlling printing timing in the subsequent printing section based on the information read by the reading means.

According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the positional relationship between the printing execution position in the subsequent printing unit and the reading unit is determined by comparing the printing execution position in the first printing unit with the printing execution position. The control unit is controlled to start printing in the subsequent printing unit when the reading unit reads the print start information included in the information. It is characterized by doing.

According to a third aspect of the present invention, in the printing apparatus according to the first aspect, the reading unit is provided on an upstream side in the transport direction with respect to a predetermined print execution position in the subsequent printing unit. The control means calculates, based on the information read by the reading means, a difference between a transport speed when the print medium is printed in the leading print portion and a transport speed in the subsequent print portion by calculation. The printing timing in the subsequent printing unit is adjusted.

According to a fourth aspect of the present invention, in the printing apparatus according to the first aspect, a width of the transport belt is set to be larger than a printing width of the plurality of printing units.
The magnetic unit is provided at a portion of the transport belt that is larger than the printing width, and the recording unit and the reading unit are provided at print execution positions in respective printing units. .

According to a fifth aspect of the present invention, in the printing apparatus according to any one of the first to fourth aspects, the printing apparatus further includes a transport belt correcting means for applying a displacement in the width direction to the transport belt. A plurality of the reading units are arranged side by side in the width direction of the conveyor belt, and the control unit drives the conveyor belt correction unit based on a plurality of signal levels obtained by the plurality of reading units reading the information. By doing so, the transport belt is displaced in the width direction.

According to a sixth aspect of the present invention, in the printing apparatus according to any one of the first to fifth aspects, a plurality of the transport belts are connected, and the print medium is connected at a connecting portion of the plurality of transport belts. The information is recorded on the magnetic portion of the one conveyor belt at the connecting portion and is transferred to the magnetic portion of the other conveyor belt. And a magnetic transfer unit for performing the transfer.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, a magnetic section is provided along a conveying direction on a conveying belt for conveying a print medium in a predetermined conveying direction, and predetermined information is magnetically recorded on the magnetic section. By doing so, it is configured to correct positional deviation in a plurality of printing units.

Hereinafter, some embodiments will be described with reference to the drawings. To simplify the description, an example in which two printing units are provided in the printing apparatus will be described first.

<First Embodiment> First, a first embodiment will be described. The configuration described here is also a basic configuration in each of the following embodiments.

FIG. 1 is a schematic diagram showing the configuration of a printing apparatus 100 according to the first embodiment. The printing device 100
First printing unit 1 that prints the first color on print medium 8
00a and a second printing unit 100b for printing the second color. Here, the first printing unit 100a is the printing medium 8
Is a first printing unit that performs printing first, and the second printing unit 100b is a subsequent printing unit that performs printing on the printing medium 8 after the second printing unit 100b.

First printing unit 100a and second printing unit 100b
A transport belt 5 supported by rollers 2 and 3 is provided between the two. The transport belt 5 rotates in a certain direction by driving the rollers 2 and 3 by a driving unit (not shown).

The print medium 8 is attracted and held on the upper surface side of the transport belt 5, and the transport belt 5 is rotated in a certain direction, whereby the first print unit 1 is rotated in the X direction.
00a to the second printing unit 100b.

The first printing section 100a is provided with a cylindrical photosensitive drum 11 which rotates at a predetermined speed in a predetermined direction so as to transfer toner to the printing medium 8 by an electrophotographic method. Around the photosensitive drum 11, a charging unit (not shown), a developing unit, a charge removing unit, a cleaning unit, and an exposure unit 12 that forms a latent image based on an image to be printed on the surface of the photosensitive drum 11 are provided. Is provided. A transfer roller 13 is provided below the photosensitive drum 11 with the conveyance belt 5 interposed therebetween.
The transfer roller 13 applies electrostatic force to the toner particles of the first color attached to the surface of the photoconductor drum 11 so that the transfer belt 5 is moved from the surface side of the photoconductor drum 11. The toner transfer is performed on the print medium 8 that is attracted and conveyed to the upper surface side. The position where the toner transfer is performed is determined by the first printing unit 10.
This is referred to as a print execution position at 0a.

The second printing unit 100b has the same configuration. A photosensitive drum 21 is provided to transfer the toner to the print medium 8 by an electrophotographic method, and the second color toner adheres to the latent image formed on the surface of the photosensitive drum 21 by the exposure unit 22. Then, the toner is transferred by the transfer roller 23 to the print medium 8 transported by the transport belt 5. The second printing unit 1
Also in 00b, the position where the toner transfer is performed is referred to as a print execution position.

FIG. 2 is a view showing the transport belt 5 for transporting the print medium 8. As shown in FIG.
Are rotated by driving means (not shown), so that the upper side of the conveyor belt 5 moves in the X direction, and the lower side moves in the −X direction. Therefore, when the print medium 8 is arranged on the upper surface side of the transport belt 5, the transport operation of the transport belt 5 causes the print medium 8 to be transported in the X direction.

