JPH0620226B2 - Image processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image processing apparatus that outputs an image signal to a recording unit that performs recording by electrophotography using a laser beam, for example.

2. Description of the Related Art Conventionally, as a recording device using an electrophotographic method, a device that exposes an image of a character or the like on a photosensitive drum using a laser beam and obtains a permanent image on a transfer paper by a process using the electrophotographic method is known. There is.

FIG. 1 shows a schematic configuration diagram of the recording unit of the recording apparatus described above.

Reference numeral 1 denotes a photosensitive drum having a semiconductor layer such as selenium or cadmium sulfide on its surface, which rotates in the direction of arrow A. 2 is a charger, 3a is a semiconductor laser which emits a laser beam 3 for forming an output image, 4 is a developing device for visualizing an electrostatic image with toner, and 5 is a pick-up for supplying transfer paper. Rollers 6, 6 and 7 are registration rollers, which temporarily stop the transfer paper feed by stopping the rotation in the direction of arrow B, and rotate again at an appropriate timing to transfer the transfer paper and the image on the photosensitive drum 1. It has the function of aligning. Reference numerals 8, 9 and 10 denote transfer sheets, the transfer sheet 8 is in a state of transferring the toner image formed on the photosensitive drum 1, and the transfer sheet 9 is a case 1 containing the transfer sheet 10.
It is in a state where it is taken out from the first group by the pick-up roller 5 and reaches the registration rollers 6 and 7.

Since such electrophotographic process is well known, its detailed description is omitted.

By the way, in order to obtain a stable and good image in a recording apparatus using the electrophotographic method of this kind, the photosensitive drum is rotated while performing exposure with a laser beam for actually forming an output image (such as Before the rotation is referred to as normal rotation, the photosensitive drum is rotated by an appropriate number (for example, 3 times) while the charger 2 and the laser beam 3 are fixed in a fixed state (such rotation is hereinafter referred to as preparatory rotation). Called.)
There is a need. The surface of the photosensitive drum 1 is uniformly charged or discharged by the preparatory rotation, and the non-uniform state of the surface due to the output image before that is eliminated.

Next, a conventional control method in the recording apparatus using the electrophotography described above will be described with reference to FIGS. 2 and 3. Second
In the figure, reference numeral 202 denotes a recording unit, which has the configuration described in FIG. 1 (photosensitive drum 1, semiconductor laser 3a, a motor (not shown) for driving the photosensitive drum 1, etc.). A control unit 201 sends out an image signal according to a command from an operation unit (not shown) and controls the operation of the recording unit 202. Also, the operation of the recording unit 202 is controlled according to the signal output from the recording unit 202.

First, when a signal instructing to start recording is input to the control unit 201 from an operation unit (not shown), the PRINT signal a is applied from the control unit 201 side to the recording unit 202. PRI
The photosensitive drum 1 starts preparatory rotation by the NT signal a. When the recording unit 202 finishes the preparatory rotation and enters the normal rotation, the recording unit 202 outputs the TOP signal b to the control unit 201 at an appropriate timing. Then, the control unit 201 sends out the VIDEO signal c synchronized with the TOP signal b to the recording unit 202 side. The laser beam 3 is modulated by the VIDEO signal c, and an output image is formed on the photosensitive drum.

Further, the recording section feeds the transfer paper by the registration rollers 6 and 7 at an appropriate timing synchronized with the TOP signal b, and transfers the toner image on the photosensitive drum 1 onto the transfer paper 8.

The operation of the recording unit 202 will be described with reference to the timing chart of FIG. The recording unit 202 is activated by the PRINT signal a, at the time T3 when the preparatory rotation is completed and the normal rotation is started.
The PRINT signal a is checked at 1 and if the PRINT signal a is "true", the TOP signal b is output after t time. Further, the PRINT signal a is examined at the time point T32 during normal rotation, and if the PRINT signal a is "true", the TO
The P signal b is output. At time T33, the PRINT signal a is checked again, and if the PRINT signal a is “false”, TOP is determined.
The sequence for ending the normal rotation is entered without outputting the signal b.

