JPH1056545A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make storage capacity smaller and furthermore, to start printing without managing up to the last page in an image forming device which decodes encoded data and simultaneously prints. SOLUTION: A decode sequential managing means 11 calculates the time which subtracts the decode estimated time of encoded data of image data from transfer start time of the image data of each partitioned image to a printing means 6, and a decoding means 3 decides the order of decoding in the means 3 in accordance with before and after of the time. The means 3 decodes decoding data in this order. Decoded image data is transferred in the order of transfer in response to the position of the partitioned image to the means 6 through a band buffer 4. The means 3 allocates encoded data, and when the allocation of a prescribed partitioned image is failed, a print start control means 17 delays print processing of the page to which the failed partitioned image belongs or the following pages in the means 6.

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, and more particularly, to an image forming apparatus that prints encoded image data (hereinafter referred to as code data) while decoding the image data. Further, the present invention relates to an image forming apparatus which is most suitable for image formation of a color tandem printer system for printing while decoding encoded color image data.

[0002]

2. Description of the Related Art When decoding coded data without deterioration in image quality, decoding time usually varies depending on the type of image. Therefore, in an environment using a printer that operates at a constant speed, such as a printer configured by an electrophotographic process,
When decoding and printing encoded data, it is necessary to absorb fluctuations in decoding time. Therefore, a method is known in which a storage device for one or more pages is provided, and code data for at least one page is decoded and then printed.

On the other hand, the applicant of the present invention divides image data into bands extending in the main scanning line direction, predicts coded data and decoding time for the bands, and reduces the capacity of a storage device. (Japanese Patent Application Hei 7-
296155, unpublished).

This undisclosed image forming apparatus prints image data continuously input in the main scanning direction as shown in FIG. 10, and the image data is printed on a band as shown in FIG. The image data is coded, compressed, and stored as coded data in units of divided image data. Thereafter, the code data is decoded and printed.

As shown in FIG. 12, the undisclosed image forming apparatus includes a code data storage unit 1, a data supply unit 2,
It comprises one or more decoding means 3, a band buffer 4, a transfer means 5, a printing means 6, a prediction means 7, a start time storage means 8, a control means 9 and the like. The prediction means 7 predicts the decoding time of the code data of the code data storage means 1,
In order to supply the data to the printer means 6 in time, it is determined when decoding should be performed (start time). In this way, decoding is performed with an appropriate lead time, and the printing process does not fail. Further, since decoding and buffering are performed in units of divided images, there is no need to increase the storage capacity.

However, this image forming apparatus has the following problems. (1) Since the divided images are decoded in the order of arrangement, printing may not be possible if the band buffer is not larger than one page. That is, when it takes an extremely long time to decode the code data of a predetermined divided image, it is necessary to take a sufficient lead time before that and decode the previous divided image more in order to cancel the time. This is because more decoded data of the previous divided image must be stored in the buffer. (2) The decoding start time is calculated by summing the decoding time from the last page to the latest page and subtracting this from the start time of the printing process of the printer. Therefore, printing cannot be started unless the last page is known. In addition, since printing cannot be performed unless all pages are managed, it is difficult to print multiple pages.

The prior art related to the present invention is as follows. Japanese Patent Application Laid-Open No. 7-195759 categorizes band expansion (encoding) into possible and impossible bands in time.
It discloses that possible bands are assigned to one drawing means, and impossible bands are assigned to the other drawing means. Japanese Unexamined Patent Publication No. Hei 7-314780 discloses that if bands cannot be developed in an order according to their positions, it is too late to develop bands that cannot be decoded. Both and relate to a monochrome printer.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in an image forming apparatus which prints while decoding code data, the storage capacity can be reduced. It is an object of the present invention to be able to start printing irrespective of the presence / absence of page management information or without managing the last page.

[0009]

According to the present invention, in order to achieve the above object, a divided image generated by dividing an input image into a plurality of band regions extending in the main scanning line direction is provided to an image forming apparatus. Storage means for storing code data for each of
Means for predicting the time for decoding the code data of the divided image, means for determining a decoding order based on the predicted time, one or more decoding means for decoding the code data according to the determined decoding order, A buffer configured to temporarily store decoded image data, a printer configured by a unit for each color component for printing by superimposing the corresponding color ink on paper in accordance with the image data for each color component, and an image stored in the buffer. Means for sequentially transferring data to the printer for each color component.