The transfer roller 13 in the first printing unit 100a is configured to be able to adjust the local transport speed of the transport belt 5 at the printing position by the drive motor 13a. The transfer roller 23 is also configured to be able to adjust the local transport speed of the transport belt 5 at the print execution position by the drive motor 23a. That is, since the transport belt 5 is generally formed of a member having a lower rigidity than metal or the like, the transport belt 5 may generate undulations or the like. Even if it rotates at a speed, the transport speed of the transport belt 5 may not be constant when viewed locally. For this reason, drive motors 13a and 23a for the transfer rollers 13 and 23 are provided to adjust the transport speed at the print execution position in each of the printing units 100a and 100b.

As shown by hatching in FIG. 2, a magnetic portion 6 is provided on at least a portion of the back surface (inner surface) of the conveyor belt 5 in the width direction (Y direction) over substantially the entire circumference of the conveyor belt 5. Is provided. The magnetic part 6 may be formed by applying a magnetic paint, for example. As the magnetic section 6, predetermined information can be magnetically recorded by a recording head 16 described later, and information magnetically recorded can be read by a reading head 27 described later. A member capable of erasing information magnetically recorded by the method is used. In general, the printing medium 8 is not set for conveyance at the joint portion of the conveyance belt 5, so that
It is not necessary to provide the magnetic part 6 in that part.

Returning to FIG. 1, in the first printing unit 100a, the position corresponding to the position where the magnetic unit 6 of the conveyor belt 5 is provided, and the downstream side in the conveyance direction from the printing execution position by the transfer roller 13 ( (The X direction side), a recording bed 16 for magnetically recording predetermined information on the magnetic unit 6, and a position corresponding to the position where the magnetic unit 6 is similarly provided and a printing execution position by the transfer roller 13. An erasing head 14 for erasing magnetic information recorded on the magnetic unit 6 is provided at a position upstream (−X direction side) of the transport direction.

Therefore, in the first printing section 100a, when the transport belt 5 is driven to move in the X direction,
After the information written in the magnetic part 6 is erased by the erasing head 14, the recording head 16
The predetermined information is written in.

The first printing unit 100a includes a control unit 1
0 and a detection sensor 15 are provided. Detection sensor 1
Reference numeral 5 denotes a sensor for detecting that the print medium 8 has been conveyed to a predetermined position of the first printing unit 100a, and its output is sent to the control unit 10. On the other hand, the control unit 30 controls the exposure unit 12 to start the latent image on the photosensitive drum 11 at a predetermined timing based on the detection result of the detection sensor 15.
And the recording head 16 is driven to write predetermined print start information to the magnetic unit 6. Further, the control unit 10 drives the recording head 16 to write information indicating the transport speed of the print medium 8 to the magnetic unit 6 at least during a printing operation on the print medium 8.

On the other hand, in the second printing section 100b, the reading head 27 is set so that the recording head 16 in the first printing section 100a has the same positional relationship as the relationship established with the print execution position of the first printing section 100a. Is provided. That is, the positional relationship between the print execution position and the reading head 27 in the second printing unit 100b and the positional relationship between the print execution position and the recording head 16 in the first printing unit 100a are the same.

In the example of FIG. 1, the first printing unit 1
00a, the recording head 16 is located downstream (+ X direction side) in the transport direction from the print execution position.
In the second printing unit 100b as well, the read head 27 is disposed downstream of the print execution position in the transport direction, but in the first print unit 100a, the recording head 16 is located upstream of the print execution position in the transport direction. In the case where the reading head 27 is arranged on the (−X direction side), the reading head 27 is also arranged on the upstream side in the transport direction from the printing execution position in the second printing unit 100b.

The second printing unit 100b includes a control unit 20.
The magnetic information written in the magnetic unit 6 read by the read head 27 is sent to the control unit 20. Therefore, the control unit 20 sets the timing for starting the printing operation on the print medium 8 conveyed to the second printing unit 100b by the conveyance belt 5 to the first printing unit 10b.
0a, it can be obtained based on the print start information written in the magnetic section 6. Further, the control unit 20 can also acquire the transport speed information at the print execution position of the print medium 8 via the read head 27. For this reason, the control unit 20 controls the exposure timing in the exposure unit 22 based on the print start information obtained via the read head 27, and also controls the transfer roller 2 based on the transport speed information.
By controlling the drive motor 23a for driving the rotation of the belt 3, the local transport speed of the transport belt 5 at the print execution position of the second printing unit 100b can be adjusted.