The points of time T31, T32, T33, etc. are timings appropriately determined by the recording unit side, for example, timings at which the transfer sheet is taken out by the pick-up roller.

When operating a plurality of recording units by using the conventional control method as shown in FIGS. 2 and 3, the plurality of recording units are simultaneously operated by using the VIDEO signal from the single control unit 201, and the same recording unit is operated. It is extremely difficult to obtain an accurate image output of each content. This is because the TOP signal b is generated with time variations due to the convenience of each recording unit, and which recording unit should the control unit apply the VIDEO signal in synchronization with the TOP signal? This is because it will be difficult to judge. Temporarily, TOP from any one recording section
If the VIDEO signal synchronized with the signal is applied to all the recording units, the toner image will not be transferred to the correct position on the transfer paper in the other recording units.

The reason why the TOP signal is generated due to the time variation among the recording units is, for example, the difference in the paper transport path length between the devices,
This is because of differences in the operation timing of the registration rollers, differences in the time of preparatory rotation, and the like, and it is difficult to make the TOP signals of the recording units exactly match.

The present invention has been made in view of the above points, and it is possible to output an image signal without being constrained by the conveyance timing of the recording medium in the recording unit, and to perform recording at a correct position on the transfer paper. An image processing device is provided.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows a recording apparatus according to this embodiment, which is composed of a control unit 401, a first recording unit 402, a second recording unit 403, and the like. The first recording unit 402 and the second recording unit 403 each have the structure shown in FIG. FIG. 5 is a timing chart of each signal in this embodiment. Fourth
In the figure, both 404 and 405 are AND circuits,
Although it should be originally included in the control unit 401, it is specifically shown for convenience of explanation.

First, when a signal instructing to start recording is input to the control unit 401 from an operation unit (not shown), the control unit 401 outputs PREPA.
The RE signal e is applied to the first recording unit 402 and the second recording unit 403. The first recording unit 402 and the second recording unit 403 each start the preparatory rotation, and when the normal rotation is started, the PRINT REQ1 signal f from the first recording unit 402 and the PRINT REQ2 signal g from the second recording unit 403 are received. returned. PRINT REQ1 signal f and PRINT REQ
The two signals g are ANDed by the AND circuit 404 and the AND signal h is returned to the control unit 401.

The control unit 401 then sends the PRINT signal i to the first recording unit 40.
2, applied to the second recording unit 403. In order to output the PRINT signal i, the control unit 401 does not necessarily have to wait until the logical product signal h is returned. However, when the PRINT signal i is output after receiving the logical product signal h, the VS REQ 1 signal j and the VS REQ 2 signal k described below can be received almost at the same time, and the VS REQ is unnecessary.
Since there is no need to wait for the logical product signal 1 of the 1 signal j and the VS REQ 2 signal k, the processing efficiency in the control unit can be improved.

Upon receiving the PRINT signal i, the first recording unit 402 prints at the time points T51, T52, and T53 shown in FIG.
The signal i is checked for authenticity, and if “true”, the pick-up roller 5 performs the paper feeding operation, and when the transfer paper 9 reaches the stopped registration rollers 6 and 7, VS REQ
Output 1 j.

Similarly to the first recording unit 402, the second recording unit 403 which has received the PRINT signal i also has time points T56 and T5 shown in FIG.
7. Check the truth of the PRINT signal i at T58, and check "true"
If so, perform the paper feeding operation with the pick-up roller,
When the transfer paper 9 reaches the registration rollers 6 and 7, VS
Output REQ 2k. Incidentally, at time points T51, T52,
T53 and time points T56, T57, and T58 are timings appropriately determined by the recording units 401 and 402, respectively.

The logical product of the VS REQ 1 j and the VS REQ 2 k is ANDed by the AND circuit 405, and the logical product signal 1 is output.
Returned to 1. The fact that the logical product signal 1 is "true" means that the first recording unit 402 and the second recording unit 403 are always VSYN.
This shows that the recording operation can be started in response to the C signal and the VIDEO signal.