In this configuration, since the decoding order is determined based on the predicted time, decoding can be performed with a sufficient lead time for each code data of each divided image. In addition, since it is not necessary to calculate the total decoding time, printing can be started immediately without managing the last page. In addition, code data of a divided image that takes a long time to decode is decoded by taking more lead time,
Code data that does not take a long time for decoding is decoded with a shorter lead time, so that a large amount of decoded data is prevented from being kept in the buffer, and the buffer capacity can be reduced. Further, the divided images of the respective color components are efficiently allocated to the encoding means, so that the color print processing can be performed efficiently.

Further, in this configuration, the code data is decoded in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. And assign
When the allocation of all the divided images of a page is successful, the printer can start printing the page.

Further, the decoding means is assigned to the code data in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. When the allocation of a predetermined divided image fails, the print processing of the page to which the divided image belongs or the next page and subsequent pages in the printer may be delayed.

According to the present invention, in order to achieve the above object, a printer stores code data for each divided image generated by dividing an input image into a plurality of band areas extending in the main scanning line direction. The image forming apparatus includes a storage unit, a plurality of decoding units for decoding the code data, a buffer for temporarily storing the decoded image data, and a unit for transferring the image data in the buffer to the printer. Means for predicting the time to decode the data, and, in accordance with the order of the time obtained by subtracting the decoding prediction time of the code data of the image data from the transfer start time of the image data of each divided image to the printer, Means for determining the decoding order of the code data. Also in this configuration, since the decoding order is determined based on the predicted time, decoding can be performed with a sufficient lead time for each code data of each divided image. In addition, since it is not necessary to calculate the total decoding time, printing can be started immediately without managing the last page. Also, the code data of the divided image that takes a long time to decode is decoded with more lead time, and the code data that does not take longer to decode is decoded with less lead time. It is possible to avoid being kept in the buffer and to reduce the capacity of the buffer.

Further, in this configuration, the code data is decoded in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. And assign
When the allocation of all the divided images of a page is successful, the printer may start printing the page.

Further, decoding means is allocated to the code data in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. When the allocation of a predetermined divided image fails, the print processing of the page to which the divided image belongs or the next page and subsequent pages in the printer may be delayed.

[0016]

Embodiments of the present invention will be described below. FIG. 1 shows an image forming apparatus according to this embodiment. In this figure, the image forming apparatus includes a code data storage unit 1, a data supply unit 2, a plurality of decoding units 3, a band buffer 4, a transfer unit 5, Printing means 6, prediction means 7, start time storage means 8, control means 9, decoding order management means 11, code data selection means 12, primary storage management means 1.
3, band buffer control means 14, transfer order management means 1
5, transfer selection means 16, print start control means 17, and the like. In FIG. 1, portions corresponding to those in FIG. 12 are denoted by corresponding reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, the printing means 6 has a printing unit for each color component and performs a color printing process on paper in a pipeline.

The decoding order management means 11 calculates the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printing means 6, and calculates the time after this time. Thus, the decoding order in the decoding means 3 is determined. The code data selecting means 12 takes out the code data according to the decoding order and supplies it to the decoding means 3 at the subsequent stage. The control means 9 controls the decoding means 3 to decode the code data supplied from the data supply means 2.

The temporary storage management means 13 temporarily stores data in the decoding order, and controls reading and writing of the band buffer 4 according to the decoding order. The transfer order managing means 15 manages the transfer order of the data from the band buffer 4, and the transfer selecting means 16 transfers the decoded data in the transfer order to the printing means 6.

The print start control means 17 controls a print start time. Code data decoding means 3
Is assigned, and when the allocation of all the divided images on the page is successful, the print start control means 17 starts the print processing of the page. Specifically, print processing is performed at a default start time. On the other hand, the decoding means 3
When the allocation of the predetermined divided image fails, the print start control unit 17 delays the printing process in the printing unit 6 for the page to which the divided image belongs or the next page and thereafter.