The control unit 20 includes a read head 27
Can correct the position of the transport belt 5 in the horizontal direction based on the information read. FIG. 3 is a schematic diagram when the transport belt 5 is viewed from above. As shown in FIG.
The read heads 27 in the printing unit 100b are two read heads 27 in the width direction (Y direction) of the transport belt 5.
a and 27b are installed adjacent to each other, and the respective read heads 27a and 27b
It is provided to read information recorded at the same position in the direction. Therefore, the control unit 20 moves the transport belt 5 in the horizontal direction (Y direction) based on the difference between the signal levels of the information read from each of the read heads 27a and 27b.
By controlling the driving of the conveyor belt correcting units 28a and 28b for correcting the position of the conveyor belt 5, the positional deviation of the conveyor belt 5 in the lateral direction can be eliminated. Conveyor belt correction unit 28
a and 28b are constituted by cylinders and the like,
The lateral position of the conveyor belt 5 is corrected by applying a pressure to the side end portion of the conveyor belt 5 based on a drive command from the printer.

For example, when most of the magnetic signals recorded on the magnetic section 6 are located on the read head 27a side,
The signal level obtained by the read head 27a becomes higher than the signal level obtained by the read head 27b. In this case, the control unit 20 instructs the conveyance belt correction unit 28a to apply a pressure, so that the conveyance belt 5 moves downward (−Y direction) in FIG. The obtained signal levels can be made equal.
Conversely, when most of the magnetic signals recorded on the magnetic section 6 are located on the read head 27b side, the signal level obtained by the read head 27b is
7a, the control unit 20 in this case controls the conveyor belt correction unit 28b
Will be instructed to give pressure.

In this embodiment, the printing apparatus 100 is configured as described above, and a specific operation of each unit for eliminating the displacement of the print medium 8 by the printing apparatus 100 will be described.

FIG. 4 is a conceptual diagram showing information recorded on the magnetic section 6. As shown in FIG. 4A, when the control section 10 in the first printing section 100a starts the latent image on the photoconductor drum 11 in the exposure section 12, the recording head 16 uses the print start information having a high signal level. S1 is recorded on the magnetic part 6. After recording the print start information S1, the control unit 10 causes the recording head 16 to record a pulse signal having a lower signal level than the print start information S1 on the magnetic unit 6 at predetermined time intervals. This pulse signal is transport speed information S2 when the print medium 8 is transferred to the toner at the print execution position in the first printing unit 100a.
It is.

In this embodiment, as described above, the print execution position in the first printing unit 100a and the recording head 1
6 and the positional relationship between the print execution position and the read head 27 in the second printing unit 100b are arranged so as to establish the same relationship. Therefore, in the second printing unit 100b, FIG. As shown in (b), when the control unit 20 starts the exposure unit 22 when the read head 27 reads the print start information S1, the first print unit 100a
, The printing operation in the second printing unit 100b can be started at the same timing as when the printing is performed on the print medium 8. Therefore, the print medium 8
Even when the conveying belt 5 that conveys the print data is beaten or the like and the conveyance at a constant speed is not realized, the timing of the printing start in the second printing unit 100b is such that the printing is started in the first printing unit 100a. Timing can be matched.

In this embodiment, the transport speed information S2 when the print medium 8 passes between the photosensitive drum 11 and the transfer roller 13 in the first printing section 100a, that is, when the print medium 8 passes the print execution position, is transmitted by a fixed pulse. Since the signal is recorded on the magnetic portion 6, the second printing portion 100b controls the rotation speed of the transfer roller 23 based on the transport speed information S2, so that the first printing portion 100a The same conveyor belt 5 as when the first color was printed
Transport of the print medium 8 can be realized.

For example, as shown in FIG. 4C, when the pulse width of the transport speed information S2 detected by the read head 27 of the second printing unit 100b is extended, the first printing unit 100a This indicates that the transport speed has increased when printing the first color. This is because, in the first printing unit 100a, each pulse signal of the transport speed information S2 is recorded at a constant time interval.
Is increased. For this reason,
When the conveyance speed information S2 as shown in FIG. 4C is obtained in the second printing unit 100b, the control unit 20 sends a command to the drive motor 23a to increase the rotation speed, and By increasing the rotation speed, a transport speed similar to that at the time of printing in the first printing unit 100a is realized.

Conversely, when the pulse width of the transport speed information S2 detected by the read head 27 of the second printing unit 100b is reduced, the transport speed is reduced during printing in the first printing unit 100a. Therefore, the control unit 20 sends a command to the drive motor 23a to reduce the rotation speed, and reduces the rotation speed of the transfer roller 23 to perform the same operation as when printing in the first printing unit 100a. Transport speed.

Further, since the speed control by the control unit 20 can be performed even during the printing operation in the printing unit 100b, the transfer roller 23 is controlled based on the transport speed information S1 obtained after the printing start information S1. If the rotation speed is adjusted, it is possible to appropriately cope with speed fluctuations of the transport belt 5 that occur during printing on the print medium 8.

As a result, the image printed by the second printing unit 100b on the print medium 8 is appropriately overprinted on the image portion where the first color is printed by the first printing unit 100a. That is, it is possible to avoid the occurrence of a positional shift in the X direction.

During the printing on the printing medium 8, the above-mentioned correction in the horizontal direction (Y direction) by the transport belt correction units 28a and 28b is of course also performed.