The control unit 401 then outputs the VSYNC signal m to the first recording unit 40.
2, applied to the second recording unit 403. In addition, the VIDEO signal n (that is, the image signal) synchronized with the VSYNC signal m
The voltage is applied to the recording unit 402 and the second recording unit 403.

The first recording unit 402 that has received the VSYNC signal m
The registration rollers 6 and 7 start rotating at an appropriate timing synchronized with the C signal m, and the toner image on the photosensitive drum 1 formed by the VIDEO signal n is transferred to an appropriate position on the transfer paper 9. The paper 9 is conveyed.

Similarly, the second recording unit 403 which has received the VSYNC signal m also outputs V
The registration rollers 6 and 7 start rotating at an appropriate timing synchronized with the SYNC signal m, and the toner image on the photosensitive drum 1 formed by the VIDEO signal n is transferred to an appropriate position on the transfer paper 9. The paper 9 is conveyed.

As described above, according to this embodiment, the VI output from the control unit 401 in the two recording units connected to the control unit 401 side.
The DEO signal is recorded at the correct position on the transfer paper.

In this embodiment, the time when VS REQ 1 j is returned is the time when the transfer paper reaches the registration rollers 6 and 7.
In particular, the present invention is not limited to this case, and the point is that VS REQ 1 is set at the time when the condition for transferring the toner image formed by the VIDEO signal n applied in synchronization with the VSYNC signal m to the correct position on the transfer sheet is established. j can be output. The same applies to VS REQ 2k. Further, in the present embodiment, the case where the number of recording portions is two is shown, but it goes without saying that the present invention can be applied in the same manner even when the number of recording portions is three or more.

Further, the present invention is extremely useful for a recording system in which the control unit determines the timing of sending an image signal even if there is only one recording unit.

For example, when the control unit has a document image reading unit and the reading unit has a mechanically moving portion such as a movable document table, the control unit is controlled by the VS REQ signal from the recording unit. By starting the movement of the table and outputting the VSYNC signal when the platen reaches a stable speed and passes a specific point, the unstable state at the time of starting the platen is avoided and the VSYNC signal is accurately output. The synchronized read image signal can be sent to the recording unit. The recording unit side is also VSYN
Since the rotation of the registration roller can be started at an appropriate timing in synchronization with the C signal, it is possible to output a recorded image that is accurately aligned on the transfer paper.

Effect As described above, according to the present invention, the vertical synchronization signal is output by the image processing apparatus itself without being synchronized with the synchronization request signal from the recording unit. Therefore, the conveyance timing of the recording medium in the recording unit is restricted. The image signal can be output without being processed. Therefore, it can be applied to various image processing apparatuses and the versatility is improved. Moreover, since the recording unit can control the conveyance of the recording medium based on the vertical synchronizing signal, it is possible to output the recording operation accurately aligned on the transfer paper.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a recording unit of the recording apparatus, FIG. 2 is a block diagram showing a conventional recording apparatus, FIG. 3 is a timing chart of each signal of the recording apparatus shown in FIG. 2, and FIG. FIG. 5 is a block diagram showing a configuration example of the invention recording apparatus, and FIG. 5 is a timing chart of each signal of the recording apparatus shown in FIG. Here, 1 is a photosensitive drum, 3a is a semiconductor laser, 5 is a big-up roller, 6 and 7 are registration rollers, and 8, 9, and 1.
0 is a transfer sheet, 401 is a control unit, 402 is a first recording unit, 4
Reference numeral 03 is a second recording unit, and reference numerals 404 and 405 are AND circuits.

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Claims (1)

[Claims] 1. An image processing apparatus connected to a recording section for recording an image while conveying a recording medium, comprising start signal output means for outputting a start signal for instructing recording to the recording section, and the start signal. And a vertical synchronization signal that is a signal that is not synchronized with the synchronization request signal and that is used to control the conveyance of the recording medium. A vertical synchronization signal output means capable of outputting to the recording section on condition that a synchronization request signal is inputted by the input means; and an image signal output for outputting the image signal to the recording section in synchronization with the vertical synchronization signal. And an image processing apparatus.