Next, the operation of the above embodiment will be described with reference to FIGS. 2 and 3, first, when a print request is made, variables and the like are initialized (S1, S2). Here, N is the page number, and TFN is the time at which the printer unit 6 (see FIG. 4) feeds N pages of paper. Next, at least the page to be printed,
Then, a predicted time for a band transferred at the same time when the page is transferred is calculated or read (S3). T
Since the transfer start time of each color and each band is obtained from the FN, the respective decode start times are calculated based on the transfer start times (S4). The decoding means 3 is assigned in ascending order of the decoding start time of each color and each band (S5).

If the allocation to the last band of page N is successful (the allocation start time of each band is earlier than the decoding start time), the Nth page is fed at time TFN (S6, S7). The actual decoding is performed according to the assignment. If the processing has not been performed up to the last page, the N + 1 pages are allocated (S8, S9). Here, TC indicates a time interval until the next page is fed. When the processing is performed up to the last page, the printing is completed (S8, S1).
0).

In the case where the allocation has failed by the last band of page N, if the allocation time of the earliest band after page N + 1 in the band for which the prediction time is required is earlier than the latest allocation time of page N. , N + 1 page feed time is delayed (S6, S11, S12). Along with this, the feed times for pages after the (N + 1) th page are also delayed. Thus, the decoding means 3 is assigned again (S4, S5).

The allocation time of the earliest band after the (N + 1) th page in the band for which the prediction time is required is later than the latest allocation time of the Nth page.
If is not full, the feed time for pages N and later is delayed (S11, S13, S14), and the decoding means is assigned again (S4, S5). If the band buffer 4 becomes full when allocating N pages, this page cannot be printed (S13, S15).

Next, a specific operation in this embodiment will be described. FIG. 5 shows an example in which assignment is actually performed. First, consider the printing operation of one page. It comprises four decoding means 3 and a band buffer 4 for 16 bands.
It is assumed that the page is composed of eight bands of four colors. It is also assumed that the transfer of the first band of K is started in one unit after the feed.

First, all the predicted decoding times of the first page are read. Here, it is assumed that for each color, the fourth, fifth, and sixth bands require two units of decoding time, and the other bands require one unit of decoding time (first stage). Next, the decoding time is obtained by subtracting the decoding time from the transfer start time of each band (second stage). Bands are assigned to decoders in order from the earliest decoding time. In this example, the assignments are K1, K2, Y1, K3, K
4, Y2, K5, M1, Y2, Y4, K6, M2, Y
5, C1, M3, M4, Y6, K7, C2, M5, K
8, C3, C4, M6, Y7, C5, Y8, C6, M
7, M8, C7 and C8 in this order. The numerical value shown in parentheses in the figure indicates the number of the band buffer 4 used at that time.

As described above, if the decoding means allocation time is earlier than the decoding start time over all bands, this page can be printed according to this allocation. Here, the band whose transfer start time is the same is allocated from the rear of the pipeline. For example, the decoding start band numbers 3 and 4 for black K and the decoding start band number 1 for yellow Y are at the same time, but since yellow is behind the pipeline, decoding is performed in the order of Y1, K3, and K5. The data is sent to the third, fourth, and fifth band buffers 4, respectively.

FIGS. 6 and 7 show other examples of actual assignment. In the example of FIGS. 6 and 7, the allocation of two pages fails the first time and succeeds the second time. The conditions are the same as in the example of FIG. 5, and it is assumed that four decoding means 3 and a band buffer 4 for 16 bands are provided, and one page is composed of eight bands of four colors. Also, after feeding, K
It is assumed that the transfer of the first band starts.

In FIG. 6, first, the predicted decoding times of the first page and part of the second page are read. As in the example of FIG. 5, bands are assigned to the decoding means 3 in order from the band with the earliest decoding time. When the twelfth black band (K12) is reached, allocation fails.

Here, as shown in FIG. 7, the paper feed time of the second page is moved backward by one unit by using the print start time control means 17. The reallocation is performed according to this. This time, the assignment of the first page is successful over all the bands, so that the printing of the first page can be started.

FIGS. 8 and 9 show another example of the actual assignment. This example shows an example in which the assignment of one page fails the first time and succeeds the second time. The conditions are the same as in the examples of FIGS. 5 to 7, and it is assumed that four decoding means 3 and a band buffer 4 for 16 bands are provided, and one page is composed of eight bands of four colors. It is also assumed that the transfer of the first band of K is started in one unit after the feed.