Therefore, according to the printing apparatus 100 of this embodiment, the magnetic section 6 provided on the transport belt 5
First, predetermined information is magnetically recorded in the first printing unit 100a, and information recorded in the magnetic unit 6 is read with the conveyance of the print medium 8 in the second printing unit 100b, and the second printing is performed based on the information. By adjusting the transport speed at the print execution position of the unit 100b, the positional deviation in the transport direction is eliminated. In this embodiment, the second printing unit 10
0b are provided with conveyor belt correction units 28a and 28b that apply a displacement in the width direction to the conveyor belt 5 so that the lateral position of the conveyor belt 5 is corrected based on information recorded on the magnetic unit 6. With this configuration, it is possible to eliminate the positional deviation that occurs in the lateral direction of the transport belt perpendicular to the transport direction.

That is, the printing apparatus 10 according to this embodiment
By applying 0, it is possible to improve the accuracy of overprinting on the print medium 8 with a simpler configuration and more accurately, and to improve the conveyance belt which could not be corrected conventionally. Can also be corrected for the positional deviation occurring in the horizontal direction.

In the above description, an example in which two printing units 100a and 100b are provided in the printing apparatus has been described. However, when color printing is performed on the printing medium 8 in general, as shown in FIG. As described above, the printing units 100a to 100d are provided for each of the four color components of Y (yellow), M (magenta), C (cyan), and K (black). In this case, the printing units 100c and 100d also function as subsequent printing units if realized with the same configuration as that described for the second printing unit 100b in the above description. That is,
First, predetermined information is magnetically recorded on the magnetic unit in the printing unit 100a that prints on the print medium 8, and is recorded on the magnetic unit in the printing units 100b to 100d that print on the print medium 8 after the second time. And print timing can be controlled based on the read information.

Therefore, even when four color components are overprinted, it is possible to avoid the occurrence of positional deviation when printing each color component, and to improve the overprinting accuracy for each color component. Can be done.

It is apparent that the present invention can be applied to an arbitrary number of printing units provided that a plurality of printing units are provided.

<Second Embodiment> Next, a second embodiment will be described. FIG. 6 is a schematic diagram illustrating a configuration of a printing apparatus 100 according to the second embodiment.

The configuration of the printing apparatus 100 in this embodiment is basically the same as that of the first embodiment shown in FIG. Therefore, in this embodiment, as shown in FIG. 2, at least a part of the width (Y direction) on the back surface (inner surface) side of the transport belt 5 is provided with the magnetic portion 6 over almost the entire circumference of the transport belt 5. Have been.

The printing apparatus 100 of this embodiment differs from the configuration of FIG. 1 in the position of the read head 27 in the second printing section 100b. In this embodiment, the reading head 27 in the second printing unit 100b is
It is provided on the upstream side (−X direction side) in the transport direction of the print execution position in the printing unit 100b, that is, the position between the photosensitive drum 21 and the transfer roller 23.

In other words, in the case of this embodiment, the positional relationship between the print execution position and the recording head 16 in the first printing unit 100a, and the positional relationship between the print execution position and the reading head 27 in the second printing unit 100b. Are not in the same positional relationship.

Here, in the first printing section 100a, the recording head 16 transmits the print start information S1 and the transport speed information S2 as shown in FIG. 4A in the same manner as the contents described in the first embodiment. Consider a case where predetermined information is recorded on the magnetic part 6 of the transport belt 5. Second printing unit 1
In 00b, if the control unit 20 starts the latent image on the photosensitive drum 21 by the exposure unit 22 when the reading head 27 reads the print start information S1, the printing operation starts too early. .

That is, in this embodiment, the recording head 16 is arranged on the downstream side in the transport direction of the printing execution position in the first printing unit 100a, whereas the reading head 27 is arranged in the second printing unit 100b. Since the print head is located upstream of the print execution position in the transport direction, when the print operation is started when the read head 27 reads the print start information S1, the positions of the recording head 16 and the read head 27 are determined. A shift corresponding to the difference in the relationship will occur.

For this reason, in this embodiment, when the control unit 20 previously stores the information about the difference in the positional relationship as distance information in the X direction, and the reading head 27 reads the print start information S1. The printing operation is not started until the conveyor belt 5 moves by a distance corresponding to the above-mentioned distance information, and a standby state is set. Then, when the conveyor belt 5 moves by a distance corresponding to the above-mentioned distance information, the exposure unit 22 To start the latent image on the photosensitive drum 21 with respect to.

Note that the control unit 30 controls the transport speed at the time of printing in the first printing unit 100a and the transport speed in the second printing unit 100b based on the transport speed information S2 read by the read head 27 even in the standby state. Is calculated by calculation, the rotational speed of the transfer roller 23 is adjusted based on the deviation, and it is determined whether the transport belt 5 has moved by a distance corresponding to the distance information based on the adjusted transport speed. It is configured to be.

That is, in this embodiment, the control unit 30 performs an operation relating to the transport speed based on the information recorded on the magnetic unit 6 read by the read head 27, thereby printing in the second printing unit 100b. It is configured to adjust the timing of the operation.

Therefore, by applying the printing apparatus 100 according to this embodiment, a simpler configuration can be achieved.
In addition, it is possible to more accurately improve the accuracy of overprinting on the print medium 8 and to correct the lateral displacement of the transport belt that could not be corrected conventionally in the lateral direction. Can be.

In the first embodiment, the print execution position and the read head 2 in the second printing section 100b are set.
7 and the positional relationship between the print execution position and the recording head 16 in the first printing unit 100a need to be the same positional relationship. However, as shown in this embodiment, If the control unit 20 is configured to adjust the timing of the printing operation by performing an operation related to the transport speed, the positional relationship between the printing execution position and the read head 27 in the second printing unit 100b and the first printing unit 10
0a, the positional relationship between the print execution position and the recording head 16 need not always be the same.
There is also an effect that restrictions on the device configuration are eased.

In this embodiment, it is needless to say that the transfer belt correcting portion shown in the first embodiment can be used to eliminate the positional deviation of the transfer belt in the horizontal direction.

Further, in this embodiment, the reading head 27 in the second printing section 100b is
00b, that is, the photosensitive drum 2
1 is provided on the upstream side (−X direction side) in the transport direction from the position between the transfer roller 1 and the transfer roller 23, but the rotation speed of the transfer roller 23 is adjusted based on the transport speed information S 1. By doing so, it is possible to appropriately cope with the speed fluctuation of the transport belt 5 that occurs during printing on the print medium 8, so that it is possible to eliminate the occurrence of a displacement or the like while the transport belt moves to the print execution position. You can also.

In this embodiment, an example in which two printing units 100a and 100b are provided in the printing apparatus has been described. However, as described in the first embodiment, the number of printing units is two. The present invention is not limited thereto, and any number can be applied as long as the number is plural.

<Third Embodiment> Next, a third embodiment will be described. FIG. 7 is a schematic diagram illustrating a configuration of a printing apparatus 100 according to the third embodiment.

The configuration of the printing apparatus 100 in this embodiment is basically the same as that of the first embodiment shown in FIG. Therefore, in this embodiment, as shown in FIG. 2, at least a part of the width (Y direction) on the back surface (inner surface) side of the transport belt 5 is provided with the magnetic portion 6 over almost the entire circumference of the transport belt 5. Have been.

The difference of the printing apparatus 100 of this embodiment from the configuration of FIG. 1 is that the width of the transport belt 5 and the first printing unit 10
0a and the arrangement position of the read head 27 in the second printing unit 100b.

FIG. 8 shows the second printing unit 100 of this embodiment.
FIG. 5B is a schematic perspective view showing the vicinity of the print execution position in FIG.
As shown in FIG. 8, in this embodiment, the width of the transport belt 5 is provided to be larger than the printing width in each printing unit. Here, the printing width is a width in the Y direction in which toner transfer to the printing medium 8 can be performed by the photoconductor drum 21 and the transfer roller 23 at the printing execution position of each printing unit. Then, as shown in FIG. 8, the magnetic portion 6 is provided outside the transfer area of the conveyor belt 5 (that is, a portion larger than the printing width).

By doing so, the first printing unit 100a
In, the recording head 16 can be arranged at the same position as the print execution position in the X direction, and in the second printing section 100b, the reading head 27 can be arranged at the same position as the print execution position in the X direction. .

For this reason, as shown in FIG.
00a, when the transport belt 5 passes through the print execution position, the recording head 16 moves the transport speed information S at the print execution position.
2 can be recorded and the second printing unit 100
b, the reading head 27 can read the transport speed information S2 at the print execution position. Therefore, the second
In the printing unit 100b, when the transport belt 5 actually passes the print execution position, the transport speed information S2
Is read, and the control unit 20 controls the rotation speed of the transfer roller 23 so that the speed at which the transport belt 5 passes the respective printing execution positions of the first printing unit 100a and the second printing unit 100b is made to match. be able to.

Also in this embodiment, as shown in FIG. 8, the read head 27 is provided with two read heads 27a and 27b adjacent to each other in the width direction (Y direction) of the conveyor belt 5. Each of the read heads 27a and 27b is provided so as to read information recorded at the same position of the magnetic unit 6 in the X direction. Therefore, the control unit 20 can correct the position of the transport belt 5 in the horizontal direction (Y direction) based on the difference between the signal levels of the information read from each of the read heads 27a and 27b as described above. Then, the lateral correction of the transport belt 5 is also performed so that the positional deviation is eliminated at the print execution position of the second printing unit 100b, so that the most appropriate correction can be performed.

As for the control of the print timing based on the print start information S1, the same control content as described in the first embodiment is applied.