In FIG. 8, first, all the predicted decoding times of the first page are read. As in the examples of FIGS. 5 to 7, bands are assigned to decoders in order from the band with the earliest decoding time. At the time of the eighth band (Y8) of yellow, allocation fails.

Here, there are 16 band buffers,
Since the maximum number of bands to be used is 12, as shown in FIG. 9, the paper feed time of the first page is moved backward by one unit by using the print start time control means 17. The reallocation is performed according to this. This time, the assignment of the first page is successful over all the bands, so that the printing of the first page can be started.

[0034]

According to the present invention, since printing can be performed with a small amount of band buffer, a low-cost system can be realized. In addition, since printing can be started at a point when some processing has been performed from the first page, the overall printing time is also reduced.
Since there is no possibility that decoding cannot be performed during printing, a sheet lacking an image is not discharged.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of the embodiment.

FIG. 3 is a flowchart illustrating an operation procedure of the embodiment.

FIG. 4 is a diagram schematically illustrating a configuration of a printing unit 6 according to the embodiment.

FIG. 5 is a diagram illustrating the operation of the above embodiment.

FIG. 6 is a diagram for explaining the operation of the above embodiment.

FIG. 7 is a diagram for explaining the operation of the above embodiment.

FIG. 8 is a diagram for explaining the operation of the above embodiment.

FIG. 9 is a diagram for explaining the operation of the above embodiment.

FIG. 10 is a diagram illustrating an image forming apparatus proposed by the present applicant.

FIG. 11 is a diagram illustrating an image forming apparatus proposed by the present applicant.

FIG. 12 is a diagram illustrating an image forming apparatus proposed by the present applicant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Code data storage means 2 Data supply means 3 One or more decoding means 4 Band buffer 5 Transfer means 6 Printing means 7 Prediction means 8 Start time storage means 9 Control means 11 Decoding order management means 12 Code data selection means 13 Primary storage Management means 14 band buffer control means 15 transfer order management means 16 transfer selection means 17 print start control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 1/32 H04N 1/41 C 1/41 B41J 3/00 B 1/46 H04N 1/46 Z

Claims (6)

[Claims] 1. A storage means for storing code data for each divided image generated by dividing an input image into a plurality of band regions extending in the main scanning line direction, and predicting a time for decoding the code data of the divided image. Means for determining a decoding order based on the predicted time; one or more decoding means for decoding the code data in accordance with the determined decoding order; a buffer for temporarily storing decoded image data; A printer comprising a unit for each color component for printing by superimposing the corresponding color ink on paper in accordance with the image data for each component, and means for sequentially transferring the image data in the buffer to the printer for each color component An image forming apparatus comprising: 2. Decoding means is assigned to the code data in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. 2. The image forming apparatus according to claim 1, wherein, when the allocation of all divided images of the page is successful, the printer starts printing processing of the page. 3. A decoding means is assigned to the code data in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. If the assignment of a predetermined divided image fails, the page to which the divided image belongs or
2. The image forming apparatus according to claim 1, wherein a printing process in the printer after the next page is delayed. 4. A printer, storage means for storing code data for each divided image generated by dividing an input image into a plurality of band areas extending in the main scanning line direction, a plurality of decoding means for decoding the code data, decoding A buffer for temporarily storing the divided image data, and a means for transferring the image data in the buffer to the printer; a means for predicting a time for decoding the code data of the divided image; Means for determining the decoding order of the code data of the divided image according to the order of the time obtained by subtracting the decoding prediction time of the code data of the image data from the transfer start time of the image data to the printer. Image forming apparatus. 5. A decoding means is allocated to the code data in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. 5. The image forming apparatus according to claim 4, wherein when the allocation of all the divided images of the page is successful, the printer starts printing processing of the page. 6. A decoding means is assigned to the code data in accordance with the order of the time obtained by subtracting the predicted decoding time of the code data of the image data from the transfer start time of the image data of each divided image to the printer. If the assignment of a predetermined divided image fails, the page to which the divided image belongs or
5. The image forming apparatus according to claim 4, wherein print processing in the printer after the next page is delayed.