As described above, in this embodiment, the width of the transport belt 5 is set to be larger than the print width of the print execution position in each printing section, and the magnetic section 6 is wider than the print width of the transport belt 5. Since the recording head 16 and the read head 27 are provided at the print execution positions in the printing units 100a and 100b, the transport speed at the print execution position where toner transfer is performed on the print medium 8 is provided. Can be strictly adjusted.

In this embodiment, an example in which two printing units 100a and 100b are provided in the printing apparatus has been described. However, as described in the first embodiment, the number of printing units is two. The present invention is not limited thereto, and any number can be applied as long as the number is plural.

<Fourth Embodiment> Next, a fourth embodiment will be described. In this embodiment, utilization of magnetic information recorded on the magnetic unit 6 in a case where a plurality of transport belts are connected will be described.

FIG. 9 is a view showing a connecting portion where a plurality of conveyor belts 5a and 5b are connected. The conveyor belt 5a is supported by rollers 32 and driven in a predetermined direction. It is supported and driven in a predetermined direction.

Then, the print medium 8 is transferred from the upper surface of the conveyor belt 5a to the upper surface of the conveyor belt 5b. That is, the printing medium 8 is transferred at the connecting portion of the plurality of transport belts 5a and 5b, so that the printing medium 8 is sequentially transported between the plurality of printing units.

An intermediate member 39 is provided for appropriately transferring the print medium 8 between the transport belts 5a and 5b. Therefore, when the print medium 8 is transported in the X direction, it moves from the upper surface of the transport belt 5a to the upper surface of the transport belt 5b via the upper surface of the intermediate member 39. Each of the transport belts 5a and 5b is provided with the magnetic portion 6 at a predetermined position as described above.

In the configuration shown in FIG. 9A, the reading head 37 is located at a position facing the roller 33 on the roller 32.
Is provided.
The recording head 36 is provided at a position facing the recording head 2.
Further, the reading head 37 and the recording head 36 are connected to a magnetic transfer unit 38. An erasing head 34 for erasing magnetic information recorded on the magnetic section 6 is provided below the transport belt 5b.

When the read head 37 reads the information recorded on the magnetic section 6 of the transport belt 5a, it sends the information to the magnetic transfer section 38. Then, the magnetic transfer unit 38
Is configured to transmit information having the same content as the information obtained from the reading head 37 to the recording head 36 and record the information on the magnetic portion 6 of the transport belt 5b.

That is, the read head 37, the magnetic transfer section 38, and the recording head 36 function as magnetic transfer means.
The information recorded on the magnetic section 6 of the transport belt 5a is transferred to the magnetic section 6 of the transport belt 5b.

As a result, the magnetic information recorded on the magnetic portion 6 of the transport belt 5a in the first printing section is effectively transferred to a different transport belt 5b, and the transport belt 5b transfers the magnetic information. In the printing section where the conveyance is performed, the printing timing can be adjusted based on information such as the conveyance speed information S2 recorded on the magnetic section 6 of the conveyance belt 5b. That is, even if the transport belt is different, the transport speed and the like at the time of printing in the first printing section are reproduced in the other printing sections even if the transport belt is different. Can improve the accuracy of overprinting.

In the configuration shown in FIG. 9B, the read head 37 and the recording head 3 are provided inside the rollers 32 and 33.
6 shows an example of a configuration that can be easily applied when it is difficult to provide. That is, the read head 37 for reading information recorded on the magnetic portion 6 of the transport belt 5a is disposed on the −X direction side of the roller 32, and records information on the magnetic portion 6 of the transport belt 5b. The recording head 36 to be used is disposed on the −X direction side of the erasing head 34 provided at the same position as in FIG. 9A.

With this configuration, the magnetic information recorded on the magnetic section 6 of the transport belt 5a in the first printing section is effectively transferred to a different transport belt 5b. In the printing section where the print medium 8 is transported, the printing timing can be adjusted based on information such as the transport speed information S2 recorded on the magnetic section 6 of the transport belt 5b. In other words, the transport speed and the like when printing in the first printing section will be reproduced in other printing sections even if the transport belt is different,
It is possible to improve the accuracy of overprinting on the print medium 8 with a simpler configuration and more accurately.

9A and 9B, the position where the reading head 37 and the recording head 36 are disposed depends on the position of the printing medium 8 and the printing start information to be recorded on the magnetic unit 6. The position where S1 is recorded is the position of the conveyance belt 5.
It is preferable to arrange them so that they have the same positional relationship in a and 5b.

Next, FIG. 10 is a view showing a connecting portion in which a plurality of transport belts 5a and 5b are connected similarly to FIG. 9, but FIG. Fig. 3 shows a connection part when the connection is performed.

That is, FIG. 10 differs from FIG. 9 in that the rollers 32 and 33 are configured to rotate in opposite directions, respectively, and the print medium 8 is conveyed from the upper side of the conveyer belt 5a. It is configured to be conveyed to the lower surface side of the belt 5b. By adopting such a transport mode, both sides of the print medium 8 can be reversed. If a photosensitive drum or the like is provided on the lower surface side of the transport belt 5b, printing is performed on the reverse side of the print medium 8. be able to.

In the configuration shown in FIG. 9A, a reading head 37 is provided at a position of the roller 32 facing the roller 33, and a recording head 36 is provided at a position of the roller 33 facing the roller 32. Is provided. Further, the reading head 37 and the recording head 36 are connected to a magnetic transfer unit 38. Also,
An erasing head 34 for erasing magnetic information recorded on the magnetic section 6 is provided above the conveyor belt 5b.

When the read head 37 reads the information recorded on the magnetic section 6 of the conveyor belt 5a, it sends the information to the magnetic transfer section 38. Then, the magnetic transfer unit 38
Is configured to transmit information having the same content as the information obtained from the reading head 37 to the recording head 36 and record the information on the magnetic portion 6 of the transport belt 5b.

Therefore, also in the configuration of FIG. 10, the read head 37, the magnetic transfer section 38, and the recording head 36 function as magnetic transfer means, and transfer the information recorded on the magnetic section 6 of the transport belt 5a to the transport belt 5b. It is configured to transfer to the magnetic part 6.

As a result, in the configuration of FIG. 10, it is possible to eliminate the positional deviation between the position where the front image is printed and the position where the back image is printed when printing on the front and back sides of the print medium 8. .

The configuration shown in FIG. 10B shows a configuration example which can be easily applied when it is difficult to provide the read head 37 and the recording head 36 inside the rollers 32 and 33. I have. That is, the transport belt 5a
A reading head 37 for reading information recorded on the magnetic section 6 of the transport belt 5b is disposed on the −X direction side of the roller 32. It is arranged on the −X direction side of the erasing head 34 provided at the same position as in FIG.

With this configuration, the magnetic information recorded on the magnetic section 6 of the transport belt 5a in the first printing section is effectively transferred to a different transport belt 5b. In the printing section where the print medium 8 is transported, the printing timing can be adjusted based on information such as the transport speed information S2 recorded on the magnetic section 6 of the transport belt 5b.

In each of the configurations shown in FIGS. 10A and 10B, the position where the reading head 37 and the recording head 36 are disposed depends on the position of the printing medium 8 and the printing start information to be recorded on the magnetic unit 6. It is preferable to arrange the transport belts 5a and 5b such that the position where S1 is recorded has the same positional relationship in the transport belts 5a and 5b.

<Modifications> The embodiments described above are merely examples for carrying out the present invention, and the present invention is not limited to the above embodiments.

Further, the magnetic part 6 in the above description can be formed by applying a magnetic paint to the conveyor belt, for example, but is not limited to this.

Even if only one of the print start information S1 and the transport speed information S2 is recorded in the magnetic unit 6, the information is recorded at the start of the printing operation or at the transport speed. It is clear from the above description that either one of the print timings can be adjusted. Note that other information may be recorded on the magnetic unit 6.

Although not particularly limited in the above description, when the transport belt 5 is an endless belt, the magnetic portion 6 extends substantially all around the transport belt 5 in the circumferential direction. What is necessary is just to provide in at least one part of the width direction.

[0097]

As described above, according to the first aspect of the present invention, the magnetic section is provided on the conveying belt along the conveying direction, and the magnetic section is first applied to the printing medium among the plurality of printing sections. In a leading printing unit that performs printing of the first printing unit, the recording unit magnetically records predetermined information on a magnetic unit, and in a subsequent printing unit that performs printing on a printing medium in the second and subsequent printing units, a reading unit includes Since the control unit is configured to read the information magnetically recorded on the magnetic unit and control the printing timing in the subsequent printing unit based on the information, the printing is performed on the printing medium by the leading printing unit. Printing in the subsequent printing section can be performed at the same timing as the timing, and the accuracy of overprinting on a print medium can be improved with a simple configuration and accurately.

According to the second aspect of the invention, the positional relationship between the printing execution position and the reading means in the subsequent printing unit is determined to be the same as the positional relationship between the printing execution position and the recording unit in the first printing unit. In addition, the control unit controls to start printing in the subsequent printing unit when the reading unit reads the print start information, so that the printing timing can be adjusted with a simple configuration.

According to the third aspect of the invention, the reading means is provided on the upstream side in the transport direction with respect to the predetermined printing execution position in the subsequent printing section, and the control means reads the information read by the reading means. Based on the calculation, the difference between the transport speed when the print medium is printed in the leading print section and the transport speed in the subsequent print section is obtained by calculation, and the print timing in the subsequent print section is configured to be adjusted. With a simple configuration, it is possible to accurately improve the accuracy of overprinting on a print medium.

According to the fourth aspect of the invention, the width of the conveying belt is set to be larger than the printing width of the plurality of printing sections, and the magnetic section is provided at a portion larger than the printing width of the conveying belt. Since the recording unit and the reading unit are provided at the print execution positions in the respective printing units, it is possible to match the speed at which the transport belt passes through the print execution position in the first printing unit and the subsequent printing unit. It is possible to further improve the accuracy of overprinting.

According to the fifth aspect of the present invention, the apparatus further comprises a conveying belt correcting means for applying a displacement to the conveying belt in the width direction, and a plurality of reading means are arranged in parallel in the width direction of the conveying belt. The control unit is configured to displace the transport belt in the width direction by driving the transport belt correction unit based on a plurality of signal levels obtained by reading information by the plurality of reading units. Can be corrected to an appropriate position even if the position shifts in the width direction, and the overprint accuracy can be improved.

According to the sixth aspect of the present invention, a plurality of transport belts are connected, and a print medium is transferred from one transport belt to the other transport belt at a connection portion of the plurality of transport belts. Since the connecting portion further includes magnetic transfer means for transferring information recorded on the magnetic portion of one of the conveyor belts to the magnetic portion of the other conveyor belt, even if the plurality of conveyor belts are connected, The information recorded in the copy unit can be transmitted, and the accuracy of overprinting on a print medium can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a transport belt that transports a print medium.

FIG. 3 is a schematic diagram when the transport belt is viewed from above.

FIG. 4 is a conceptual diagram showing information recorded on a magnetic unit.

FIG. 5 is a diagram illustrating a configuration example in which a plurality of printing units are provided.

FIG. 6 is a schematic diagram illustrating a configuration of a printing apparatus according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a configuration of a printing apparatus according to a third embodiment of the present invention.

FIG. 8 is a schematic perspective view illustrating the vicinity of a print execution position in a second printing unit according to a third embodiment.

FIG. 9 is a diagram illustrating an example of a connecting portion where a plurality of transport belts are connected.

FIG. 10 is a diagram illustrating an example of a connecting portion in which a plurality of transport belts are connected.

[Explanation of symbols]

5 Conveyor belt 6 Magnetic unit 8 Print medium 10 Control unit 11, 21 Photoreceptor drum 12, 22 Exposure unit 14 Erase head 15 Detection sensor 16 Recording head (recording unit) 20 Control unit (control unit) 27 (27a, 27b) Reading Heads (reading means) 28a, 28b Transport belt correction section (transport belt correction section) 100a First printing section 100b Second printing section 100 Printing apparatus S1 Printing start information S2 Transport speed information

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA38 DE04 EB04 EC06 EC20 ED02 ED06 ED16 EE02 EE07 EF09 2H030 AA01 AB02 AD05 BB02 BB16 BB23 BB44 BB53 BB56 3F049 BB11 DA03 EA24 LA04 LB03

Claims (6)

[Claims] 1. A printing apparatus for sequentially performing printing on a print medium in a plurality of printing units while transporting the print medium in a predetermined transport direction by a transport belt, wherein: A magnetic unit provided on a transport belt; a recording unit for magnetically recording predetermined information on the magnetic unit in a leading printing unit that first performs printing on the print medium among the plurality of printing units; A reading unit that reads the information magnetically recorded on the magnetic unit in a subsequent printing unit that performs printing on the printing medium in the second and subsequent printing units of the printing unit, based on the information read by the reading unit. A control unit for controlling a print timing in the subsequent printing unit. 2. The printing apparatus according to claim 1, wherein a positional relationship between a printing execution position in the subsequent printing unit and the reading unit is a positional relationship between a printing execution position in the first printing unit and the recording unit. Wherein the control unit controls to start printing in the subsequent printing unit when the reading unit reads the printing start information included in the information. apparatus. 3. The printing apparatus according to claim 1, wherein the reading unit is provided on an upstream side in the transport direction with respect to a predetermined printing execution position in the subsequent printing unit, and the control unit performs the reading. Means for calculating, based on the information read by the means, a deviation between a transport speed when the print medium is printed in the leading print unit and a transport speed in the subsequent print unit, and calculating the print speed in the subsequent print unit. A printing apparatus for adjusting timing. 4. The printing device according to claim 1, wherein a width of the transport belt is set to be larger than a print width of the plurality of printing units, and the magnetic unit is configured to have the print width of the transport belt. A printing unit, wherein the printing unit and the reading unit are provided at print execution positions in respective printing units. 5. The printing apparatus according to claim 1, further comprising: a conveyor belt correcting unit that applies a displacement in a width direction to the conveyor belt, wherein the reading unit is configured to read the image data. A plurality of the conveyor belts are arranged side by side in a width direction of the conveyor belt, and the control unit drives the conveyor belt correction unit based on a plurality of signal levels obtained by reading the information by the plurality of reading units. A printing apparatus which is displaced in the width direction. 6. The printing apparatus according to claim 1, wherein a plurality of the transport belts are connected, and the print medium is transferred from one transport belt to another at a connection portion of the plurality of transport belts. And a magnetic transfer unit configured to transfer the information recorded on the magnetic unit of the one conveyor belt to the magnetic unit of the other conveyor belt at the connection unit. A printing device characterized by the above-mentioned.